Add opal/simple_server for simple non cached apps

The quickest way to get up and running with Opal: rackup -ropal -ropal/simple_server -b 'Opal.append_path("app"); run Opal::SimpleServer.new'
opal · Oct 9, 2016 · 87caa64 · 87caa64
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -53,6 +53,7 @@ Whitespace conventions:
 - Added `JS::Error` error class that can be used to catch any JS error.
 - Added `Method#source_location` and `Method#comments`.
 - Added a deprecation API that can be set to raise on deprecation with: `Opal.raise_on_deprecation = true`
+- Added `Opal::SimpleServer` as the quickest way to get up and running with Opal: `rackup -ropal -ropal/simple_server -b 'Opal.append_path("app"); run Opal::SimpleServer.new'`
 
 
 ### Changed

diff --git a/lib/opal.rb b/lib/opal.rb
@@ -12,4 +12,5 @@
 # in any JavaScript environment.
 module Opal
   autoload :Server, 'opal/server'
+  autoload :SimpleServer, 'opal/simple_server'
 end
diff --git a/lib/opal/simple_server.rb b/lib/opal/simple_server.rb
@@ -0,0 +1,99 @@
+require 'opal/deprecations'
+
+# Opal::SimpleServer is a very basic Rack server for Opal assets, it relies on
+# Opal::Builder and Ruby corelib/stdlib. It's meant to be used just for local
+# development.
+#
+# For a more complete implementation see opal-sprockets (Rubygems) or
+# opal-webpack (NPM).
+#
+# @example (CLI)
+#   rackup -ropal -ropal/simple_server -b 'Opal.append_path("app"); run Opal::SimpleServer.new'
+class Opal::SimpleServer
+  require 'set'
+  require 'erb'
+
+  def initialize(options = {})
+    @prefix = options.fetch(:prefix, 'assets')
+    @main = options.fetch(:main, 'application')
+    yield self if block_given?
+    freeze
+  end
+
+  attr_accessor :main, :index_path
+
+  # @deprecated
+  # It's here for compatibility with Opal::Sprockets::Server
+  def append_path(path)
+    Opal.deprecation 'Please use `Opal.append_path(path)` instead.'
+    Opal.append_path path
+  end
+
+  def call(env)
+    case env['PATH_INFO']
+    when %r{\A/#{@prefix}/(.*)\.map\z}
+      path, cache_invalidator = $1.split('?', 2)
+      call_map(path)
+    when %r{\A/#{@prefix}/(.*)\z}
+      path, cache_invalidator = $1.split('?', 2)
+      call_asset(path)
+    else call_index
+    end
+  end
+
+  def call_asset(path)
+    asset = fetch_asset(path)
+    [
+      200,
+      { 'Content-Type' => 'application/javascript',
+        'X-SourceMap' => "/#{@prefix}/#{path}.map#{cache_invalidator}}" },
+      [asset[:data]]
+    ]
+  end
+
+  def call_map(path)
+    asset = fetch_asset(path)
+    [
+      200,
+      { 'Content-Type' => 'application/json' },
+      [asset[:map]]
+    ]
+  end
+
+  def fetch_asset(path)
+    builder = Opal::Builder.new
+    builder.build(path.gsub(/(\.(?:rb|js|opal))*\z/, ''))
+    {
+      data: builder.to_s,
+      map: builder.source_map.to_json
+    }
+  end
+
+  def javascript_include_tag(path)
+    %{<script src="/#{@prefix}/#{path}.js#{cache_invalidator}"></script>}
+  end
+
+  def cache_invalidator
+    "?#{Time.now.to_i}"
+  end
+
+  def call_index
+    if @index_path
+      contents = File.read(@index_path)
+      html = ERB.new(contents).result binding
+    else
+      html = <<-HTML
+      <!doctype html>
+      <html>
+        <head>
+          <meta charset="utf8">
+          #{javascript_include_tag(main)}
+        </head>
+        <body></body>
+      </html>
+      HTML
+    end
+    [200, {'Content-Type' => 'text/html'}, [html]]
+  end
+end
+
diff --git a/spec/lib/simple_server_spec.rb b/spec/lib/simple_server_spec.rb
@@ -0,0 +1,45 @@
+require 'lib/spec_helper'
+require 'rack/test'
+
+describe Opal::SimpleServer do
+  include Rack::Test::Methods
+
+  attr_accessor :app
+
+  before do
+    Opal.append_path "#{__dir__}/fixtures"
+    self.app = described_class.new(main: 'console')
+  end
+
+  it 'serves opal assets' do
+    response = get '/assets/console.js'
+    expect(response.body).to eq(Opal::Builder.build('console').to_s)
+  end
+
+  it 'serves index for all non opal paths' do
+    %w[/ /foo /foo/bar/baz].each do |path|
+      response = get path
+      expect(response.body).to include('<html>')
+      expect(response.body).to include('<script')
+      expect(response.body).to include('src="/assets/console.js')
+      expect(response.headers['Content-type']).to eq('text/html')
+    end
+  end
+
+  it 'serves the source map for the compiled asset' do
+    response = get '/assets/console.map'
+    expect(response.body).to eq(Opal::Builder.build('console').source_map.to_json)
+  end
+
+  it 'takes a :prefix option to set the assets prefix' do
+    self.app = described_class.new(main: 'opal', prefix: 'foo')
+    expect(get('/foo/console.js').body).to eq(Opal::Builder.build('console').to_s)
+    self.app = described_class.new(main: 'opal', prefix: '/foo')
+    expect(get('/foo/console.js').body).to eq(Opal::Builder.build('console').to_s)
+  end
+
+  it 'takes a :main option to set the main asset' do
+    self.app = described_class.new(main: 'foo')
+    expect(get('/').body).to include('src="/assets/foo.js')
+  end
+end