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DESCRIPTION
1. Brief introduction about HTTP request life cycle 2. Main workflow 3. Some basic and classic solutions
Citation preview
Type URL, Enter, and Then …
By Jinglun Li
Goal
• Brief introduction about HTTP request life cycle
• Main workflow• Some basic and classic solutions
Agenda
• A Brief Glance• HTTP• Browser• Sever
Topic
• Type URL in browser. Enter. Then what happens in your browser?
A brief glance
1. DNS2. Send Request3. Get Response4. Render Page
Domain Name System (DNS)
Send Request• GET http://facebook.com/ HTTP/1.1
Accept: application/x-ms-application, image/jpeg, application/xaml+xml, [...]User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; [...]Accept-Encoding: gzip, deflateConnection: Keep-AliveHost: facebook.comCookie: datr=1265876274-[...]; locale=en_US; lsd=WW[...]; c_user=2101[...]
Get Response• HTTP/1.1 200 OK
Cache-Control: private, no-store, no-cache, must-revalidate, post-check=0,pre-check=0Expires: Sat, 01 Jan 2000 00:00:00 GMTP3P: CP="DSP LAW"Pragma: no-cacheContent-Encoding: gzipContent-Type: text/html; charset=utf-8X-Cnection: closeTransfer-Encoding: chunkedDate: Fri, 12 Feb 2010 09:05:55 GMT
Render• Image
http://static.ak.fbcdn.net/rsrc.php/z12E0/hash/8q2anwu7.gifhttp://static.ak.fbcdn.net/rsrc.php/zBS5C/hash/7hwy7at6.gif…
• CSShttp://static.ak.fbcdn.net/rsrc.php/z448Z/hash/2plh8s4n.csshttp://static.ak.fbcdn.net/rsrc.php/zANE1/hash/cvtutcee.css…
• JavaScripthttp://static.ak.fbcdn.net/rsrc.php/zEMOA/hash/c8yzb6ub.jshttp://static.ak.fbcdn.net/rsrc.php/z6R9L/hash/cq2lgbs8.js…
A brief glance
1. DNS2. Send Request3. Get Response4. Render Page
Hypertext Transfer Protocol (HTTP)
The Hypertext Transfer Protocol (HTTP) is a networking protocol for distributed, collaborative, hypermedia information systems.[1] HTTP is the foundation of data communication for the World Wide Web.
HTTP Request & Response// Example of http://www.somehost.com/path/file.html// Request:string request_header = “”;request_header += “GET /path/file.html HTTP/1.0\r\n”;request_header += “Accept: application/x-ms-application, image/jpeg, [...]\r\n”; request_header += “Host: somehost.com\r\n\r\n”; // End of HTTP Headersend(socket_conn, request_header.c_str(), requestion.size(), 0);
// Response:string reply = “”;reply += "HTTP/1.1 200 OK\r\n“; // Status-Linereply +=" Content-Encoding : gzip \r\n“;
…reply += "Connection: close\r\n\r\n“; // End of HTTP Response Headerreply += “<html> … </html>\r\n"; // HTTP Response Bodysend(socket_conn, reply.c_str(), reply.size(), 0);
Hypertext Transfer Protocol (HTTP)
• Application Layer• Request/Response• Stateless• Full Duplex• Cache• …
How does a browser work?
Browser's main subjects
• http://jsfiddle.net/lijinglun/px2hF/6/
Behavior
Presentation
Content
Browser's High Level Structure
Rendering Engines
Render Tree Relation to DOM Tree
Webkit Main Flow
Mozilla's Gecko Main Flow
Render Tree Relation to DOM Tree
HTTP Servers
Server Modes
• Single Process• Fork• Prefork
IO Model
Common Gateway Interface (CGI)
FastCGI
PHP
MVC with PHP
HTTP Servers
Thanks!
Back up
HTTP
HTTP• Request message
– Request line, such as GET /images/logo.png HTTP/1.1, which requests a resource called /images/logo.png from server
– Headers, such as Accept-Language: en– An empty line– An optional message body
• Request methods– HEAD– GET– POST– PUT– DELETE– TRACE– OPTIONS– CONNECT
• Status codes• Cache• …
Cgi, Fastcgi, mod_php
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