HTTP1.1-1.0差别
备注:本文主要基于HTTP1.1规范的角度进行两个版本的对比。
Protocol Parameters
Date/Time Formats
(接收方向)
无论是HTTP1.0还是HTTP1.1,都要能解析下面三种date/time stamp:
Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
(发送方向)
HTTP1.0要求不能生成第三种asctime格式的date/time stamp;
HTTP1.1则要求只生成RFC 1123(第一种)格式的date/time stamp。
Content Codings
HTTP1.1支持:
gzip、compress、deflate(zlib格式)
HTTP1.0支持:
gzip、compress
Transfer Codings
HTTP1.1:
支持chunked transfer,所以可以有Transfer-Encoding头部域:
Transfer-Encoding: chunked
备注:(详见rfc2616-3.6.1)
chunked 编码修饰消息的主体,为了以一系列的大块传输它,每块都有它自己的大小指示符,接在【可选】的包含实体头部域的尾巴后。这允许动态生成的内容与必要信息一起传输,以便接收者检验它已经接收完全部的消息。
Quality Values
HTTP1.1:
HTTP 内容协商(12 节)使用简短的“浮点”数来指出各种协商参数的相对重要性(“权重”。权重通常是 0 到 1 范围内的实数,这里 0 是最小的,1 是最大的。如果某个参数的质) 量值为 0,则该参数对于该客户来说“不可接受”。
Entity Tags
HTTP1.1:
实体标签用来从相同的请求资源来比较两个或多个实体。HTTP/1.1在ETag、If-Match、If-None-Match和If-Range头部域中使用实体 标签。这几个标签在HTTP in Cache中使用。
Range Units
HTTP1.1:
允许客户端只请求响应实体的某部分包含在响应中。HTTP/1.1 在 Range 和Content-Range头部域中使用范围单位。实体可以依据各种结构
化单位分割为子范围。
bytes-unit = "bytes"
other-range-unit = token
HTTP/1.1 定义的唯一范围单位是“bytes”。
HTTP Message
General Header Fields
红色为HTTP1.1新增:
general-header = Cache-Control ; Section 14.9
| Connection ; Section 14.10 | Date ; Section 14.18 | Pragma ; Section 14.32 | Trailer ; Section 14.40 | Transfer-Encoding ; Section 14.41 | Upgrade ; Section 14.42 | Via ; Section 14.45 | Warning ; Section 14.46
Request
Method
红色为HTTP1.1新增:
Method = "OPTIONS" ; Section 9.2 | "GET" ; Section 9.3 | "HEAD" ; Section 9.4 | "POST" ; Section 9.5 | "PUT" ; Section 9.6 | "DELETE" ; Section 9.7 | "TRACE" ; Section 9.8 | "CONNECT" ; Section 9.9 | extension-method
Request Header Fields
红色为HTTP1.1新增:
request-header = Accept ; Section 14.1 | Accept-Charset ; Section 14.2 | Accept-Encoding ; Section 14.3 | Accept-Language ; Section 14.4 | Authorization ; Section 14.8 | Expect ; Section 14.20 | From ; Section 14.22 | Host ; Section 14.23 | If-Match ; Section 14.24 | If-Modified-Since ; Section 14.25 | If-None-Match ; Section 14.26 | If-Range ; Section 14.27 | If-Unmodified-Since ; Section 14.28 | Max-Forwards ; Section 14.31 | Proxy-Authorization ; Section 14.34 | Range ; Section 14.35 | Referer ; Section 14.36 | TE ; Section 14.39 | User-Agent ; Section 14.43
Response
Status Code
红色为HTTP1.1新增:
Status-Code = "100" ; Section 10.1.1: Continue | "101" ; Section 10.1.2: Switching Protocols | "200" ; Section 10.2.1: OK | "201" ; Section 10.2.2: Created | "202" ; Section 10.2.3: Accepted | "203" ; Section 10.2.4: Non-Authoritative Information | "204" ; Section 10.2.5: No Content | "205" ; Section 10.2.6: Reset Content | "206" ; Section 10.2.7: Partial Content | "300" ; Section 10.3.1: Multiple Choices | "301" ; Section 10.3.2: Moved Permanently | "302" ; Section 10.3.3: Found(与HTTP1.0中的302意义不一样) | "303" ; Section 10.3.4: See Other | "304" ; Section 10.3.5: Not Modified | "305" ; Section 10.3.6: Use Proxy | "307" ; Section 10.3.8: Temporary Redirect | "400" ; Section 10.4.1: Bad Request | "401" ; Section 10.4.2: Unauthorized | "402" ; Section 10.4.3: Payment Required | "403" ; Section 10.4.4: Forbidden | "404" ; Section 10.4.5: Not Found | "405" ; Section 10.4.6: Method Not Allowed | "406" ; Section 10.4.7: Not Acceptable | "407" ; Section 10.4.8: Proxy Authentication Required | "408" ; Section 10.4.9: Request Time-out | "409" ; Section 10.4.10: Conflict | "410" ; Section 10.4.11: Gone | "411" ; Section 10.4.12: Length Required | "412" ; Section 10.4.13: Precondition Failed | "413" ; Section 10.4.14: Request Entity Too Large | "414" ; Section 10.4.15: Request-URI Too Large | "415" ; Section 10.4.16: Unsupported Media Type | "416" ; Section 10.4.17: Requested range not satisfiable | "417" ; Section 10.4.18: Expectation Failed | "500" ; Section 10.5.1: Internal Server Error | "501" ; Section 10.5.2: Not Implemented | "502" ; Section 10.5.3: Bad Gateway | "503" ; Section 10.5.4: Service Unavailable | "504" ; Section 10.5.5: Gateway Time-out | "505" ; Section 10.5.6: HTTP Version not supported | extension-code
Response Header Fields
红色为HTTP1.1新增:
response-header = Accept-Ranges ; Section 14.5 | Age ; Section 14.6 | ETag ; Section 14.19 | Location ; Section 14.30 | Proxy-Authenticate ; Section 14.33 | Retry-After ; Section 14.37 | Server ; Section 14.38 | Vary ; Section 14.44 | WWW-Authenticate ; Section 14.47
Entity
Entity Header Fields
红色为HTTP1.1新增:
entity-header = Allow ; Section 14.7 | Content-Encoding ; Section 14.11 | Content-Language ; Section 14.12 | Content-Length ; Section 14.13 | Content-Location ; Section 14.14 | Content-MD5 ; Section 14.15 | Content-Range ; Section 14.16 | Content-Type ; Section 14.17 | Expires ; Section 14.21 | Last-Modified ; Section 14.29 | extension-header
Connection
Persistent connection
HTTP1.1:
支持persistent connection,并且默认使用
HTTP1.0:
支持persistent connection需要显性增加Connection: Keep-Alive header,默认不使用
Pipelining
HTTP1.1:
支持永久连接的客户端<可以>按“管道”方式请求(如,发送多个请求而不需等待每个响应)。服务器<必须>必须以收到请求的相同顺序来响应发送这些请求的响应。
Caching in HTTP
HTTP1.1:
完整的cache管理机制,引入Expiration Model、Validation Model模型
HTTP1.0:
只包括几种cache处理机制:no-cache\If-Modified-Since\Last-Modified\Expires,只是通过简单的计算时间进行处理
备注:详细情况参见参考文献【2】。
总结
从对比HTTP1.1和1.0的情况看有如下几个需要注意的特性:
业务相关
-
Range机制
该机制提供基于range的请求,如果我们的CDN后续需要引入视频等业务时,则在我们的CDN系统中必须支持该特性。
功能相关
-
Cache机制
HTTP1.1的Cache机制远比1.0复杂和高效,在我们的Cache系统中主要注意兼容性问题。
-
Chunk编码机制
Chunk编码机制在需要输出动态内容时可以有效的提高用户体验,让用户及时的得到部分数据。
性能相关
-
Persistent Connection
-
Pipeline
参考文献
【1】rfc2616 http://www.ietf.org/rfc/rfc2616.txt
【2】rfc1945 http://www.ietf.org/rfc/rfc1945.txt