从多部分表单上传Content-Length标头获取文件大小 [英] Get file size from multipart form upload Content-Length header
问题描述
所以,我上传了一个文件,然后下载了......但是上传标题中的Content-Length与文件大小不匹配。我猜这个计算和转移涉及到其他一些数据,但具体到底是什么?如何从Content-Length获得准确的文件大小?它甚至可能吗?
So, I'm uploading a file, and then downloading it... but the Content-Length in the upload headers do not match the file size. I'm guessing there is some other data involved with this calculation and transfer, but what exactly? How do I get an accurate file size from the Content-Length? Is it even possible?
我知道有边界,也许还有其他一些东西,但检查一下:
I know there are the boundaries, and maybe some other things, but check it:
5380216 - 5379906 = 310
"----WebKitFormBoundaryeoFyqD4zr6smwYDG".size
→ 38
所以边界大小为38 ... 310有一些5,10,31的LCD ...那些在任何38都没有用方式...我输了!
So the boundary size is 38... 310 has some LCDs of 5, 10, 31... those don't work well with 38 in any way... I'm lost!
文件大小:
-rw-r--r--@ 1 williamcotton staff 5379906 Jul 2 12:02 testfile-downloaded.zip
-rw-r--r--@ 1 williamcotton staff 5379906 Jun 8 14:23 testfile-uploaded.zip
HTTP标头
{
host: 'localhost:8887',
connection: 'keep-alive',
'content-length': '5380217',
'cache-control': 'max-age=0',
origin: 'http://localhost:8887',
'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/22.0.1193.0 Safari/537.1',
'content-type': 'multipart/form-data; boundary=----WebKitFormBoundaryeoFyqD4zr6smwYDG',
accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
referer: 'http://localhost:8887/',
'accept-encoding': 'gzip,deflate,sdch',
'accept-language': 'en-US,en;q=0.8',
'accept-charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.3'
}
tl; dr
文件大小为5379906
File size is 5379906
Content-Length报告为5380216
Content-Length is reported as 5380216
为什么?
推荐答案
我认为multipart / form-data请求的每个部分都计入主Content-Length头的总大小。
I think that each section of the multipart/form-data request counts toward the overall size of the main Content-Length header.
发现这个作为参考:
http://chxo.com/be2/20050724_93bf.html
所以,也许在你的标题之后,你可能有:
So, perhaps after your headers, you might have:
----WebKitFormBoundaryeoFyqD4zr6smwYDG
Content-Disposition: form-data; name="file"; filename="testfile-downloaded.zip"; size=<file size could be here>
Content-Length: <file size could also be here>
<some other content headers>
<file data>
----WebKitFormBoundaryeoFyqD4zr6smwYDG
所有这些都将计入内容 - 长度。
All of which would count toward the Content-Length size.
编辑
刚才意识到我没有回答你的问题。不确定如何从请求的文件部分提取文件大小。对不起!
Just realized I didn't answer your question. Not sure how to pull out the file size from the file section of the request. Sorry!
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