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HTTP      -              https://zh.wikipedia.org/wiki/HTTP     
HTTP                  
HTTP                  (HTTP)                                             
  
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5.1           
6     
6.1           
7     
8     
    
            request     response                                                        /        (CR)   (LF)                                                                                             (SP)         (HT)                           [1] 
   
           (IETF)           7231                                                  
         IANA                               
                                                             X-                   2012                                                        Downgraded-              
   
               (        User-Agent   Server   Via     )                  
               quality ( q )                               
                                                                                              Apache 2.3                            8190                   100        [2] 
    
      
  
  
  
Accept
            Content-Types         
Accept: text/plain
Permanent
Accept-Charset
        
Accept-Charset: utf-8
Permanent
Accept-Encoding
                          
Accept-Encoding: gzip, deflate
Permanent
Accept-Language
                          
Accept-Language: en-US
Permanent
Accept-Datetime
               
Accept-Datetime: Thu, 31 May 2007 20:35:00
GMT
Provisional
Authorization
                 
Authorization: Basic
QWxhZGRpbjpvcGVuIHNlc2FtZQ==
Permanent
Cache-Control
          /                     
Cache-Control: no-cache
Permanent
Connection
               
[3]
Connection: keep-alive
Connection: Upgrade
Permanent
Cookie
         Set- Cookie                     Cookie
Cookie: $Version=1; Skin=new;
Permanent: standard
Content-Length
          8              
Content-Length: 348
Permanent
Content-MD5
           MD5       Base64      
Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==
Obsolete[4]
Content-Type
              POST PUT    
Content-Type: application/x-www-form-
urlencoded
Permanent
Date
           (   RFC 7231     "          "     )
Date: Tue, 15 Nov 1994 08:12:31 GMT
Permanent
Expect
                 
Expect: 100-continue
Permanent
From
             
From: user@example.com
Permanent
Host
      (         )                                                       
[5]           1.1 HTTP/1.1          
Host: en.wikipedia.org:80
Host: en.wikipedia.org
Permanent
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