curl_easy_getinfo CURLINFO_EFFECTIVE_URL is the same for all handles created in the PUSHFUNCTION callback

[JCMais]

When using libcurl multi handle with the PUSHFUNCTION option set to allow PUSH_PROMISE frames, if you call curl_get_info(handle, CURLINFO_EFFECTIVE_URL, &result) on one of the handles libcurl created, it returns the URL of the original easy handle.

I don't know if this is the intended behavior or a possible bug, so I'm opening this issue here.

If this is in fact the intended behavior, a new info option to retrieve the pushed data URL would be very helpful, or at least some kind of flag saying this easy handle was created to transfer data pushed by the server.

I know this is possible by passing a custom structure to the CURLOPT_PRIVATE option of each handle, but in my particular scenario, this option is already bound to something else.

I did this

Ran the example at https://curl.haxx.se/libcurl/c/http2-pushinmemory.html with some minor edits:

1. Changed URL to https://http2.golang.org/serverpush
2. Allowed all pushes on CURLMOPT_PUSHFUNCTION callback
3. Called curl_easy_getinfo(e, CURLINFO_EFFECTIVE_URL, &result); before curl_easy_cleanup(e); in the do/while loop.

It shows the same URL for all requests.

I expected the following

Different URLs for each easy handle.

curl/libcurl version

Version: libcurl/7.69.1-DEV OpenSSL/1.1.1d zlib/1.2.11 WinIDN libssh2/1.9.0_DEV nghttp2/1.40.0
Protocols: dict, file, ftp, ftps, gopher, http, https, imap, imaps, ldap, ldaps, pop3, pop3s, rtsp, scp, sftp, smb, smbs, smtp, smtps, telnet, tftp
Features: AsynchDNS, IDN, IPv6, Largefile, SSPI, Kerberos, SPNEGO, NTLM, SSL, libz, HTTP2, HTTPS-proxy

operating system

Windows 10 x64

[bagder]

I think it is an omission (bug). The pushed stream gets its 'easy' handle created internally by duplicating the "source stream", which is why it gets that particular effective URL. It simply isn't updated to the correct URL.

It probably makes sense for curl to create the URL proper to allow CURLINFO_EFFECTIVE_URL to work exactly the way you tried to use it.