code:
# PSR-7 Message Implementation

This repository contains a full [PSR-7](http://www.php-fig.org/psr/psr-7/)
message implementation, several stream decorators, and some helpful
functionality like query string parsing.

[![Build Status](https://travis-ci.org/guzzle/psr7.svg?branch=master)](https://travis-ci.org/guzzle/psr7)

# Stream implementation

This package comes with a number of stream implementations and stream
decorators.

## AppendStream

`GuzzleHttp\Psr7\AppendStream`

Reads from multiple streams, one after the other.

```php
use GuzzleHttp\Psr7;

$a = Psr7\stream_for('abc, ');
$b = Psr7\stream_for('123.');
$composed = new Psr7\AppendStream([$a, $b]);

$composed->addStream(Psr7\stream_for(' Above all listen to me'));

echo $composed; // abc, 123. Above all listen to me.
```

## BufferStream

`GuzzleHttp\Psr7\BufferStream`

Provides a buffer stream that can be written to fill a buffer, and read
from to remove bytes from the buffer.

This stream returns a "hwm" metadata value that tells upstream consumers
what the configured high water mark of the stream is, or the maximum
preferred size of the buffer.

```php
use GuzzleHttp\Psr7;

// When more than 1024 bytes are in the buffer, it will begin returning
// false to writes. This is an indication that writers should slow down.
$buffer = new Psr7\BufferStream(1024);
```

## CachingStream

The CachingStream is used to allow seeking over previously read bytes on
non-seekable streams. This can be useful when transferring a non-seekable
entity body fails due to needing to rewind the stream (for example, resulting
from a redirect). Data that is read from the remote stream will be buffered in
a PHP temp stream so that previously read bytes are cached first in memory,
then on disk.

```php
use GuzzleHttp\Psr7;

$original = Psr7\stream_for(fopen('http://www.google.com', 'r'));
$stream = new Psr7\CachingStream($original);

$stream->read(1024);
echo $stream->tell();
// 1024

$stream->seek(0);
echo $stream->tell();
// 0
```

## DroppingStream

`GuzzleHttp\Psr7\DroppingStream`

Stream decorator that begins dropping data once the size of the underlying
stream becomes too full.

```php
use GuzzleHttp\Psr7;

// Create an empty stream
$stream = Psr7\stream_for();

// Start dropping data when the stream has more than 10 bytes
$dropping = new Psr7\DroppingStream($stream, 10);

$dropping->write('01234567890123456789');
echo $stream; // 0123456789
```

## FnStream

`GuzzleHttp\Psr7\FnStream`

Compose stream implementations based on a hash of functions.

Allows for easy testing and extension of a provided stream without needing
to create a concrete class for a simple extension point.

```php

use GuzzleHttp\Psr7;

$stream = Psr7\stream_for('hi');
$fnStream = Psr7\FnStream::decorate($stream, [
    'rewind' => function () use ($stream) {
        echo 'About to rewind - ';
        $stream->rewind();
        echo 'rewound!';
    }
]);

$fnStream->rewind();
// Outputs: About to rewind - rewound!
```

## InflateStream

`GuzzleHttp\Psr7\InflateStream`

Uses PHP's zlib.inflate filter to inflate deflate or gzipped content.

This stream decorator skips the first 10 bytes of the given stream to remove
the gzip header, converts the provided stream to a PHP stream resource,
then appends the zlib.inflate filter. The stream is then converted back
to a Guzzle stream resource to be used as a Guzzle stream.

## LazyOpenStream

`GuzzleHttp\Psr7\LazyOpenStream`

Lazily reads or writes to a file that is opened only after an IO operation
take place on the stream.

```php
use GuzzleHttp\Psr7;

$stream = new Psr7\LazyOpenStream('/path/to/file', 'r');
// The file has not yet been opened...

echo $stream->read(10);
// The file is opened and read from only when needed.
```

## LimitStream

`GuzzleHttp\Psr7\LimitStream`

LimitStream can be used to read a subset or slice of an existing stream object.
This can be useful for breaking a large file into smaller pieces to be sent in
chunks (e.g. Amazon S3's multipart upload API).

```php
use GuzzleHttp\Psr7;

$original = Psr7\stream_for(fopen('/tmp/test.txt', 'r+'));
echo $original->getSize();
// >>> 1048576

// Limit the size of the body to 1024 bytes and start reading from byte 2048
$stream = new Psr7\LimitStream($original, 1024, 2048);
echo $stream->getSize();
// >>> 1024
echo $stream->tell();
// >>> 0
```

## MultipartStream

`GuzzleHttp\Psr7\MultipartStream`

Stream that when read returns bytes for a streaming multipart or
multipart/form-data stream.

## NoSeekStream

`GuzzleHttp\Psr7\NoSeekStream`

NoSeekStream wraps a stream and does not allow seeking.

```php
use GuzzleHttp\Psr7;

$original = Psr7\stream_for('foo');
$noSeek = new Psr7\NoSeekStream($original);

echo $noSeek->read(3);
// foo
var_export($noSeek->isSeekable());
// false
$noSeek->seek(0);
var_export($noSeek->read(3));
// NULL
```

## PumpStream

`GuzzleHttp\Psr7\PumpStream`

Provides a read only stream that pumps data from a PHP callable.

When invoking the provided callable, the PumpStream will pass the amount of
data requested to read to the callable. The callable can choose to ignore
this value and return fewer or more bytes than requested. Any extra data
returned by the provided callable is buffered internally until drained using
the read() function of the PumpStream. The provided callable MUST return
false when there is no more data to read.

## Implementing stream decorators

Creating a stream decorator is very easy thanks to the
`GuzzleHttp\Psr7\StreamDecoratorTrait`. This trait provides methods that
implement `Psr\Http\Message\StreamInterface` by proxying to an underlying
stream. Just `use` the `StreamDecoratorTrait` and implement your custom
methods.

For example, let's say we wanted to call a specific function each time the last
byte is read from a stream. This could be implemented by overriding the
`read()` method.

```php
use Psr\Http\Message\StreamInterface;
use GuzzleHttp\Psr7\StreamDecoratorTrait;

class EofCallbackStream implements StreamInterface
{
    use StreamDecoratorTrait;

    private $callback;

    public function __construct(StreamInterface $stream, callable $cb)
    {
        $this->stream = $stream;
        $this->callback = $cb;
    }

    public function read($length)
    {
        $result = $this->stream->read($length);

        // Invoke the callback when EOF is hit.
        if ($this->eof()) {
            call_user_func($this->callback);
        }

        return $result;
    }
}
```

This decorator could be added to any existing stream and used like so:

```php
use GuzzleHttp\Psr7;

$original = Psr7\stream_for('foo');

$eofStream = new EofCallbackStream($original, function () {
    echo 'EOF!';
});

$eofStream->read(2);
$eofStream->read(1);
// echoes "EOF!"
$eofStream->seek(0);
$eofStream->read(3);
// echoes "EOF!"
```

## PHP StreamWrapper

You can use the `GuzzleHttp\Psr7\StreamWrapper` class if you need to use a
PSR-7 stream as a PHP stream resource.

Use the `GuzzleHttp\Psr7\StreamWrapper::getResource()` method to create a PHP
stream from a PSR-7 stream.

```php
use GuzzleHttp\Psr7\StreamWrapper;

$stream = GuzzleHttp\Psr7\stream_for('hello!');
$resource = StreamWrapper::getResource($stream);
echo fread($resource, 6); // outputs hello!
```

# Function API

There are various functions available under the `GuzzleHttp\Psr7` namespace.

## `function str`

`function str(MessageInterface $message)`

Returns the string representation of an HTTP message.

```php
$request = new GuzzleHttp\Psr7\Request('GET', 'http://example.com');
echo GuzzleHttp\Psr7\str($request);
```

## `function uri_for`

`function uri_for($uri)`

This function accepts a string or `Psr\Http\Message\UriInterface` and returns a
UriInterface for the given value. If the value is already a `UriInterface`, it
is returned as-is.

```php
$uri = GuzzleHttp\Psr7\uri_for('http://example.com');
assert($uri === GuzzleHttp\Psr7\uri_for($uri));
```

## `function stream_for`

`function stream_for($resource = '', array $options = [])`

Create a new stream based on the input type.

Options is an associative array that can contain the following keys:

* - metadata: Array of custom metadata.
* - size: Size of the stream.

This method accepts the following `$resource` types:

- `Psr\Http\Message\StreamInterface`: Returns the value as-is.
- `string`: Creates a stream object that uses the given string as the contents.
- `resource`: Creates a stream object that wraps the given PHP stream resource.
- `Iterator`: If the provided value implements `Iterator`, then a read-only
  stream object will be created that wraps the given iterable. Each time the
  stream is read from, data from the iterator will fill a buffer and will be
  continuously called until the buffer is equal to the requested read size.
  Subsequent read calls will first read from the buffer and then call `next`
  on the underlying iterator until it is exhausted.
- `object` with `__toString()`: If the object has the `__toString()` method,
  the object will be cast to a string and then a stream will be returned that
  uses the string value.
- `NULL`: When `null` is passed, an empty stream object is returned.
- `callable` When a callable is passed, a read-only stream object will be
  created that invokes the given callable. The callable is invoked with the
  number of suggested bytes to read. The callable can return any number of
  bytes, but MUST return `false` when there is no more data to return. The
  stream object that wraps the callable will invoke the callable until the
  number of requested bytes are available. Any additional bytes will be
  buffered and used in subsequent reads.

```php
$stream = GuzzleHttp\Psr7\stream_for('foo');
$stream = GuzzleHttp\Psr7\stream_for(fopen('/path/to/file', 'r'));

$generator = function ($bytes) {
    for ($i = 0; $i < $bytes; $i++) {
        yield ' ';
    }
}

$stream = GuzzleHttp\Psr7\stream_for($generator(100));
```

## `function parse_header`

`function parse_header($header)`

Parse an array of header values containing ";" separated data into an array of
associative arrays representing the header key value pair data of the header.
When a parameter does not contain a value, but just contains a key, this
function will inject a key with a '' string value.

## `function normalize_header`

`function normalize_header($header)`

Converts an array of header values that may contain comma separated headers
into an array of headers with no comma separated values.

## `function modify_request`

`function modify_request(RequestInterface $request, array $changes)`

Clone and modify a request with the given changes. This method is useful for
reducing the number of clones needed to mutate a message.

The changes can be one of:

- method: (string) Changes the HTTP method.
- set_headers: (array) Sets the given headers.
- remove_headers: (array) Remove the given headers.
- body: (mixed) Sets the given body.
- uri: (UriInterface) Set the URI.
- query: (string) Set the query string value of the URI.
- version: (string) Set the protocol version.

## `function rewind_body`

`function rewind_body(MessageInterface $message)`

Attempts to rewind a message body and throws an exception on failure. The body
of the message will only be rewound if a call to `tell()` returns a value other
than `0`.

## `function try_fopen`

`function try_fopen($filename, $mode)`

Safely opens a PHP stream resource using a filename.

When fopen fails, PHP normally raises a warning. This function adds an error
handler that checks for errors and throws an exception instead.

## `function copy_to_string`

`function copy_to_string(StreamInterface $stream, $maxLen = -1)`

Copy the contents of a stream into a string until the given number of bytes
have been read.

## `function copy_to_stream`

`function copy_to_stream(StreamInterface $source, StreamInterface $dest, $maxLen = -1)`

Copy the contents of a stream into another stream until the given number of
bytes have been read.

## `function hash`

`function hash(StreamInterface $stream, $algo, $rawOutput = false)`

Calculate a hash of a Stream. This method reads the entire stream to calculate
a rolling hash (based on PHP's hash_init functions).

## `function readline`

`function readline(StreamInterface $stream, $maxLength = null)`

Read a line from the stream up to the maximum allowed buffer length.

## `function parse_request`

`function parse_request($message)`

Parses a request message string into a request object.

## `function parse_response`

`function parse_response($message)`

Parses a response message string into a response object.

## `function parse_query`

`function parse_query($str, $urlEncoding = true)`

Parse a query string into an associative array.

If multiple values are found for the same key, the value of that key value pair
will become an array. This function does not parse nested PHP style arrays into
an associative array (e.g., `foo[a]=1&foo[b]=2` will be parsed into
`['foo[a]' => '1', 'foo[b]' => '2']`).

## `function build_query`

`function build_query(array $params, $encoding = PHP_QUERY_RFC3986)`

Build a query string from an array of key value pairs.

This function can use the return value of parse_query() to build a query string.
This function does not modify the provided keys when an array is encountered
(like http_build_query would).

## `function mimetype_from_filename`

`function mimetype_from_filename($filename)`

Determines the mimetype of a file by looking at its extension.

## `function mimetype_from_extension`

`function mimetype_from_extension($extension)`

Maps a file extensions to a mimetype.

# Additional URI Methods

Aside from the standard `Psr\Http\Message\UriInterface` implementation in form of the `GuzzleHttp\Psr7\Uri` class,
this library also provides additional functionality when working with URIs as static methods.

## URI Types

An instance of `Psr\Http\Message\UriInterface` can either be an absolute URI or a relative reference.
An absolute URI has a scheme. A relative reference is used to express a URI relative to another URI,
the base URI. Relative references can be divided into several forms according to
[RFC 3986 Section 4.2](https://tools.ietf.org/html/rfc3986#section-4.2):

- network-path references, e.g. `//example.com/path`
- absolute-path references, e.g. `/path`
- relative-path references, e.g. `subpath`

The following methods can be used to identify the type of the URI.

### `GuzzleHttp\Psr7\Uri::isAbsolute`

`public static function isAbsolute(UriInterface $uri): bool`

Whether the URI is absolute, i.e. it has a scheme.

### `GuzzleHttp\Psr7\Uri::isNetworkPathReference`

`public static function isNetworkPathReference(UriInterface $uri): bool`

Whether the URI is a network-path reference. A relative reference that begins with two slash characters is
termed an network-path reference.

### `GuzzleHttp\Psr7\Uri::isAbsolutePathReference`

`public static function isAbsolutePathReference(UriInterface $uri): bool`

Whether the URI is a absolute-path reference. A relative reference that begins with a single slash character is
termed an absolute-path reference.

### `GuzzleHttp\Psr7\Uri::isRelativePathReference`

`public static function isRelativePathReference(UriInterface $uri): bool`

Whether the URI is a relative-path reference. A relative reference that does not begin with a slash character is
termed a relative-path reference.

### `GuzzleHttp\Psr7\Uri::isSameDocumentReference`

`public static function isSameDocumentReference(UriInterface $uri, UriInterface $base = null): bool`

Whether the URI is a same-document reference. A same-document reference refers to a URI that is, aside from its
fragment component, identical to the base URI. When no base URI is given, only an empty URI reference
(apart from its fragment) is considered a same-document reference.

## URI Components

Additional methods to work with URI components.

### `GuzzleHttp\Psr7\Uri::isDefaultPort`

`public static function isDefaultPort(UriInterface $uri): bool`

Whether the URI has the default port of the current scheme. `Psr\Http\Message\UriInterface::getPort` may return null
or the standard port. This method can be used independently of the implementation.

### `GuzzleHttp\Psr7\Uri::composeComponents`

`public static function composeComponents($scheme, $authority, $path, $query, $fragment): string`

Composes a URI reference string from its various components according to
[RFC 3986 Section 5.3](https://tools.ietf.org/html/rfc3986#section-5.3). Usually this method does not need to be called
manually but instead is used indirectly via `Psr\Http\Message\UriInterface::__toString`.

### `GuzzleHttp\Psr7\Uri::fromParts`

`public static function fromParts(array $parts): UriInterface`

Creates a URI from a hash of [`parse_url`](http://php.net/manual/en/function.parse-url.php) components.

### `GuzzleHttp\Psr7\Uri::withQueryValue`

`public static function withQueryValue(UriInterface $uri, $key, $value): UriInterface`

Creates a new URI with a specific query string value. Any existing query string values that exactly match the
provided key are removed and replaced with the given key value pair. A value of null will set the query string
key without a value, e.g. "key" instead of "key=value".

### `GuzzleHttp\Psr7\Uri::withQueryValues`

`public static function withQueryValues(UriInterface $uri, array $keyValueArray): UriInterface`

Creates a new URI with multiple query string values. It has the same behavior as `withQueryValue()` but for an
associative array of key => value.

### `GuzzleHttp\Psr7\Uri::withoutQueryValue`

`public static function withoutQueryValue(UriInterface $uri, $key): UriInterface`

Creates a new URI with a specific query string value removed. Any existing query string values that exactly match the
provided key are removed.

## Reference Resolution

`GuzzleHttp\Psr7\UriResolver` provides methods to resolve a URI reference in the context of a base URI according
to [RFC 3986 Section 5](https://tools.ietf.org/html/rfc3986#section-5). This is for example also what web browsers
do when resolving a link in a website based on the current request URI.

### `GuzzleHttp\Psr7\UriResolver::resolve`

`public static function resolve(UriInterface $base, UriInterface $rel): UriInterface`

Converts the relative URI into a new URI that is resolved against the base URI.

### `GuzzleHttp\Psr7\UriResolver::removeDotSegments`

`public static function removeDotSegments(string $path): string`

Removes dot segments from a path and returns the new path according to
[RFC 3986 Section 5.2.4](https://tools.ietf.org/html/rfc3986#section-5.2.4).

### `GuzzleHttp\Psr7\UriResolver::relativize`

`public static function relativize(UriInterface $base, UriInterface $target): UriInterface`

Returns the target URI as a relative reference from the base URI. This method is the counterpart to resolve():

```php
(string) $target === (string) UriResolver::resolve($base, UriResolver::relativize($base, $target))
```

One use-case is to use the current request URI as base URI and then generate relative links in your documents
to reduce the document size or offer self-contained downloadable document archives.

```php
$base = new Uri('http://example.com/a/b/');
echo UriResolver::relativize($base, new Uri('http://example.com/a/b/c'));  // prints 'c'.
echo UriResolver::relativize($base, new Uri('http://example.com/a/x/y'));  // prints '../x/y'.
echo UriResolver::relativize($base, new Uri('http://example.com/a/b/?q')); // prints '?q'.
echo UriResolver::relativize($base, new Uri('http://example.org/a/b/'));   // prints '//example.org/a/b/'.
```

## Normalization and Comparison

`GuzzleHttp\Psr7\UriNormalizer` provides methods to normalize and compare URIs according to
[RFC 3986 Section 6](https://tools.ietf.org/html/rfc3986#section-6).

### `GuzzleHttp\Psr7\UriNormalizer::normalize`

`public static function normalize(UriInterface $uri, $flags = self::PRESERVING_NORMALIZATIONS): UriInterface`

Returns a normalized URI. The scheme and host component are already normalized to lowercase per PSR-7 UriInterface.
This methods adds additional normalizations that can be configured with the `$flags` parameter which is a bitmask
of normalizations to apply. The following normalizations are available:

- `UriNormalizer::PRESERVING_NORMALIZATIONS`

    Default normalizations which only include the ones that preserve semantics.

- `UriNormalizer::CAPITALIZE_PERCENT_ENCODING`

    All letters within a percent-encoding triplet (e.g., "%3A") are case-insensitive, and should be capitalized.

    Example: `http://example.org/a%c2%b1b` → `http://example.org/a%C2%B1b`

- `UriNormalizer::DECODE_UNRESERVED_CHARACTERS`

    Decodes percent-encoded octets of unreserved characters. For consistency, percent-encoded octets in the ranges of
    ALPHA (%41–%5A and %61–%7A), DIGIT (%30–%39), hyphen (%2D), period (%2E), underscore (%5F), or tilde (%7E) should
    not be created by URI producers and, when found in a URI, should be decoded to their corresponding unreserved
    characters by URI normalizers.

    Example: `http://example.org/%7Eusern%61me/` → `http://example.org/~username/`

- `UriNormalizer::CONVERT_EMPTY_PATH`

    Converts the empty path to "/" for http and https URIs.

    Example: `http://example.org` → `http://example.org/`

- `UriNormalizer::REMOVE_DEFAULT_HOST`

    Removes the default host of the given URI scheme from the URI. Only the "file" scheme defines the default host
    "localhost". All of `file:/myfile`, `file:///myfile`, and `file://localhost/myfile` are equivalent according to
    RFC 3986.

    Example: `file://localhost/myfile` → `file:///myfile`

- `UriNormalizer::REMOVE_DEFAULT_PORT`

    Removes the default port of the given URI scheme from the URI.

    Example: `http://example.org:80/` → `http://example.org/`

- `UriNormalizer::REMOVE_DOT_SEGMENTS`

    Removes unnecessary dot-segments. Dot-segments in relative-path references are not removed as it would
    change the semantics of the URI reference.

    Example: `http://example.org/../a/b/../c/./d.html` → `http://example.org/a/c/d.html`

- `UriNormalizer::REMOVE_DUPLICATE_SLASHES`

    Paths which include two or more adjacent slashes are converted to one. Webservers usually ignore duplicate slashes
    and treat those URIs equivalent. But in theory those URIs do not need to be equivalent. So this normalization
    may change the semantics. Encoded slashes (%2F) are not removed.

    Example: `http://example.org//foo///bar.html` → `http://example.org/foo/bar.html`

- `UriNormalizer::SORT_QUERY_PARAMETERS`

    Sort query parameters with their values in alphabetical order. However, the order of parameters in a URI may be
    significant (this is not defined by the standard). So this normalization is not safe and may change the semantics
    of the URI.

    Example: `?lang=en&article=fred` → `?article=fred&lang=en`

### `GuzzleHttp\Psr7\UriNormalizer::isEquivalent`

`public static function isEquivalent(UriInterface $uri1, UriInterface $uri2, $normalizations = self::PRESERVING_NORMALIZATIONS): bool`

Whether two URIs can be considered equivalent. Both URIs are normalized automatically before comparison with the given
`$normalizations` bitmask. The method also accepts relative URI references and returns true when they are equivalent.
This of course assumes they will be resolved against the same base URI. If this is not the case, determination of
equivalence or difference of relative references does not mean anything.


type: library

description: PSR-7 message implementation that also provides common utility methods

keywords: request response message stream http uri url psr-7

license: MIT

zendframework/zend-httphandlerrunner: Emit PSR-7 responses

GuzzleHttp\Psr7\: src/

GuzzleHttp\Tests\Psr7\: tests/

repo_name: ksuudilla/gnu

license: mit


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Reads from multiple streams, one after the other.
 *
 * This is a read-only stream decorator.
 */
class AppendStream implements StreamInterface
{
    /** @var StreamInterface[] Streams being decorated */
    private $streams = [];

    private $seekable = true;
    private $current = 0;
    private $pos = 0;

    /**
     * @param StreamInterface[] $streams Streams to decorate. Each stream must
     *                                   be readable.
     */
    public function __construct(array $streams = [])
    {
        foreach ($streams as $stream) {
            $this->addStream($stream);
        }
    }

    public function __toString()
    {
        try {
            $this->rewind();
            return $this->getContents();
        } catch (\Exception $e) {
            return '';
        }
    }

    /**
     * Add a stream to the AppendStream
     *
     * @param StreamInterface $stream Stream to append. Must be readable.
     *
     * @throws \InvalidArgumentException if the stream is not readable
     */
    public function addStream(StreamInterface $stream)
    {
        if (!$stream->isReadable()) {
            throw new \InvalidArgumentException('Each stream must be readable');
        }

        // The stream is only seekable if all streams are seekable
        if (!$stream->isSeekable()) {
            $this->seekable = false;
        }

        $this->streams[] = $stream;
    }

    public function getContents()
    {
        return copy_to_string($this);
    }

    /**
     * Closes each attached stream.
     *
     * {@inheritdoc}
     */
    public function close()
    {
        $this->pos = $this->current = 0;
        $this->seekable = true;

        foreach ($this->streams as $stream) {
            $stream->close();
        }

        $this->streams = [];
    }

    /**
     * Detaches each attached stream.
     *
     * Returns null as it's not clear which underlying stream resource to return.
     *
     * {@inheritdoc}
     */
    public function detach()
    {
        $this->pos = $this->current = 0;
        $this->seekable = true;

        foreach ($this->streams as $stream) {
            $stream->detach();
        }

        $this->streams = [];
    }

    public function tell()
    {
        return $this->pos;
    }

    /**
     * Tries to calculate the size by adding the size of each stream.
     *
     * If any of the streams do not return a valid number, then the size of the
     * append stream cannot be determined and null is returned.
     *
     * {@inheritdoc}
     */
    public function getSize()
    {
        $size = 0;

        foreach ($this->streams as $stream) {
            $s = $stream->getSize();
            if ($s === null) {
                return null;
            }
            $size += $s;
        }

        return $size;
    }

    public function eof()
    {
        return !$this->streams ||
            ($this->current >= count($this->streams) - 1 &&
             $this->streams[$this->current]->eof());
    }

    public function rewind()
    {
        $this->seek(0);
    }

    /**
     * Attempts to seek to the given position. Only supports SEEK_SET.
     *
     * {@inheritdoc}
     */
    public function seek($offset, $whence = SEEK_SET)
    {
        if (!$this->seekable) {
            throw new \RuntimeException('This AppendStream is not seekable');
        } elseif ($whence !== SEEK_SET) {
            throw new \RuntimeException('The AppendStream can only seek with SEEK_SET');
        }

        $this->pos = $this->current = 0;

        // Rewind each stream
        foreach ($this->streams as $i => $stream) {
            try {
                $stream->rewind();
            } catch (\Exception $e) {
                throw new \RuntimeException('Unable to seek stream '
                    . $i . ' of the AppendStream', 0, $e);
            }
        }

        // Seek to the actual position by reading from each stream
        while ($this->pos < $offset && !$this->eof()) {
            $result = $this->read(min(8096, $offset - $this->pos));
            if ($result === '') {
                break;
            }
        }
    }

    /**
     * Reads from all of the appended streams until the length is met or EOF.
     *
     * {@inheritdoc}
     */
    public function read($length)
    {
        $buffer = '';
        $total = count($this->streams) - 1;
        $remaining = $length;
        $progressToNext = false;

        while ($remaining > 0) {

            // Progress to the next stream if needed.
            if ($progressToNext || $this->streams[$this->current]->eof()) {
                $progressToNext = false;
                if ($this->current === $total) {
                    break;
                }
                $this->current++;
            }

            $result = $this->streams[$this->current]->read($remaining);

            // Using a loose comparison here to match on '', false, and null
            if ($result == null) {
                $progressToNext = true;
                continue;
            }

            $buffer .= $result;
            $remaining = $length - strlen($buffer);
        }

        $this->pos += strlen($buffer);

        return $buffer;
    }

    public function isReadable()
    {
        return true;
    }

    public function isWritable()
    {
        return false;
    }

    public function isSeekable()
    {
        return $this->seekable;
    }

    public function write($string)
    {
        throw new \RuntimeException('Cannot write to an AppendStream');
    }

    public function getMetadata($key = null)
    {
        return $key ? null : [];
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Provides a buffer stream that can be written to to fill a buffer, and read
 * from to remove bytes from the buffer.
 *
 * This stream returns a "hwm" metadata value that tells upstream consumers
 * what the configured high water mark of the stream is, or the maximum
 * preferred size of the buffer.
 */
class BufferStream implements StreamInterface
{
    private $hwm;
    private $buffer = '';

    /**
     * @param int $hwm High water mark, representing the preferred maximum
     *                 buffer size. If the size of the buffer exceeds the high
     *                 water mark, then calls to write will continue to succeed
     *                 but will return false to inform writers to slow down
     *                 until the buffer has been drained by reading from it.
     */
    public function __construct($hwm = 16384)
    {
        $this->hwm = $hwm;
    }

    public function __toString()
    {
        return $this->getContents();
    }

    public function getContents()
    {
        $buffer = $this->buffer;
        $this->buffer = '';

        return $buffer;
    }

    public function close()
    {
        $this->buffer = '';
    }

    public function detach()
    {
        $this->close();
    }

    public function getSize()
    {
        return strlen($this->buffer);
    }

    public function isReadable()
    {
        return true;
    }

    public function isWritable()
    {
        return true;
    }

    public function isSeekable()
    {
        return false;
    }

    public function rewind()
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        throw new \RuntimeException('Cannot seek a BufferStream');
    }

    public function eof()
    {
        return strlen($this->buffer) === 0;
    }

    public function tell()
    {
        throw new \RuntimeException('Cannot determine the position of a BufferStream');
    }

    /**
     * Reads data from the buffer.
     */
    public function read($length)
    {
        $currentLength = strlen($this->buffer);

        if ($length >= $currentLength) {
            // No need to slice the buffer because we don't have enough data.
            $result = $this->buffer;
            $this->buffer = '';
        } else {
            // Slice up the result to provide a subset of the buffer.
            $result = substr($this->buffer, 0, $length);
            $this->buffer = substr($this->buffer, $length);
        }

        return $result;
    }

    /**
     * Writes data to the buffer.
     */
    public function write($string)
    {
        $this->buffer .= $string;

        // TODO: What should happen here?
        if (strlen($this->buffer) >= $this->hwm) {
            return false;
        }

        return strlen($string);
    }

    public function getMetadata($key = null)
    {
        if ($key == 'hwm') {
            return $this->hwm;
        }

        return $key ? null : [];
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream decorator that can cache previously read bytes from a sequentially
 * read stream.
 */
class CachingStream implements StreamInterface
{
    use StreamDecoratorTrait;

    /** @var StreamInterface Stream being wrapped */
    private $remoteStream;

    /** @var int Number of bytes to skip reading due to a write on the buffer */
    private $skipReadBytes = 0;

    /**
     * We will treat the buffer object as the body of the stream
     *
     * @param StreamInterface $stream Stream to cache
     * @param StreamInterface $target Optionally specify where data is cached
     */
    public function __construct(
        StreamInterface $stream,
        StreamInterface $target = null
    ) {
        $this->remoteStream = $stream;
        $this->stream = $target ?: new Stream(fopen('php://temp', 'r+'));
    }

    public function getSize()
    {
        return max($this->stream->getSize(), $this->remoteStream->getSize());
    }

    public function rewind()
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        if ($whence == SEEK_SET) {
            $byte = $offset;
        } elseif ($whence == SEEK_CUR) {
            $byte = $offset + $this->tell();
        } elseif ($whence == SEEK_END) {
            $size = $this->remoteStream->getSize();
            if ($size === null) {
                $size = $this->cacheEntireStream();
            }
            $byte = $size + $offset;
        } else {
            throw new \InvalidArgumentException('Invalid whence');
        }

        $diff = $byte - $this->stream->getSize();

        if ($diff > 0) {
            // Read the remoteStream until we have read in at least the amount
            // of bytes requested, or we reach the end of the file.
            while ($diff > 0 && !$this->remoteStream->eof()) {
                $this->read($diff);
                $diff = $byte - $this->stream->getSize();
            }
        } else {
            // We can just do a normal seek since we've already seen this byte.
            $this->stream->seek($byte);
        }
    }

    public function read($length)
    {
        // Perform a regular read on any previously read data from the buffer
        $data = $this->stream->read($length);
        $remaining = $length - strlen($data);

        // More data was requested so read from the remote stream
        if ($remaining) {
            // If data was written to the buffer in a position that would have
            // been filled from the remote stream, then we must skip bytes on
            // the remote stream to emulate overwriting bytes from that
            // position. This mimics the behavior of other PHP stream wrappers.
            $remoteData = $this->remoteStream->read(
                $remaining + $this->skipReadBytes
            );

            if ($this->skipReadBytes) {
                $len = strlen($remoteData);
                $remoteData = substr($remoteData, $this->skipReadBytes);
                $this->skipReadBytes = max(0, $this->skipReadBytes - $len);
            }

            $data .= $remoteData;
            $this->stream->write($remoteData);
        }

        return $data;
    }

    public function write($string)
    {
        // When appending to the end of the currently read stream, you'll want
        // to skip bytes from being read from the remote stream to emulate
        // other stream wrappers. Basically replacing bytes of data of a fixed
        // length.
        $overflow = (strlen($string) + $this->tell()) - $this->remoteStream->tell();
        if ($overflow > 0) {
            $this->skipReadBytes += $overflow;
        }

        return $this->stream->write($string);
    }

    public function eof()
    {
        return $this->stream->eof() && $this->remoteStream->eof();
    }

    /**
     * Close both the remote stream and buffer stream
     */
    public function close()
    {
        $this->remoteStream->close() && $this->stream->close();
    }

    private function cacheEntireStream()
    {
        $target = new FnStream(['write' => 'strlen']);
        copy_to_stream($this, $target);

        return $this->tell();
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream decorator that begins dropping data once the size of the underlying
 * stream becomes too full.
 */
class DroppingStream implements StreamInterface
{
    use StreamDecoratorTrait;

    private $maxLength;

    /**
     * @param StreamInterface $stream    Underlying stream to decorate.
     * @param int             $maxLength Maximum size before dropping data.
     */
    public function __construct(StreamInterface $stream, $maxLength)
    {
        $this->stream = $stream;
        $this->maxLength = $maxLength;
    }

    public function write($string)
    {
        $diff = $this->maxLength - $this->stream->getSize();

        // Begin returning 0 when the underlying stream is too large.
        if ($diff <= 0) {
            return 0;
        }

        // Write the stream or a subset of the stream if needed.
        if (strlen($string) < $diff) {
            return $this->stream->write($string);
        }

        return $this->stream->write(substr($string, 0, $diff));
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Compose stream implementations based on a hash of functions.
 *
 * Allows for easy testing and extension of a provided stream without needing
 * to create a concrete class for a simple extension point.
 */
class FnStream implements StreamInterface
{
    /** @var array */
    private $methods;

    /** @var array Methods that must be implemented in the given array */
    private static $slots = ['__toString', 'close', 'detach', 'rewind',
        'getSize', 'tell', 'eof', 'isSeekable', 'seek', 'isWritable', 'write',
        'isReadable', 'read', 'getContents', 'getMetadata'];

    /**
     * @param array $methods Hash of method name to a callable.
     */
    public function __construct(array $methods)
    {
        $this->methods = $methods;

        // Create the functions on the class
        foreach ($methods as $name => $fn) {
            $this->{'_fn_' . $name} = $fn;
        }
    }

    /**
     * Lazily determine which methods are not implemented.
     * @throws \BadMethodCallException
     */
    public function __get($name)
    {
        throw new \BadMethodCallException(str_replace('_fn_', '', $name)
            . '() is not implemented in the FnStream');
    }

    /**
     * The close method is called on the underlying stream only if possible.
     */
    public function __destruct()
    {
        if (isset($this->_fn_close)) {
            call_user_func($this->_fn_close);
        }
    }

    /**
     * An unserialize would allow the __destruct to run when the unserialized value goes out of scope.
     * @throws \LogicException
     */
    public function __wakeup()
    {
        throw new \LogicException('FnStream should never be unserialized');
    }

    /**
     * Adds custom functionality to an underlying stream by intercepting
     * specific method calls.
     *
     * @param StreamInterface $stream  Stream to decorate
     * @param array           $methods Hash of method name to a closure
     *
     * @return FnStream
     */
    public static function decorate(StreamInterface $stream, array $methods)
    {
        // If any of the required methods were not provided, then simply
        // proxy to the decorated stream.
        foreach (array_diff(self::$slots, array_keys($methods)) as $diff) {
            $methods[$diff] = [$stream, $diff];
        }

        return new self($methods);
    }

    public function __toString()
    {
        return call_user_func($this->_fn___toString);
    }

    public function close()
    {
        return call_user_func($this->_fn_close);
    }

    public function detach()
    {
        return call_user_func($this->_fn_detach);
    }

    public function getSize()
    {
        return call_user_func($this->_fn_getSize);
    }

    public function tell()
    {
        return call_user_func($this->_fn_tell);
    }

    public function eof()
    {
        return call_user_func($this->_fn_eof);
    }

    public function isSeekable()
    {
        return call_user_func($this->_fn_isSeekable);
    }

    public function rewind()
    {
        call_user_func($this->_fn_rewind);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        call_user_func($this->_fn_seek, $offset, $whence);
    }

    public function isWritable()
    {
        return call_user_func($this->_fn_isWritable);
    }

    public function write($string)
    {
        return call_user_func($this->_fn_write, $string);
    }

    public function isReadable()
    {
        return call_user_func($this->_fn_isReadable);
    }

    public function read($length)
    {
        return call_user_func($this->_fn_read, $length);
    }

    public function getContents()
    {
        return call_user_func($this->_fn_getContents);
    }

    public function getMetadata($key = null)
    {
        return call_user_func($this->_fn_getMetadata, $key);
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Uses PHP's zlib.inflate filter to inflate deflate or gzipped content.
 *
 * This stream decorator skips the first 10 bytes of the given stream to remove
 * the gzip header, converts the provided stream to a PHP stream resource,
 * then appends the zlib.inflate filter. The stream is then converted back
 * to a Guzzle stream resource to be used as a Guzzle stream.
 *
 * @link http://tools.ietf.org/html/rfc1952
 * @link http://php.net/manual/en/filters.compression.php
 */
class InflateStream implements StreamInterface
{
    use StreamDecoratorTrait;

    public function __construct(StreamInterface $stream)
    {
        // read the first 10 bytes, ie. gzip header
        $header = $stream->read(10);
        $filenameHeaderLength = $this->getLengthOfPossibleFilenameHeader($stream, $header);
        // Skip the header, that is 10 + length of filename + 1 (nil) bytes
        $stream = new LimitStream($stream, -1, 10 + $filenameHeaderLength);
        $resource = StreamWrapper::getResource($stream);
        stream_filter_append($resource, 'zlib.inflate', STREAM_FILTER_READ);
        $this->stream = $stream->isSeekable() ? new Stream($resource) : new NoSeekStream(new Stream($resource));
    }

    /**
     * @param StreamInterface $stream
     * @param $header
     * @return int
     */
    private function getLengthOfPossibleFilenameHeader(StreamInterface $stream, $header)
    {
        $filename_header_length = 0;

        if (substr(bin2hex($header), 6, 2) === '08') {
            // we have a filename, read until nil
            $filename_header_length = 1;
            while ($stream->read(1) !== chr(0)) {
                $filename_header_length++;
            }
        }

        return $filename_header_length;
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Lazily reads or writes to a file that is opened only after an IO operation
 * take place on the stream.
 */
class LazyOpenStream implements StreamInterface
{
    use StreamDecoratorTrait;

    /** @var string File to open */
    private $filename;

    /** @var string $mode */
    private $mode;

    /**
     * @param string $filename File to lazily open
     * @param string $mode     fopen mode to use when opening the stream
     */
    public function __construct($filename, $mode)
    {
        $this->filename = $filename;
        $this->mode = $mode;
    }

    /**
     * Creates the underlying stream lazily when required.
     *
     * @return StreamInterface
     */
    protected function createStream()
    {
        return stream_for(try_fopen($this->filename, $this->mode));
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Decorator used to return only a subset of a stream
 */
class LimitStream implements StreamInterface
{
    use StreamDecoratorTrait;

    /** @var int Offset to start reading from */
    private $offset;

    /** @var int Limit the number of bytes that can be read */
    private $limit;

    /**
     * @param StreamInterface $stream Stream to wrap
     * @param int             $limit  Total number of bytes to allow to be read
     *                                from the stream. Pass -1 for no limit.
     * @param int             $offset Position to seek to before reading (only
     *                                works on seekable streams).
     */
    public function __construct(
        StreamInterface $stream,
        $limit = -1,
        $offset = 0
    ) {
        $this->stream = $stream;
        $this->setLimit($limit);
        $this->setOffset($offset);
    }

    public function eof()
    {
        // Always return true if the underlying stream is EOF
        if ($this->stream->eof()) {
            return true;
        }

        // No limit and the underlying stream is not at EOF
        if ($this->limit == -1) {
            return false;
        }

        return $this->stream->tell() >= $this->offset + $this->limit;
    }

    /**
     * Returns the size of the limited subset of data
     * {@inheritdoc}
     */
    public function getSize()
    {
        if (null === ($length = $this->stream->getSize())) {
            return null;
        } elseif ($this->limit == -1) {
            return $length - $this->offset;
        } else {
            return min($this->limit, $length - $this->offset);
        }
    }

    /**
     * Allow for a bounded seek on the read limited stream
     * {@inheritdoc}
     */
    public function seek($offset, $whence = SEEK_SET)
    {
        if ($whence !== SEEK_SET || $offset < 0) {
            throw new \RuntimeException(sprintf(
                'Cannot seek to offset %s with whence %s',
                $offset,
                $whence
            ));
        }

        $offset += $this->offset;

        if ($this->limit !== -1) {
            if ($offset > $this->offset + $this->limit) {
                $offset = $this->offset + $this->limit;
            }
        }

        $this->stream->seek($offset);
    }

    /**
     * Give a relative tell()
     * {@inheritdoc}
     */
    public function tell()
    {
        return $this->stream->tell() - $this->offset;
    }

    /**
     * Set the offset to start limiting from
     *
     * @param int $offset Offset to seek to and begin byte limiting from
     *
     * @throws \RuntimeException if the stream cannot be seeked.
     */
    public function setOffset($offset)
    {
        $current = $this->stream->tell();

        if ($current !== $offset) {
            // If the stream cannot seek to the offset position, then read to it
            if ($this->stream->isSeekable()) {
                $this->stream->seek($offset);
            } elseif ($current > $offset) {
                throw new \RuntimeException("Could not seek to stream offset $offset");
            } else {
                $this->stream->read($offset - $current);
            }
        }

        $this->offset = $offset;
    }

    /**
     * Set the limit of bytes that the decorator allows to be read from the
     * stream.
     *
     * @param int $limit Number of bytes to allow to be read from the stream.
     *                   Use -1 for no limit.
     */
    public function setLimit($limit)
    {
        $this->limit = $limit;
    }

    public function read($length)
    {
        if ($this->limit == -1) {
            return $this->stream->read($length);
        }

        // Check if the current position is less than the total allowed
        // bytes + original offset
        $remaining = ($this->offset + $this->limit) - $this->stream->tell();
        if ($remaining > 0) {
            // Only return the amount of requested data, ensuring that the byte
            // limit is not exceeded
            return $this->stream->read(min($remaining, $length));
        }

        return '';
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Trait implementing functionality common to requests and responses.
 */
trait MessageTrait
{
    /** @var array Map of all registered headers, as original name => array of values */
    private $headers = [];

    /** @var array Map of lowercase header name => original name at registration */
    private $headerNames  = [];

    /** @var string */
    private $protocol = '1.1';

    /** @var StreamInterface */
    private $stream;

    public function getProtocolVersion()
    {
        return $this->protocol;
    }

    public function withProtocolVersion($version)
    {
        if ($this->protocol === $version) {
            return $this;
        }

        $new = clone $this;
        $new->protocol = $version;
        return $new;
    }

    public function getHeaders()
    {
        return $this->headers;
    }

    public function hasHeader($header)
    {
        return isset($this->headerNames[strtolower($header)]);
    }

    public function getHeader($header)
    {
        $header = strtolower($header);

        if (!isset($this->headerNames[$header])) {
            return [];
        }

        $header = $this->headerNames[$header];

        return $this->headers[$header];
    }

    public function getHeaderLine($header)
    {
        return implode(', ', $this->getHeader($header));
    }

    public function withHeader($header, $value)
    {
        $this->assertHeader($header);
        $value = $this->normalizeHeaderValue($value);
        $normalized = strtolower($header);

        $new = clone $this;
        if (isset($new->headerNames[$normalized])) {
            unset($new->headers[$new->headerNames[$normalized]]);
        }
        $new->headerNames[$normalized] = $header;
        $new->headers[$header] = $value;

        return $new;
    }

    public function withAddedHeader($header, $value)
    {
        $this->assertHeader($header);
        $value = $this->normalizeHeaderValue($value);
        $normalized = strtolower($header);

        $new = clone $this;
        if (isset($new->headerNames[$normalized])) {
            $header = $this->headerNames[$normalized];
            $new->headers[$header] = array_merge($this->headers[$header], $value);
        } else {
            $new->headerNames[$normalized] = $header;
            $new->headers[$header] = $value;
        }

        return $new;
    }

    public function withoutHeader($header)
    {
        $normalized = strtolower($header);

        if (!isset($this->headerNames[$normalized])) {
            return $this;
        }

        $header = $this->headerNames[$normalized];

        $new = clone $this;
        unset($new->headers[$header], $new->headerNames[$normalized]);

        return $new;
    }

    public function getBody()
    {
        if (!$this->stream) {
            $this->stream = stream_for('');
        }

        return $this->stream;
    }

    public function withBody(StreamInterface $body)
    {
        if ($body === $this->stream) {
            return $this;
        }

        $new = clone $this;
        $new->stream = $body;
        return $new;
    }

    private function setHeaders(array $headers)
    {
        $this->headerNames = $this->headers = [];
        foreach ($headers as $header => $value) {
            if (is_int($header)) {
                // Numeric array keys are converted to int by PHP but having a header name '123' is not forbidden by the spec
                // and also allowed in withHeader(). So we need to cast it to string again for the following assertion to pass.
                $header = (string) $header;
            }
            $this->assertHeader($header);
            $value = $this->normalizeHeaderValue($value);
            $normalized = strtolower($header);
            if (isset($this->headerNames[$normalized])) {
                $header = $this->headerNames[$normalized];
                $this->headers[$header] = array_merge($this->headers[$header], $value);
            } else {
                $this->headerNames[$normalized] = $header;
                $this->headers[$header] = $value;
            }
        }
    }

    private function normalizeHeaderValue($value)
    {
        if (!is_array($value)) {
            return $this->trimHeaderValues([$value]);
        }

        if (count($value) === 0) {
            throw new \InvalidArgumentException('Header value can not be an empty array.');
        }

        return $this->trimHeaderValues($value);
    }

    /**
     * Trims whitespace from the header values.
     *
     * Spaces and tabs ought to be excluded by parsers when extracting the field value from a header field.
     *
     * header-field = field-name ":" OWS field-value OWS
     * OWS          = *( SP / HTAB )
     *
     * @param string[] $values Header values
     *
     * @return string[] Trimmed header values
     *
     * @see https://tools.ietf.org/html/rfc7230#section-3.2.4
     */
    private function trimHeaderValues(array $values)
    {
        return array_map(function ($value) {
            if (!is_scalar($value) && null !== $value) {
                throw new \InvalidArgumentException(sprintf(
                    'Header value must be scalar or null but %s provided.',
                    is_object($value) ? get_class($value) : gettype($value)
                ));
            }

            return trim((string) $value, " \t");
        }, $values);
    }

    private function assertHeader($header)
    {
        if (!is_string($header)) {
            throw new \InvalidArgumentException(sprintf(
                'Header name must be a string but %s provided.',
                is_object($header) ? get_class($header) : gettype($header)
            ));
        }

        if ($header === '') {
            throw new \InvalidArgumentException('Header name can not be empty.');
        }
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream that when read returns bytes for a streaming multipart or
 * multipart/form-data stream.
 */
class MultipartStream implements StreamInterface
{
    use StreamDecoratorTrait;

    private $boundary;

    /**
     * @param array  $elements Array of associative arrays, each containing a
     *                         required "name" key mapping to the form field,
     *                         name, a required "contents" key mapping to a
     *                         StreamInterface/resource/string, an optional
     *                         "headers" associative array of custom headers,
     *                         and an optional "filename" key mapping to a
     *                         string to send as the filename in the part.
     * @param string $boundary You can optionally provide a specific boundary
     *
     * @throws \InvalidArgumentException
     */
    public function __construct(array $elements = [], $boundary = null)
    {
        $this->boundary = $boundary ?: sha1(uniqid('', true));
        $this->stream = $this->createStream($elements);
    }

    /**
     * Get the boundary
     *
     * @return string
     */
    public function getBoundary()
    {
        return $this->boundary;
    }

    public function isWritable()
    {
        return false;
    }

    /**
     * Get the headers needed before transferring the content of a POST file
     */
    private function getHeaders(array $headers)
    {
        $str = '';
        foreach ($headers as $key => $value) {
            $str .= "{$key}: {$value}\r\n";
        }

        return "--{$this->boundary}\r\n" . trim($str) . "\r\n\r\n";
    }

    /**
     * Create the aggregate stream that will be used to upload the POST data
     */
    protected function createStream(array $elements)
    {
        $stream = new AppendStream();

        foreach ($elements as $element) {
            $this->addElement($stream, $element);
        }

        // Add the trailing boundary with CRLF
        $stream->addStream(stream_for("--{$this->boundary}--\r\n"));

        return $stream;
    }

    private function addElement(AppendStream $stream, array $element)
    {
        foreach (['contents', 'name'] as $key) {
            if (!array_key_exists($key, $element)) {
                throw new \InvalidArgumentException("A '{$key}' key is required");
            }
        }

        $element['contents'] = stream_for($element['contents']);

        if (empty($element['filename'])) {
            $uri = $element['contents']->getMetadata('uri');
            if (substr($uri, 0, 6) !== 'php://') {
                $element['filename'] = $uri;
            }
        }

        list($body, $headers) = $this->createElement(
            $element['name'],
            $element['contents'],
            isset($element['filename']) ? $element['filename'] : null,
            isset($element['headers']) ? $element['headers'] : []
        );

        $stream->addStream(stream_for($this->getHeaders($headers)));
        $stream->addStream($body);
        $stream->addStream(stream_for("\r\n"));
    }

    /**
     * @return array
     */
    private function createElement($name, StreamInterface $stream, $filename, array $headers)
    {
        // Set a default content-disposition header if one was no provided
        $disposition = $this->getHeader($headers, 'content-disposition');
        if (!$disposition) {
            $headers['Content-Disposition'] = ($filename === '0' || $filename)
                ? sprintf('form-data; name="%s"; filename="%s"',
                    $name,
                    basename($filename))
                : "form-data; name=\"{$name}\"";
        }

        // Set a default content-length header if one was no provided
        $length = $this->getHeader($headers, 'content-length');
        if (!$length) {
            if ($length = $stream->getSize()) {
                $headers['Content-Length'] = (string) $length;
            }
        }

        // Set a default Content-Type if one was not supplied
        $type = $this->getHeader($headers, 'content-type');
        if (!$type && ($filename === '0' || $filename)) {
            if ($type = mimetype_from_filename($filename)) {
                $headers['Content-Type'] = $type;
            }
        }

        return [$stream, $headers];
    }

    private function getHeader(array $headers, $key)
    {
        $lowercaseHeader = strtolower($key);
        foreach ($headers as $k => $v) {
            if (strtolower($k) === $lowercaseHeader) {
                return $v;
            }
        }

        return null;
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream decorator that prevents a stream from being seeked
 */
class NoSeekStream implements StreamInterface
{
    use StreamDecoratorTrait;

    public function seek($offset, $whence = SEEK_SET)
    {
        throw new \RuntimeException('Cannot seek a NoSeekStream');
    }

    public function isSeekable()
    {
        return false;
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Provides a read only stream that pumps data from a PHP callable.
 *
 * When invoking the provided callable, the PumpStream will pass the amount of
 * data requested to read to the callable. The callable can choose to ignore
 * this value and return fewer or more bytes than requested. Any extra data
 * returned by the provided callable is buffered internally until drained using
 * the read() function of the PumpStream. The provided callable MUST return
 * false when there is no more data to read.
 */
class PumpStream implements StreamInterface
{
    /** @var callable */
    private $source;

    /** @var int */
    private $size;

    /** @var int */
    private $tellPos = 0;

    /** @var array */
    private $metadata;

    /** @var BufferStream */
    private $buffer;

    /**
     * @param callable $source Source of the stream data. The callable MAY
     *                         accept an integer argument used to control the
     *                         amount of data to return. The callable MUST
     *                         return a string when called, or false on error
     *                         or EOF.
     * @param array $options   Stream options:
     *                         - metadata: Hash of metadata to use with stream.
     *                         - size: Size of the stream, if known.
     */
    public function __construct(callable $source, array $options = [])
    {
        $this->source = $source;
        $this->size = isset($options['size']) ? $options['size'] : null;
        $this->metadata = isset($options['metadata']) ? $options['metadata'] : [];
        $this->buffer = new BufferStream();
    }

    public function __toString()
    {
        try {
            return copy_to_string($this);
        } catch (\Exception $e) {
            return '';
        }
    }

    public function close()
    {
        $this->detach();
    }

    public function detach()
    {
        $this->tellPos = false;
        $this->source = null;
    }

    public function getSize()
    {
        return $this->size;
    }

    public function tell()
    {
        return $this->tellPos;
    }

    public function eof()
    {
        return !$this->source;
    }

    public function isSeekable()
    {
        return false;
    }

    public function rewind()
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        throw new \RuntimeException('Cannot seek a PumpStream');
    }

    public function isWritable()
    {
        return false;
    }

    public function write($string)
    {
        throw new \RuntimeException('Cannot write to a PumpStream');
    }

    public function isReadable()
    {
        return true;
    }

    public function read($length)
    {
        $data = $this->buffer->read($length);
        $readLen = strlen($data);
        $this->tellPos += $readLen;
        $remaining = $length - $readLen;

        if ($remaining) {
            $this->pump($remaining);
            $data .= $this->buffer->read($remaining);
            $this->tellPos += strlen($data) - $readLen;
        }

        return $data;
    }

    public function getContents()
    {
        $result = '';
        while (!$this->eof()) {
            $result .= $this->read(1000000);
        }

        return $result;
    }

    public function getMetadata($key = null)
    {
        if (!$key) {
            return $this->metadata;
        }

        return isset($this->metadata[$key]) ? $this->metadata[$key] : null;
    }

    private function pump($length)
    {
        if ($this->source) {
            do {
                $data = call_user_func($this->source, $length);
                if ($data === false || $data === null) {
                    $this->source = null;
                    return;
                }
                $this->buffer->write($data);
                $length -= strlen($data);
            } while ($length > 0);
        }
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use InvalidArgumentException;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\StreamInterface;
use Psr\Http\Message\UriInterface;

/**
 * PSR-7 request implementation.
 */
class Request implements RequestInterface
{
    use MessageTrait;

    /** @var string */
    private $method;

    /** @var null|string */
    private $requestTarget;

    /** @var UriInterface */
    private $uri;

    /**
     * @param string                               $method  HTTP method
     * @param string|UriInterface                  $uri     URI
     * @param array                                $headers Request headers
     * @param string|null|resource|StreamInterface $body    Request body
     * @param string                               $version Protocol version
     */
    public function __construct(
        $method,
        $uri,
        array $headers = [],
        $body = null,
        $version = '1.1'
    ) {
        $this->assertMethod($method);
        if (!($uri instanceof UriInterface)) {
            $uri = new Uri($uri);
        }

        $this->method = strtoupper($method);
        $this->uri = $uri;
        $this->setHeaders($headers);
        $this->protocol = $version;

        if (!isset($this->headerNames['host'])) {
            $this->updateHostFromUri();
        }

        if ($body !== '' && $body !== null) {
            $this->stream = stream_for($body);
        }
    }

    public function getRequestTarget()
    {
        if ($this->requestTarget !== null) {
            return $this->requestTarget;
        }

        $target = $this->uri->getPath();
        if ($target == '') {
            $target = '/';
        }
        if ($this->uri->getQuery() != '') {
            $target .= '?' . $this->uri->getQuery();
        }

        return $target;
    }

    public function withRequestTarget($requestTarget)
    {
        if (preg_match('#\s#', $requestTarget)) {
            throw new InvalidArgumentException(
                'Invalid request target provided; cannot contain whitespace'
            );
        }

        $new = clone $this;
        $new->requestTarget = $requestTarget;
        return $new;
    }

    public function getMethod()
    {
        return $this->method;
    }

    public function withMethod($method)
    {
        $this->assertMethod($method);
        $new = clone $this;
        $new->method = strtoupper($method);
        return $new;
    }

    public function getUri()
    {
        return $this->uri;
    }

    public function withUri(UriInterface $uri, $preserveHost = false)
    {
        if ($uri === $this->uri) {
            return $this;
        }

        $new = clone $this;
        $new->uri = $uri;

        if (!$preserveHost || !isset($this->headerNames['host'])) {
            $new->updateHostFromUri();
        }

        return $new;
    }

    private function updateHostFromUri()
    {
        $host = $this->uri->getHost();

        if ($host == '') {
            return;
        }

        if (($port = $this->uri->getPort()) !== null) {
            $host .= ':' . $port;
        }

        if (isset($this->headerNames['host'])) {
            $header = $this->headerNames['host'];
        } else {
            $header = 'Host';
            $this->headerNames['host'] = 'Host';
        }
        // Ensure Host is the first header.
        // See: http://tools.ietf.org/html/rfc7230#section-5.4
        $this->headers = [$header => [$host]] + $this->headers;
    }

    private function assertMethod($method)
    {
        if (!is_string($method) || $method === '') {
            throw new \InvalidArgumentException('Method must be a non-empty string.');
        }
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamInterface;

/**
 * PSR-7 response implementation.
 */
class Response implements ResponseInterface
{
    use MessageTrait;

    /** @var array Map of standard HTTP status code/reason phrases */
    private static $phrases = [
        100 => 'Continue',
        101 => 'Switching Protocols',
        102 => 'Processing',
        200 => 'OK',
        201 => 'Created',
        202 => 'Accepted',
        203 => 'Non-Authoritative Information',
        204 => 'No Content',
        205 => 'Reset Content',
        206 => 'Partial Content',
        207 => 'Multi-status',
        208 => 'Already Reported',
        300 => 'Multiple Choices',
        301 => 'Moved Permanently',
        302 => 'Found',
        303 => 'See Other',
        304 => 'Not Modified',
        305 => 'Use Proxy',
        306 => 'Switch Proxy',
        307 => 'Temporary Redirect',
        400 => 'Bad Request',
        401 => 'Unauthorized',
        402 => 'Payment Required',
        403 => 'Forbidden',
        404 => 'Not Found',
        405 => 'Method Not Allowed',
        406 => 'Not Acceptable',
        407 => 'Proxy Authentication Required',
        408 => 'Request Time-out',
        409 => 'Conflict',
        410 => 'Gone',
        411 => 'Length Required',
        412 => 'Precondition Failed',
        413 => 'Request Entity Too Large',
        414 => 'Request-URI Too Large',
        415 => 'Unsupported Media Type',
        416 => 'Requested range not satisfiable',
        417 => 'Expectation Failed',
        418 => 'I\'m a teapot',
        422 => 'Unprocessable Entity',
        423 => 'Locked',
        424 => 'Failed Dependency',
        425 => 'Unordered Collection',
        426 => 'Upgrade Required',
        428 => 'Precondition Required',
        429 => 'Too Many Requests',
        431 => 'Request Header Fields Too Large',
        451 => 'Unavailable For Legal Reasons',
        500 => 'Internal Server Error',
        501 => 'Not Implemented',
        502 => 'Bad Gateway',
        503 => 'Service Unavailable',
        504 => 'Gateway Time-out',
        505 => 'HTTP Version not supported',
        506 => 'Variant Also Negotiates',
        507 => 'Insufficient Storage',
        508 => 'Loop Detected',
        511 => 'Network Authentication Required',
    ];

    /** @var string */
    private $reasonPhrase = '';

    /** @var int */
    private $statusCode = 200;

    /**
     * @param int                                  $status  Status code
     * @param array                                $headers Response headers
     * @param string|null|resource|StreamInterface $body    Response body
     * @param string                               $version Protocol version
     * @param string|null                          $reason  Reason phrase (when empty a default will be used based on the status code)
     */
    public function __construct(
        $status = 200,
        array $headers = [],
        $body = null,
        $version = '1.1',
        $reason = null
    ) {
        $this->assertStatusCodeIsInteger($status);
        $status = (int) $status;
        $this->assertStatusCodeRange($status);

        $this->statusCode = $status;

        if ($body !== '' && $body !== null) {
            $this->stream = stream_for($body);
        }

        $this->setHeaders($headers);
        if ($reason == '' && isset(self::$phrases[$this->statusCode])) {
            $this->reasonPhrase = self::$phrases[$this->statusCode];
        } else {
            $this->reasonPhrase = (string) $reason;
        }

        $this->protocol = $version;
    }

    public function getStatusCode()
    {
        return $this->statusCode;
    }

    public function getReasonPhrase()
    {
        return $this->reasonPhrase;
    }

    public function withStatus($code, $reasonPhrase = '')
    {
        $this->assertStatusCodeIsInteger($code);
        $code = (int) $code;
        $this->assertStatusCodeRange($code);

        $new = clone $this;
        $new->statusCode = $code;
        if ($reasonPhrase == '' && isset(self::$phrases[$new->statusCode])) {
            $reasonPhrase = self::$phrases[$new->statusCode];
        }
        $new->reasonPhrase = $reasonPhrase;
        return $new;
    }

    private function assertStatusCodeIsInteger($statusCode)
    {
        if (filter_var($statusCode, FILTER_VALIDATE_INT) === false) {
            throw new \InvalidArgumentException('Status code must be an integer value.');
        }
    }

    private function assertStatusCodeRange($statusCode)
    {
        if ($statusCode < 100 || $statusCode >= 600) {
            throw new \InvalidArgumentException('Status code must be an integer value between 1xx and 5xx.');
        }
    }
}


code:
<?php

namespace GuzzleHttp\Psr7;

final class Rfc7230
{
    /**
     * Header related regular expressions (copied from amphp/http package)
     * (Note: once we require PHP 7.x we could just depend on the upstream package)
     *
     * Note: header delimiter (\r\n) is modified to \r?\n to accept line feed only delimiters for BC reasons.
     *
     * @link    https://github.com/amphp/http/blob/v1.0.1/src/Rfc7230.php#L12-L15
     * @license https://github.com/amphp/http/blob/v1.0.1/LICENSE
     */
    const HEADER_REGEX = "(^([^()<>@,;:\\\"/[\]?={}\x01-\x20\x7F]++):[ \t]*+((?:[ \t]*+[\x21-\x7E\x80-\xFF]++)*+)[ \t]*+\r?\n)m";
    const HEADER_FOLD_REGEX = "(\r?\n[ \t]++)";
}


code:
<?php

namespace GuzzleHttp\Psr7;

use InvalidArgumentException;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\UriInterface;
use Psr\Http\Message\StreamInterface;
use Psr\Http\Message\UploadedFileInterface;

/**
 * Server-side HTTP request
 *
 * Extends the Request definition to add methods for accessing incoming data,
 * specifically server parameters, cookies, matched path parameters, query
 * string arguments, body parameters, and upload file information.
 *
 * "Attributes" are discovered via decomposing the request (and usually
 * specifically the URI path), and typically will be injected by the application.
 *
 * Requests are considered immutable; all methods that might change state are
 * implemented such that they retain the internal state of the current
 * message and return a new instance that contains the changed state.
 */
class ServerRequest extends Request implements ServerRequestInterface
{
    /**
     * @var array
     */
    private $attributes = [];

    /**
     * @var array
     */
    private $cookieParams = [];

    /**
     * @var null|array|object
     */
    private $parsedBody;

    /**
     * @var array
     */
    private $queryParams = [];

    /**
     * @var array
     */
    private $serverParams;

    /**
     * @var array
     */
    private $uploadedFiles = [];

    /**
     * @param string                               $method       HTTP method
     * @param string|UriInterface                  $uri          URI
     * @param array                                $headers      Request headers
     * @param string|null|resource|StreamInterface $body         Request body
     * @param string                               $version      Protocol version
     * @param array                                $serverParams Typically the $_SERVER superglobal
     */
    public function __construct(
        $method,
        $uri,
        array $headers = [],
        $body = null,
        $version = '1.1',
        array $serverParams = []
    ) {
        $this->serverParams = $serverParams;

        parent::__construct($method, $uri, $headers, $body, $version);
    }

    /**
     * Return an UploadedFile instance array.
     *
     * @param array $files A array which respect $_FILES structure
     * @throws InvalidArgumentException for unrecognized values
     * @return array
     */
    public static function normalizeFiles(array $files)
    {
        $normalized = [];

        foreach ($files as $key => $value) {
            if ($value instanceof UploadedFileInterface) {
                $normalized[$key] = $value;
            } elseif (is_array($value) && isset($value['tmp_name'])) {
                $normalized[$key] = self::createUploadedFileFromSpec($value);
            } elseif (is_array($value)) {
                $normalized[$key] = self::normalizeFiles($value);
                continue;
            } else {
                throw new InvalidArgumentException('Invalid value in files specification');
            }
        }

        return $normalized;
    }

    /**
     * Create and return an UploadedFile instance from a $_FILES specification.
     *
     * If the specification represents an array of values, this method will
     * delegate to normalizeNestedFileSpec() and return that return value.
     *
     * @param array $value $_FILES struct
     * @return array|UploadedFileInterface
     */
    private static function createUploadedFileFromSpec(array $value)
    {
        if (is_array($value['tmp_name'])) {
            return self::normalizeNestedFileSpec($value);
        }

        return new UploadedFile(
            $value['tmp_name'],
            (int) $value['size'],
            (int) $value['error'],
            $value['name'],
            $value['type']
        );
    }

    /**
     * Normalize an array of file specifications.
     *
     * Loops through all nested files and returns a normalized array of
     * UploadedFileInterface instances.
     *
     * @param array $files
     * @return UploadedFileInterface[]
     */
    private static function normalizeNestedFileSpec(array $files = [])
    {
        $normalizedFiles = [];

        foreach (array_keys($files['tmp_name']) as $key) {
            $spec = [
                'tmp_name' => $files['tmp_name'][$key],
                'size'     => $files['size'][$key],
                'error'    => $files['error'][$key],
                'name'     => $files['name'][$key],
                'type'     => $files['type'][$key],
            ];
            $normalizedFiles[$key] = self::createUploadedFileFromSpec($spec);
        }

        return $normalizedFiles;
    }

    /**
     * Return a ServerRequest populated with superglobals:
     * $_GET
     * $_POST
     * $_COOKIE
     * $_FILES
     * $_SERVER
     *
     * @return ServerRequestInterface
     */
    public static function fromGlobals()
    {
        $method = isset($_SERVER['REQUEST_METHOD']) ? $_SERVER['REQUEST_METHOD'] : 'GET';
        $headers = getallheaders();
        $uri = self::getUriFromGlobals();
        $body = new CachingStream(new LazyOpenStream('php://input', 'r+'));
        $protocol = isset($_SERVER['SERVER_PROTOCOL']) ? str_replace('HTTP/', '', $_SERVER['SERVER_PROTOCOL']) : '1.1';

        $serverRequest = new ServerRequest($method, $uri, $headers, $body, $protocol, $_SERVER);

        return $serverRequest
            ->withCookieParams($_COOKIE)
            ->withQueryParams($_GET)
            ->withParsedBody($_POST)
            ->withUploadedFiles(self::normalizeFiles($_FILES));
    }

    private static function extractHostAndPortFromAuthority($authority)
    {
        $uri = 'http://'.$authority;
        $parts = parse_url($uri);
        if (false === $parts) {
            return [null, null];
        }

        $host = isset($parts['host']) ? $parts['host'] : null;
        $port = isset($parts['port']) ? $parts['port'] : null;

        return [$host, $port];
    }

    /**
     * Get a Uri populated with values from $_SERVER.
     *
     * @return UriInterface
     */
    public static function getUriFromGlobals()
    {
        $uri = new Uri('');

        $uri = $uri->withScheme(!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' ? 'https' : 'http');

        $hasPort = false;
        if (isset($_SERVER['HTTP_HOST'])) {
            list($host, $port) = self::extractHostAndPortFromAuthority($_SERVER['HTTP_HOST']);
            if ($host !== null) {
                $uri = $uri->withHost($host);
            }

            if ($port !== null) {
                $hasPort = true;
                $uri = $uri->withPort($port);
            }
        } elseif (isset($_SERVER['SERVER_NAME'])) {
            $uri = $uri->withHost($_SERVER['SERVER_NAME']);
        } elseif (isset($_SERVER['SERVER_ADDR'])) {
            $uri = $uri->withHost($_SERVER['SERVER_ADDR']);
        }

        if (!$hasPort && isset($_SERVER['SERVER_PORT'])) {
            $uri = $uri->withPort($_SERVER['SERVER_PORT']);
        }

        $hasQuery = false;
        if (isset($_SERVER['REQUEST_URI'])) {
            $requestUriParts = explode('?', $_SERVER['REQUEST_URI'], 2);
            $uri = $uri->withPath($requestUriParts[0]);
            if (isset($requestUriParts[1])) {
                $hasQuery = true;
                $uri = $uri->withQuery($requestUriParts[1]);
            }
        }

        if (!$hasQuery && isset($_SERVER['QUERY_STRING'])) {
            $uri = $uri->withQuery($_SERVER['QUERY_STRING']);
        }

        return $uri;
    }

    /**
     * {@inheritdoc}
     */
    public function getServerParams()
    {
        return $this->serverParams;
    }

    /**
     * {@inheritdoc}
     */
    public function getUploadedFiles()
    {
        return $this->uploadedFiles;
    }

    /**
     * {@inheritdoc}
     */
    public function withUploadedFiles(array $uploadedFiles)
    {
        $new = clone $this;
        $new->uploadedFiles = $uploadedFiles;

        return $new;
    }

    /**
     * {@inheritdoc}
     */
    public function getCookieParams()
    {
        return $this->cookieParams;
    }

    /**
     * {@inheritdoc}
     */
    public function withCookieParams(array $cookies)
    {
        $new = clone $this;
        $new->cookieParams = $cookies;

        return $new;
    }

    /**
     * {@inheritdoc}
     */
    public function getQueryParams()
    {
        return $this->queryParams;
    }

    /**
     * {@inheritdoc}
     */
    public function withQueryParams(array $query)
    {
        $new = clone $this;
        $new->queryParams = $query;

        return $new;
    }

    /**
     * {@inheritdoc}
     */
    public function getParsedBody()
    {
        return $this->parsedBody;
    }

    /**
     * {@inheritdoc}
     */
    public function withParsedBody($data)
    {
        $new = clone $this;
        $new->parsedBody = $data;

        return $new;
    }

    /**
     * {@inheritdoc}
     */
    public function getAttributes()
    {
        return $this->attributes;
    }

    /**
     * {@inheritdoc}
     */
    public function getAttribute($attribute, $default = null)
    {
        if (false === array_key_exists($attribute, $this->attributes)) {
            return $default;
        }

        return $this->attributes[$attribute];
    }

    /**
     * {@inheritdoc}
     */
    public function withAttribute($attribute, $value)
    {
        $new = clone $this;
        $new->attributes[$attribute] = $value;

        return $new;
    }

    /**
     * {@inheritdoc}
     */
    public function withoutAttribute($attribute)
    {
        if (false === array_key_exists($attribute, $this->attributes)) {
            return $this;
        }

        $new = clone $this;
        unset($new->attributes[$attribute]);

        return $new;
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * PHP stream implementation.
 *
 * @var $stream
 */
class Stream implements StreamInterface
{
    /**
     * Resource modes.
     *
     * @var string
     *
     * @see http://php.net/manual/function.fopen.php
     * @see http://php.net/manual/en/function.gzopen.php
     */
    const READABLE_MODES = '/r|a\+|ab\+|w\+|wb\+|x\+|xb\+|c\+|cb\+/';
    const WRITABLE_MODES = '/a|w|r\+|rb\+|rw|x|c/';

    private $stream;
    private $size;
    private $seekable;
    private $readable;
    private $writable;
    private $uri;
    private $customMetadata;

    /**
     * This constructor accepts an associative array of options.
     *
     * - size: (int) If a read stream would otherwise have an indeterminate
     *   size, but the size is known due to foreknowledge, then you can
     *   provide that size, in bytes.
     * - metadata: (array) Any additional metadata to return when the metadata
     *   of the stream is accessed.
     *
     * @param resource $stream  Stream resource to wrap.
     * @param array    $options Associative array of options.
     *
     * @throws \InvalidArgumentException if the stream is not a stream resource
     */
    public function __construct($stream, $options = [])
    {
        if (!is_resource($stream)) {
            throw new \InvalidArgumentException('Stream must be a resource');
        }

        if (isset($options['size'])) {
            $this->size = $options['size'];
        }

        $this->customMetadata = isset($options['metadata'])
            ? $options['metadata']
            : [];

        $this->stream = $stream;
        $meta = stream_get_meta_data($this->stream);
        $this->seekable = $meta['seekable'];
        $this->readable = (bool)preg_match(self::READABLE_MODES, $meta['mode']);
        $this->writable = (bool)preg_match(self::WRITABLE_MODES, $meta['mode']);
        $this->uri = $this->getMetadata('uri');
    }

    /**
     * Closes the stream when the destructed
     */
    public function __destruct()
    {
        $this->close();
    }

    public function __toString()
    {
        try {
            $this->seek(0);
            return (string) stream_get_contents($this->stream);
        } catch (\Exception $e) {
            return '';
        }
    }

    public function getContents()
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        $contents = stream_get_contents($this->stream);

        if ($contents === false) {
            throw new \RuntimeException('Unable to read stream contents');
        }

        return $contents;
    }

    public function close()
    {
        if (isset($this->stream)) {
            if (is_resource($this->stream)) {
                fclose($this->stream);
            }
            $this->detach();
        }
    }

    public function detach()
    {
        if (!isset($this->stream)) {
            return null;
        }

        $result = $this->stream;
        unset($this->stream);
        $this->size = $this->uri = null;
        $this->readable = $this->writable = $this->seekable = false;

        return $result;
    }

    public function getSize()
    {
        if ($this->size !== null) {
            return $this->size;
        }

        if (!isset($this->stream)) {
            return null;
        }

        // Clear the stat cache if the stream has a URI
        if ($this->uri) {
            clearstatcache(true, $this->uri);
        }

        $stats = fstat($this->stream);
        if (isset($stats['size'])) {
            $this->size = $stats['size'];
            return $this->size;
        }

        return null;
    }

    public function isReadable()
    {
        return $this->readable;
    }

    public function isWritable()
    {
        return $this->writable;
    }

    public function isSeekable()
    {
        return $this->seekable;
    }

    public function eof()
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        return feof($this->stream);
    }

    public function tell()
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }

        $result = ftell($this->stream);

        if ($result === false) {
            throw new \RuntimeException('Unable to determine stream position');
        }

        return $result;
    }

    public function rewind()
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        $whence = (int) $whence;

        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->seekable) {
            throw new \RuntimeException('Stream is not seekable');
        }
        if (fseek($this->stream, $offset, $whence) === -1) {
            throw new \RuntimeException('Unable to seek to stream position '
                . $offset . ' with whence ' . var_export($whence, true));
        }
    }

    public function read($length)
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->readable) {
            throw new \RuntimeException('Cannot read from non-readable stream');
        }
        if ($length < 0) {
            throw new \RuntimeException('Length parameter cannot be negative');
        }

        if (0 === $length) {
            return '';
        }

        $string = fread($this->stream, $length);
        if (false === $string) {
            throw new \RuntimeException('Unable to read from stream');
        }

        return $string;
    }

    public function write($string)
    {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Stream is detached');
        }
        if (!$this->writable) {
            throw new \RuntimeException('Cannot write to a non-writable stream');
        }

        // We can't know the size after writing anything
        $this->size = null;
        $result = fwrite($this->stream, $string);

        if ($result === false) {
            throw new \RuntimeException('Unable to write to stream');
        }

        return $result;
    }

    public function getMetadata($key = null)
    {
        if (!isset($this->stream)) {
            return $key ? null : [];
        } elseif (!$key) {
            return $this->customMetadata + stream_get_meta_data($this->stream);
        } elseif (isset($this->customMetadata[$key])) {
            return $this->customMetadata[$key];
        }

        $meta = stream_get_meta_data($this->stream);

        return isset($meta[$key]) ? $meta[$key] : null;
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream decorator trait
 * @property StreamInterface stream
 */
trait StreamDecoratorTrait
{
    /**
     * @param StreamInterface $stream Stream to decorate
     */
    public function __construct(StreamInterface $stream)
    {
        $this->stream = $stream;
    }

    /**
     * Magic method used to create a new stream if streams are not added in
     * the constructor of a decorator (e.g., LazyOpenStream).
     *
     * @param string $name Name of the property (allows "stream" only).
     *
     * @return StreamInterface
     */
    public function __get($name)
    {
        if ($name == 'stream') {
            $this->stream = $this->createStream();
            return $this->stream;
        }

        throw new \UnexpectedValueException("$name not found on class");
    }

    public function __toString()
    {
        try {
            if ($this->isSeekable()) {
                $this->seek(0);
            }
            return $this->getContents();
        } catch (\Exception $e) {
            // Really, PHP? https://bugs.php.net/bug.php?id=53648
            trigger_error('StreamDecorator::__toString exception: '
                . (string) $e, E_USER_ERROR);
            return '';
        }
    }

    public function getContents()
    {
        return copy_to_string($this);
    }

    /**
     * Allow decorators to implement custom methods
     *
     * @param string $method Missing method name
     * @param array  $args   Method arguments
     *
     * @return mixed
     */
    public function __call($method, array $args)
    {
        $result = call_user_func_array([$this->stream, $method], $args);

        // Always return the wrapped object if the result is a return $this
        return $result === $this->stream ? $this : $result;
    }

    public function close()
    {
        $this->stream->close();
    }

    public function getMetadata($key = null)
    {
        return $this->stream->getMetadata($key);
    }

    public function detach()
    {
        return $this->stream->detach();
    }

    public function getSize()
    {
        return $this->stream->getSize();
    }

    public function eof()
    {
        return $this->stream->eof();
    }

    public function tell()
    {
        return $this->stream->tell();
    }

    public function isReadable()
    {
        return $this->stream->isReadable();
    }

    public function isWritable()
    {
        return $this->stream->isWritable();
    }

    public function isSeekable()
    {
        return $this->stream->isSeekable();
    }

    public function rewind()
    {
        $this->seek(0);
    }

    public function seek($offset, $whence = SEEK_SET)
    {
        $this->stream->seek($offset, $whence);
    }

    public function read($length)
    {
        return $this->stream->read($length);
    }

    public function write($string)
    {
        return $this->stream->write($string);
    }

    /**
     * Implement in subclasses to dynamically create streams when requested.
     *
     * @return StreamInterface
     * @throws \BadMethodCallException
     */
    protected function createStream()
    {
        throw new \BadMethodCallException('Not implemented');
    }
}


code:
<?php
namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Converts Guzzle streams into PHP stream resources.
 */
class StreamWrapper
{
    /** @var resource */
    public $context;

    /** @var StreamInterface */
    private $stream;

    /** @var string r, r+, or w */
    private $mode;

    /**
     * Returns a resource representing the stream.
     *
     * @param StreamInterface $stream The stream to get a resource for
     *
     * @return resource
     * @throws \InvalidArgumentException if stream is not readable or writable
     */
    public static function getResource(StreamInterface $stream)
    {
        self::register();

        if ($stream->isReadable()) {
            $mode = $stream->isWritable() ? 'r+' : 'r';
        } elseif ($stream->isWritable()) {
            $mode = 'w';
        } else {
            throw new \InvalidArgumentException('The stream must be readable, '
                . 'writable, or both.');
        }

        return fopen('guzzle://stream', $mode, null, self::createStreamContext($stream));
    }

    /**
     * Creates a stream context that can be used to open a stream as a php stream resource.
     *
     * @param StreamInterface $stream
     *
     * @return resource
     */
    public static function createStreamContext(StreamInterface $stream)
    {
        return stream_context_create([
            'guzzle' => ['stream' => $stream]
        ]);
    }

    /**
     * Registers the stream wrapper if needed
     */
    public static function register()
    {
        if (!in_array('guzzle', stream_get_wrappers())) {
            stream_wrapper_register('guzzle', __CLASS__);
        }
    }

    public function stream_open($path, $mode, $options, &$opened_path)
    {
        $options = stream_context_get_options($this->context);

        if (!isset($options['guzzle']['stream'])) {
            return false;
        }

        $this->mode = $mode;
        $this->stream = $options['guzzle']['stream'];

        return true;
    }

    public function stream_read($count)
    {
        return $this->stream->read($count);
    }

    public function stream_write($data)
    {
        return (int) $this->stream->write($data);
    }

    public function stream_tell()
    {
        return $this->stream->tell();
    }

    public function stream_eof()
    {
        return $this->stream->eof();
    }

    public function stream_seek($offset, $whence)
    {
        $this->stream->seek($offset, $whence);

        return true;
    }

    public function stream_cast($cast_as)
    {
        $stream = clone($this->stream);

        return $stream->detach();
    }

    public function stream_stat()
    {
        static $modeMap = [
            'r'  => 33060,
            'rb' => 33060,
            'r+' => 33206,
            'w'  => 33188,
            'wb' => 33188
        ];

        return [
            'dev'     => 0,
            'ino'     => 0,
            'mode'    => $modeMap[$this->mode],
            'nlink'   => 0,
            'uid'     => 0,
            'gid'     => 0,
            'rdev'    => 0,
            'size'    => $this->stream->getSize() ?: 0,
            'atime'   => 0,
            'mtime'   => 0,
            'ctime'   => 0,
            'blksize' => 0,
            'blocks'  => 0
        ];
    }

    public function url_stat($path, $flags)
    {
        return [
            'dev'     => 0,
            'ino'     => 0,
            'mode'    => 0,
            'nlink'   => 0,
            'uid'     => 0,
            'gid'     => 0,
            'rdev'    => 0,
            'size'    => 0,
            'atime'   => 0,
            'mtime'   => 0,
            'ctime'   => 0,
            'blksize' => 0,
            'blocks'  => 0
        ];
    }
}