syohex / nghttp2

nghttp2 - HTTP/2 C Library

nghttp2 - HTTP/2 C Library

This is an implementation of the Hypertext Transfer Protocol version 2 in C.

The framing layer of HTTP/2 is implemented as a reusable C library. On top of that, we have implemented an HTTP/2 client, server and proxy. We have also developed load test and benchmarking tools for HTTP/2 and SPDY.

An HPACK encoder and decoder are available as a public API.

An experimental high level C++ library is also available.

We have Python bindings of this libary, but we do not have full code coverage yet.

Development Status

We started to implement h2-14 (http://tools.ietf.org/html/draft-ietf-httpbis-http2-14), and header compression (http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09).

The nghttp2 code base was forked from the spdylay project.

HTTP/2 Features	Support
Core frames handling	Yes
Dependency Tree	Yes
Large header (CONTINUATION)	Yes

Public Test Server

The following endpoints are available to try out our nghttp2 implementation.

• https://nghttp2.org/ (TLS + ALPN/NPN)

  This endpoint supports h2, h2-16, h2-14, spdy/3.1 and http/1.1 via ALPN/NPN and requires TLSv1.2 for HTTP/2 connection.

• http://nghttp2.org/ (Upgrade / Direct)

  h2c-14 and http/1.1.

Requirements

The following package is required to build the libnghttp2 library:

• pkg-config >= 0.20

To build and run the unit test programs, the following package is required:

• cunit >= 2.1

To build the documentation, you need to install:

• sphinx (http://sphinx-doc.org/)

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

• OpenSSL >= 1.0.1
• libev >= 4.15
• zlib >= 1.2.3

ALPN support requires OpenSSL >= 1.0.2 (released 22 January 2015).

To enable the SPDY protocol in the application program nghttpx and h2load, the following package is required:

• spdylay >= 1.3.0

To enable -a option (getting linked assets from the downloaded resource) in nghttp, the following package is required:

• libxml2 >= 2.7.7

The HPACK tools require the following package:

• jansson >= 2.5

To build sources under the examples directory, libevent is required:

• libevent-openssl >= 2.0.8

To mitigate heap fragmentation in long running server programs (nghttpd and nghttpx), jemalloc is recommended:

• jemalloc

libnghttp2_asio C++ library requires the following packages:

• libboost-dev >= 1.54.0
• libboost-thread-dev >= 1.54.0

The Python bindings require the following packages:

• cython >= 0.19
• python >= 2.7

If you are using Ubuntu 14.04 LTS (trusty), run the following to install the needed packages:

sudo apt-get install make binutils autoconf  automake autotools-dev libtool pkg-config \
  zlib1g-dev libcunit1-dev libssl-dev libxml2-dev libev-dev libevent-dev libjansson-dev \
  libjemalloc-dev cython python3.4-dev

spdylay is not packaged in Ubuntu, so you need to build it yourself: http://tatsuhiro-t.github.io/spdylay/

Building 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

To compile the source code, gcc >= 4.8.3 or clang >= 3.4 is required.

Note

Mac OS X users may need the --disable-threads configure option to disable multi-threading in nghttpd, nghttpx and h2load to prevent them from crashing. A patch is welcome to make multi threading work on Mac OS X platform.

Notes for building on Windows (Mingw/Cygwin)

Under Mingw environment, you can only compile the library, it's libnghttp2-X.dll and libnghttp2.a.

If you want to compile the applications(h2load, nghttp, nghttpx, nghttpd), you need to use the Cygwin environment.

Under Cygwin environment, to compile the applications you need to compile and install the libev first.

Secondly, you need to undefine the macro __STRICT_ANSI__, if you not, the functions fdopen, fileno and strptime will not available.

the sample command like this:

$ export CFLAGS="-U__STRICT_ANSI__ -I$libev_PREFIX/include -L$libev_PREFIX/lib"
$ export CXXFLAGS=$CFLAGS
$ ./configure
$ make

If you want to compile the applications under examples/, you need to remove or rename the event.h from libev's installation, because it conflicts with libevent's installation.

Building the documentation

Note

Documentation is still incomplete.

To build the documentation, run:

$ make html

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

The generated documents will not be installed with make install.

The online documentation is available at https://nghttp2.org/documentation/

Unit tests

Unit tests are done by simply running make check.

Integration tests

We have the integration tests for the nghttpx proxy server. The tests are written in the Go programming language and uses its testing framework. We depend on the following libraries:

• https://github.com/bradfitz/http2
• https://github.com/tatsuhiro-t/go-nghttp2
• https://golang.org/x/net/spdy

To download the above packages, after settings GOPATH, run the following command under integration-tests directory:

$ make itprep

To run the tests, run the following command under integration-tests directory:

$ make it

Inside the tests, we use port 3009 to run the test subject server.

Client, Server and Proxy programs

The src directory contains the HTTP/2 client, server and proxy programs.

nghttp - client

nghttp is a HTTP/2 client. It can connect to the HTTP/2 server with prior knowledge, HTTP Upgrade and NPN/ALPN TLS extension.

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

$ nghttp -nv https://nghttp2.org
[  0.033][NPN] server offers:
          * h2-14
          * spdy/3.1
          * http/1.1
The negotiated protocol: h2-14
[  0.068] send SETTINGS frame <length=15, flags=0x00, stream_id=0>
          (niv=3)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_INITIAL_WINDOW_SIZE(4):65535]
          [SETTINGS_COMPRESS_DATA(5):1]
[  0.068] send HEADERS frame <length=46, flags=0x05, stream_id=1>
          ; END_STREAM | END_HEADERS
          (padlen=0)
          ; Open new stream
          :authority: nghttp2.org
          :method: GET
          :path: /
          :scheme: https
          accept: */*
          accept-encoding: gzip, deflate
          user-agent: nghttp2/0.4.0-DEV
[  0.068] recv SETTINGS frame <length=10, flags=0x00, stream_id=0>
          (niv=2)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_INITIAL_WINDOW_SIZE(4):65535]
[  0.068] send SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[  0.079] recv SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[  0.080] (stream_id=1, noind=0) :status: 200
[  0.080] (stream_id=1, noind=0) accept-ranges: bytes
[  0.080] (stream_id=1, noind=0) age: 15
[  0.080] (stream_id=1, noind=0) content-length: 40243
[  0.080] (stream_id=1, noind=0) content-type: text/html
[  0.080] (stream_id=1, noind=0) date: Wed, 14 May 2014 15:14:30 GMT
[  0.080] (stream_id=1, noind=0) etag: "535d0eea-9d33"
[  0.080] (stream_id=1, noind=0) last-modified: Sun, 27 Apr 2014 14:06:34 GMT
[  0.080] (stream_id=1, noind=0) server: nginx/1.4.6 (Ubuntu)
[  0.080] (stream_id=1, noind=0) x-varnish: 2114900538 2114900537
[  0.080] (stream_id=1, noind=0) via: 1.1 varnish, 1.1 nghttpx
[  0.080] (stream_id=1, noind=0) strict-transport-security: max-age=31536000
[  0.080] recv HEADERS frame <length=162, flags=0x04, stream_id=1>
          ; END_HEADERS
          (padlen=0)
          ; First response header
[  0.080] recv DATA frame <length=3786, flags=0x00, stream_id=1>
[  0.080] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.081] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.093] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.093] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.094] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.094] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.094] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.096] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.096] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=0>
          (window_size_increment=36554)
[  0.096] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=1>
          (window_size_increment=36554)
[  0.108] recv DATA frame <length=3689, flags=0x00, stream_id=1>
[  0.108] recv DATA frame <length=0, flags=0x01, stream_id=1>
          ; END_STREAM
[  0.108] send GOAWAY frame <length=8, flags=0x00, stream_id=0>
          (last_stream_id=0, error_code=NO_ERROR(0), opaque_data(0)=[])

The HTTP Upgrade is performed like this:

$ nghttp -nvu http://nghttp2.org
[  0.013] HTTP Upgrade request
GET / HTTP/1.1
Host: nghttp2.org
Connection: Upgrade, HTTP2-Settings
Upgrade: h2c-14
HTTP2-Settings: AwAAAGQEAAD__wUAAAAB
Accept: */*
User-Agent: nghttp2/0.4.0-DEV


[  0.024] HTTP Upgrade response
HTTP/1.1 101 Switching Protocols
Connection: Upgrade
Upgrade: h2c-14


[  0.024] HTTP Upgrade success
[  0.024] send SETTINGS frame <length=15, flags=0x00, stream_id=0>
          (niv=3)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_INITIAL_WINDOW_SIZE(4):65535]
          [SETTINGS_COMPRESS_DATA(5):1]
[  0.024] recv SETTINGS frame <length=10, flags=0x00, stream_id=0>
          (niv=2)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_INITIAL_WINDOW_SIZE(4):65535]
[  0.024] send SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[  0.024] (stream_id=1, noind=0) :status: 200
[  0.024] (stream_id=1, noind=0) accept-ranges: bytes
[  0.024] (stream_id=1, noind=0) age: 10
[  0.024] (stream_id=1, noind=0) content-length: 40243
[  0.024] (stream_id=1, noind=0) content-type: text/html
[  0.024] (stream_id=1, noind=0) date: Wed, 14 May 2014 15:16:34 GMT
[  0.024] (stream_id=1, noind=0) etag: "535d0eea-9d33"
[  0.024] (stream_id=1, noind=0) last-modified: Sun, 27 Apr 2014 14:06:34 GMT
[  0.024] (stream_id=1, noind=0) server: nginx/1.4.6 (Ubuntu)
[  0.024] (stream_id=1, noind=0) x-varnish: 2114900541 2114900540
[  0.024] (stream_id=1, noind=0) via: 1.1 varnish, 1.1 nghttpx
[  0.024] recv HEADERS frame <length=148, flags=0x04, stream_id=1>
          ; END_HEADERS
          (padlen=0)
          ; First response header
[  0.024] recv DATA frame <length=3786, flags=0x00, stream_id=1>
[  0.025] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.031] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.031] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.032] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.032] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.033] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.033] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.033] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=0>
          (window_size_increment=33164)
[  0.033] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=1>
          (window_size_increment=33164)
[  0.038] recv DATA frame <length=4096, flags=0x00, stream_id=1>
[  0.038] recv DATA frame <length=3689, flags=0x00, stream_id=1>
[  0.038] recv DATA frame <length=0, flags=0x01, stream_id=1>
          ; END_STREAM
[  0.038] recv SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[  0.038] send GOAWAY frame <length=8, flags=0x00, stream_id=0>
          (last_stream_id=0, error_code=NO_ERROR(0), opaque_data(0)=[])

Using the -s option, nghttp prints out some timing information for requests, sorted by completion time:

$ nghttp -nas https://nghttp2.org/
***** Statistics *****

Request timing:
  complete: relative time from protocol handshake to stream close
   request: relative   time  from   protocol   handshake  to   request
            transmission.  If '*' is shown, this was pushed by server.
   process: time for request and response
      code: HTTP status code
      size: number  of   bytes  received  as  response   body  without
            inflation.
       URI: request URI

sorted by 'complete'

complete  request    process  code size request path
 +11.07ms     +120us  10.95ms  200   9K /
 +16.77ms *  +8.80ms   7.98ms  200   8K /stylesheets/screen.css
 +27.00ms   +11.16ms  15.84ms  200   3K /javascripts/octopress.js
 +27.40ms   +11.16ms  16.24ms  200   3K /javascripts/modernizr-2.0.js
 +76.14ms   +11.17ms  64.97ms  200 171K /images/posts/with-pri-blog.png
 +88.52ms   +11.17ms  77.36ms  200 174K /images/posts/without-pri-blog.png

Using the -r option, nghttp writes more detailed timing data to the given file in HAR format.

nghttpd - server

nghttpd is a multi-threaded static web server.

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

nghttpd only accepts HTTP/2 connections via NPN/ALPN or direct HTTP/2 connections. No HTTP Upgrade is supported.

The -p option allows users to configure server push.

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

$ nghttpd --no-tls -v 8080
IPv4: listen on port 8080
IPv6: listen on port 8080
[id=1] [ 15.921] send SETTINGS frame <length=10, flags=0x00, stream_id=0>
          (niv=2)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_COMPRESS_DATA(5):1]
[id=1] [ 15.921] recv SETTINGS frame <length=15, flags=0x00, stream_id=0>
          (niv=3)
          [SETTINGS_MAX_CONCURRENT_STREAMS(3):100]
          [SETTINGS_INITIAL_WINDOW_SIZE(4):65535]
          [SETTINGS_COMPRESS_DATA(5):1]
[id=1] [ 15.921] (stream_id=1, noind=0) :authority: localhost:8080
[id=1] [ 15.921] (stream_id=1, noind=0) :method: GET
[id=1] [ 15.921] (stream_id=1, noind=0) :path: /
[id=1] [ 15.921] (stream_id=1, noind=0) :scheme: http
[id=1] [ 15.921] (stream_id=1, noind=0) accept: */*
[id=1] [ 15.921] (stream_id=1, noind=0) accept-encoding: gzip, deflate
[id=1] [ 15.921] (stream_id=1, noind=0) user-agent: nghttp2/0.4.0-DEV
[id=1] [ 15.921] recv HEADERS frame <length=48, flags=0x05, stream_id=1>
          ; END_STREAM | END_HEADERS
          (padlen=0)
          ; Open new stream
[id=1] [ 15.921] recv SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[id=1] [ 15.921] send SETTINGS frame <length=0, flags=0x01, stream_id=0>
          ; ACK
          (niv=0)
[id=1] [ 15.921] send HEADERS frame <length=82, flags=0x04, stream_id=1>
          ; END_HEADERS
          (padlen=0)
          ; First response header
          :status: 200
          cache-control: max-age=3600
          content-length: 612
          date: Wed, 14 May 2014 15:19:03 GMT
          last-modified: Sat, 08 Mar 2014 16:04:06 GMT
          server: nghttpd nghttp2/0.4.0-DEV
[id=1] [ 15.922] send DATA frame <length=381, flags=0x20, stream_id=1>
          ; COMPRESSED
[id=1] [ 15.922] send DATA frame <length=0, flags=0x01, stream_id=1>
          ; END_STREAM
[id=1] [ 15.922] stream_id=1 closed
[id=1] [ 15.922] recv GOAWAY frame <length=8, flags=0x00, stream_id=0>
          (last_stream_id=0, error_code=NO_ERROR(0), opaque_data(0)=[])
[id=1] [ 15.922] closed

nghttpx - proxy

nghttpx is a multi-threaded reverse proxy for h2-14, SPDY and HTTP/1.1, and powers http://nghttp2.org and supports HTTP/2 server push.

nghttpx implements important performance-oriented features in TLS, such as session IDs, session tickets (with automatic key rotation), OCSP stapling, dynamic record sizing, ALPN/NPN, forward secrecy and SPDY & HTTP/2.

nghttpx has several operational modes:

Mode option	Frontend	Backend	Note
default mode	HTTP/2, SPDY, HTTP/1.1 (TLS)	HTTP/1.1	Reverse proxy
--http2-proxy	HTTP/2, SPDY, HTTP/1.1 (TLS)	HTTP/1.1	SPDY proxy
--http2-bridge	HTTP/2, SPDY, HTTP/1.1 (TLS)	HTTP/2 (TLS)
--client	HTTP/2, HTTP/1.1	HTTP/2 (TLS)
--client-proxy	HTTP/2, HTTP/1.1	HTTP/2 (TLS)	Forward proxy

The interesting mode at the moment is the default mode. It works like a reverse proxy and listens for h2-14, SPDY and HTTP/1.1 and can be deployed as a SSL/TLS terminator for existing web server.

The default mode, --http2-proxy and --http2-bridge modes use SSL/TLS in the frontend connection by default. To disable SSL/TLS, use the --frontend-no-tls option. If that option is used, SPDY is disabled in the frontend and incoming HTTP/1.1 connections can be upgraded to HTTP/2 through HTTP Upgrade.

The --http2-bridge, --client and --client-proxy modes use SSL/TLS in the backend connection by deafult. To disable SSL/TLS, use the --backend-no-tls option.

nghttpx supports a configuration file. See the --conf option and sample configuration file nghttpx.conf.sample.

In the default mode, (without any of --http2-proxy, --http2-bridge, --client-proxy and --client options), nghttpx works as reverse proxy to the backend server:

Client <-- (HTTP/2, SPDY, HTTP/1.1) --> nghttpx <-- (HTTP/1.1) --> Web Server
                                      [reverse proxy]

With the --http2-proxy option, it works as a so called secure proxy (aka SPDY proxy):

Client <-- (HTTP/2, SPDY, HTTP/1.1) --> nghttpx <-- (HTTP/1.1) --> Proxy
                                       [secure proxy]          (e.g., Squid, ATS)

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

At the time of this writing, Chrome is the only browser which supports secure proxy. One way to configure Chrome to use a secure proxy is to create a 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 on. Please note that Chrome requires a valid certificate for secure proxy.

Then run Chrome with the following arguments:

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

With --http2-bridge, it accepts HTTP/2, SPDY and HTTP/1.1 connections and communicates with the backend in HTTP/2:

Client <-- (HTTP/2, SPDY, HTTP/1.1) --> nghttpx <-- (HTTP/2) --> Web or HTTP/2 Proxy etc
                                                                     (e.g., nghttpx -s)

With --client-proxy, it works as a forward proxy and expects that the backend is an HTTP/2 proxy:

Client <-- (HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/2) --> HTTP/2 Proxy
                                 [forward proxy]               (e.g., nghttpx -s)

The Client needs to be configured to use nghttpx as a forward proxy. The frontend HTTP/1.1 connection can be upgraded to HTTP/2 through HTTP Upgrade. With the above configuration, one can use HTTP/1.1 client to access and test their HTTP/2 servers.

With --client, it works as a reverse proxy and expects that the backend is an HTTP/2 Web server:

Client <-- (HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/2) --> Web Server
                                [reverse proxy]

The frontend HTTP/1.1 connection can be upgraded to HTTP/2 through HTTP Upgrade.

For the operation modes which talk to the backend in HTTP/2 over SSL/TLS, the backend connections can be tunneled through an HTTP proxy. The proxy is specified using --backend-http-proxy-uri. The following figure illustrates the example of the --http2-bridge and --backend-http-proxy-uri options to talk to the outside HTTP/2 proxy through an HTTP proxy:

Client <-- (HTTP/2, SPDY, HTTP/1.1) --> nghttpx <-- (HTTP/2) --

        --===================---> HTTP/2 Proxy
          (HTTP proxy tunnel)     (e.g., nghttpx -s)

Benchmarking tool

The h2load program is a benchmarking tool for HTTP/2 and SPDY. The SPDY support is enabled if the program was built with the spdylay library. The UI of h2load is heavily inspired by weighttp (https://github.com/lighttpd/weighttp). The typical usage is as follows:

$ h2load -n100000 -c100 -m100 https://localhost:8443/
starting benchmark...
spawning thread #0: 100 concurrent clients, 100000 total requests
Protocol: TLSv1.2
Cipher: ECDHE-RSA-AES128-GCM-SHA256
progress: 10% done
progress: 20% done
progress: 30% done
progress: 40% done
progress: 50% done
progress: 60% done
progress: 70% done
progress: 80% done
progress: 90% done
progress: 100% done

finished in 7.10s, 14092 req/s, 55.67MB/s
requests: 100000 total, 100000 started, 100000 done, 100000 succeeded, 0 failed, 0 errored
status codes: 100000 2xx, 0 3xx, 0 4xx, 0 5xx
traffic: 414200800 bytes total, 2723100 bytes headers, 409600000 bytes data
                     min         max         mean         sd        +/- sd
time for request:   283.86ms       1.46s    659.70ms    150.87ms    84.68%

The above example issued total 100,000 requests, using 100 concurrent clients (in other words, 100 HTTP/2 sessions), and a maximum of 100 streams per client. With the -t option, h2load will use multiple native threads to avoid saturating a single core on client side.

Warning

Don't use this tool against publicly available servers. That is considered a DOS attack. Please only use it against your private servers.

HPACK tools

The src directory contains the HPACK tools. The deflatehd program is a command-line header compression tool. The inflatehd program is a command-line header decompression tool. Both tools read input from stdin and write output to stdout. Errors are written to stderr. They take JSON as input and output. We (mostly) use the same JSON data format described at https://github.com/http2jp/hpack-test-case.

deflatehd - header compressor

The deflatehd program reads JSON data or HTTP/1-style header fields from stdin and outputs compressed header block in JSON.

For the JSON input, the root JSON object must include a cases key. Its value has to include the sequence of input header set. They share the same compression context and are processed in the order they appear. Each item in the sequence is a JSON object and it must include a headers key. Its value is an array of JSON objects, which includes exactly one name/value pair.

Example:

{
  "cases":
  [
    {
      "headers": [
        { ":method": "GET" },
        { ":path": "/" }
      ]
    },
    {
      "headers": [
        { ":method": "POST" },
        { ":path": "/" }
      ]
    }
  ]
}

With the -t option, the program can accept more familiar HTTP/1 style header field blocks. Each header set is delimited by an empty line:

Example:

:method: GET
:scheme: https
:path: /

:method: POST
user-agent: nghttp2

The output is in JSON object. It should include a cases key and its value is an array of JSON objects, which has at least the following keys:

seq

The index of header set in the input.

input_length

The sum of the length of the name/value pairs in the input.

output_length

The length of the compressed header block.

percentage_of_original_size

input_length / output_length * 100

wire

The compressed header block as a hex string.

headers

The input header set.

header_table_size

The header table size adjusted before deflating the header set.

Examples:

{
  "cases":
  [
    {
      "seq": 0,
      "input_length": 66,
      "output_length": 20,
      "percentage_of_original_size": 30.303030303030305,
      "wire": "01881f3468e5891afcbf83868a3d856659c62e3f",
      "headers": [
        {
          ":authority": "example.org"
        },
        {
          ":method": "GET"
        },
        {
          ":path": "/"
        },
        {
          ":scheme": "https"
        },
        {
          "user-agent": "nghttp2"
        }
      ],
      "header_table_size": 4096
    }
    ,
    {
      "seq": 1,
      "input_length": 74,
      "output_length": 10,
      "percentage_of_original_size": 13.513513513513514,
      "wire": "88448504252dd5918485",
      "headers": [
        {
          ":authority": "example.org"
        },
        {
          ":method": "POST"
        },
        {
          ":path": "/account"
        },
        {
          ":scheme": "https"
        },
        {
          "user-agent": "nghttp2"
        }
      ],
      "header_table_size": 4096
    }
  ]
}

The output can be used as the input for inflatehd and deflatehd.

With the -d option, the extra header_table key is added and its associated value includes the state of dynamic header table after the corresponding header set was processed. The value includes at least the following keys:

entries

The entry in the header table. If referenced is true, it is in the reference set. The size includes the overhead (32 bytes). The index corresponds to the index of header table. The name is the header field name and the value is the header field value.

size

The sum of the spaces entries occupied, this includes the entry overhead.

max_size

The maximum header table size.

deflate_size

The sum of the spaces entries occupied within max_deflate_size.

max_deflate_size

The maximum header table size the encoder uses. This can be smaller than max_size. In this case, the encoder only uses up to first max_deflate_size buffer. Since the header table size is still max_size, the encoder has to keep track of entries ouside the max_deflate_size but inside the max_size and make sure that they are no longer referenced.

Example:

{
  "cases":
  [
    {
      "seq": 0,
      "input_length": 66,
      "output_length": 20,
      "percentage_of_original_size": 30.303030303030305,
      "wire": "01881f3468e5891afcbf83868a3d856659c62e3f",
      "headers": [
        {
          ":authority": "example.org"
        },
        {
          ":method": "GET"
        },
        {
          ":path": "/"
        },
        {
          ":scheme": "https"
        },
        {
          "user-agent": "nghttp2"
        }
      ],
      "header_table_size": 4096,
      "header_table": {
        "entries": [
          {
            "index": 1,
            "name": "user-agent",
            "value": "nghttp2",
            "referenced": true,
            "size": 49
          },
          {
            "index": 2,
            "name": ":scheme",
            "value": "https",
            "referenced": true,
            "size": 44
          },
          {
            "index": 3,
            "name": ":path",
            "value": "/",
            "referenced": true,
            "size": 38
          },
          {
            "index": 4,
            "name": ":method",
            "value": "GET",
            "referenced": true,
            "size": 42
          },
          {
            "index": 5,
            "name": ":authority",
            "value": "example.org",
            "referenced": true,
            "size": 53
          }
        ],
        "size": 226,
        "max_size": 4096,
        "deflate_size": 226,
        "max_deflate_size": 4096
      }
    }
    ,
    {
      "seq": 1,
      "input_length": 74,
      "output_length": 10,
      "percentage_of_original_size": 13.513513513513514,
      "wire": "88448504252dd5918485",
      "headers": [
        {
          ":authority": "example.org"
        },
        {
          ":method": "POST"
        },
        {
          ":path": "/account"
        },
        {
          ":scheme": "https"
        },
        {
          "user-agent": "nghttp2"
        }
      ],
      "header_table_size": 4096,
      "header_table": {
        "entries": [
          {
            "index": 1,
            "name": ":method",
            "value": "POST",
            "referenced": true,
            "size": 43
          },
          {
            "index": 2,
            "name": "user-agent",
            "value": "nghttp2",
            "referenced": true,
            "size": 49
          },
          {
            "index": 3,
            "name": ":scheme",
            "value": "https",
            "referenced": true,
            "size": 44
          },
          {
            "index": 4,
            "name": ":path",
            "value": "/",
            "referenced": false,
            "size": 38
          },
          {
            "index": 5,
            "name": ":method",
            "value": "GET",
            "referenced": false,
            "size": 42
          },
          {
            "index": 6,
            "name": ":authority",
            "value": "example.org",
            "referenced": true,
            "size": 53
          }
        ],
        "size": 269,
        "max_size": 4096,
        "deflate_size": 269,
        "max_deflate_size": 4096
      }
    }
  ]
}

inflatehd - header decompressor

The inflatehd program reads JSON data from stdin and outputs decompressed name/value pairs in JSON.

The root JSON object must include the cases key. Its value has to include the sequence of compressed header blocks. They share the same compression context and are processed in the order they appear. Each item in the sequence is a JSON object and it must have at least a wire key. Its value is a compressed header block as a hex string.

Example:

{
  "cases":
  [
    { "wire": "8285" },
    { "wire": "8583" }
  ]
}

The output is a JSON object. It should include a cases key and its value is an array of JSON objects, which has at least following keys:

seq

The index of the header set in the input.

headers

A JSON array that includes decompressed name/value pairs.

wire

The compressed header block as a hex string.

header_table_size

The header table size adjusted before inflating compressed header block.

Example:

{
  "cases":
  [
    {
      "seq": 0,
      "wire": "01881f3468e5891afcbf83868a3d856659c62e3f",
      "headers": [
        {
          ":authority": "example.org"
        },
        {
          ":method": "GET"
        },
        {
          ":path": "/"
        },
        {
          ":scheme": "https"
        },
        {
          "user-agent": "nghttp2"
        }
      ],
      "header_table_size": 4096
    }
    ,
    {
      "seq": 1,
      "wire": "88448504252dd5918485",
      "headers": [
        {
          ":method": "POST"
        },
        {
          ":path": "/account"
        },
        {
          "user-agent": "nghttp2"
        },
        {
          ":scheme": "https"
        },
        {
          ":authority": "example.org"
        }
      ],
      "header_table_size": 4096
    }
  ]
}

The output can be used as the input for deflatehd and inflatehd.

With the -d option, the extra header_table key is added and its associated value includes the state of the dynamic header table after the corresponding header set was processed. The format is the same as deflatehd.

libnghttp2_asio: High level HTTP/2 C++ library

libnghttp2_asio is C++ library built on top of libnghttp2 and provides high level abstraction API to build HTTP/2 applications. It depends on the Boost::ASIO library and OpenSSL. Currently libnghttp2_asio provides both client and server APIs.

libnghttp2_asio is not built by default. Use the --enable-asio-lib configure flag to build libnghttp2_asio. The required Boost libraries are:

• Boost::Asio
• Boost::System
• Boost::Thread

The server API is designed to build an HTTP/2 server very easily to utilize C++11 anonymous functions and closures. The bare minimum example of an HTTP/2 server looks like this:

#include <nghttp2/asio_http2_server.h>

using namespace nghttp2::asio_http2;
using namespace nghttp2::asio_http2::server;

int main(int argc, char *argv[]) {
  boost::system::error_code ec;
  http2 server;

  server.handle("/", [](const request &req, const response &res) {
    res.write_head(200);
    res.end("hello, world\n");
  });

  if (server.listen_and_serve(ec, "localhost", "3000")) {
    std::cerr << "error: " << ec.message() << std::endl;
  }
}

Here is sample code to use the client API:

#include <iostream>

#include <nghttp2/asio_http2_client.h>

using boost::asio::ip::tcp;

using namespace nghttp2::asio_http2;
using namespace nghttp2::asio_http2::client;

int main(int argc, char *argv[]) {
  boost::system::error_code ec;
  boost::asio::io_service io_service;

  // connect to localhost:3000
  session sess(io_service, "localhost", "3000");

  sess.on_connect([&sess](tcp::resolver::iterator endpoint_it) {
    boost::system::error_code ec;

    auto req = sess.submit(ec, "GET", "http://localhost:3000/");

    req->on_response([](const response &res) {
      // print status code and response header fields.
      std::cerr << "HTTP/2 " << res.status_code() << std::endl;
      for (auto &kv : res.header()) {
        std::cerr << kv.first << ": " << kv.second.value << "\n";
      }
      std::cerr << std::endl;

      res.on_data([](const uint8_t *data, std::size_t len) {
        std::cerr.write(reinterpret_cast<const char *>(data), len);
        std::cerr << std::endl;
      });
    });

    req->on_close([&sess](uint32_t error_code) {
      // shutdown session after first request was done.
      sess.shutdown();
    });
  });

  sess.on_error([](const boost::system::error_code &ec) {
    std::cerr << "error: " << ec.message() << std::endl;
  });

  io_service.run();
}

For more details, see the documentation of libnghttp2_asio.

Python bindings

The python directory contains nghttp2 Python bindings. The bindings currently provide HPACK compressor and decompressor classes and an HTTP/2 server.

The extension module is called nghttp2.

make will build the bindings and target Python version is determined by the configure script. If the detected Python version is not what you expect, specify a path to Python executable in a PYTHON variable as an argument to configure script (e.g., ./configure PYTHON=/usr/bin/python3.4).

The following example code illustrates basic usage of the HPACK compressor and decompressor in Python:

import binascii
import nghttp2

deflater = nghttp2.HDDeflater()
inflater = nghttp2.HDInflater()

data = deflater.deflate([(b'foo', b'bar'),
                         (b'baz', b'buz')])
print(binascii.b2a_hex(data))

hdrs = inflater.inflate(data)
print(hdrs)

The nghttp2.HTTP2Server class builds on top of the asyncio event loop. On construction, RequestHandlerClass must be given, which must be a subclass of nghttp2.BaseRequestHandler class.

The BaseRequestHandler class is used to handle the HTTP/2 stream. By default, it does nothing. It must be subclassed to handle each event callback method.

The first callback method invoked is on_headers(). It is called when HEADERS frame, which includes the request header fields, has arrived.

If the request has a request body, on_data(data) is invoked for each chunk of received data.

Once the entire request is received, on_request_done() is invoked.

When the stream is closed, on_close(error_code) is called.

The application can send a response using send_response() method. It can be used in on_headers(), on_data() or on_request_done().

The application can push resources using the push() method. It must be used before the send_response() call.

The following instance variables are available:

client_address

Contains a tuple of the form (host, port) referring to the client's address.

stream_id

Stream ID of this stream.

scheme

Scheme of the request URI. This is a value of :scheme header field.

method

Method of this stream. This is a value of :method header field.

host

This is a value of :authority or host header field.

path

This is a value of :path header field.

The following example illustrates the HTTP2Server and BaseRequestHandler usage:

#!/usr/bin/env python

import io, ssl
import nghttp2

class Handler(nghttp2.BaseRequestHandler):

    def on_headers(self):
        self.push(path='/css/bootstrap.css',
                  request_headers = [('content-length', '3')],
                  status=200,
                  body='foo')

        self.push(path='/js/bootstrap.js',
                  method='GET',
                  request_headers = [('content-length', '10')],
                  status=200,
                  body='foobarbuzz')

        self.send_response(status=200,
                           headers = [('content-type', 'text/plain')],
                           body=io.BytesIO(b'nghttp2-python FTW'))

ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
ctx.options = ssl.OP_ALL | ssl.OP_NO_SSLv2
ctx.load_cert_chain('server.crt', 'server.key')

# give None to ssl to make the server non-SSL/TLS
server = nghttp2.HTTP2Server(('127.0.0.1', 8443), Handler, ssl=ctx)
server.serve_forever()

Contribution

[This text was composed based on 1.2. License section of curl/libcurl project.]

When contributing with code, you agree to put your changes and new code under the same license nghttp2 is already using unless stated and agreed otherwise.

When changing existing source code, do not alter the copyright of the original file(s). The copyright will still be owned by the original creator(s) or those who have been assigned copyright by the original author(s).

By submitting a patch to the nghttp2 project, you (or your employer, as the case may be) agree to assign the copyright of your submission to us. .. the above really needs to be reworded to pass legal muster. We will credit you for your changes as far as possible, to give credit but also to keep a trace back to who made what changes. Please always provide us with your full real name when contributing!

See Contribution Guidelines for more details.