php: check file exists
php: check file exists

ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration,ONLYOFFICE/document-server-integration