Http协议内容长度 [英] Http protocol content-length
问题描述
我正在开发一个简单的下载应用程序.在请求以下文件时，firefox和我的应用程序均未获取content-length字段.但是，如果我使用wget服务器发出请求，则不会发送content-length字段.我确实更改了wgets用户代理字符串进行测试，但它仍然具有content-length字段.
I am working on a simple download application. While making a request for the following file both firefox and my application doesn't get the content-length field. But if i make the request using wget server does send the content-length field. I did change wgets user agent string to test and it still got the content-length field.
有任何想法为什么会发生这种情况?
Any ideas why this is happening?
wget请求
---request begin---
GET /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.0
User-Agent: test
Accept: */*
Host: media.defcon.org
Connection: Keep-Alive
---request end---
HTTP request sent, awaiting response...
---response begin---
HTTP/1.0 200 OK
Server: lighttpd
Date: Sun, 05 Apr 2009 04:40:08 GMT
Last-Modified: Tue, 23 May 2006 22:18:19 GMT
Content-Type: video/mp4
Content-Length: 104223909
Connection: keep-alive
firefox请求
GET /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.1
Host: media.defcon.org
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.0.8) Gecko/2009032608 Firefox/3.0.8
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.defcon.org/html/links/defcon-media-archives.html
Pragma: no-cache
Cache-Control: no-cache
HTTP/1.x 200 OK
Server: lighttpd
Date: Sun, 05 Apr 2009 05:20:12 GMT
Last-Modified: Tue, 23 May 2006 22:18:19 GMT
Content-Type: video/mp4
Transfer-Encoding: chunked
更新:
我是否可以发送一个标头，告诉Lighthttpd不要使用分块编码.我的原始问题是我正在使用urlConnection来获取Java应用程序中的文件，该应用程序会自动发送HTTP 1.1请求.
Is there a header that I can send that will tell Lighthttpd not to use chunked encoding.My original problem is that I am using urlConnection to grab the file in my java application which automatically sends HTTP 1.1 request.
我想知道文件的大小，以便我可以更新百分比.
I would like to know the size of the file so i can update my percentage.
推荐答案
获取 /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.1
GET /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.1
Firefox正在执行HTTP 1.1 GET请求. Lighthttpd了解到客户端将支持分块传输编码，并以块的形式返回内容，每个块都报告其自己的长度.
Firefox is performing an HTTP 1.1 GET request. Lighthttpd understands that the client will support chunked-transfer encoding and returns the content in chunks, with each chunk reporting its own length.
获取 /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.0
GET /dc-13/video/2005_Defcon_V2-P_Zimmerman-Unveiling_My_Next_Big_Project.mp4 HTTP/1.0
另一方面，Wget执行HTTP 1.0 GET请求. Lighthttpd了解到客户端不支持HTTP 1.1(因此不支持分块传输编码)，因此将其内容以一个单独的块形式返回，其长度在响应头中报告.
Wget on the other hand performs an HTTP 1.0 GET request. Lighthttpd, understanding that the client doesn't support HTTP 1.1 (and thus chunked-transfer encoding), returns the content in one single chunk, with the length reported in the response header.
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