Content-Length HTTP/1.1 documentation HTTP/1.1 documentation HTTP spec section 14.19 Server HTTP header Pragma Cache-Control RFC 2616 section 14.9 RFC2616 section 14.44 Vary Accept ETag section 14.32 HTTP spec section 14.1 HTTP Accept Header Warning Warning Cache-Control If-Match: * HTTP spec section 14.21 Warning HTTP Upgrade W3C say about Cache-control HTTP/1.1 documentation HTTP Range RFC2616 section 14.28 accept Pragma HTTP/1.1 documentation If-None-Match HTTP Host header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP Header Field Definitions header w3.org HTTP/1.1 documentation Pragma http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Cache-Control HTTP Range Retrieval Requests HTTP/1.1 Cache-Control directives HTTP 1.0 Expires header Last-Modified HTTP spec section 14.30 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html um mecanismo para isso HTTP spec section 14.9 w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9 Accept ETag If-None-Match RFC 2616 section 14.9 HTTP protocol allows for this kind of stuff. http://www.w3.org/Protocols/rfc2616/....html#sec14.10 Cache-Control HTTP/1.1 documentation Content-Encoding RFC 2616 section 14.9 header RFC 2616 section 14.9 Warning Pragma HTTP 1.1 Standard Accept HTTP Range Retrieval Requests Accept header If-none-match RFC 2616 section 14.9 Warning Warning Retry-After RFC2616 section 14.26 HTTP spec section 14.28 RFC 2616 section 14.9 Accept-Encoding compression Accept header HTTP/1.1 documentation HTTP spec section 14.31 w3.org http/1.1 protocol Referer Header Fields in the HTTP/1.1 RFC states RFC 2616 section 14.9 RFC 2616, 14.9 Àý RFC 2616 section 14.9 HTTP/1.1 section 14.9.3 If-None-Match HTTP/1.1 section 14.9.1 Warning Accept-Ranges HTTP/1.1 documentation RFC2616 section 14.19 Etag RFC Server If-Match RFC 2616 section 14.9 RFC2616 section 14.44 Vary HTTP/1.1 documentation Accept-Language Cache-Control Trailer header Warning If-None-Match section 14.4 de la spécification HTTP/1.1 User-Agent HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616, 14.9 Àý Expires Warning HTTP/1.1 documentation Trailer Warning http://www.w3.org/Protocols/rfc2616/....html#sec14.10 HTTP specification HTTP spec section 14.1 If-None-Match HTTP/1.1 documentation Cache-Control HTTP spec section 14.1 HTTP spec section 14.31 If-Modified-Since Accept-Ranges Accept-Language s-maxage Cache-Control 14.21 Expires Pragma http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.28 Accept-Language If-Modified-Since w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35 RFC2616 section 14.26 um mecanismo para isso HTTP Header "User-Agent" RFC2616 section 14.32 Pragma http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 section 14.9 Warning accept If-Match Warning Upgrade RFC 2616 section 14.9 RFC2616 section 14.19 Etag RFC Pragma header RFC 2616 section 14.9 HTTP/1.1 documentation RFC2616 section 14.32 Pragma RFC2616 section 14.26 header RFC 2616 section 14.9 Expires header RFC 2616 Sec 14.24 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP Host header RFC 2616, 14.9 Àý Warning HTTP/1.1 documentation RFC2616 section 14.25 If-Match Server HTTP header RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Warning HTTP/1.1: Header Field Definitions HTTP/1.1 section 14.9.4 Cache-Control HTTP Accept Header Cache-Control HTTP spec section 14.9 Range HTTP/1.1 documentation w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.1 HTTP Header Field Definitions HTTP/1.1 documentation HTTP/1.1 section 14.9 Warning www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11 RFC 2616 section 14.9 Content-MD5 RFC 2616 section 14.9 HTTP spec section 14.9 Pragma HTTP spec section 14.35 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.32 Pragma HTTP spec section 14.18 Actually, yes. HTTP/1.1 documentation HTTP/1.1 documentation HTTP/1.1 documentation Range RFC 2616 section 14.9 RFC 2616 section 14.9 ETags ETag RFC2616 section 14.25 Range HTTP spec section 14.12 Cache-Control http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Cache-Control Cache Control header Content-Type Warning Accept-Charset HTTP/1.1 documentation RFC2616 Cache-Control Last-Modified Warning RFC 2616 section 14.9 RFC2616 section 14.24 If-None-Match If-Range Etag Host RFC2616 section 14.9.1 What is Cacheable Accept-Encoding RFC 2616 section 14.9 Content-Length the RFC RFC2616 section 14.32 Pragma If-None-Match Accept request header HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616... http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 section 14.9 HTTP spec section 14.8 HTTP/1.1 documentation HTTP/1.1 documentation HTTP Location header field Pragma HTTP/1.1 section 14.9.3 RFC 2616 Feed 304 HTTP/1.1 documentation Server HTTP spec section 14.28 If-None-Match Retry-After Accept-Language header If-None-Match HTTP protocol allows for this kind of stuff. en-tête Upgrade Content-Type HTTP header field http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept RFC2616 section 14.9.1 What is Cacheable RFC 2616 no-cache option HTTP/1.1: Header Field Definitions HTTP Vary http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP/1.1 section 14.9.4 HTTP/1.1 section 14.9.1 Etag header Cache-Control Accept RFC2616 section 14.24 location RFC 2616 section 14.9 HTTP/1.1 documentation „Last-Modified“ HTTP response header field Accept header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/....html#sec14.10 RFC 2616 section 14.9 expires http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Vary HTTP Header Cache-Control Warning RFC2616 section 14.25 RFC2616 section 14.27 If-None-Match HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-Range ETag Content-Type RFC2616 section 14.24 Those directives Accept via header http://w3.org/Protocols/rfc2616/… HTTP header "Referer" field Pragma Content-Length RFC 2616 section 14.9 Warning RFC 2616 section 14.9 request header "Accept-Ranges: bytes" Warning HTTP/1.1 section 14.9.4 RFC2616 section 14.27 Accept-Language Warning HTTP spec section 14.37 no-cache HTTP/1.1 documentation el RFC de las cabeceras Server HTTP header RFC 2316, section 14.23 RFC2616 section 14.19 Etag RFC 2616 section 14.9 Warning RFC 2616 HTTP protocol allows for this kind of stuff. Accept HTTP/1.1 documentation RFC 2616 section 14.9 Accept-Encoding RFC 2616 section 14.9 RFC 2616 section 14.9 HTTP/1.1 documentation RFC 2616 section 14.9 Cache-Control http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-None-Match Upgrade header Warning Content-Length HTTP/1.1 documentation Accept header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP spec section 14.8 RFC2616 section 14.24 Server If-Modified-Since HTTP Host header Accept header Server HTTP header If-None-Match RFC2616 section 14.29 Last-Modified RFC 2616 section 14.9 RFC 2616 section 14.9 RFC 2616 section 14.9 ETag Cache-Control explanations Content-Type Pragma RFC 2616, 14.9 Àý HTTP/1.1 documentation Warning Cache-Control no-store HTTP/1.1 documentation Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP/1.1 section 14.9 RFC 2616 section 14.9 RFC Location: header Warning Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.24 section 14.5 of RFC2616 section 14.16 of RFC2616 RFC 2616 section 14.9 HTTP spec section 14.13 Accept If-modified-since Content- Language RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.19 Etag Via HTTP specification RFC2616 section 14.29 Last-Modified Warning Pragma Retry-After header HTTP-1.1-Range-Requests If-None-Match Pragma RFC2616 section 14.44 Vary HTTP spec section 14.36 Pragma Referer RFC 2616 section 14.9 RFC 2616 section 14.9 RFC 2616 section 14.9 „HTTP/1.1: Header Field Definitions” HTTP/1.1 specification HTTP/1.1 documentation RFC2616 section 14.27 RFC 2616 section 14.9 header RFC 2616 section 14.9 RFC 2616 section 14.9 Pragma Page 304 header Pragma RFC 2616 section 14.9 RFC2616 section 14.25 Warning Content-Type If-None-Match http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html section 14.29 HTTP/1.1 documentation RFC 2616 supports multiple Content-Encoding HTTP Header Field Definitions If-Match Cache-Control Accept-Language HTTP/1.1 documentation HTTP/1.1 documentation Section 14.13 of the HTTP/1.1 RFC2616 section 14.19 Etag If-None-Match Page 304 Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP spec section 14.8 Page 304 RFC2616 section 14.32 Pragma Pragma RFC2616 section 14.24 HTTP spec section 14.16 RFC2616 section 14.44 Vary Pragma HTTP/1.1 documentation Warning HTTP spec section 14.13 “If-Modified-Since” header Warning HTTP/1.1 documentation Warning RFC 2616 sec. 14.35 HTTP/1.1 documentation Trailer RFC2616 section 14.29 Last-Modified Cache-Control HTTP/1.1 documentation Cache-Control RFC2616 section 14.9.1 What is Cacheable If-None-Match HTTP spec section 14.7 Feed 304 http://w3.org/Protocols/rfc2616/… RFC 2616 section 14.9 Cache control headers HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept-Encoding Content-Language Age If-None-Match If-Range request header HTTP/1.1 documentation HTTP spec section 14.8 If-Modified-Since http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept-Ranges RFC2616 section 14.24 Content-Length Accept-Charset If-None-Match HTTP spec section 14.29 Warning ETag Authorization Accept RFC2616 section 14.27 Retry-After Content-Type RFC 2616, 14.9 Àý RFC 2616, 14.9 절 HTTP "if-match" header Accept-Type http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 section 14.9 RFC2616 section 14.25 Warning Location Cache-Control RFC 2616 section 14.9 RFC 2616 section 14.9 HTTP/1.1 documentation Content-Type HTTP/1.1 documentation RFC 2616 If-Range HTTP/1.1 documentation RFC 2616 section 14.9 Accept header ETag Vary Warning Cache-Control: no-cache RFC 2616 section 14.9 header If-None-Match RFC RFC2616 section 14.29 Last-Modified RFC2616 section 14.44 Vary RFC 2616 section 14.9 Content Location http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 section 14.9 section 14.9 section 14.21 ETag If-None-Match RFC2616 section 14.27 Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Content-Type Accept-Language Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP/1.1 documentation HTTP spec section 14.36 RFC2616 section 14.19 Etag HTTP/1.1 section 14.9.1 standards compliant From: Pragma If-None-Match Accept Cache-Control Range Header Field Definition HTTP/1.1 documentation Last-Modified HTTP/1.1 documentation Cache-Control RFC2616 section 14.27 Cache-Control RFC 2616 section 14.9 HTTP spec section 14.18 RFC 2616 section 14.9 HTTP/1.1 documentation HTTP/1.1 documentation RFC2616 section 14.27 HTTP/1.1 documentation Pragma HTTP Location header field RFC2616 section 14.25 WWW-Authenticate WC3 HTTP Protocol specifies request headers since 1992 or so request header Referrer HTTP/1.1: Header Field Definitions header Feed 304 RFC 2616 section 14.9 Warning Accept-Language Last-modified Expires http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.44 Vary Range Section 14.1 of RFC 2616 RFC 2616, 14.9 Àý If-Modified-Since Cache Control for HTTP 1.1 header HTTP spec section 14.36 Warning Referer Vary header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP/1.1 Specification, §14.4 14.35.2 Range Retrieval Requests header Server HTTP header HTTP/1.1 documentation HTTP/1.1 documentation Connection RFC2616 section 14.9.1 What is Cacheable content-type HTTP/1.1 documentation Cache-Control Trailer Headers HTTP/1.1 section 14.9.4 HTTP/1.1 documentation Pragma Accept-Language RFC2616 section 14.9.1 What is Cacheable If-None-Match Allow RFC 2616 section 14.9 HTTP Accept Headers Content-Type RFC 2616, 14.9 Àý RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Expires HTTP spec section 14.44 header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616, 14.9 Àý Accept header header RFC 2616 section 14.9 Section 14.1 of RFC 2616 structure of an UA is defined in the HTTP specification HTTP/1.1 documentation RFC2616 section 14.44 Vary HTTP/1.1 section 14.9.1 HTTP/1.1 documentation Cache-Control RFC 2616 section 14.9 HTTP/1.1 documentation Accept-Language RFC2616 section 14.29 Last-Modified ETag value HTTP header HTTP spec section 14.37 Range HTTP/1.1 documentation RFC 2616 section 14.9 RFC2616 section 14.32 Pragma Content-Range accept RFC2616 section 14.24 HTTP/1.1 documentation Warning If-None-Match HTTP/1.1 documentation RFC 2616 section 14.9 Expires RFC2616 section 14.27 RFC 2616 section 14.9 RFC 2616 section 14.9 If-None-Match HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.19 Etag RFC2616 section 14.19 Etag HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/...4.html#sec14.9 Expect HTTP/1.1 Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Retry-After header RFC 2616 section 14.9 Accept header Warning HTTP/1.1 documentation Pragma um mecanismo para isso RFC 2616 HTTP/1.1 documentation HTTP/1.1 documentation RFC2616 section 14.29 Last-Modified location Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Content-MD5 HTTP Header content-range headers If-None-Match Warning HTTP spec section 14.13 RFC2616 section 14.28 RFC 2616, 14.9 Àý Last-Modified http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html rfc2616 #14.11 Accept HTTP/1.1 documentation HTTP/1.1 documentation HTTP specification Pragma HTTP/1.1 documentation HTTP/1.1 specification HTTP response encoding Content-Type RFC2616 section 14.9.1 What is Cacheable Cache-Control Pragma Accept Accept Request Header Pragma ETag If-None-Match Referer Warning Trailer Headers If-Modified-Since Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC2616 section 14.27 Content-Type HTTP header field "If-Modified-Since" HTTP spec section 14.29 http://www.w3.org/Protocols/rfc2616/....html#sec14.10 the HTTP spec makes it header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-None-Match Trailer HTTP spec section 14.21 RFC2616 section 14.29 Last-Modified Warning HTTP/1.1 documentation RFC2616 section 14.28 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14 Warning RFC 2616 section 14.9 If-None-Match max-age Cache-Control RFC 2616 section 14.9 Warning HTTP/1.1 documentation RFC2616 section 14.24 HTTP spec section 14.2 Content-Type HTTP Location header field RFC2616 section 14.24 HTTP/1.1 documentation Cache-Control HTTP/1.1 section 14.9.3 WC3 HTTP Protocol specifies request headers since 1992 or so HTTP/1.1 specification RFC 2616 section 14.9 HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Retry-After Cache Control for HTTP 1.1 accept RFC2616 section 14.19 Etag Pragma Warning “Cache-Control: no-store” HTTP spec section 14.27 HTTP Vary RFC2616 section 14.25 Warning RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC HTTP/1.1 documentation Cache-Control Cache-Control cache-control HTTP specification Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Trailer Headers If-Modified-Since Warning Content-Type header Accept HTTP Header If-None-Match Warning RFC2616 section 14.32 Pragma request Section 14.42 W3C HTTP 1.1 spec http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-None-Match Content-Range HTTP/1.1: Header Field Definitions HTTP/1.1 documentation Content-Type RFC2616 section 14.29 Last-Modified spec states Accept-Encoding Accept-Language Warning HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html WWW-Authenticate Pragma RFC 2616 section 14.9 W3C recommend Cache-Control header RFC 2616 section 14.9 HTTP/1.1 documentation RFC 2616 section 14.9 HTTP 1.1 Last-Modified RFC 2616 section 14.9 If-None-Match RFC2616 section 14.26 Upgrade The definition of referer RFC 2616 section 14.9 Content-Type Content-Type Warning HTTP/1.1 documentation HTTP spec section 14.32 w3.org http/1.1 protocol Accept header http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html range requests Accept-Encoding If-Modified-Since RFC 2616 section 14.9 Accept-Encoding RFC 2616 section 14.9 RFC2616 section 14.32 Pragma ETags ETag Location: header HTTP Vary header HTTP spec section 14.47 Cache-Control spec http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept HTTP header HTTP headers header HTTP/1.1 documentation Section 14.14 HTTP/1.1 documentation Page 304 RFC 2616 section 14.9 HTTP/1.1 documentation Content-Type RFC 2616 section 14.9 a Vary: * header RFC for HTTP/1.1 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Pragma HTTP/1.1 documentation HTTP 1.1 spec HTTP/1.1 documentation Range Accept-Encoding RFC 2616 section 14.9 RFC specification for HTTP headers Cache-Control RFC 2616 section 14.9 If-Match http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept RFC 2616 section 14.9 Accept-Language HTTP spec section 14.14 HTTP headers http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-Range Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Warning Server HTTP header header RFC2616 section 14.44 Vary HTTP/1.1 documentation ETag http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Warning Pragma If-None-Match RFC 2616 section 14.9 Warning If-None-Match Warning Warning HTTP/1.1 documentation RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html ETag Content-Type Content-MD5 HTTP Header HTTP spec section 14.4 Proxy-Authenticate Accept RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Location Pragma Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Content-Type http://www.w3.org/Protocols/rfc2616/....html#sec14.10 HTTP/1.1 documentation HTTP spec section 14.35 header ETag Connection RFC2616 section 14.25 Content-Length header HTTP/1.1 documentation If-None-Match RFC 2616 section 14.9 content-type part of the HTTP protocol HTTP/1.1 documentation the RFC RFC RFC2616 section 14.19 Etag RFC2616 section 14.24 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html header HTTP/1.1 documentation location Server Section 14.1 of RFC 2616 RFC2616 section 14.9.1 What is Cacheable If-None-Match Pragma Warning Cache-Control HTTP/1.1: Header Field Definitions: Connection Vary header official Vary spec If-Modified-Since http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html If-Match Accept-Language ETag Accept Pragma Warning Cache-Control all media types Warning HTTP 1.1 Specification - Header Field Definitions RFC 2616 section 14.9 HTTP/1.1 documentation http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Content-Length the RFC If-None-Match HTTP Range requests HTTP spec section 14.21 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Pragma RFC 2616 section 14.9 If-None-Match HTTP 1.1 Header Fields Definition RFC If-None-Match Location HTTP header field HTTP/1.1 documentation Pragma HTTP spec section 14.9 HTTP/1.1 section 14.9.5 Warning Accept-Language http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Accept header Warning Accept-Charset Pragma HTTP spec section 14.4 HTTP/1.1 documentation HTTP/1.1 documentation Accept-Encoding Warning Warning http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html Referer Cache-Control RFC2616 section 14.24 Cache-Control RFC2616 Section 14.25 ETag RFC 2616 section 14.9 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 section 14.9 HTTP spec section 14.18 HTTP/1.1 documentation RFC2616 section 14.9.1 What is Cacheable header HTTP spec section 14.14 HTTP spec section 14.21 Accept-Language Cache-Control HTTP/1.1 documentation RFC2616 Section 14.9.3 Content-Language HTTP header HTTP 1.1 Specification RFC 2616 section 14.9 If-None-Match ETag RFC 2616 section 14.9 Via HTTP/1.1 documentation HTTP Range headers RFC 2616 section 14.9 User-Agent