We released nghttp2 v0.7.7.

This is basically the same as v0.7.6. We missed updating man pages in v0.7.6 release, so v0.7.7.

We released nghttp2 v0.7.6.

This release made several enhancements to the library. First we made sending trailer part (trailer header field) easier. Previously, nghttp2_submit_request() and nghttp2_submit_response() sets END_STREAM flag set for the last DATA frame and we have no way to send trailer part. To fix this issue, we added NGHTTP2_DATA_FLAG_NO_END_STREAM flag. If application sets this flag along side with NGHTTP2_DATA_FLAG_EOF in nghttp2_data_source_read_callback, the library does not set END_STREAM flag. Then the application can use new nghttp2_submit_trailer() function to send trailer part, which is a HEADERS frame with END_STREAM flag set. The all bundled applications and libnghttp2_asio utilize this feature to send trailer part.

Second enhancement is that now library refuses PUSH_PROMISE frame if unacked local SETTINGS includes ENABLE_PUSH == 0 (disabling server push). Previously the library refuses PUSH_PROMISE only after SETTINGS are acked.

nghttpx has several enhancements in this release. It now accepts multiple backend server addresses for HTTP/2 backend. Previously the number of HTTP/2 backend server is limited to 1 per worker. In this release, we added --backend-http2-connections-per-worker option to specify the number of HTTP/2 backend connection per worker. As the library gets enhanced support for trailer part, nghttpx now supports trailer part for both HTTP/2 and HTTP/1. That means nghttpx can proxy gRPC traffic, which requires trailer support. we also fixed the bug that server push is broken after HTTP upgrade. The another bug, which crashes nghttpx when upgrading HTTP/2 failed, was also fixed.

Stefan Eissing wrote a patch to nghttpx to replace C++11 thread_local keyword with traditional pthread functions. Since Mac OS X’s xcode toolchain does not support thread_local, it may be possible to use nghttpx in multi-threaded mode on Mac OS X finally.

For nghttpd and nghttp, we added --trailer option to send trailer part to exercise trailer part functionality.

For nghttp, Kazuho Oku kindly sent us a patch not to send pseudo-headers in HTTP Upgrade request (which itself is HTTP/1.1 message).

nghttp now treats request as success only if it sees the END_STREAM from peer. Previously it treated a request as success if it is closed (with/without error), before connection close.

We fixed nghttpd bug that “date” header field value is not updated.

For python binding, we fixed bug that push response header fields are not passed to callback in client library.

We rewrite libnghttp2_asio library and its API is not compatible to the earlier versions. Also we added client API. See libnghttp2_asio documentation about the example use of these APIs.

We released nghttp2 v0.7.5. This release still uses h2-14 identifier in library code, but h2-14 through to final draft version is binary compatible and nghttp2 supports all features in the latest draft.

In this release, we implemented validation against HTTP Messaging semantics described in HTTP/2 draft, section 8.. We do not perform all the checks described in that section, but this time we implemented basic and fundamental checks which makes application code much cleaner. This validation pretty much restricts nghttp2 library to HTTP/2 use only. For those applications to use nghttp2 as non-http use case, use nghttp2_option_set_no_http_messaging() to disable this feature. For more detailed information about this subject, see the manual.

Previously, in verbose output of nghttp, nghttpd and nghttpx, we show “noind=1” if header field is encoded in HPACK Never Indexed representation. Now it is shown as “sensitive” to make its meaning more clearer. Other implementations use the same wording.

nghttpd got new option -a, --address=<ADDR> that allows nghttpd to bind to a non-default address. This feature was contributed by Brian Card.

In the previous release, we updated nghttp --stat option. Now we make its terminology and processing model to match those in Resource Timing TR.

Let’s talk about nghttpx proxy server. It now supports UNIX domain socket for both frontend and backend. We omitted minor version in Via header field and access logging if HTTP version is HTTP/2. We fixed the bug that nghttpx crashes if it receives more bytes than Content-Length from HTTP/1 backend.

We fixed asio-sv2 so that it compiles under OS X.

And finally as we know HTTP/2 specification was approved by IETF, we now announce h2 ALPN ID in nghttp, nghttpd, nghttpx and h2load!

For future release plan, we continue to develop nghttp2 in 0.7 series until HTTP/2 RFC is published. After RFC publication we’ll finally release version 1.0.0.

We released nghttp2 v0.7.4. This release still uses h2-14 identifier in library code.

In this release, we fixed few corner case bugs in the library code.

We rewrite nghttp’s --stat option output completely. It now shows the timings of request and completion of each resources:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

$ 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
 +12.76ms     +118us  12.65ms  200   9K /
 +20.75ms * +10.51ms  10.23ms  200   8K /stylesheets/screen.css
 +32.89ms   +12.86ms  20.03ms  200   3K /javascripts/octopress.js
 +33.12ms   +12.86ms  20.26ms  200   3K /javascripts/modernizr-2.0.js
+124.05ms   +12.87ms 111.18ms  200 171K /images/posts/with-pri-blog.png
+150.66ms   +12.86ms 137.80ms  200 174K /images/posts/without-pri-blog.png

The list is sorted by complete time, that is time point its stream was closed. Notice that request field of /stylesheets/screen.css has *, which means that it was pushed by server.

nghttpd has a bug that multiple -p option won’t work, but it is not fixed.

As we wrote in nghttp2.org enabled HTTP/2 server push, nghttpx gets HTTP/2 server push support by inspecting Link header field from backend server. nghttpx now rewrites Host and :authority header fields when forwarding to backend server by default. --no-host-rewrite option to disable it.

h2load now shows time for request min, max, mean and standard deviation:

1
2
3
4
5
6

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%

To make command-line operation easier, we added bash_completion files for nghttp, nghttpd, nghttpx and h2load. They reside in doc/bash_completion directory.

We implemented HTTP/2 server push in nghttpx and we enabled server push in nghttp2.org site.

When you access https://nghttp2.org via HTTP/2 protocol, CSS file /stylesheets/screen.css is pushed to client. If you inspect the response header closely, you will find Link header field like this:

1

link: </stylesheets/screen.css>; rel=preload; as=stylesheet

We operate nghttp2.org site using nghttpx proxy server in front and nginx on its back. The Link header field above is generated by nginx. When nghttpx proxy sees this in response header, it initiates server push for resource denoted by path enclosed by ‘<’ and ‘>’. We specifically check link relation preload to decide the resource should be pushed or not. See the manual page to enable this feature in nghttpx.

We also push different resources, CSS and font files, under https://nghttp2.org/documentation/

We released nghttp2 v0.7.3. v0.7.2 was replaced with v0.7.3 shortly after its release because it contains apparent bugs. The v0.7.3 release still uses h2-14 identifier in library code.

Since v0.7.3 is quick bug fix release, we summarize changes made in both v0.7.3 and v0.7.2. We added nghttp2_submit_shutdown_notice() API function. It is intended to be used by server and tells client that server has started graceful shutdown by sending GOAWAY with (1 << 31) - 1 as last-stream-ID. We also added nghttp2_session_get_last_proc_stream_id(), which returns the largest stream ID the library called nghttp2_on_frame_recv_callback() for and can be passed as last-stream-id paramter to nghttp2_submit_goaway() if application has no more specific knowledge about last-stream-ID.

nghttpx has several options added. They are mostly optimzation purpose. We tightened up HTTP header field validation in nghttpx, particularly for Content-Length header field.

To upgrade ease of use, options which take SIZE as metavar can use units (K, M and G, powers of 1024) along with leading digits. For example, now we can specify --read-rate=4K, which is identical to --read-rate=4096.

Since nghttpx has many features, we started to add integration testing framework using Go programming language and its go test feature. It resides in integration-tests directory.

We just released nghttp2 v0.7.1. The library documentation is still based on h2-14. nghttp, nghttpd, nghttpx and h2load additionally advertise h2-16 ALPN token to interop with the implementations which require h2-16.

This release fixes GOAWAY handling to conform to the HTTP/2 specification. TLS read/write error in nghttp, nghttpd, nghttpx and h2load has been fixed. We enabled TLS session ticket with automatic key rotation in nghttpx. We also add an option to specify key parameter from file (but without automatic rotation) to nghttpx to share same keys with multiple instances. For documentation wise, man pages are now now generated using Sphinx. We don’t use help2man anymore.

We just released nghttp2 v0.7.0. The library documentation is still based on h2-14. nghttp, nghttpd, nghttpx and h2load additionally advertise h2-16 ALPN token to interop with the implementations which require h2-16.

We added some new APIs. The custom memory allocator nghttp2_mem was introduced in this release. We have also added several initialization fucntions to use this allocator. The new nghttp2_session_set_next_stream_id() and nghttp2_session_get_next_stream_id() functions have been added. nghttp2_session_set_next_stream_id() sets next outgoing stream ID, while nghttp2_session_get_next_stream_id() returns the next outgoing stream ID. These fucntions are useful when streams are used as anchors in dependency tree and leave them idle.

Now nghttp, nghttpd, nghttpx and h2load applications use libev instead of libevent. Libevent is still required to build source files under examples directory.

nghttp has supported the feature to reading files from stdin to upload to a server for quite some time, but it only supported files and did not work with non-file (e.g., echo -n "foo" | nghttp -d- http://nghttp2.org/). Kazuho Oku contributed the patch to fix this issue.

nghttp2 v0.6.7 has been released. We still advertises h2-14 support in ALPN, but we have merged h2-16 features in this release. They are binary compatible, so we use h2-14, which is the interop draft version.

For library code, there are several changes. Due to the change made into h2-16, PRIORITY frame is now allowed in any state state. Also we refined GOAWAY handling by utilizing last-stream-id extensively. nghttp2_session_want_read() and nghttp2_session_want_write() reflect this change so as to make graceful shutdown easier.

nghttpx got some enhancement. It now has the feature to configure access logging format. In addition to the usual combined log fields, we have added additional custom fields. Some of the new custom fields were contributed by Lucas Pardue. The cipher suite requirement in nghttpx was now removed and it only requires TLSv1.2 for HTTP/2 connection due to the changes in h2-16. nghttpx also disabled spdy/3 and spdy/2 by default, since they are now being deprecated world wide.

nghttp got some interesting options. The most notable option is -r. If it is given with file name, nghttp saves HTTP transactions in well-known HAR format. It is expected to be used with -a option.

h2load finally got ALPN support.

For python bindings, client implementation was contributed by Kyle Schomp.

nghttp command-line client has some useful options to test your HTTP/2 server implementation. This blog post introduces such command-line options.

We recommend to enable -nv options for nghttp to see what is happening on HTTP/2 framing layer. It is very good source of information for debugging.

Flow control

To test whether server enfoces flow control window size advertised by client, use -W and/or -w option. -W option specifies connection level flow control window size. It specifies the number of bits rather than the size directly, so if you specify -W14, the window size becomes 16383 (= 2 ** 14 - 1). Similarly, -w option specifies stream level flow control window size. Since HTTP/2 does not have dedicated way to reduce connection level window size, we achieve this by not sending WINDOW_UPDATE frame to server to keep the available window size less than or equal to the specified size. Therefore, to test connection window size less than default value which is 65535, nghttp should request resource more than 65535 bytes, otherwise -W has no effect. If nghttp found any errors related to flow control, it emits FLOW_CONTROL_ERROR and exists nonzero.

Header compression and multiplexing

HTTP/2 uses header compression technique called HPACK. We know that, by iterop experience, single request/response is not enough to test HPACK. The problem is more likely happening after several request/response transactions. This is because HPACK uses stateful compression mechanism and it requires both server and client share same compression context. If they are out of sync, problem appears. So testing HPACK must be done with multiple requests and responses. This means that it also exercises multiplexing.

For this purpose, -a option is handy. If -a is used, nghttp parses downloaded HTML file and finds statically linked resources, such as CSS, Javascript and images. Then it requests them which are multiplexed in the same HTTP/2 session (same connection).

If nghttp client found an error while decoding header block, it emits COMPRESSION_ERROR and exists nonzero.

Uploading

To upload the content of a file, use -d option. By default, nghttp adds content-length header field when uploading data. Specifying --no-content-length option will omit content-length header field from request header.

Padding

-b option adds given number of bytes to HEADERS or DATA frame as padding. This will verify that whether server can correctly parse frames by taking into account the existence of padding bytes.

CONTINUATION frame

Using --continuation will send very large headers to server using CONTINUATION frame. The total header block size (HEADERS + CONTINUATION) is around 18K bytes.

Priority

Use -a option and see that how server reacts to priority hints given from client. If -a is used, nghttp parses downloaded HTML file and finds statically linked resources, such as CSS, Javascript and images. Then it requests them which are multiplexed in the same HTTP/2 session (same connection). By default, nghttp prioritizes resources as follows:

1. HTML (highest)
2. CSS (high)
3. Javascripts (JS) (middle)
4. images (low)

Then it creates dependency tree and issues requests with this dependency hints. To verify how server reacts to this hints, -r option is very useful. It saves the HTTP transactions to given file as HAR format. Then you can use HAR file viewer to see the load times. To compare the result without prority, issue the same request with --no-dep option, which entirely omits priority hints.