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 # Plum [![Build Status](https://travis-ci.org/rhenium/plum.png?branch=master)](https://travis-ci.org/rhenium/plum) [![Code Climate](https://codeclimate.com/github/rhenium/plum/badges/gpa.svg)](https://codeclimate.com/github/rhenium/plum) [![Test Coverage](https://codeclimate.com/github/rhenium/plum/badges/coverage.svg)](https://codeclimate.com/github/rhenium/plum/coverage)
-A minimal implementation of HTTP/2 server.
-
-## Examples
-* examples/ - Minimal usage.
-* [rhenium/plum-server](https://github.com/rhenium/plum-server) - A example server for https://rhe.jp and http://rhe.jp.
+A minimal pure Ruby implementation of HTTP/2 library / server.
 
 ## Requirements
 * Ruby
   * Ruby 2.2 with [ALPN support patch](https://gist.github.com/rhenium/b1711edcc903e8887a51) and [ECDH support patch (r51348)](https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/51348/diff?format=diff)
   * or latest Ruby 2.3.0-dev
 * OpenSSL 1.0.2 or newer (HTTP/2 requires ALPN)
-* [http-parser.rb gem](https://rubygems.org/gems/http_parser.rb) (HTTP/1.1 parser; if you use "http" URI scheme)
+* Optional:
+  * [http-parser.rb gem](https://rubygems.org/gems/http_parser.rb) (HTTP/1.1 parser; if you use "http" URI scheme)
+  * [rack gem](https://rubygems.org/gems/rack) if you use Plum as Rack server.
+
+## Usage
+### As a library
+See examples in `examples/`
+
+### As a Rack-compatible server
+Insert `require "plum/rack"` to your `config.ru`
+```ruby
+require "plum/rack"
+
+App = -> env {
+  [
+    200,
+    { "Content-Type" => "text/plain" },
+    [" request: #{env["REQUEST_METHOD"]} #{env["PATH_INFO"]}"]
+  ]
+}
+
+run App
+```
+Then run it with:
+```sh
+% rackup -s plum config.ru -E production
+```
+By default, Plum generates a dummy server certificate and listens `0.0.0.0:9292` in HTTPS mode.
+
+## Examples
+* examples/ - Minimal usage.
+* [rhenium/plum-server](https://github.com/rhenium/plum-server) - A example server for https://rhe.jp and http://rhe.jp.
 
 ## TODO
 * **Better API**