nghttp2 - HTTP/2.0 C Library

This is an experimental implementation of Hypertext Transfer Protocol version 2.0.

Development Status

We started to implement HTTP-defat-04/2.0 (http://tools.ietf.org/html/draft-ietf-httpbis-http2-04) based on spdylay code base.

The following features are not implemented:

  • Header continuation
  • ALPN: instead, NPN is used
  • HTTP Upgrade dance

Requirements

The following packages are needed to build the library:

  • pkg-config >= 0.20
  • zlib >= 1.2.3

To build and run the unit test programs, the following packages are required:

  • cunit >= 2.1

To build and run the application programs (nghttp, nghttpd and nghttpx) in src directory, the following packages are required:

  • OpenSSL >= 1.0.1
  • libevent-openssl >= 2.0.8

To enable SPDY protocol in the application program nghttpx, the following packages are required:

  • spdylay >= 1.0.0

To enable -a option (getting linked assets from the downloaded resouce) in nghttp, the following packages are needed:

  • libxml2 >= 2.7.7

If you are using Ubuntu 12.04, you need the following packages installed:

  • autoconf
  • automake
  • autotools-dev
  • libtool
  • pkg-config
  • zlib1g-dev
  • libcunit1-dev
  • libssl-dev
  • libxml2-dev
  • libevent-dev

spdylay is not packaged in Ubuntu, so you need to build it yourself: http://spdylay.sourceforge.net/

Build from git

Building from git is easy, but please be sure that at least autoconf 2.68 is used:

$ autoreconf -i
$ automake
$ autoconf
$ ./configure
$ make

Building documentation

Note

Documentation is still incomplete.

To build documentation, run:

$ make html

The documents will be generated under doc/manual/html/.

The generated documents will not be installed with make install.

Client, Server and Proxy programs

The src directory contains HTTP/2.0 client, server and proxy programs.

nghttp - client

nghttp is HTTP-default04/2.0 client. It can connect to the HTTP/2.0 server with prior knowledge (without HTTP Upgrade) and NPN in TLS extension.

By default, it uses SSL/TLS connection. Use --no-tls option to disable it.

It has verbose output mode for framing information. Here is sample output from nghttp client:

$ src/nghttp -nv https://localhost:3000/
[  0.000] NPN select next protocol: the remote server offers:
          * HTTP-draft-04/2.0
          * spdy/3
          * spdy/2
          * http/1.1
          NPN selected the protocol: HTTP-draft-04/2.0
[  0.005] send SETTINGS frame <length=0, flags=0, stream_id=0>
          (niv=0)
[  0.005] send HEADERS frame <length=58, flags=5, stream_id=1>
          ; END_STREAM | END_HEADERS
          ; Open new stream
          :host: localhost:3000
          :method: GET
          :path: /
          :scheme: https
          accept: */*
          accept-encoding: gzip, deflate
          user-agent: nghttp2/0.1.0-DEV
[  0.005] recv SETTINGS frame <length=16, flags=0, stream_id=0>
          (niv=2)
          [4:100]
          [7:65536]
[  0.005] recv WINDOW_UPDATE frame <length=4, flags=1, stream_id=0>
          ; END_FLOW_CONTROL
          (window_size_increment=0)
[  0.006] recv HEADERS frame <length=179, flags=4, stream_id=1>
          ; END_HEADERS
          ; First response header
          :status: 200 OK
          accept-ranges: bytes
          content-encoding: gzip
          content-length: 56
          content-type: text/html
          date: Sat, 27 Jul 2013 12:08:56 GMT
          etag: "cf405c-2d-45adabdf282c0"
          last-modified: Tue, 04 Nov 2008 10:44:03 GMT
          server: Apache/2.2.22 (Debian)
          vary: Accept-Encoding
          via: 1.1 nghttpx
[  0.006] recv DATA frame (length=56, flags=0, stream_id=1)
[  0.006] recv DATA frame (length=0, flags=1, stream_id=1)
[  0.006] send GOAWAY frame <length=8, flags=0, stream_id=0>
          (last_stream_id=0, error_code=NO_ERROR(0), opaque_data=)

nghttpd - server

nghttpd is static web server. It is single threaded and multiplexes connections using non-blocking socket.

By default, it uses SSL/TLS connection. Use --no-tls option to disable it.

Just like nghttp, it has verbose output mode for framing information. Here is sample output from nghttpd server:

$ src/nghttpd 3000 --no-tls -v
IPv4: listen on port 3000
IPv6: listen on port 3000
[id=1] [  1.020] send SETTINGS frame <length=8, flags=0, stream_id=0>
          (niv=1)
          [4:100]
[id=1] [  1.020] closed
[id=2] [  1.838] send SETTINGS frame <length=8, flags=0, stream_id=0>
          (niv=1)
          [4:100]
[id=2] [  1.838] recv SETTINGS frame <length=0, flags=0, stream_id=0>
          (niv=0)
[id=2] [  1.838] recv HEADERS frame <length=58, flags=5, stream_id=1>
          ; END_STREAM | END_HEADERS
          ; Open new stream
          :host: localhost:3000
          :method: GET
          :path: /
          :scheme: http
          accept: */*
          accept-encoding: gzip, deflate
          user-agent: nghttp2/0.1.0-DEV
[id=2] [  1.838] send HEADERS frame <length=105, flags=4, stream_id=1>
          ; END_HEADERS
          ; First response header
          :status: 404 Not Found
          content-encoding: gzip
          content-type: text/html; charset=UTF-8
          date: Sat, 27 Jul 2013 12:32:10 GMT
          server: nghttpd nghttp2/0.1.0-DEV
[id=2] [  1.838] send DATA frame (length=127, flags=0, stream_id=1)
[id=2] [  1.838] send DATA frame (length=0, flags=1, stream_id=1)
[id=2] [  1.838] stream_id=1 closed
[id=2] [  1.839] closed

nghttpx - proxy

The nghttpx is a multi-threaded reverse proxy for HTTP-draft-04/2.0, SPDY/HTTPS. It has several operation modes:

Mode option Frontend Backend Note
default HTTP/2.0, SPDY, HTTPS HTTP/1.1 Reverse proxy
--spdy HTTP/2.0, SPDY, HTTPS HTTP/1.1 SPDY proxy
--spdy-bridge HTTP/2.0, SPDY, HTTPS HTTP/2.0 SPDY proxy
--client HTTP/1.1 HTTP/2.0 1.1 <-> 2.0 conversion
--client-proxy HTTP/1.1 HTTP/2.0 Forward proxy

The interesting mode at the moment is the default mode. It works like a reverse proxy and listens HTTP-draft-04/2.0 as well as SPDY and HTTPS and can be deployed SSL/TLS terminator for existing web server.

By default, it uses SSL/TLS connection for HTTP/2.0 and SPDY. Use --frontend-spdy--no-tls to disable it in frontend connection. Likewise, use --backend-spdy-no-tls option to disable it in backend connection.

The nghttpx supports configuration file. See --conf option and sample configuration file nghttpx.conf.sample.

The nghttpx is ported from shrpx in spdylay project, and it still has SPDY color in option names. They will be fixed as the development goes.

Without any of -s, --spdy-bridge, -p and --client options, nghttpx works as reverse proxy to the backend server:

Client <-- (HTTP/2.0, SPDY, HTTPS) --> nghttpx <-- (HTTP) --> Web Server
                                   [reverse proxy]

With -s option, it works as so called secure SPDY proxy:

Client <-- (HTTP/2.0, SPDY, HTTPS) --> nghttpx <-- (HTTP) --> Proxy
                                   [SPDY proxy]            (e.g., Squid)

The Client in the above is needs to be configured to use nghttpx as secure SPDY proxy.

At the time of this writing, Chrome is the only browser which supports secure SPDY proxy. The one way to configure Chrome to use secure SPDY proxy is create proxy.pac script like this:

function FindProxyForURL(url, host) {
    return "HTTPS SERVERADDR:PORT";
}

SERVERADDR and PORT is the hostname/address and port of the machine nghttpx is running. Please note that Chrome requires valid certificate for secure SPDY proxy.

Then run chrome with the following arguments:

$ google-chrome --proxy-pac-url=file:///path/to/proxy.pac --use-npn

With --spdy-bridge, it accepts HTTP/2.0, SPDY and HTTPS connections and communicates with backend in HTTP/2.0:

Client <-- (HTTP/2.0, SPDY, HTTPS) --> nghttpx <-- (HTTP/2.0) --> Web or HTTP/2.0 Proxy etc
                                    [SPDY bridge]              (e.g., nghttpx -s)

With -p option, it works as forward proxy and expects that the backend is HTTP/2.0 proxy:

Client <-- (HTTP) --> nghttpx <-- (HTTP/2.0) --> HTTP/2.0 Proxy
                 [forward proxy]                 (e.g., nghttpx -s)

The Client is needs to be configured to use nghttpx as forward proxy.

With the above configuration, one can use HTTP/1.1 client to access and test their HTTP/2.0 servers.

With --client option, it works as reverse proxy and expects that the backend is HTTP/2.0 Web server:

Client <-- (HTTP) --> nghttpx <-- (HTTP/2.0) --> Web Server
                 [reverse proxy]

For the operation modes which talk to the backend in HTTP/2.0, the backend connections can be tunneled though HTTP proxy. The proxy is specified using --backend-http-proxy-uri option. The following figure illustrates the example of --spdy-bridge and --backend-http-proxy-uri option to talk to the outside HTTP/2.0 proxy through HTTP proxy:

Client <-- (HTTP/2.0, SPDY, HTTPS) --> nghttpx <-- (HTTP/2.0) --
                                   [SPDY bridge]

        --===================---> HTTP/2.0 Proxy
          (HTTP proxy tunnel)     (e.g., nghttpx -s)