HTTP Header 详解

爱被打了一巴掌 2021-09-15 08:42 302阅读 0赞

搜集资料

HTTP（HyperTextTransferProtocol）即超文本传输协议，目前网页传输的的通用协议。HTTP协议采用了请求/响应模型，浏览器或其他客户端发出请求，服务器给与响应。就整个网络资源传输而言，包括message-header和message-body两部分。首先传递message- header，即http header消息 。http header 消息通常被分为4个部分：general  header, request header, response header, entity header。但是这种分法就理解而言，感觉界限不太明确。根据维基百科对http header内容的组织形式，大体分为Request和Response两部分。

## Requests部分 ##

<table style="margin:0px auto;padding:0px;background:rgb(255,255,255) none repeat scroll 0px 0px;border:1px solid #C0C0C0;font-size:12px;color:rgb(35,35,35);font-family:verdana, Arial, Helvetica, sans-serif;"> 
 <tbody style="margin:0px;padding:0px;"> 
  <tr style="margin:0px;padding:0px;"> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">Header</th> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">解释</th> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">示例</th> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">指定客户端能够接收的内容类型</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept: text/plain, text/html</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Charset</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">浏览器可以接受的字符编码集。</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Charset: iso-8859-5</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Encoding</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">指定浏览器可以支持的web服务器返回内容压缩编码类型。</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Encoding: compress, gzip</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Language</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">浏览器可接受的语言</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Language: en,zh</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Ranges</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">可以请求网页实体的一个或者多个子范围字段</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Ranges: bytes</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Authorization</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">HTTP授权的授权证书</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cache-Control</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">指定请求和响应遵循的缓存机制</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cache-Control: no-cache</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Connection</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">表示是否需要持久连接。（HTTP 1.1默认进行持久连接）</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Connection: close</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cookie</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">HTTP请求发送时，会把保存在该请求域名下的所有cookie值一起发送给web服务器。</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cookie: $Version=1; Skin=new;</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Length</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求的内容长度</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Length: 348</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Type</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求的与实体对应的MIME信息</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Type: application/x-www-form-urlencoded</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Date</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求发送的日期和时间</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Date: Tue, 15 Nov&nbsp;2010 08:12:31 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Expect</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求的特定的服务器行为</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Expect: 100-continue</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">From</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">发出请求的用户的Email</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">From: user@email.com</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Host</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">指定请求的服务器的域名和端口号</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Host: www.zcmhi.com</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Match</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">只有请求内容与实体相匹配才有效</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Match: “737060cd8c284d8af7ad3082f209582d”</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Modified-Since</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">如果请求的部分在指定时间之后被修改则请求成功，未被修改则返回304代码</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Modified-Since: Sat, 29 Oct 2010 19:43:31 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-None-Match</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">如果内容未改变返回304代码，参数为服务器先前发送的Etag，与服务器回应的Etag比较判断是否改变</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-None-Match: “737060cd8c284d8af7ad3082f209582d”</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Range</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">如果实体未改变，服务器发送客户端丢失的部分，否则发送整个实体。参数也为Etag</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Range: “737060cd8c284d8af7ad3082f209582d”</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Unmodified-Since</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">只在实体在指定时间之后未被修改才请求成功</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">If-Unmodified-Since: Sat, 29 Oct 2010 19:43:31 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Max-Forwards</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">限制信息通过代理和网关传送的时间</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Max-Forwards: 10</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Pragma</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">用来包含实现特定的指令</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Pragma: no-cache</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Proxy-Authorization</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">连接到代理的授权证书</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Range</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">只请求实体的一部分，指定范围</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Range: bytes=500-999</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Referer</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">先前网页的地址，当前请求网页紧随其后,即来路</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Referer: http://www.zcmhi.com/archives/71.html</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">TE</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">客户端愿意接受的传输编码，并通知服务器接受接受尾加头信息</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">TE: trailers,deflate;q=0.5</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Upgrade</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">向服务器指定某种传输协议以便服务器进行转换（如果支持）</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">User-Agent</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">User-Agent的内容包含发出请求的用户信息</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">User-Agent: Mozilla/5.0 (Linux; X11)</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Via</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">通知中间网关或代理服务器地址，通信协议</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1)</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Warning</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">关于消息实体的警告信息</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Warn: 199 Miscellaneous warning</td> 
  </tr> 
 </tbody> 
</table>

## Responses 部分     ##

<table style="margin:0px auto;padding:0px;background:rgb(255,255,255) none repeat scroll 0px 0px;border:1px solid #C0C0C0;font-size:12px;color:rgb(35,35,35);font-family:verdana, Arial, Helvetica, sans-serif;"> 
 <tbody style="margin:0px;padding:0px;"> 
  <tr style="margin:0px;padding:0px;"> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">Header</th> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">解释</th> 
   <th style="margin:0px;padding:3px;background:rgb(237,239,240) none repeat scroll 0px 0px;text-align:center;border-color:#C0C0C0;border-collapse:collapse;">示例</th> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Ranges</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">表明服务器是否支持指定范围请求及哪种类型的分段请求</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Accept-Ranges: bytes</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Age</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">从原始服务器到代理缓存形成的估算时间（以秒计，非负）</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Age: 12</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Allow</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">对某网络资源的有效的请求行为，不允许则返回405</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Allow: GET, HEAD</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cache-Control</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">告诉所有的缓存机制是否可以缓存及哪种类型</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Cache-Control: no-cache</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Encoding</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">web服务器支持的返回内容压缩编码类型。</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Encoding: gzip</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Language</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">响应体的语言</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Language: en,zh</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Length</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">响应体的长度</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Length: 348</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Location</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求资源可替代的备用的另一地址</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Location: /index.htm</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-MD5</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">返回资源的MD5校验值</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Range</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">在整个返回体中本部分的字节位置</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Range: bytes 21010-47021/47022</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Type</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">返回内容的MIME类型</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Content-Type: text/html; charset=utf-8</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Date</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">原始服务器消息发出的时间</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Date: Tue, 15 Nov 2010 08:12:31 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">ETag</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求变量的实体标签的当前值</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">ETag: “737060cd8c284d8af7ad3082f209582d”</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Expires</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">响应过期的日期和时间</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Expires: Thu, 01 Dec 2010 16:00:00 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Last-Modified</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">请求资源的最后修改时间</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Last-Modified: Tue, 15 Nov 2010 12:45:26 GMT</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Location</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">用来重定向接收方到非请求URL的位置来完成请求或标识新的资源</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Location: http://www.zcmhi.com/archives/94.html</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Pragma</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">包括实现特定的指令，它可应用到响应链上的任何接收方</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Pragma: no-cache</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Proxy-Authenticate</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">它指出认证方案和可应用到代理的该URL上的参数</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Proxy-Authenticate: Basic</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">refresh</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">应用于重定向或一个新的资源被创造，在5秒之后重定向（由网景提出，被大部分浏览器支持）</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;"> 
    <div style="margin:0px;padding:0px;line-height:25.2px;"> 
     <span style="margin:0px;padding:0px;font-family:monospace;">&nbsp;</span> 
    </div><p style="margin-top:5px;margin-bottom:5px;font-family:'PingFang SC', 'Helvetica Neue', Helvetica, Arial, sans-serif;color:rgb(35,35,35);"><span style="margin:0px;padding:0px;font-family:monospace;">&nbsp;</span></p> 
    <div style="margin:0px;padding:0px;line-height:25.2px;"> 
     <span style="margin:0px;padding:0px;font-family:Georgia, 'Times New Roman', 'Bitstream Charter', Times, serif;">Refresh: 5; url=</span> 
    </div> 
    <div style="margin:0px;padding:0px;line-height:25.2px;"> 
     <span style="margin:0px;padding:0px;font-family:Georgia, 'Times New Roman', 'Bitstream Charter', Times, serif;">http://www.zcmhi.com/archives/94.html</span> 
    </div></td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Retry-After</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">如果实体暂时不可取，通知客户端在指定时间之后再次尝试</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Retry-After: 120</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Server</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">web服务器软件名称</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Server: Apache/1.3.27 (Unix) (Red-Hat/Linux)</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Set-Cookie</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">设置Http Cookie</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Set-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Trailer</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">指出头域在分块传输编码的尾部存在</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Trailer: Max-Forwards</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Transfer-Encoding</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">文件传输编码</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;"><span style="margin:0px;padding:0px;font-family:monospace;"><span style="margin:0px;padding:0px;font-family:Georgia, 'Times New Roman', 'Bitstream Charter', Times, serif;">Transfer-Encoding:chunked</span></span></td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Vary</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">告诉下游代理是使用缓存响应还是从原始服务器请求</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Vary: *</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Via</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">告知代理客户端响应是通过哪里发送的</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1)</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Warning</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">警告实体可能存在的问题</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">Warning: 199 Miscellaneous warning</td> 
  </tr> 
  <tr style="margin:0px;padding:0px;"> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">WWW-Authenticate</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">表明客户端请求实体应该使用的授权方案</td> 
   <td style="margin:0px;padding:5px;line-height:21.6px;border-color:#C0C0C0;vertical-align:top;border-collapse:collapse;">WWW-Authenticate: Basic</td> 
  </tr> 
 </tbody> 
</table>

更多参见 w3c官网[Header Field Definitions][]

[Header Field Definitions]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html