Request Header Field Response Messages status line followed by one or more general, response and entity headers, Authorization followed by optional entity bo a If modified since aStatus-line=http-version<sp> Status-Code <SP> Reason-Phrase <CRLF> Status Codes Response Header Fields Informational a Location a Successful Proxy authentication Redirection a Client error Retry after a Server error a Server WWw-Authenticate Entity Header Field Entity Body Arbitrary sequence of octets Content encoding Last modified Http transfers any type of data including Content language. Link Content length Title audio n Content MD5 Transfer encode a Content range a Content type a Extension header Interpretation of data determined by a Content versio header field a Derived from Content encoding, content type, transfer9 哈工大计算机学院 李全龙 Network Application Development Server Software Design 49 Request Header Field „ Accept „ Accept charset „ Accept encoding „ Accept language „ Authorization „ From „ Host „ If modified since „ Proxy authentication „ Range „ Referrer „ Unless „ User agent 哈工大计算机学院 李全龙 Network Application Development Server Software Design 50 Response Messages „ Status line followed by one or more general, response and entity headers, followed by optional entity body „ Status-Line = HTTP-Version <SP> Status-Code <SP> Reason-Phrase <CRLF> 哈工大计算机学院 李全龙 Network Application Development Server Software Design 51 Status Codes „ Informational „ Successful „ Redirection „ Client error „ Server error 哈工大计算机学院 李全龙 Network Application Development Server Software Design 52 Response Header Fields „ Location „ Proxy authentication „ Public „ Retry after „ Server „ WWW-Authenticate 哈工大计算机学院 李全龙 Network Application Development Server Software Design 53 Entity Header Fields „ Allow „ Content encoding „ Content language „ Content length „ Content MD5* „ Content range* „ Content type „ Content version „ Derived from „ Expires „ Last modified „ Link „ Title „ Transfer encoding „ URL header „ Extension header 哈工大计算机学院 李全龙 Network Application Development Server Software Design 54 Entity Body „ Arbitrary sequence of octets „ HTTP transfers any type of data including: „ text „ binary data „ audio „ images „ video „ Interpretation of data determined by header fields „ Content encoding, content type, transfer encoding