Add notifications support for Gitter

config/locales/client.en.yml

@@ -178,3 +178,16 @@ en:
               help: "e.g. #channel, @username."
           errors:
             invalid_channel: "That channel does not exist on Rocket Chat"
+
+        #######################################
+        ############ GITTER STRINGS ###########
+        #######################################
+        gitter:
+          title: "Gitter"
+          param:
+            name:
+              title: "Name"
+              help: "A Gitter room's name e.g. gitterHQ/services."
+            webhook_url:
+              title: "Webhook URL"
+              help: "The URL provided when you create a new integration in a Gitter room."

config/locales/server.en.yml

@@ -72,6 +72,11 @@ en:
     chat_integration_rocketchat_webhook_url: "The URL for the Rocket Chat integration webhook"
     chat_integration_rocketchat_excerpt_length: "Rocket Chat post excerpt length"
 
+    #######################################
+    ############ GITTER SETTINGS ##########
+    #######################################
+    chat_integration_gitter_enabled: "Enable the Gitter chat integration provider"
+
   chat_integration:
 
     all_categories: "(all categories)"

config/settings.yml

@@ -108,3 +108,9 @@ plugins:
     default: ''
   chat_integration_rocketchat_excerpt_length:
     default: 400
+
+#######################################
+########## GITTER SETTINGS ############
+#######################################
+  chat_integration_gitter_enabled:
+    default: false

lib/discourse_chat/provider.rb

@@ -97,3 +97,4 @@ require_relative "provider/mattermost/mattermost_provider.rb"
 require_relative "provider/matrix/matrix_provider.rb"
 require_relative "provider/zulip/zulip_provider.rb"
 require_relative "provider/rocketchat/rocketchat_provider.rb"
+require_relative "provider/gitter/gitter_provider.rb"

lib/discourse_chat/provider/gitter/gitter_provider.rb

@@ -0,0 +1,30 @@
+module DiscourseChat
+  module Provider
+    module GitterProvider
+      PROVIDER_NAME = 'gitter'.freeze
+      PROVIDER_ENABLED_SETTING = :chat_integration_gitter_enabled
+      CHANNEL_PARAMETERS = [
+        { key: "name", regex: '^\S+$', unique: true },
+        { key: "webhook_url", regex: '^https://webhooks.gitter.im/e/\S+$', unique: true, hidden: true }
+      ]
+
+      def self.trigger_notification(post, channel)
+        message = gitter_message(post)
+        response = Net::HTTP.post_form(URI(channel.data['webhook_url']), message: message)
+        unless response.kind_of? Net::HTTPSuccess
+          error_key = nil
+          raise ::DiscourseChat::ProviderError.new info: { error_key: error_key, message: message, response_body: response.body }
+        end
+      end
+
+      def self.gitter_message(post)
+        display_name = post.user.username
+        topic = post.topic
+        parent_category = topic.category.try :parent_category
+        category_name = parent_category ? "[#{parent_category.name}/#{topic.category.name}]" : "[#{topic.category.name}]"
+
+        "[__#{display_name}__ - #{topic.title} - #{category_name}](#{post.full_url})"
+      end
+    end
+  end
+end

spec/lib/discourse_chat/provider/gitter/gitter_provider_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+RSpec.describe DiscourseChat::Provider::GitterProvider do
+  let(:post) { Fabricate(:post) }
+
+  describe '.trigger_notifications' do
+    before do
+      SiteSetting.chat_integration_gitter_enabled = true
+    end
+
+    let(:chan1) { DiscourseChat::Channel.create!(provider: 'gitter', data: { name: 'gitterHQ/services', webhook_url: 'https://webhooks.gitter.im/e/a1e2i3o4u5' }) }
+
+    it 'sends a webhook request' do
+      stub1 = stub_request(:post, chan1.data['webhook_url']).to_return(body: "OK")
+      described_class.trigger_notification(post, chan1)
+      expect(stub1).to have_been_requested.once
+    end
+
+    it 'handles errors correctly' do
+      stub1 = stub_request(:post, chan1.data['webhook_url']).to_return(status: 404, body: "{ \"error\": \"Not Found\"}")
+      expect(stub1).to have_been_requested.times(0)
+      expect { described_class.trigger_notification(post, chan1) }.to raise_exception(::DiscourseChat::ProviderError)
+      expect(stub1).to have_been_requested.once
+    end
+  end
+end