forest

This README is the one indexed from the repository at its latest ref, not from the tag for this version.

<div align = "center"><img src="images/icon.png" width="256" height="256" /></div>

<div align = "center">
  <h1>Forest.cr - HTTP2 Client and Server</h1>
</div>

<p align="center">
  <a href="https://crystal-lang.org">
    <img src="https://img.shields.io/badge/built%20with-crystal-000000.svg" /></a>
  <a href="https://github.com/636f7374/forest.cr/actions">
    <img src="https://github.com/636f7374/forest.cr/workflows/Continuous%20Integration/badge.svg" /></a>
  <a href="https://github.com/636f7374/forest.cr/releases">
    <img src="https://img.shields.io/github/release/636f7374/forest.cr.svg" /></a>
  <a href="https://github.com/636f7374/forest.cr/blob/master/license">
    <img src="https://img.shields.io/github/license/636f7374/forest.cr.svg"></a>
</p>

## Description

* Since Crystal language lacks a perfect HTTP2 implementation, we implemented it.
  * We spent some time to do this, it is not very easy.
  * We started looking at [many documents](#references) and started researching how to build a HTTP2 server.
* In the `Hpack`, `Huffman` part, we reference to the design of [ysbaddaden](https://github.com/ysbaddaden).
* Channel design (ConnectionPool) is used inside HTTP2 server.
* It currently supports most HTTP2 flow control features (excluding priority).
* It can currently be perfectly combined with HTTP1 server.
  * Including `Chunked`, `Compress`, and `Empty body`, ...
* Currently it needs to be regularly synchronized with Crystal upstream.
  * Some monkey patches were used at the junction (E.g. `Server::RequestProcessor`, `Server::Response`).
  * Currently only supports up to Crystal `0.36`.

## Features

* [X] Basic HTTP2 server features.
* [X] HTTP Server compatibility (HTTP1 & HTTP2).
* [X] Simplify the complex, Clear code syntax.
* [ ] HTTP2 client feature.
* [ ] More Spec tests.
* [ ] More Contributions.

## Test Information

* h2load

```text
$ h2load -n 100000 -c 100 -t 1 -T 5 -m 10 -H 'Accept-Encoding: gzip,deflate' https://127.0.0.1:9876
starting benchmark...
spawning thread #0: 100 total client(s). 100000 total requests
TLS Protocol: TLSv1.3
Cipher: TLS_AES_256_GCM_SHA384
Server Temp Key: ECDH P-256 256 bits
Application protocol: h2
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 12.11s, 8255.80 req/s, 508.46KB/s
requests: 100000 total, 100000 started, 100000 done, 100000 succeeded, 0 failed, 0 errored, 0 timeout
status codes: 100000 2xx, 0 3xx, 0 4xx, 0 5xx
traffic: 6.01MB (6306700) total, 1.24MB (1300000) headers (space savings 71.74%), 3.05MB (3200000) data
                     min         max         mean         sd        +/- sd
time for request:    27.49ms       3.00s    105.87ms    165.93ms    99.04%
time for connect:    45.34ms       2.89s       1.47s    831.38ms    58.00%
time to 1st byte:      2.96s       3.08s       3.02s     32.89ms    58.00%
req/s           :      82.57       83.63       82.95        0.34    74.00%
```

* Curl

```text
$ curl -v "https://127.0.0.1:9876" --insecure
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 9876 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/cert.pem
  CApath: none
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: C=FI; ST= ; L= ; O= ; OU= ; CN=Finland; emailAddress= 
*  start date: Jun 30 08:22:14 2019 GMT
*  expire date: Jun 29 08:22:14 2021 GMT
*  issuer: C=FI; ST= ; L= ; O= ; OU= ; CN=Finland; emailAddress= 
*  SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x7fde8580dc00)
> GET / HTTP/2
> Host: 127.0.0.1:9876
> User-Agent: curl/7.64.1
> Accept: */*
> 
* Connection state changed (MAX_CONCURRENT_STREAMS == 100)!
< HTTP/2 200 
< content-length: 12
< 
* Connection #0 to host 127.0.0.1 left intact
Hello World!
* Closing connection 0
```

## Multithreading (Parallel)

* Crystal enabling `-Dpreview_mt` will cause a lot of `failed` in h2load.
  * This will increase the speed by `1x`, this problem needs to be resolved.

```text
$ h2load -n 100000 -c 100 -t 1 -T 5 -m 10 -H 'Accept-Encoding: gzip,deflate' https://127.0.0.1:9876
starting benchmark...
spawning thread #0: 100 total client(s). 100000 total requests
TLS Protocol: TLSv1.3
Cipher: TLS_AES_256_GCM_SHA384
Server Temp Key: ECDH P-256 256 bits
Application protocol: h2
progress: 10% done
progress: 20% done
progress: 30% done
progress: 40% done
progress: 50% done
progress: 60% done
progress: 70% done
progress: 80% done

finished in 5.51s, 14877.00 req/s, 916.71KB/s
requests: 100000 total, 82180 started, 82000 done, 82000 succeeded, 18000 failed, 18000 errored, 0 timeout
status codes: 82018 2xx, 0 3xx, 0 4xx, 0 5xx
traffic: 4.93MB (5174068) total, 1.02MB (1066234) headers (space savings 71.74%), 2.50MB (2624000) data
                     min         max         mean         sd        +/- sd
time for request:      105us    970.27ms     46.09ms     95.82ms    90.93%
time for connect:    53.03ms    789.04ms    413.19ms    219.45ms    60.00%
time to 1st byte:   785.89ms       1.20s    872.68ms     84.87ms    89.02%
req/s           :       0.00      254.78      163.72       78.86    79.00%
```

## Usage

* Need to be used with [Cherry.cr](https://github.com/636f7374/cherry.cr) (load certificate / private key via Text)

```crystal
require "forest"
require "cherry"

context = OpenSSL::SSL::Context::Server.new
context.ca_certificate_text = Base64.decode_string "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"
context.private_key_text = Base64.decode_string "-----BEGIN RSA PRIVATE KEY-----
MIISJwIBAAKCBAEA/vEOPNqfVddVJXro28GAIxsE1tblYv0U2PcMqoGz/KSpYvYv
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MSn4D6RqNTICJ418D24//haluwX2bwfSwmtds/DG3+wDhrzJgkRQAveM9g==
-----END RSA PRIVATE KEY-----
"
context.alpn_protocol = "h2"

server = HTTP::Server.new [HTTP::CompressHandler.new] do |context|
  STDOUT.puts [context]
  context.response << "Hello World!"
end

address = server.bind_tls Socket::IPAddress.new("0.0.0.0", 9876_i32), context
STDOUT.puts "Listening on https://#{address}"
server.listen
```


### Installation

```bash
$ git clone https://github.com/636f7374/forest.cr.git
$ cd forest.cr && make build && make install
```

## Development

```bash
$ make test
```

## References

* [StackOverflow - Why do web browsers not support h2c (HTTP/2 without TLS)?](https://stackoverflow.com/questions/46788904/why-do-web-browsers-not-support-h2c-http-2-without-tls)
* [HttpWG - Hypertext Transfer Protocol Version 2 (HTTP/2)](https://http2.github.io/http2-spec/)
* [Blog - Programmersought HTTP2 detailed](http://www.programmersought.com/article/6185820249/)
* [StackOverflow - WINDOW_UPDATE HTTP/2 frame](https://stackoverflow.com/questions/51538391/window-update-http-2-frame)
* [Blog - HTTP: HTTP/2 - High Performance Browser Networking (O'Reilly)](https://hpbn.co/http2/)
* [Medium - HTTP/2 Flow Control](https://medium.com/coderscorner/http-2-flow-control-77e54f7fd518)
* [Cloudflare - HTTP/2 For Web Developers](https://blog.cloudflare.com/http-2-for-web-developers/)
* [Wireshark - Hypertext Transfer Protocol version 2](https://wiki.wireshark.org/HTTP2)

## Credit

* [\_Icon - Freepik/WebDevelopment](https://www.flaticon.com/packs/web-development-79)

## Contributors

|Name|Creator|Maintainer|Contributor|
|:---:|:---:|:---:|:---:|
|**[636f7374](https://github.com/636f7374)**|√|√||
|**[ysbaddaden](https://github.com/ysbaddaden)**|||√|

## License

* MIT License