Validate author_id and return 404 for missing data
Validate author_id and return 404 for missing data

wfxiang08/changes,dropbox/changes,bowlofstew/changes,dropbox/changes,bowlofstew/changes,wfxiang08/changes,dropbox/changes,wfxiang08/changes,dropbox/changes,bowlofstew/changes,wfxiang08/changes,bowlofstew/changes