How can I make a pycurl http2 request?

Question

I am trying to make a http2 request through pycurl. I have installed the nghttp2 c library that libcurl needs and I am able to do an http2 request with curl.

I tried something like this with pycurl:

import pycurl
import cStringIO


if __name__ == '__main__':
    c = pycurl.Curl()

    buf = cStringIO.StringIO()

    c = pycurl.Curl()
    c.setopt(c.URL, 'https://nghttp2.org')
    c.setopt(pycurl.HTTP_VERSION, pycurl.VERSION_HTTP2)
    c.setopt(c.WRITEFUNCTION, buf.write)
    c.setopt(pycurl.VERBOSE, 1)
    c.perform()

    buf.close()

And the output that I get is:

* Rebuilt URL to: https://nghttp2.org/
*   Trying 106.186.112.116...
* Connected to nghttp2.org (106.186.112.116) port 443 (#0)
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
 CApath: none
* NPN, negotiated HTTP1.1
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* Server certificate:
*    subject: CN=nghttp2.org
*    start date: Jan 21 22:58:00 2017 GMT
*    expire date: Apr 21 22:58:00 2017 GMT
*    subjectAltName: nghttp2.org matched
*    issuer: C=US; O=Let's Encrypt; CN=Let's Encrypt Authority X3
*    SSL certificate verify ok.
> GET / HTTP/1.1
Host: nghttp2.org
User-Agent: PycURL/7.43.0 libcurl/7.46.0 OpenSSL/1.0.1f zlib/1.2.8          libidn/1.28 nghttp2/1.21.0-DEV librtmp/2.3
Accept: */*
Connection: Upgrade, HTTP2-Settings
Upgrade: h2c
HTTP2-Settings:

< HTTP/1.1 200 OK
< Date: Tue, 14 Mar 2017 13:33:48 GMT
< Content-Type: text/html
< Last-Modified: Sun, 26 Feb 2017 12:19:00 GMT
< Etag: "58b2c7b4-19e1"
< Accept-Ranges: bytes
< Content-Length: 6625
< X-Backend-Header-Rtt: 0.001418
< Strict-Transport-Security: max-age=31536000
< Server: nghttpx
< Via: 2 nghttpx
< x-frame-options: SAMEORIGIN
< x-xss-protection: 1; mode=block
< x-content-type-options: nosniff
<
* Connection #0 to host nghttp2.org left intact

What am I doing wrong in this request?

Edit: As per the comment I made sure that pycurl uses OpenSSL/1.0.2k. Now the User-Agent header looks like this: User-Agent: PycURL/7.43.0 libcurl/7.46.0 OpenSSL/1.0.2k zlib/1.2.11 libidn/1.28 nghttp2/1.21.0-DEV librtmp/2.3 but I get the same result as above.

Answer 1

It seems that the pycurl script was using the wrong http version constant. The correct one is c.setopt(pycurl.HTTP_VERSION, pycurl.CURL_HTTP_VERSION_2_0).