Introduction to HTTP
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HTTP was created in 1989 by Tim Berners-Lee at CERN to allow information sharing through hypertext. The first web server and website launched in 1990-1991. HTTP uses a client-server model with requests containing a start line with method, URL, and protocol version followed by headers and an optional message body. Responses contain a status line, headers, and body. Key concepts are persistent connections, caching, content types, and new versions that add functionality while maintaining backward compatibility.
Introduction to HTTP
- 1. Introduction to HTTP History, Knowledge and Usages code4crafter@gmail.com 2015.4.1
- 2. O U T L I N E • History • HTTP Basics • Extended Topics
- 3. Background - Beyond text • Hypertext is text which is not constrained to be linear. Hypertext is text which contains links to other texts. ——《Computer Lib/Dream Machines》 Ted Nelson
- 4. W h a t i s “ h y p e r ” ?
- 5. P r o j e c t X a n a d u ( 1 9 6 0 - 2 0 1 4 ? )
- 6. The Birth of Web 1989 • Tim Beners-Lee @CERN
- 7. T h e F i r s t B r o w s e r • “WorldWideWeb”(Nexus)
- 8. The First Web Server • CERN httpd on NeXT
- 9. The First Website • http://info.cern.ch/hypertext/WWW/TheProject.html
- 10. WWW and Internet
- 11. O U T L I N E • History • HTTP Basics • Extended Topics
- 13. HTTP Message Structure — Start Line • Method • OPTIONS/GET/HEAD/POST/PUT/DELETE/TRACE/CONNECT • http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html • URL • URL is an impl of URI • Status Code(Response) • 1xx/2xx/3xx/4xx/5xx • http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html • Reason-Phrase(Response) • 200 OK, 404 Not Found, • CRLF • Carriage-Return r Line-Feed n
- 14. HTTP Message Structure — Headers • Request Headers • Accept headers: • Accept, Accept-Charset, Accept-Encoding , Accept-Language • Conditional request headers: • If-Match, If-None-Match, If-Modified-Since, If-Unmodified-Since • Request security headers: • Authorization, Cookie, Cookie2 • Proxy request headers: • Max-Forwards, Proxy-Authorization, Proxy-Connection
- 15. HTTP Message Structure — Headers • Response Headers • Negotiation headers: • Accept-Ranges, Vary • Response security headers: • Proxy-Authenticate, Set-Cookie, Set-Cookie2, WWW-Authenticate, Access-Control-Allow-Origin • Content cache headers: • ETag, Last-Modified, Expires, Cache-Control
- 16. HTTP Message Structure — Body • Content Headers • Content-Type • Content-Type: application/x-www-form-urlencoded • Content-Type: text/html; charset=utf-8 • Content-Length • Content-Encoding • Content-Range • Content-Language
- 17. O U T L I N E • History • HTTP Basics • Extended Topics
- 18. Persistent Connection • Why Keep-Alive • The TCP connection setup handshake • TCP slow-start congestion control • Nagle’s Algorithm and TCP_NODELAY • HTTP 1.0 • Connection: Keep-Alive • HTTP 1.1 • By Default Keep Alive • To Close: Connection: Close
- 19. Caching • Browser Caching • Document Expires? • Cache-Control: max-age=604800 • Expire: Tue, 07 Apr 2015 15:26:18 GMT
- 20. Caching — Revalidation with Server • Date • Tag
- 21. Content-Type — Internet media type • image/audio/video/text/application/multipart • http://en.wikipedia.org/wiki/Internet_media_type • Application • application/x-www-form-urlencoded • Query String => Post Body • application/xml, application/json
- 22. Content-Type — Multipart & MIME • Multipart • multipart/form-data • MIME—Multi-Purpose Internet Mail Extensions
- 23. Range • Response • Content-Length/ Accept-Ranges • Request • Range
- 24. H t t p v e r s i o n s • HTTP V 0.9(1991) • Request-Response, only GET • HTTP V 1.0(1992 draft,1996 release) • Version Code, More Operations, Headers, Mime • HTTP V 1.1(1992 draft,1999 release) • Keep-alive, Proxy • HTTP V 2.0(2014 draft,? release) • Header Compression, Parallel Loading over single connection
- 25. E n d • Thanks!
Editor's Notes
- #6: http://www.xanadu.com/
- #7: http://en.wikipedia.org/wiki/Tim_Berners-Lee http://home.web.cern.ch/topics/birth-web
- #10: http://en.wikipedia.org/wiki/Tim_Berners-Lee
- #11: 引用：http://en.wikipedia.org/wiki/World_Wide_Web
- #13: http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html http://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html 图片来自：《HTTP权威指南》 HTTP: The Definitive Guide
- #14: http://www.w3.org/Protocols/rfc2616/rfc2616.html => rfc 7230-7237 https://tools.ietf.org/html/rfc7237 <scheme>://<user>:<password>@<host>:<port>/<path>;<params>? <query>#<frag> http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
- #15: http://en.wikipedia.org/wiki/List_of_HTTP_header_fields http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
- #16: http://en.wikipedia.org/wiki/List_of_HTTP_header_fields http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
- #17: http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1
- #20: http://www.w3.org/Protocols/rfc2616/rfc2616.html http://tools.ietf.org/html/rfc7234
- #22: http://en.wikipedia.org/wiki/Internet_media_type https://tools.ietf.org/html/rfc7231
- #23: http://en.wikipedia.org/wiki/MIME http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1
- #24: http://tools.ietf.org/html/rfc7233 curl -I http://t1.s2.dpfile.com/pc/mc/40b121f4c768759de07b2320b67e5565(640x1024)/thumb.jpg curl -H”Range:bytes=0-30224" http://t1.s2.dpfile.com/pc/mc/40b121f4c768759de07b2320b67e5565\(640x1024\)/thumb.jpg curl -H”Range:bytes=30225-“ http://t1.s2.dpfile.com/pc/mc/40b121f4c768759de07b2320b67e5565\(640x1024\)/thumb.jpg
- #25: http://www.w3.org/Protocols/HTTP/AsImplemented.html 0.9 http://tools.ietf.org/html/rfc1945 1.0