nghttp2 - HTTP/2 C Library¶
This is an implementation of Hypertext Transfer Protocol version 2 in C.
The framing layer of HTTP/2 is implemented as a form of reusable C library. On top of that, we have implemented HTTP/2 client, server and proxy. We have also developed load test and benchmarking tool for HTTP/2 and SPDY.
HPACK encoder and decoder are available as public API.
The experimental high level C++ library is also available.
We have Python binding of this libary, but we have not covered everything yet.
Development Status¶
We started to implement h2-14 (http://tools.ietf.org/html/draft-ietf-httpbis-http2-14), the header compression (http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09).
The nghttp2 code base was forked from 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 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 src directory, the following packages are required:
- OpenSSL >= 1.0.1
- libev >= 4.15
- zlib >= 1.2.3
ALPN support requires unreleased version OpenSSL >= 1.0.2.
To enable 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 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, you need the following packages installed:
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/
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
To compile source code, gcc >= 4.8.3 or clang >= 3.4 is required.
Note
Mac OS X users may need --disable-threads configure option to disable multi threading in nghttpd, nghttpx and h2load to prevent them from crashing. Patch is welcome to make multi threading work on Mac OS X platform.
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.
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 nghttpx proxy server. The tests are written in 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 test subject server.
Client, Server and Proxy programs¶
The src directory contains 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)=[])
With -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
With -r option, nghttp writes more detailed timing data to 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 the HTTP/2 connection via NPN/ALPN or direct HTTP/2 connection. No HTTP Upgrade is supported.
-p option allows users to configure server push.
Just like nghttp, it has verbose output mode for framing information. Here is sample output from nghttpd server:
$ 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 nghttp2.org site and supports HTTP/2 server push. It has several operation 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 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 --frontend-no-tls option. If that option is used, SPDY is disabled in the frontend and incoming HTTP/1.1 connection 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 --backend-no-tls option.
nghttpx supports configuration file. See --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 --http2-proxy option, it works as 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 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. The one way to configure Chrome to use secure 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 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 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 option, it works as forward proxy and expects that the backend is 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 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 option, it works as reverse proxy and expects that the backend is 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 HTTP proxy. The proxy is specified using --backend-http-proxy-uri option. The following figure illustrates the example of --http2-bridge and --backend-http-proxy-uri options to talk to the outside HTTP/2 proxy through 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 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 100000 requests, using 100 concurrent clients (in other words, 100 HTTP/2 sessions), and maximum 100 streams per client. With -t option, h2load will use multiple native threads to avoid saturating single core on client side.
Warning
Don't use this tool against publicly available servers. That is considered a DOS attack. Please only use against your private servers.
HPACK tools¶
The src directory contains HPACK tools. The deflatehd is a command-line header compression tool. The inflatehd is command-line header decompression tool. Both tools read input from stdin and write output to stdout. The errors are written to stderr. They take JSON as input and output. We use (mostly) same JSON data format described at https://github.com/http2jp/hpack-test-case
deflatehd - header compressor¶
The deflatehd 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 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 headers key. Its value is an array of a JSON object, which includes exactly one name/value pair.
Example:
{
"cases":
[
{
"headers": [
{ ":method": "GET" },
{ ":path": "/" }
]
},
{
"headers": [
{ ":method": "POST" },
{ ":path": "/" }
]
}
]
}
With -t option, the program can accept more familiar HTTP/1 style header field block. Each header set is delimited by empty line:
Example:
:method: GET
:scheme: https
:path: /
:method: POST
user-agent: nghttp2
The output is JSON object. It should include cases key and its value is an array of JSON object, which has at least following keys:
- seq
- The index of header set in the input.
- input_length
- The sum of length of name/value pair in the input.
- output_length
- The length of compressed header block.
- percentage_of_original_size
- input_length / output_length * 100
- wire
- The compressed header block in hex string.
- headers
- The input header set.
- header_table_size
- The header table size adjusted before deflating 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 -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 encoder uses. This can be smaller than max_size. In this case, 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 reads JSON data from stdin and outputs decompressed name/value pairs in JSON.
The root JSON object must include cases key. Its value has to include the sequence of compressed header block. 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 wire key. Its value is a compressed header block in hex string.
Example:
{
"cases":
[
{ "wire": "8285" },
{ "wire": "8583" }
]
}
The output is JSON object. It should include cases key and its value is an array of JSON object, which has at least following keys:
- seq
- The index of header set in the input.
- headers
- The JSON array includes decompressed name/value pairs.
- wire
- The compressed header block in 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 -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 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 Boost::ASIO library and OpenSSL. Currently libnghttp2_asio provides client and server API.
libnghttp2_asio is not built by default. Use --enable-asio-lib configure flag to build libnghttp2_asio. The required Boost libraries are:
- Boost::Asio
- Boost::System
- Boost::Thread
Server API is designed to build HTTP/2 server very easily to utilize C++11 anonymous function and closure. The bare minimum example of 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 the sample code for client API use:
#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¶
This python directory contains nghttp2 Python bindings. The bindings currently provide HPACK compressor and decompressor classes and HTTP/2 server.
The extension module is called nghttp2.
make will build the bindings and target Python version is determined by configure script. If the detected Python version is not what you expect, specify a path to Python executable in PYTHON variable as an argument to configure script (e.g., ./configure PYTHON=/usr/bin/python3.4).
The following example code illustrates basic usage of 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 request header fields, has arrived.
If request has request body, on_data(data) is invoked for each chunk of received data.
When whole request is received, on_request_done() is invoked.
When stream is closed, on_close(error_code) is called.
The application can send response using send_response() method. It can be used in on_headers(), on_data() or on_request_done().
The application can push resource using push() method. It must be used before 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, you 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 are assumed to have the right to the code and to be allowed by your employer or whatever to hand over that patch/code to us. 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.