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即使不包含 Content-Length 或 Transfer-Encoding，HTTP 响应标头（如下所示）是否合法？

- Http: Response, HTTP/1.1, Status: Ok, URL: /AAA/B.json
  ProtocolVersion: HTTP/1.1
  StatusCode: 200, Ok
  Reason: OK
  Expires:  Fri, 05 Oct 2012 01:41:30 GMT
  Date:  Fri, 05 Oct 2012 01:40:46 GMT
  Vary:  Accept-Encoding
  Accept-Ranges:  bytes
  Cache-Control:  public, max-age=43
  Server:  Noelios-Restlet-Engine/1.1.10
  ContentType:  application/json;charset=UTF-8
  ContentEncoding:  gzip
  Connection:  close
  X-Served-By:  85.111
  HeaderEnd: CRLF

我希望看到 Content-Length 或 Transfer-Encoding，但它们都不存在。

我阅读了 HTTP-RFC，但仍然不确定。

@CodeCaster，我确实阅读了 RFC 第 4.4 节，但仍不清楚，如您所见，响应标头用于返回 json 流，因此：

  • 第 4.4 节，规则 1 定义不得包含消息正文，似乎不适用于我的情况。
  • 第 4.4 节，规则 4，对此不确定，但由于我在响应标头中没有看到“multipart/byteranges” - 这是否意味着该规则不适用于我？
  • 第 4.4 节规则 5，这对我来说很不清楚，因为标题实际包含“连接：关闭”，是否相关？

那么，还有什么意见吗？

4

1 回答 1

3

Yes, it is valid. There are five ways to determine the message length:

RFC 2616 Section 4.4. Message Length:

The transfer-length of a message is the length of the message-body as it appears in the message; that is, after any transfer-codings have been applied. When a message-body is included with a message, the transfer-length of that body is determined by one of the following (in order of precedence):

  1. Any response message which "MUST NOT" include a message-body (such as the 1xx, 204, and 304 responses and any response to a HEAD request) is always terminated by the first empty line after the header fields, regardless of the entity-header fields present in the message.
  1. If a Transfer-Encoding header field (section 14.41) is present and has any value other than "identity", then the transfer-length is defined by use of the "chunked" transfer-coding (section 3.6), unless the message is terminated by closing the connection.
  1. If a Content-Length header field (section 14.13) is present, its decimal value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header field MUST NOT be sent if these two lengths are different (i.e., if a Transfer-Encoding header field is present). If a message is received with both a Transfer-Encoding header field and a Content-Length header field, the latter MUST be ignored.
  1. If the message uses the media type "multipart/byteranges", and the transfer-length is not otherwise specified, then this self- delimiting media type defines the transfer-length. This media type [M]UST NOT be used unless the sender knows that the recipient can parse it; the presence in a request of a Range header with multiple byte- range specifiers from a 1.1 client implies that the client can parse multipart/byteranges responses.
  A range header might be forwarded by a 1.0 proxy that does not

   understand multipart/byteranges; in this case the server MUST
   delimit the message using methods defined in items 1,3 or 5 of
   this section.
  1. By the server closing the connection. (Closing the connection cannot be used to indicate the end of a request body, since that would leave no possibility for the server to send back a response.)
于 2012-10-05T13:17:39.663 回答