Add web client

.gitignore

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+/client/web/lrpc.js
+/s
+/c

client/web/Gemfile

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+source 'https://rubygems.org'
+
+gem 'ruby2js'

client/web/Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    parser (3.1.2.0)
+      ast (~> 2.4.1)
+    regexp_parser (2.1.1)
+    ruby2js (5.0.1)
+      parser
+      regexp_parser (~> 2.1.1)
+
+PLATFORMS
+  x86_64-linux
+
+DEPENDENCIES
+  ruby2js
+
+BUNDLED WITH
+   2.3.15

client/web/Makefile

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+lrpc.js: convert.rb lrpc.rb
+	bundle install
+	ruby convert.rb > lrpc.js

client/web/convert.rb

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+#!/usr/bin/ruby
+
+require 'ruby2js'
+require 'ruby2js/filter/functions'
+
+puts Ruby2JS.convert(File.read('lrpc.rb'), eslevel: 2016)

client/web/lrpc.rb

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+# LRPCResponseType represents the various types an LRPC
+# response can have.
+LRPCResponseType = {
+  Normal: 0,
+  Error: 1,
+  Channel: 2,
+  ChannelDone: 3,
+}
+
+# LRPCClient represents a client for the LRPC protocol
+# using WebSockets and the JSON codec
+class LRPCClient
+  def initialize(addr)
+    # Set self variables
+    @callMap = Map.new()
+    @enc = TextEncoder.new()
+    @dec = TextDecoder.new()
+    
+    # Create connection to lrpc server
+    @conn = WebSocket.new(addr)
+    @conn.binaryType = "arraybuffer"
+    @conn.onmessage = proc do |msg|
+      # if msg.data is string
+      if msg.data.instance_of? String
+        # Set json to msg.data
+        json = msg.data
+      else
+        # Set json to decoded msg.data
+        json = @dec.decode(msg.data)
+      end
+      # Parse JSON string
+      val = JSON.parse(json)
+      # Get id from callMap
+      fns = @callMap.get(val.ID)
+      # If fns is undefined (key does not exist), and this is
+      # a normal response, return
+      return if !fns && val.Type == LRPCResponseType.Normal
+
+      case val.Type
+      when LRPCResponseType.Normal
+        # If fns is a channel, send the value. Otherwise,
+        # resolve the promise with the value.
+        if fns.isChannel
+          fns.send(val.Return)
+        else
+          fns.resolve(val.Return)
+        end
+      when LRPCResponseType.Channel
+        # Get channel ID from response
+        chID = val.Return
+        # Create new LRPCChannel
+        ch = LRPCChannel.new(self, chID)
+        # Set channel in map
+        @callMap.set(chID, ch)
+        # Resolve promise with channel
+        fns.resolve(ch)
+      when LRPCResponseType.ChannelDone
+        # Close and delete channel
+        fns.close()
+        @callMap.delete(val.ID)
+      when LRPCResponseType.Error
+        # Reject promise with error
+        fns.reject(val.Error)
+      end
+
+      # Delete item from map unless it is a channel
+      @callMap.delete(val.ID) unless fns.isChannel
+    end
+  end
+  
+  # call calls a method on the server with the given
+  # argument and returns a promise.
+  def call(rcvr, method, arg)
+    return Promise.new do |resolve, reject|
+      # Get random UUID (this only works with TLS)
+      id = crypto.randomUUID()
+      # Add resolve/reject functions to callMap
+      @callMap.set(id, {
+        resolve: resolve,
+        reject: reject,
+      })
+
+      # Encode data as JSON
+      data = @enc.encode({
+        Receiver: rcvr,
+        Method: method,
+        Arg: arg,
+        ID: id,
+      }.to_json())
+
+      # Send data to lrpc server
+      @conn.send(data.buffer)
+    end
+  end
+end
+
+# LRPCChannel represents a channel used for lrpc.
+class LRPCChannel
+  def initialize(client, id)
+    # Set self variables
+    @client = client
+    @id = id
+    @arr = []
+    # Set function variables to no-ops
+    @onMessage = proc {|fn|}
+    @onClose = proc {}
+  end
+
+  # isChannel is defined to allow identifying whether
+  # an object is a channel.
+  def isChannel() end
+
+  # send sends a value on the channel. This should not
+  # be called by the consumer of the channel.
+  def send(val)
+    @arr.push(val)
+    fn = @onMessage
+    fn(val)
+  end
+
+  # done cancels the context corresponding to the channel
+  # on the server side and closes the channel.
+  def done()
+    @client.call("lrpc", "ChannelDone", @id)
+    self.close()
+    @client._callMap.delete(@id)
+  end
+  
+  # onMessage sets the callback to be called whenever a
+  # message is received. The function should have one parameter
+  # that will be set to the value received. Subsequent calls
+  # will overwrite the callback
+  def onMessage(fn)
+    @onMessage = fn
+  end
+
+  # onClose sets the callback to be called whenever the client
+  # is closed. The function should have no parameters. 
+  # Subsequent calls will overwrite the callback
+  def onClose(fn)
+    @onClose = fn
+  end
+
+  # close closes the channel. This should not be called by the
+  # consumer of the channel. Use done() instead.
+  def close()
+    fn = @onClose
+    fn()
+  end
+end