Share Link Redirect URL has no Content-Length

[Roon]

I'm trying to get the filesize from a shared link:

Looking at the answer to [this post] - the shared link creates a redirect to the file, which should provide a filesize in the headers.. 

It seems that the "Content-Length" Header is no longer available on the redirect link. 

Is there an alternative method?

[Greg-DB]

My sample there is still returning Content-Length for me. Can you share a sample and output that isn't working as expected for you? Thanks in advance!

[Roon]

Hi Greg, 

heres my output 

$ curl -I https://www.dropbox.com/sh/j1msw4e8dup2c5q/AAANYUWXcyBDgxVGkveU7AFla?dl=1
HTTP/1.1 302 Found
Server: nginx
Date: Thu, 30 Nov 2017 11:03:23 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
Cache-Control: no-cache
Content-Security-Policy: sandbox
Location: https://dl.dropboxusercontent.com/content_link_zip/liyObwdrElvSIeElexmq1AqHMTZhWtSFoGu0KKJOo63xs0INfWNSflheo9qjap41/file
Pragma: no-cache
Referrer-Policy: origin-when-cross-origin
Set-Cookie: locale=en; Domain=dropbox.com; expires=Tue, 29 Nov 2022 11:03:23 GMT; Path=/; secure
Set-Cookie: gvc=Mjk4NTU0NTY4OTI3NDA1ODI1NDAzMTI2Mjk5ODM5MTkxNzY2NDU0; expires=Tue, 29 Nov 2022 11:03:23 GMT; httponly; Path=/; secure
Set-Cookie: flash=; Domain=dropbox.com; expires=Thu, 30 Nov 2017 11:03:23 GMT; Path=/; secure
Set-Cookie: puc=; expires=Thu, 30 Nov 2017 11:03:23 GMT; httponly; Path=/; secure
Set-Cookie: bang=; Domain=dropbox.com; expires=Thu, 30 Nov 2017 11:03:23 GMT; Path=/; secure
Set-Cookie: t=Xdr_KsdQvptCBofiAcYwgGSY; Domain=dropbox.com; expires=Sun, 29 Nov 2020 11:03:23 GMT; httponly; Path=/; secure
Set-Cookie: __Host-js_csrf=Xdr_KsdQvptCBofiAcYwgGSY; expires=Sun, 29 Nov 2020 11:03:23 GMT; Path=/; secure
X-Content-Type-Options: nosniff
X-Dropbox-Request-Id: 760ad66de5a8c9aa75c7e535a0491e38
X-Frame-Options: DENY
X-Robots-Tag: noindex, nofollow, noimageindex
X-Xss-Protection: 1; mode=block
Strict-Transport-Security: max-age=15552000; includeSubDomains

and then if i try the redirect link directly (from the Location: xxx in the above)

$ curl -I https://dl.dropboxusercontent.com/content_link_zip/liyObwdrElvSIeElexmq1AqHMTZhWtSFoGu0KKJOo63xs0INfWNSflheo9qjap41/file
HTTP/1.1 200 OK
Server: nginx
Date: Thu, 30 Nov 2017 11:03:45 GMT
Content-Type: application/zip
Connection: keep-alive
referrer-policy: no-referrer
x-robots-tag: noindex, nofollow, noimageindex
content-disposition: attachment; filename="AscentShared.zip"; filename*=UTF-8''AscentShared.zip
set-cookie: uc_session=ouN6cNB5FrD7Kf0nDpzHHCXY6wLIJFZ2rRVH6pmLHsdY1JLMkHnoHzPQBCKnG1Pw; Domain=dropboxusercontent.com; httponly; Path=/; secure
content-security-policy: referrer no-referrer
x-dropbox-request-id: d3e420b20a4f94e73d00a6cc078b74c7
pragma: public
cache-control: max-age=0
x-content-security-policy: referrer no-referrer
x-webkit-csp: referrer no-referrer
X-Server-Response-Time: 557
Strict-Transport-Security: max-age=15552000; includeSubDomains

[deFreitas]

Content-Length is not required, Your shared link is a folder then Dropbox is probably dynamically zipping it, that is probably the reason why it have not a length

[Greg-DB]

That's correct, my sample was a link for a file, so it can offer a Content-Length. Your example is a link for a folder, which is compressed on the fly, so the Content-Length isn't available.

[Roon]

Thanks..
So I take that to mean that the compression is incomplete when the headers are sent.. and consequently there is no known size..
Leading me to the question, how am i supposed to know the compressed file-size of a folder prior to downloading it? (I need to indicate progress as a percentage)

[Greg-DB · Accepted solution]

I don't believe there is a way to find out the size ahead of time unfortunately.

[sechel]

Hey there,

there is an easy solution to this question: Do a HEAD request with a Range:bytes=0- header. Then you will have a Content-Length header in the response 😀 Hope that helps, greetings

Stefan