WebKit FAQ Summary

Some time ago someone asked me a simple question, how does HTML create parsing?　I spoke a great heap of what passed Documentloader, Cachedresourceloader, Cacheresource, Resourceloaderscheduler, Resourcehandle These classes step-by-step through the cache lookup and then request a download and so on.

Gushing, until I debug XML parsing, I found that a lot of problems are inconsistent with understanding, in the analysis of the source code only to understand the general steps. Do you really know the details?

First, HTTP header Web header request

List a few important

Requests part

accept	Specifies the content type that the client can receive	accept:text/plain, text/html
accept-charset	The set of character encodings that the browser can accept.	accept-charset:iso-8859-5
accept-encoding	Specifies the The server returns the content compression encoding type.	accept-encoding:compress, gzip
accept-language	browser acceptable language	accept-language:en,zh
connection	Indicates whether a persistent connection is required. ( http 1.1 persistent connection by default)	connection:close
cookie	http When a request is sent, all the cookie value sent to web server.	cookie: $Version = 1; skin=new;
content-length	content length of the request	content-length:537
content-type	mime information	content-type:application/x-www-form-urlencoded
date	The date and time the request was sent	date:tue, April 15:12:31 GMT
user-agent  	user-agent	user-agent:mozilla /5.0 (Linux; X11)  

Responses Part  

accept-ranges	Indicates whether the server supports the specified range request and what kind of segmentation request	accept-ranges:bytes
age	Estimated time (in seconds, non-negative) from the original server to the proxy cache	age:12
allow	Valid request behavior for a network resource is not allowed to return 405	allow:get, HEAD
cache-control	Tell if all caching mechanisms can be cached and which type of	cache-control: No-cache
content-encoding	web The server supports the return content compression encoding type.	content-encoding: Gzip
content-language	The response body language	content-language: En,zh
content-length	The length of the response body	content-length: 348
content-location	alternate address to request a resource alternative	content-location:/ index.htm
CONTENT-MD5	Returns the md5 checksum value	CONTENT-MD5: q2hly2sgsw50zwdyaxr5iq==
content-range		content-range: Bytes 21010-47021/47022
content-type	mime type	content-type:text /html; Charset=utf-8
date	The original server message was issued at the time	date:tue, Span style= "Font-size:9pt;font-family:verdana;color: #232323;" >  15 Mar 15:12:31   gmt
location	used to redirect the receiver to the non-request url location to complete the request or identify the new resource	location:   http:// Www.oschina.net/u/2335812/admin

User-agent This field user information, indicating that your browser supports the standard, the server will resolve the field to return different requests (a Web page that is compatible with multiple terminals will do compatibility processing) this point in the IPTV to pay special attention to, Many times some front-end Web page is to add some special fields to normal operation is very depressed. More information can be sent inside the HTTP request header

Second, WebKit How to distinguish the creation of html,xml and other analysis

It is determined by the Content-type field in the $ OK returned by the HTTP request , content-type:text/html; Charset=utf-8, describes the text

type HTML, character encoding utf-8.

in DOMImplementation.cpp createdocument () is created to determine whether the type is html,xml,video, etc. this type is the request returned in the OK field content-type resolved.

third, request redirection

Redirect is the URL returned in the location field of the 302 found returned by the HTTP request determines the new address of the jump

Iv. Setting the load cache size

in the loader/cache/memorycache.cpp file , the setcapacities () function can set the cache size to find a balance between the load speed of the resource and the memory usage.

There's a lot more to this, and you can tell us about the problems you're having.

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WebKit FAQ Summary