< form enctype =multipart / form- dataaction =http：// localhost：3000 / upload？upload_progress_id = 12344method =POST> < input type =hiddenname =MAX_FILE_SIZEvalue =100000/> 选择要上传的文件：< input name =uploadedfiletype =file/>< br /> < input type =submitvalue =Upload File/> < / form>
它如何在内部发送文件？该文件是否作为数据的HTTP身体的一部分发送？在这个请求的头文件中，我没有看到与文件名相关的任何内容。
我只是想知道发送文件时HTTP的内部工作方式。 解决方案
<$ p $ p> POST / upload？upload_progress_id = 12344 HTTP / 1.1 Host：localhost：3000 Content-Length：1325 Origin：http：// localhost：3000 ...其他标题... Content-Type：multipart / form-data; border = ---- WebKitFormBoundaryePkpFF7tjBAqx29L ------ WebKitFormBoundaryePkpFF7tjBAqx29L Content-Disposition：form-data; name =MAX_FILE_SIZE 100000 ------ WebKitFormBoundaryePkpFF7tjBAqx29L Content-Disposition：form-data; NAME = UploadedFile的; filename =hello.o Content-Type：application / x-object ...文件内容放在这里... ------ WebKitFormBoundaryePkpFF7tjBAqx29L -代替表单参数的URL编码，表单参数（包括文件数据）被发送在上面的例子中，你可以看到输入 MAX_FILE_SIZE
完整的详细信息是这里。
When I submit a simple form like this with a file attached:
<form enctype="multipart/form-data" action="localhost:3000/upload?upload_progress_id=12344" method="POST"> <input type="hidden" name="MAX_FILE_SIZE" value="100000" /> Choose a file to upload: <input name="uploadedfile" type="file" /><br /> <input type="submit" value="Upload File" /> </form>How does it send the file internally? Is the file sent as part of the HTTP body as data? In the headers of this request, I don't see anything related to the name of the file.
I just would like the know the internal workings of the HTTP when sending a file.
解决方案Let's take a look at what happens when you select a file and submit your form (I've truncated the headers for brevity):
POST /upload?upload_progress_id=12344 HTTP/1.1 Host: localhost:3000 Content-Length: 1325 Origin: localhost:3000 ... other headers ... Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryePkpFF7tjBAqx29L ------WebKitFormBoundaryePkpFF7tjBAqx29L Content-Disposition: form-data; name="MAX_FILE_SIZE" 100000 ------WebKitFormBoundaryePkpFF7tjBAqx29L Content-Disposition: form-data; name="uploadedfile"; filename="hello.o" Content-Type: application/x-object ... contents of file goes here ... ------WebKitFormBoundaryePkpFF7tjBAqx29L--Instead of URL encoding the form parameters, the form parameters (including the file data) are sent as sections in a multipart document in the body of the request.
In the example above, you can see the input MAX_FILE_SIZE with the value set in the form, as well as a section containing the file data. The file name is part of the Content-Disposition header.
The full details are here.
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