Add narrowcast method to client (#163)

* Add narrowcast method to client

* Fix code style

Author: toduq

lib/line/bot/client.rb

@@ -177,6 +177,32 @@ def broadcast(messages)
         post(endpoint, endpoint_path, payload, credentials)
       end
 
+      # Narrowcast messages to users
+      #
+      # API Documentation is here.
+      # https://developers.line.biz/en/reference/messaging-api/#send-narrowcast-message
+      #
+      # @param messages [Hash or Array]
+      # @param recipient [Hash]
+      # @param filter [Hash]
+      # @param limit [Hash]
+      #
+      # @return [Net::HTTPResponse]
+      def narrowcast(messages, recipient: nil, filter: nil, limit: nil)
+        channel_token_required
+
+        messages = [messages] if messages.is_a?(Hash)
+
+        endpoint_path = '/bot/message/narrowcast'
+        payload = {
+          messages: messages,
+          recipient: recipient,
+          filter: filter,
+          limit: limit
+        }.to_json
+        post(endpoint, endpoint_path, payload, credentials)
+      end
+
       def leave_group(group_id)
         channel_token_required
 

spec/line/bot/send_message_01_text_spec.rb

@@ -98,4 +98,65 @@
     }.to_json
     expect(response.body).to eq(expected)
   end
+
+  it 'narrowcast the text message without any conditions' do
+    uri_template = Addressable::Template.new Line::Bot::API::DEFAULT_ENDPOINT + '/bot/message/narrowcast'
+    stub_request(:post, uri_template).to_return { |request| {body: request.body, status: 200} }
+
+    client = Line::Bot::Client.new do |config|
+      config.channel_token = 'channel_token'
+    end
+
+    message = {
+      type: 'text',
+      text: 'Hello, world'
+    }
+    response = client.narrowcast(message)
+
+    expected = {
+      messages: [message],
+      recipient: nil,
+      filter: nil,
+      limit: nil
+    }.to_json
+    expect(response.body).to eq(expected)
+  end
+
+  it 'narrowcast the text message' do
+    uri_template = Addressable::Template.new Line::Bot::API::DEFAULT_ENDPOINT + '/bot/message/narrowcast'
+    stub_request(:post, uri_template).to_return { |request| {body: request.body, status: 200} }
+
+    client = Line::Bot::Client.new do |config|
+      config.channel_token = 'channel_token'
+    end
+
+    message = {
+      type: 'text',
+      text: 'Hello, world'
+    }
+    recipient = {
+      type: 'audience',
+      audienceGroupId: 5614991017776
+    }
+    filter = {
+      demographic: {
+        type: 'appType',
+        oneOf: [
+          'android'
+        ]
+      }
+    }
+    limit = {
+      max: 300
+    }
+    response = client.narrowcast(message, recipient: recipient, filter: filter, limit: limit)
+
+    expected = {
+      messages: [message],
+      recipient: recipient,
+      filter: filter,
+      limit: limit
+    }.to_json
+    expect(response.body).to eq(expected)
+  end
 end