上传内容时，HTTP-Request中的内容类型值是什么？ [英] Whats Content-Type value within a HTTP-Request when uploading content?

问题描述

我需要从http-trafic中提取上传内容。怎么可能呢？首先，请求方法将是POST。其次，将有一个Content-Type标头字段。我不想提取公式数据，而是上传像邮件附件。

I need to extract uploads from http-trafic. How could do that? First of all, the request-method will be POST. Secondly, there will be a Content-Type header-field. I do not want to extract formular-data, but uploads like mail-attachements.

推荐答案

内容类型规范 multipart / form-data 。

这是一种特殊的内容类型，可以在一个大请求中显示为多个子请求。每个子请求（一个表单数据元素）都有自己的标题集。实际数据的内容类型就在那里。

This is a special content type which can be visualized as multiple sub-requests in one big request. Each of those sub-requests (one form-data element) has their own set of headers. The content type of the actual data is in there.

下面是一个示例，它看起来像1个普通字段和1个文件字段（用HTML表示，当使用<$时c $ c>< input name =textfield>< input type =filename =filefield> ）：

Here's an example how it look like with 1 normal field and 1 file field (in HTML terms, when using <input name="textfield"><input type="file" name="filefield">):

Content-Type: multipart/form-data;boundary=SOME_BOUNDARY

--SOME_BOUNDARY
content-disposition: form-data;name="textfield"
content-type: text/plain;charset=UTF-8

value of textfield here
--SOME_BOUNDARY
content-disposition: form-data;name="filefield";filename="some.ext"
content-type: application/octet-stream

binary file content here

--SOME_BOUNDARY--

关于解析和提取这些数据，几乎每种编程语言为此提供内置/第三方API。由于您没有说明您正在使用哪一个，因此无法给出有针对性的答案。在例如Java的情况下，可能是第三方库Apache Commons FileUpload，或者当您使用Servlet 3.0时，API提供的 request.getPart（）方法。

As to parsing and extracting this data, practically every programming language has builtin/3rd party APIs for this. As you didn't tell anything about which one you're using, it's impossible to give a targeted answer. In case of for example Java, that would be either the 3rd party library Apache Commons FileUpload or when you're using Servlet 3.0, the API-provided request.getPart() method.

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