<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">HTTP </span><span style="font-family:"">头部解释</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">1. Accept</span><span style="font-family:"">:告诉</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器自己接受什么介质类型,</span><span style="font-family:"">*/* </span><span style="font-family:"">表示任何类型,</span><span style="font-family:"">type/* </span><span style="font-family:"">表示该类型下的所有子类型,</span><span style="font-family:"">type/sub-type</span><span style="font-family:"">。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">2. Accept-Charset</span><span style="font-family:"">:</span><span style="font-family:""> </span><span style="font-family:"">浏览器申明自己接收的字符集</span><br />
<span style="font-family:Microsoft YaHei;"> Accept-Encoding</span><span style="font-family:"">:</span><span style="font-family:""> </span><span style="font-family:"">浏览器申明自己接收的编码方法,通常指定压缩方法,是否支持压缩,支持什么压缩方法</span><span style="font-family:""> </span><span style="font-family:"">(</span><span style="font-family:"">gzip</span><span style="font-family:"">,</span><span style="font-family:"">deflate</span><span style="font-family:"">)</span>
<span style="font-family:Microsoft YaHei;"> Accept-Language</span><span style="font-family:"">::浏览器申明自己接收的语言语言跟字符集的区别:中文是语言,中文有多种字符集,比如</span><span style="font-family:"">big5</span><span style="font-family:"">,</span><span style="font-family:"">gb2312</span><span style="font-family:"">,</span><span style="font-family:"">gbk</span><span style="font-family:"">等等。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">3. Accept-Ranges</span><span style="font-family:"">:</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器表明自己是否接受获取其某个实体的一部分(比如文件的一部分)的请求。</span><span style="font-family:"">bytes</span><span style="font-family:"">:表示接受,</span><span style="font-family:"">none</span><span style="font-family:"">:表示不接受。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">4. Age</span><span style="font-family:"">:当代理服务器用自己缓存的实体去响应请求时,用该头部表明该实体从产生到现在经过多长时间了。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">5. Authorization</span><span style="font-family:"">:当客户端接收到来自</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器的 </span><span style="font-family:"">WWW-Authenticate </span><span style="font-family:"">响应时,该头部来回应自己的身份验证信息给</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">6. Cache-Control</span><span style="font-family:"">:请求:</span><span style="font-family:"">no-cache</span><span style="font-family:"">(不要缓存的实体,要求现在从</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器去取)</span><br />
<span style="font-family:Microsoft YaHei;"> max-age</span><span style="font-family:"">:(只接受 </span><span style="font-family:"">Age </span><span style="font-family:"">值小于 </span><span style="font-family:"">max-age </span><span style="font-family:"">值,并且没有过期的对象)</span>
<span style="font-family:Microsoft YaHei;"> max-stale</span><span style="font-family:"">:(可以接受过去的对象,但是过期时间必须小于 </span>
<span style="font-family:Microsoft YaHei;"> max-stale </span><span style="font-family:"">值)</span>
<span style="font-family:Microsoft YaHei;"> min-fresh</span><span style="font-family:"">:(接受其新鲜生命期大于其当前 </span><span style="font-family:"">Age </span><span style="font-family:"">跟 </span><span style="font-family:"">min-fresh </span><span style="font-family:"">值之和的</span>
<span style="font-family:"">缓存对象)</span>
<span style="font-family:"">响应:</span><span style="font-family:"">public(</span><span style="font-family:"">可以用 </span><span style="font-family:"">Cached </span><span style="font-family:"">内容回应任何用户</span><span style="font-family:"">)</span>
<span style="font-family:Microsoft YaHei;"> private</span><span style="font-family:"">(只能用缓存内容回应先前请求该内容的那个用户)</span>
<span style="font-family:Microsoft YaHei;"> no-cache</span><span style="font-family:"">(可以缓存,但是只有在跟</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器验证了其有效后,才能返回给客户端)</span>
<span style="font-family:Microsoft YaHei;"> max-age</span><span style="font-family:"">:(本响应包含的对象的过期时间)</span>
<span style="font-family:Microsoft YaHei;"> ALL: no-store</span><span style="font-family:"">(不允许缓存)</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">7. Connection</span><span style="font-family:"">:请求:</span><span style="font-family:"">close</span><span style="font-family:"">(告诉</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器或者代理服务器,在完成本次请求的响应</span><br />
<span style="font-family:"">后,断开连接,不要等待本次连接的后续请求了)。</span>
<span style="font-family:Microsoft YaHei;"> keepalive</span><span style="font-family:"">(告诉</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器或者代理服务器,在完成本次请求的</span>
<span style="font-family:"">响应后,保持连接,等待本次连接的后续请求)。</span>
<span style="font-family:"">响应:</span><span style="font-family:"">close</span><span style="font-family:"">(连接已经关闭)。</span>
<span style="font-family:Microsoft YaHei;"> keepalive</span><span style="font-family:"">(连接保持着,在等待本次连接的后续请求)。</span>
<span style="font-family:Microsoft YaHei;"> Keep-Alive</span><span style="font-family:"">:如果浏览器请求保持连接,则该头部表明希望 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器保持</span>
<span style="font-family:"">连接多长时间(秒)。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Keep-Alive</span><span style="font-family:"">:</span><span style="font-family:"">300</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">8. Content-Encoding</span><span style="font-family:"">:</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器表明自己使用了什么压缩方法(</span><span style="font-family:"">gzip</span><span style="font-family:"">,</span><span style="font-family:"">deflate</span><span style="font-family:"">)压缩响应中的对象。</span><span style="font-family:""> </span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Content-Encoding</span><span style="font-family:"">:</span><span style="font-family:"">gzip </span>
<span style="font-family:Microsoft YaHei;"> Content-Language</span><span style="font-family:"">:</span><span style="font-family:"">WEB </span><span style="font-family:"">服务器告诉浏览器自己响应的对象的语言。</span>
<span style="font-family:Microsoft YaHei;"> Content-Length</span><span style="font-family:"">:</span><span style="font-family:""> WEB </span><span style="font-family:"">服务器告诉浏览器自己响应的对象的长度。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Content-Length: 26012</span>
<span style="font-family:Microsoft YaHei;"> Content-Range</span><span style="font-family:"">:</span><span style="font-family:""> WEB </span><span style="font-family:"">服务器表明该响应包含的部分对象为整个对象的哪个部分。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Content-Range: bytes 21010-47021/47022</span>
<span style="font-family:Microsoft YaHei;"> Content-Type</span><span style="font-family:"">:</span><span style="font-family:""> WEB </span><span style="font-family:"">服务器告诉浏览器自己响应的对象的类型。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Content-Type</span><span style="font-family:"">:</span><span style="font-family:"">application/xml</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">9. ETag</span><span style="font-family:"">:就是一个对象(比如</span><span style="font-family:"">URL</span><span style="font-family:"">)的标志值,就一个对象而言,比如一个 </span><span style="font-family:"">html </span><span style="font-family:"">文件,</span><br />
<span style="font-family:"">如果被修改了,其 </span><span style="font-family:"">Etag </span><span style="font-family:"">也会别修改, 所以,</span><span style="font-family:"">ETag </span><span style="font-family:"">的作用跟 </span><span style="font-family:"">Last-Modified </span><span style="font-family:"">的</span>
<span style="font-family:"">作用差不多,主要供 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器 判断一个对象是否改变了。</span>
<span style="font-family:"">比如前一次请求某个 </span><span style="font-family:"">html </span><span style="font-family:"">文件时,获得了其 </span><span style="font-family:"">ETag</span><span style="font-family:"">,当这次又请求这个文件时,</span><span style="font-family:""> </span>
<span style="font-family:"">浏览器就会把先前获得的 </span><span style="font-family:"">ETag </span><span style="font-family:"">值发送给</span><span style="font-family:""> WEB </span><span style="font-family:"">服务器,然后 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器</span>
<span style="font-family:"">会把这个 </span><span style="font-family:"">ETag </span><span style="font-family:"">跟该文件的当前 </span><span style="font-family:"">ETag </span><span style="font-family:"">进行对比,然后就知道这个文件</span>
<span style="font-family:"">有没有改变了。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">10. Expired</span><span style="font-family:"">:</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器表明该实体将在什么时候过期,对于过期了的对象,只有在</span><br />
<span style="font-family:"">跟</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器验证了其有效性后,才能用来响应客户请求。</span>
<span style="font-family:"">是 </span><span style="font-family:"">HTTP/1.0 </span><span style="font-family:"">的头部。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Expires</span><span style="font-family:"">:</span><span style="font-family:"">Sat, 23 May 2009 10:02:12 GMT</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">11. Host</span><span style="font-family:"">:客户端指定自己想访问的</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器的域名</span><span style="font-family:"">/IP </span><span style="font-family:"">地址和端口号。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Host</span><span style="font-family:"">:</span><span style="font-family:"">rss.sina.com.cn</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">12. If-Match</span><span style="font-family:"">:如果对象的 </span><span style="font-family:"">ETag </span><span style="font-family:"">没有改变,其实也就意味著对象没有改变,才执行请求的动作。</span><br />
<span style="font-family:Microsoft YaHei;"> If-None-Match</span><span style="font-family:"">:如果对象的 </span><span style="font-family:"">ETag </span><span style="font-family:"">改变了,其实也就意味著对象也改变了,才执行请求的动作。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">13. If-Modified-Since</span><span style="font-family:"">:如果请求的对象在该头部指定的时间之后修改了,才执行请求</span><br />
<span style="font-family:"">的动作(比如返回对象),否则返回代码</span><span style="font-family:"">304</span><span style="font-family:"">,告诉浏览器该对象</span>
<span style="font-family:"">没有修改。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">If-Modified-Since</span><span style="font-family:"">:</span><span style="font-family:"">Thu, 10 Apr 2008 09:14:42 GMT</span>
<span style="font-family:Microsoft YaHei;"> If-Unmodified-Since</span><span style="font-family:"">:如果请求的对象在该头部指定的时间之后没修改过,才执行</span>
<span style="font-family:"">请求的动作(比如返回对象)。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">14. If-Range</span><span style="font-family:"">:浏览器告诉 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器,如果我请求的对象没有改变,就把我缺少的部分</span><br />
<span style="font-family:"">给我,如果对象改变了,就把整个对象给我。 浏览器通过发送请求对象的 </span>
<span style="font-family:Microsoft YaHei;"> ETag </span><span style="font-family:"">或者 自己所知道的最后修改时间给 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器,让其判断对象是否</span>
<span style="font-family:"">改变了。</span>
<span style="font-family:"">总是跟 </span><span style="font-family:"">Range </span><span style="font-family:"">头部一起使用。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">15. Last-Modified</span><span style="font-family:"">:</span><span style="font-family:"">WEB </span><span style="font-family:"">服务器认为对象的最后修改时间,比如文件的最后修改时间,</span><br />
<span style="font-family:"">动态页面的最后产生时间等等。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Last-Modified</span><span style="font-family:"">:</span><span style="font-family:"">Tue, 06 May 2008 02:42:43 GMT</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">16. Location</span><span style="font-family:"">:</span><span style="font-family:"">WEB </span><span style="font-family:"">服务器告诉浏览器,试图访问的对象已经被移到别的位置了,</span><br />
<span style="font-family:"">到该头部指定的位置去取。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Location</span><span style="font-family:"">:</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">http://i0.sinaimg.cn/dy/deco/2008/0528/sinahome_0803_ws_005_text_0.gif</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">17. Pramga</span><span style="font-family:"">:主要使用 </span><span style="font-family:"">Pramga: no-cache</span><span style="font-family:"">,相当于 </span><span style="font-family:"">Cache-Control</span><span style="font-family:"">: </span><span style="font-family:"">no-cache</span><span style="font-family:"">。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Pragma</span><span style="font-family:"">:</span><span style="font-family:"">no-cache</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">18. Proxy-Authenticate</span><span style="font-family:"">: 代理服务器响应浏览器,要求其提供代理身份验证信息。</span><br />
<span style="font-family:Microsoft YaHei;"> Proxy-Authorization</span><span style="font-family:"">:浏览器响应代理服务器的身份验证请求,提供自己的身份信息。</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">19. Range</span><span style="font-family:"">:浏览器(比如 </span><span style="font-family:"">Flashget </span><span style="font-family:"">多线程下载时)告诉 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器自己想取对象的哪部分。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Range: bytes=1173546-</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">20. Referer</span><span style="font-family:"">:浏览器向 </span><span style="font-family:"">WEB </span><span style="font-family:"">服务器表明自己是从哪个 网页</span><span style="font-family:"">/URL </span><span style="font-family:"">获得</span><span style="font-family:"">/</span><span style="font-family:"">点击 当前请求中的网址</span><span style="font-family:"">/URL</span><span style="font-family:"">。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Referer</span><span style="font-family:"">:</span><span style="font-family:"">http://www.sina.com/</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">21. Server: WEB </span><span style="font-family:"">服务器表明自己是什么软件及版本等信息。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">Server</span><span style="font-family:"">:</span><span style="font-family:"">Apache/2.0.61 (Unix)</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">22. User-Agent: </span><span style="font-family:"">浏览器表明自己的身份(是哪种浏览器)。</span><br />
<span style="font-family:"">例如:</span><span style="font-family:"">User-Agent</span><span style="font-family:"">:</span><span style="font-family:"">Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; </span>
<span style="font-family:Microsoft YaHei;"> rv:1.8.1.14) Gecko/20080404 Firefox/2.0.0.14</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">23. Transfer-Encoding: WEB </span><span style="font-family:"">服务器表明自己对本响应消息体(不是消息体里面的对象)</span><br />
<span style="font-family:"">作了怎样的编码,比如是否分块(</span><span style="font-family:"">chunked</span><span style="font-family:"">)。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Transfer-Encoding: chunked</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">24. Vary: WEB</span><span style="font-family:"">服务器用该头部的内容告诉 </span><span style="font-family:"">Cache </span><span style="font-family:"">服务器,在什么条件下才能用本响应</span><br />
<span style="font-family:"">所返回的对象响应后续的请求。</span>
<span style="font-family:"">假如源</span><span style="font-family:"">WEB</span><span style="font-family:"">服务器在接到第一个请求消息时,其响应消息的头部为:</span>
<span style="font-family:Microsoft YaHei;"> Content-Encoding: gzip; Vary: Content-Encoding </span><span style="font-family:"">那么 </span><span style="font-family:"">Cache </span><span style="font-family:"">服务器会分析后续</span>
<span style="font-family:"">请求消息的头部,检查其 </span><span style="font-family:"">Accept-Encoding</span><span style="font-family:"">,是否跟先前响应的 </span><span style="font-family:"">Vary </span><span style="font-family:"">头部值</span>
<span style="font-family:"">一致,即是否使用相同的内容编码方法,这样就可以防止 </span><span style="font-family:"">Cache </span><span style="font-family:"">服务器用自己</span>
<span style="font-family:Microsoft YaHei;"> Cache </span><span style="font-family:"">里面压缩后的实体响应给不具备解压能力的浏览器。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Vary</span><span style="font-family:"">:</span><span style="font-family:"">Accept-Encoding</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">25. Via</span><span style="font-family:"">: 列出从客户端到 </span><span style="font-family:"">OCS </span><span style="font-family:"">或者相反方向的响应经过了哪些代理服务器,他们用</span><br />
<span style="font-family:"">什么协议(和版本)发送的请求。</span>
<span style="font-family:"">当客户端请求到达第一个代理服务器时,该服务器会在自己发出的请求里面</span>
<span style="font-family:"">添加 </span><span style="font-family:"">Via </span><span style="font-family:"">头部,并填上自己的相关信息,当下一个代理服务器 收到第一个代理</span>
<span style="font-family:"">服务器的请求时,会在自己发出的请求里面复制前一个代理服务器的请求的</span><span style="font-family:"">Via </span>
<span style="font-family:"">头部,并把自己的相关信息加到后面, 以此类推,当 </span><span style="font-family:"">OCS </span><span style="font-family:"">收到最后一个代理服</span>
<span style="font-family:"">务器的请求时,检查 </span><span style="font-family:"">Via </span><span style="font-family:"">头部,就知道该请求所经过的路由。</span>
<span style="font-family:"">例如:</span><span style="font-family:"">Via</span><span style="font-family:"">:</span><span style="font-family:"">1.0 236-81.D07071953.sina.com.cn:80 (squid/2.6.STABLE13)</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">====================================</span><br />
<span style="font-family:Microsoft YaHei;"> HTTP </span><span style="font-family:"">请求消息头部实例:</span>
<span style="font-family:Microsoft YaHei;"> Host</span><span style="font-family:"">:</span><span style="font-family:"">rss.sina.com.cn</span>
<span style="font-family:Microsoft YaHei;"> User-Agent</span><span style="font-family:"">:</span><span style="font-family:"">Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.8.1.14) Gecko/20080404 Firefox/2.0.0.14</span>
<span style="font-family:Microsoft YaHei;"> Accept</span><span style="font-family:"">:</span><span style="font-family:"">text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,/;q=0.5</span>
<span style="font-family:Microsoft YaHei;"> Accept-Language</span><span style="font-family:"">:</span><span style="font-family:"">zh-cn,zh;q=0.5</span>
<span style="font-family:Microsoft YaHei;"> Accept-Encoding</span><span style="font-family:"">:</span><span style="font-family:"">gzip,deflate</span>
<span style="font-family:Microsoft YaHei;"> Accept-Charset</span><span style="font-family:"">:</span><span style="font-family:"">gb2312,utf-8;q=0.7,*;q=0.7</span>
<span style="font-family:Microsoft YaHei;"> Keep-Alive</span><span style="font-family:"">:</span><span style="font-family:"">300</span>
<span style="font-family:Microsoft YaHei;"> Connection</span><span style="font-family:"">:</span><span style="font-family:"">keep-alive</span>
<span style="font-family:Microsoft YaHei;"> Cookie</span><span style="font-family:"">:</span><span style="font-family:"">userId=C5bYpXrimdmsiQmsBPnE1Vn8ZQmdWSm3WRlEB3vRwTnRtW <– Cookie </span>
<span style="font-family:Microsoft YaHei;"> If-Modified-Since</span><span style="font-family:"">:</span><span style="font-family:"">Sun, 01 Jun 2008 12:05:30 GMT</span>
<span style="font-family:Microsoft YaHei;"> Cache-Control</span><span style="font-family:"">:</span><span style="font-family:"">max-age=0</span>
<span style="font-family:Microsoft YaHei;"> HTTP </span><span style="font-family:"">响应消息头部实例:</span>
<span style="font-family:Microsoft YaHei;"> Status</span><span style="font-family:"">:</span><span style="font-family:"">OK - 200 <– </span><span style="font-family:"">响应状态码,表示 </span><span style="font-family:"">web </span><span style="font-family:"">服务器处理的结果。 </span>
<span style="font-family:Microsoft YaHei;"> Date</span><span style="font-family:"">:</span><span style="font-family:"">Sun, 01 Jun 2008 12:35:47 GMT</span>
<span style="font-family:Microsoft YaHei;"> Server</span><span style="font-family:"">:</span><span style="font-family:"">Apache/2.0.61 (Unix)</span>
<span style="font-family:Microsoft YaHei;"> Last-Modified</span><span style="font-family:"">:</span><span style="font-family:"">Sun, 01 Jun 2008 12:35:30 GMT</span>
<span style="font-family:Microsoft YaHei;"> Accept-Ranges</span><span style="font-family:"">:</span><span style="font-family:"">bytes</span>
<span style="font-family:Microsoft YaHei;"> Content-Length</span><span style="font-family:"">:</span><span style="font-family:"">18616</span>
<span style="font-family:Microsoft YaHei;"> Cache-Control</span><span style="font-family:"">:</span><span style="font-family:"">max-age=120</span>
<span style="font-family:Microsoft YaHei;"> Expires</span><span style="font-family:"">:</span><span style="font-family:"">Sun, 01 Jun 2008 12:37:47 GMT</span>
<span style="font-family:Microsoft YaHei;"> Content-Type</span><span style="font-family:"">:</span><span style="font-family:"">application/xml</span>
<span style="font-family:Microsoft YaHei;"> Age</span><span style="font-family:"">:</span><span style="font-family:"">2</span>
<span style="font-family:Microsoft YaHei;"> X-Cache</span><span style="font-family:"">:</span><span style="font-family:"">HIT from 236-41.D07071951.sina.com.cn <– </span><span style="font-family:"">反向代理服务器使用的 </span><span style="font-family:"">HTTP </span><span style="font-family:"">头部</span>
<span style="font-family:Microsoft YaHei;"> Via</span><span style="font-family:"">:</span><span style="font-family:"">1.0 236-41.D07071951.sina.com.cn:80 (squid/2.6.STABLE13)</span>
<span style="font-family:Microsoft YaHei;"> Connection</span><span style="font-family:"">:</span><span style="font-family:"">close</span>
<span style="font-family:Microsoft YaHei;"> =====================================</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">HTTP</span><span style="font-family:"">头部信息简单说明</span><br />
<span style="font-family:Microsoft YaHei;"> 2008-02-28 03:13</span>
<span style="font-family:Microsoft YaHei;"> 一、</span><span style="font-family:"">HTTP</span><span style="font-family:"">响应码响应码由三位十进制数字组成,它们出现在由</span><span style="font-family:"">HTTP</span><span style="font-family:"">服务器发送的响应的第一行。</span>
<span style="font-family:Microsoft YaHei;"> 响应码分五种类型,由它们的第一位数字表示:</span>
<span style="font-family:Microsoft YaHei;"> 1xx</span><span style="font-family:"">:信息,请求收到,继续处理</span>
<span style="font-family:Microsoft YaHei;"> 2xx</span><span style="font-family:"">:成功,行为被成功地接受、理解和采纳</span>
<span style="font-family:Microsoft YaHei;"> 3xx</span><span style="font-family:"">:重定向,为了完成请求,必须进一步执行的动作</span>
<span style="font-family:Microsoft YaHei;"> 4xx</span><span style="font-family:"">:客户端错误,请求包含语法错误或者请求无法实现</span>
<span style="font-family:Microsoft YaHei;"> 5xx</span><span style="font-family:"">:服务器错误,服务器不能实现一种明显无效的请求</span>
<span style="font-family:Microsoft YaHei;"> 下表显示每个响应码及其含义:</span>
<span style="font-family:Microsoft YaHei;"> 100 </span><span style="font-family:"">继续</span><span style="font-family:"">101 </span><span style="font-family:"">分组交换协</span><span style="font-family:"">200 OK201 </span><span style="font-family:"">被创建</span><span style="font-family:"">202 </span><span style="font-family:"">被采纳</span><span style="font-family:"">203 </span><span style="font-family:"">非授权信息</span><span style="font-family:"">204 </span><span style="font-family:"">无内容</span><span style="font-family:"">205 </span><span style="font-family:"">重置内容</span><span style="font-family:"">206 </span><span style="font-family:"">部分内容</span><span style="font-family:"">300 </span><span style="font-family:"">多选项</span><span style="font-family:"">301 </span><span style="font-family:"">永久地传送</span><span style="font-family:"">302 </span><span style="font-family:"">找到</span><span style="font-family:"">303 </span><span style="font-family:"">参见其他</span><span style="font-family:"">304 </span><span style="font-family:"">未改动</span><span style="font-family:"">305 </span><span style="font-family:"">使用代理</span><span style="font-family:"">307 </span><span style="font-family:"">暂时重定向</span><span style="font-family:"">400 </span><span style="font-family:"">错误请求</span><span style="font-family:"">401 </span><span style="font-family:"">未授权</span><span style="font-family:"">402 </span><span style="font-family:"">要求付费</span><span style="font-family:"">403 </span><span style="font-family:"">禁止</span><span style="font-family:"">404 </span><span style="font-family:"">未找到</span><span style="font-family:"">405 </span><span style="font-family:"">不允许的方法</span><span style="font-family:"">406 </span><span style="font-family:"">不被采纳</span><span style="font-family:"">407 </span><span style="font-family:"">要求代理授权</span><span style="font-family:"">408 </span><span style="font-family:"">请求超时</span><span style="font-family:"">409 </span><span style="font-family:"">冲突</span><span style="font-family:"">410 </span><span style="font-family:"">过期的</span><span style="font-family:"">411 </span><span style="font-family:"">要求的长度</span><span style="font-family:"">412 </span><span style="font-family:"">前提不成立</span><span style="font-family:"">413 </span><span style="font-family:"">请求实例太大</span><span style="font-family:"">414 </span><span style="font-family:"">请求</span><span style="font-family:"">URI</span><span style="font-family:"">太大</span><span style="font-family:"">415 </span><span style="font-family:"">不支持的媒体类型</span><span style="font-family:"">416 </span><span style="font-family:"">无法满足的请求范围</span><span style="font-family:"">417 </span><span style="font-family:"">失败的预期</span><span style="font-family:"">500 </span><span style="font-family:"">内部服务器错误</span><span style="font-family:"">501 </span><span style="font-family:"">未被使用</span><span style="font-family:"">502 </span><span style="font-family:"">网关错误</span><span style="font-family:"">503 </span><span style="font-family:"">不可用的服务</span><span style="font-family:"">504 </span><span style="font-family:"">网关超时</span><span style="font-family:"">505 HTTP</span><span style="font-family:"">版本未被支持</span>
<span style="font-family:Microsoft YaHei;"> 二、</span><span style="font-family:"">HTTP</span><span style="font-family:"">头标头标由主键</span><span style="font-family:"">/</span><span style="font-family:"">值对组成。它们描述客户端或者服务器的属性、被传输的资源以及应该实现连接。</span>
<span style="font-family:Microsoft YaHei;"> 四种不同类型的头标:</span>
<span style="font-family:Microsoft YaHei;"> 1.</span><span style="font-family:"">通用头标:即可用于请求,也可用于响应,是作为一个整体而不是特定资源与事务相关联。</span>
<span style="font-family:Microsoft YaHei;"> 2.</span><span style="font-family:"">请求头标:允许客户端传递关于自身的信息和希望的响应形式。</span>
<span style="font-family:Microsoft YaHei;"> 3.</span><span style="font-family:"">响应头标:服务器和于传递自身信息的响应。</span>
<span style="font-family:Microsoft YaHei;"> 4.</span><span style="font-family:"">实体头标:定义被传送资源的信息。即可用于请求,也可用于响应。</span>
<span style="font-family:Microsoft YaHei;"> 头标格式:</span><span style="font-family:""><name>:<value><CRLF></span>
<span style="font-family:Microsoft YaHei;"> 下表描述在</span><span style="font-family:"">HTTP/1.1</span><span style="font-family:"">中用到的头标</span>
<span style="font-family:Microsoft YaHei;"> Accept </span><span style="font-family:"">定义客户端可以处理的媒体类型,按优先级排序;在一个以逗号为分隔的列表中,可以定义多种类型和使用通配符。例如:</span><span style="font-family:"">Accept: image/jpeg,image/png,/Accept-Charset </span><span style="font-family:"">定义客户端可以处理的字符集,按优先级排序;在一个以逗号为分隔的列表中,可以定义多种类型和使用通配符。例如:</span><span style="font-family:"">Accept-Charset: iso-8859-1,*,utf-8</span>
<span style="font-family:Microsoft YaHei;"> Accept-Encoding </span><span style="font-family:"">定义客户端可以理解的编码机制。例如:</span><span style="font-family:"">Accept-Encoding:gzip,compress</span>
<span style="font-family:Microsoft YaHei;"> Accept-Language </span><span style="font-family:"">定义客户端乐于接受的自然语言列表。例如:</span><span style="font-family:"">Accept-Language: en,de</span>
<span style="font-family:Microsoft YaHei;"> Accept-Ranges </span><span style="font-family:"">一个响应头标,它允许服务器指明:将在给定的偏移和长度处,为资源组成部分的接受请求。该头标的值被理解为请求范围的度量单位。例如</span><span style="font-family:"">Accept-Ranges: bytes</span><span style="font-family:"">或</span><span style="font-family:"">Accept-Ranges: none</span>
<span style="font-family:Microsoft YaHei;"> Age </span><span style="font-family:"">允许服务器规定自服务器生成该响应以来所经过的时间长度,以秒为单位。该头标主要用于缓存响应。例如:</span><span style="font-family:"">Age: 30</span>
<span style="font-family:Microsoft YaHei;"> Allow </span><span style="font-family:"">一个响应头标,它定义一个由位于请求</span><span style="font-family:"">URI</span><span style="font-family:"">中的次源所支持的</span><span style="font-family:"">HTTP</span><span style="font-family:"">方法列表。例如:</span><span style="font-family:"">Allow: GET,PUT</span>
<span style="font-family:Microsoft YaHei;"> aUTHORIZATION </span><span style="font-family:"">一个响应头标,用于定义访问一种资源所必需的授权(域和被编码的用户</span><span style="font-family:"">ID</span><span style="font-family:"">与口令)。例如:</span><span style="font-family:"">Authorization: Basic YXV0aG9yOnBoaWw=</span>
<span style="font-family:Microsoft YaHei;"> Cache-Control </span><span style="font-family:"">一个用于定义缓存指令的通用头标。例如:</span><span style="font-family:"">Cache-Control: max-age=30</span>
<span style="font-family:Microsoft YaHei;"> Connection </span><span style="font-family:"">一个用于表明是否保存</span><span style="font-family:"">socket</span><span style="font-family:"">连接为开放的通用头标。例如:</span><span style="font-family:"">Connection: close</span><span style="font-family:"">或</span><span style="font-family:"">Connection: keep-alive</span>
<span style="font-family:Microsoft YaHei;"> Content-Base </span><span style="font-family:"">一种定义基本</span><span style="font-family:"">URI</span><span style="font-family:"">的实体头标,为了在实体范围内解析相对</span><span style="font-family:"">URLs</span><span style="font-family:"">。如果没有定义</span><span style="font-family:"">Content-Base</span><span style="font-family:"">头标解析相对</span><span style="font-family:"">URLs</span><span style="font-family:"">,使用</span><span style="font-family:"">Content- Location URI</span><span style="font-family:"">(存在且绝对)或使用</span><span style="font-family:"">URI</span><span style="font-family:"">请求。例如:</span><span style="font-family:"">Content-Base: </span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">http://www.myweb.com</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<span style="font-family:Microsoft YaHei;">Content-Encoding </span><span style="font-family:"">一种介质类型修饰符,标明一个实体是如何编码的。例如:</span><span style="font-family:"">Content-Encoding: zipContent-Language </span><span style="font-family:"">用于指定在输入流中数据的自然语言类型。例如:</span><span style="font-family:"">Content-Language: en</span><br />
<span style="font-family:Microsoft YaHei;"> Content-Length </span><span style="font-family:"">指定包含于请求或响应中数据的字节长度。例如:</span><span style="font-family:"">Content-Length:382</span>
<span style="font-family:Microsoft YaHei;"> Content-Location </span><span style="font-family:"">指定包含于请求或响应中的资源定位(</span><span style="font-family:"">URI</span><span style="font-family:"">)。如果是一绝。对</span><span style="font-family:"">URL</span><span style="font-family:"">它也作为被解析实体的相对</span><span style="font-family:"">URL</span><span style="font-family:"">的出发点。例如:</span><span style="font-family:"">Content-Location: http://www.myweb.com/news</span>
<span style="font-family:Microsoft YaHei;"> Content-MD5 </span><span style="font-family:"">实体的一种</span><span style="font-family:"">MD5</span><span style="font-family:"">摘要,用作校验和。发送方和接受方都计算</span><span style="font-family:"">MD5</span><span style="font-family:"">摘要,接受方将其计算的值与此头标中传递的值进行比较。例如:</span><span style="font-family:"">Content-MD5: <base64 of 128 MD5 digest></span>
<span style="font-family:Microsoft YaHei;"> Content-Range </span><span style="font-family:"">随部分实体一同发送;标明被插入字节的低位与高位字节偏移,也标明此实体的总长度。例如:</span><span style="font-family:"">Content-Range: 1001-2000/5000</span>
<span style="font-family:Microsoft YaHei;"> Contern-Type </span><span style="font-family:"">标明发送或者接收的实体的</span><span style="font-family:"">MIME</span><span style="font-family:"">类型。例如:</span><span style="font-family:"">Content-Type: text/html</span>
<span style="font-family:Microsoft YaHei;"> Date </span><span style="font-family:"">发送</span><span style="font-family:"">HTTP</span><span style="font-family:"">消息的日期。例如:</span><span style="font-family:"">Date: Mon,10PR 18:42:51 GMT</span>
<span style="font-family:Microsoft YaHei;"> ETag </span><span style="font-family:"">一种实体头标,它向被发送的资源分派一个唯一的标识符。对于可以使用多种</span><span style="font-family:"">URL</span><span style="font-family:"">请求的资源,</span><span style="font-family:"">ETag</span><span style="font-family:"">可以用于确定实际被发送的资源是否为同一资源。例如:</span><span style="font-family:"">ETag: ’208f-419e-30f8dc99′</span>
<span style="font-family:Microsoft YaHei;"> Expires </span><span style="font-family:"">指定实体的有效期。例如:</span><span style="font-family:"">Expires: Mon,05 Dec 2008 12:00:00 GMT</span>
<span style="font-family:Microsoft YaHei;"> Form </span><span style="font-family:"">一种请求头标,给定控制用户代理的人工用户的电子邮件地址。例如:</span><span style="font-family:"">From: webmaster@myweb.com</span>
<span style="font-family:Microsoft YaHei;"> Host </span><span style="font-family:"">被请求资源的主机名。对于使用</span><span style="font-family:"">HTTP/1.1</span><span style="font-family:"">的请求而言,此域是强制性的。例如:</span><span style="font-family:"">Host: www.myweb.com</span>
<span style="font-family:Microsoft YaHei;"> If-Modified-Since </span><span style="font-family:"">如果包含了</span><span style="font-family:"">GET</span><span style="font-family:"">请求,导致该请求条件性地依赖于资源上次修改日期。如果出现了此头标,并且自指定日期以来,此资源已被修改,应该反回一个</span><span style="font-family:"">304</span><span style="font-family:"">响应代码。例如:</span><span style="font-family:"">If-Modified-Since: Mon,10PR 18:42:51 GMT</span>
<span style="font-family:Microsoft YaHei;"> If-Match </span><span style="font-family:"">如果包含于一个请求,指定一个或者多个实体标记。只发送其</span><span style="font-family:"">ETag</span><span style="font-family:"">与列表中标记区配的资源。例如:</span><span style="font-family:"">If-Match: ’208f-419e-308dc99′</span>
<span style="font-family:Microsoft YaHei;"> If-None-Match </span><span style="font-family:"">如果包含一个请求,指定一个或者多个实体标记。资源的</span><span style="font-family:"">ETag</span><span style="font-family:"">不与列表中的任何一个条件匹配,操作才执行。例如:</span><span style="font-family:"">If-None-Match: ’208f-419e-308dc99′</span>
<span style="font-family:Microsoft YaHei;"> If-Range </span><span style="font-family:"">指定资源的一个实体标记,客户端已经拥有此资源的一个拷贝。必须与</span><span style="font-family:"">Range</span><span style="font-family:"">头标一同使用。如果此实体自上次被客户端检索以来,还不曾修改过,那么服务器只发送指定的范围,否则它将发送整个资源。例如:</span><span style="font-family:"">Range: byte=0-499<CRLF>If-Range:’208f-419e-30f8dc99′</span>
<span style="font-family:Microsoft YaHei;"> If-Unmodified-Since </span><span style="font-family:"">只有自指定的日期以来,被请求的实体还不曾被修改过,才会返回此实体。例如:</span><span style="font-family:"">If-Unmodified-Since:Mon,10PR 18:42:51 GMT</span>
<span style="font-family:Microsoft YaHei;"> Last-Modified </span><span style="font-family:"">指定被请求资源上次被修改的日期和时间。例如:</span><span style="font-family:"">Last-Modified: Mon,10PR 18:42:51 GMT</span>
<span style="font-family:Microsoft YaHei;"> Location </span><span style="font-family:"">对于一个已经移动的资源,用于重定向请求者至另一个位置。与状态编码</span><span style="font-family:"">302</span><span style="font-family:"">(暂时移动)或者</span><span style="font-family:"">301</span><span style="font-family:"">(永久性移动)配合使用。例如:</span><span style="font-family:"">Location: http://www2.myweb.com/index.jsp</span>
<span style="font-family:Microsoft YaHei;"> Max-Forwards </span><span style="font-family:"">一个用于</span><span style="font-family:"">TRACE</span><span style="font-family:"">方法的请求头标,以指定代理或网关的最大数目,该请求通过网关才得以路由。在通过请求传递之前,代理或网关应该减少此数目。例如:</span><span style="font-family:"">Max-Forwards: 3</span>
<span style="font-family:Microsoft YaHei;"> Pragma </span><span style="font-family:"">一个通用头标,它发送实现相关的信息。例如:</span><span style="font-family:"">Pragma: no-cache</span>
<span style="font-family:Microsoft YaHei;"> Proxy-Authenticate </span><span style="font-family:"">类似于</span><span style="font-family:"">WWW-Authenticate</span><span style="font-family:"">,便是有意请求只来自请求链(代理)的下一个服务器的认证。例如:</span><span style="font-family:"">Proxy-Authenticate: Basic realm-admin</span>
<span style="font-family:Microsoft YaHei;"> Proxy-Proxy-Authorization </span><span style="font-family:"">类似于授权,但并非有意传递任何比在即时服务器链中更进一步的内容。例如:</span><span style="font-family:"">Proxy-Proxy-Authorization: Basic YXV0aG9yOnBoaWw=</span>
<span style="font-family:Microsoft YaHei;"> Public </span><span style="font-family:"">列表显示服务器所支持的方法集。例如:</span><span style="font-family:"">Public: OPTIONS,MGET,MHEAD,GET,HEAD</span>
<span style="font-family:Microsoft YaHei;"> Range </span><span style="font-family:"">指定一种度量单位和一个部分被请求资源的偏移范围。例如:</span><span style="font-family:"">Range: bytes=206-5513</span>
<span style="font-family:Microsoft YaHei;"> Refener </span><span style="font-family:"">一种请求头标域,标明产生请求的初始资源。对于</span><span style="font-family:"">HTML</span><span style="font-family:"">表单,它包含此表单的</span><span style="font-family:"">Web</span><span style="font-family:"">页面的地址。例如:</span><span style="font-family:"">Refener: http://www.myweb.com/news/search.html</span>
<span style="font-family:Microsoft YaHei;"> Retry-After </span><span style="font-family:"">一种响应头标域,由服务器与状态编码</span><span style="font-family:"">503</span><span style="font-family:"">(无法提供服务)配合发送,以标明再次请求之前应该等待多长时间。此时间即可以是一种日期,也可以是一种秒单位。例如:</span><span style="font-family:"">Retry-After: 18</span>
<span style="font-family:Microsoft YaHei;"> Server </span><span style="font-family:"">一种标明</span><span style="font-family:"">Web</span><span style="font-family:"">服务器软件及其版本号的头标。例如:</span><span style="font-family:"">Server: Apache/2.0.46(Win32)</span>
<span style="font-family:Microsoft YaHei;"> Transfer-Encoding </span><span style="font-family:"">一种通用头标,标明对应被接受方反向的消息体实施变换的类型。例如:</span><span style="font-family:"">Transfer-Encoding: chunked</span>
<span style="font-family:Microsoft YaHei;"> Upgrade </span><span style="font-family:"">允许服务器指定一种新的协议或者新的协议版本,与响应编码</span><span style="font-family:"">101</span><span style="font-family:"">(切换协议)配合使用。例如:</span><span style="font-family:"">Upgrade: HTTP/2.0</span>
<span style="font-family:Microsoft YaHei;"> User-Agent </span><span style="font-family:"">定义用于产生请求的软件类型(典型的如</span><span style="font-family:"">Web</span><span style="font-family:"">浏览器)。例如:</span><span style="font-family:"">User-Agent: Mozilla/4.0(compatible; MSIE 5.5; Windows NT; DigExt)</span>
<span style="font-family:Microsoft YaHei;"> Vary </span><span style="font-family:"">一个响应头标,用于表示使用服务器驱动的协商从可用的响应表示中选择响应实体。例如:</span><span style="font-family:"">Vary: *Via </span><span style="font-family:"">一个包含所有中间主机和协议的通用头标,用于满足请求。例如:</span><span style="font-family:"">Via: 1.0 fred.com, 1.1 wilma.com</span>
<span style="font-family:Microsoft YaHei;"> Warning </span><span style="font-family:"">用于提供关于响应状态补充信息的响应头标。例如:</span><span style="font-family:"">Warning: 99 www.myweb.com Piano needs tuning</span>
<span style="font-family:Microsoft YaHei;"> www-Authenticate </span><span style="font-family:"">一个提示用户代理提供用户名和口令的响应头标,与状态编码</span><span style="font-family:"">401</span><span style="font-family:"">(未授权)配合使用。响应一个授权头标。例如:</span><span style="font-family:"">www-Authenticate: Basic realm=zxm.mgmt</span>
</p>
<p style="color:#555555;font-family:"font-size:15px;text-indent:30px;">
<br />
</p>