HTTP范围标头 [英] HTTP Range header

问题描述

我正在阅读 http://www.w3.org /Protocols/rfc2616/rfc2616-sec14.html#sec14.35
并试图找出如何继续下载文件。

I was reading http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35 and trying to figure out how to continue a file download.

例如，假设一个文件的长度为100个字节，并且我有100个字节。但是，我不知道预期的文件大小应该是多少，所以我要求这个文件并指定一个Range头部，如下所示：

For example, suppose a file is of length 100 bytes and I have all the 100 bytes. However, I don't know what the expected file size should be, so I ask for the file and specify a Range header that looks like this:

Range: bytes=100-

这是一个有效的范围请求吗？

Is this a valid Range request?

推荐答案

这是一个语法上有效的请求，但不是可满足的请求。如果您仔细查看该部分，您会看到：

It's a syntactically valid request, but not a satisfiable request. If you look further in that section you see:

如果语法上有效的字节范围集包含至少一个字节范围spec其第一字节位置小于实体主体的当前长度，或者至少一个后缀字节位置规范具有非零后缀长度，则字节范围集合是可满足的。否则，字节范围集是不可满足的。 如果字节范围集合不可满足，服务器应该返回状态为416（请求的范围不可满足）的响应。否则，服务器应该返回状态为206（部分内容）的响应，其中包含实体主体的可满足范围。

If a syntactically valid byte-range-set includes at least one byte- range-spec whose first-byte-pos is less than the current length of the entity-body, or at least one suffix-byte-range-spec with a non- zero suffix-length, then the byte-range-set is satisfiable. Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set is unsatisfiable, the server SHOULD return a response with a status of 416 (Requested range not satisfiable). Otherwise, the server SHOULD return a response with a status of 206 (Partial Content) containing the satisfiable ranges of the entity-body.

所以我认为在你的例子中，服务器应该返回一个416，因为它不是该文件的有效字节范围。

So I think in your example, the server should return a 416 since it's not a valid byte range for that file.

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