Common development issues with WebKit browsers

Source: Internet
Author: User
Tags ranges

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


Specify what types of content clients can receive

Accept:text/plain, text/html


The set of character encodings that the browser can accept.



Specifies that the Web server that the browser can support returns the content compression encoding type.

Accept-encoding:compress, gzip


Browser-acceptable language



Indicates whether a persistent connection is required. (HTTP 1.1 defaults to persistent connection)



When an HTTP request is sent, all cookie values stored under that request domain are sent to the Web server.

Cookie: $Version = 1; Skin=new;


The requested content length



The requested MIME information corresponding to the entity



Date and time the request was sent

Date:tue, 15:12:31 GMT


The content of the user-agent contains the user information that made the request

user-agent:mozilla/5.0 (Linux; X11)

Responses part


Indicates whether the server supports the specified range request and what kind of staging request



Estimated time (in seconds, non-negative) from the original server to the proxy cache



A valid request behavior for a network resource is not allowed to return 405

Allow:get, HEAD


Tell if all caching mechanisms can be cached and which type



The type of return content compression encoding supported by the Web server.



The language of the response body



The length of the response body



Alternate alternative address to request resource substitution



Returns the MD5 checksum value of a resource



The byte position of this section in the entire return body

Content-range:bytes 21010-47021/47022


Returns the MIME type of the content

content-type:text/html; Charset=utf-8


Time the original server message was issued

Date:tue, 15:12:31 GMT


Used to redirect the receiver to the location of the non-request URL to complete the request or identify the new resource


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 suitable for multi-terminal will be compatible processing) this point in the IPTV to pay special attention, 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, explains 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.

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WebKit Browser Common development issues

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