Add Telegram provider.

Does not yet support slash commands, and is without tests.

app/controllers/chat_controller.rb

@@ -36,6 +36,7 @@ class DiscourseChat::ChatController < ApplicationController
     rescue Discourse::InvalidParameters, ActiveRecord::RecordNotFound => e
       render json: {errors: [e.message]}, status: 422
     rescue DiscourseChat::ProviderError => e
+      Rails.logger.error("Test provider failed #{e.info}")
       if e.info.key?(:error_key) and !e.info[:error_key].nil?
         render json: {error_key: e.info[:error_key]}, status: 422
       else 

app/models/channel.rb

@@ -50,6 +50,6 @@ class DiscourseChat::Channel < DiscourseChat::PluginModel
 
   scope :with_provider, ->(provider) { where("value::json->>'provider'=?", provider)} 
 
-  scope :with_data_value, ->(key, value) { where("(value::json->>'data')::json->>?=?", key, value)} 
+  scope :with_data_value, ->(key, value) { where("(value::json->>'data')::json->>?=?", key.to_s, value.to_s)} 
 
 end

config/locales/client.en.yml

@@ -63,4 +63,13 @@ en:
         #######################################
         telegram:
           title: "Telegram"
-          channel_instructions: "Enter a chat_id. You will need to add the bot to the chat first."
+          param:
+            name:
+              title: "Name"
+              help: "A name to describe the channel. It is not used for the connection for telegram."
+            chat_id:
+              title: Chat ID
+              help: A number given to you by the bot, or a broadcast channel identifier in the form @channelname
+            errors:
+              channel_not_found: "The specified channel does not exist on Telegram"
+              forbidden: "The bot does not have permission to post to this channel"

config/locales/server.en.yml

@@ -60,4 +60,12 @@ en:
 
           *List rules:* `/discourse status`
           
-          *Help:* `/discourse help`
+          *Help:* `/discourse help`
+
+      telegram:
+        unknown_chat: "This chat isn't setup on %{site_title}. Ask an administrator to add a channel with 'Chat ID' %{chat_id}."
+        known_chat: "This chat is setup on %{site_title}. Configure it in the admin panel. (Chat ID: %{chat_id})"
+        message: |-
+                <b>%{user}</b> posted in <a href="%{post_url}">%{title}</a>
+
+                <pre>%{post_excerpt}</pre>

config/settings.yml

@@ -30,3 +30,11 @@ plugins:
 #######################################
   chat_integration_telegram_enabled:
     default: false
+  chat_integration_telegram_access_token:
+    default: ''
+  chat_integration_telegram_excerpt_length:
+    default: 400
+  chat_integration_telegram_enable_slash_commands:
+    default: true
+  chat_integration_telegram_secret:
+    hidden: true

lib/discourse_chat/provider/telegram/telegram_command_controller.rb

@@ -2,9 +2,80 @@ module DiscourseChat::Provider::TelegramProvider
   class TelegramCommandController < DiscourseChat::Provider::HookController
     requires_provider ::DiscourseChat::Provider::TelegramProvider::PROVIDER_NAME
 
-    def say_hello
+    before_filter :telegram_token_valid?, only: :command
 
-    	render json: {hello: "from telegram"}
+    skip_before_filter :check_xhr,
+                       :preload_json,
+                       :verify_authenticity_token,
+                       :redirect_to_login_if_required,
+                       only: :command
+
+    def command
+
+      # If it's a new message (telegram also sends hooks for other reasons that we don't care about)
+      if params.key?('message')
+        chat_id = params['message']['chat']['id']
+
+        message_text = process_command(params['message'])
+
+        message = {
+          chat_id: chat_id,
+          text: message_text,
+          parse_mode: "html",
+          disable_web_page_preview: true,
+        }
+
+        DiscourseChat::Provider::TelegramProvider.sendMessage(message)
+
+      end
+
+    	# Always give telegram a success message, otherwise we'll stop receiving webhooks
+      data = {
+        success: true
+      }
+      render json: data
+    end
+
+    def process_command(message)
+      chat_id = params['message']['chat']['id']
+
+      provider = DiscourseChat::Provider::TelegramProvider::PROVIDER_NAME
+
+      channel = DiscourseChat::Channel.with_provider(provider).with_data_value('chat_id',chat_id).first
+
+      if channel.nil?
+        return  I18n.t(
+          "chat_integration.provider.telegram.unknown_chat",
+          site_title: CGI::escapeHTML(SiteSetting.title),
+          chat_id: chat_id,
+        )
+      end
+      
+      # If slash commands disabled, send a generic message
+      if !SiteSetting.chat_integration_telegram_enable_slash_commands
+        return  I18n.t(
+          "chat_integration.provider.telegram.known_chat",
+          site_title: CGI::escapeHTML(SiteSetting.title),
+          chat_id: chat_id,
+        )
+      end
+
+      tokens = message['text'].split(" ")
+
+      return "I don't understand how to do that yet"
+
+
+
+    end
+
+    def telegram_token_valid?
+      params.require(:token)
+
+      if SiteSetting.chat_integration_telegram_secret.blank? ||
+         SiteSetting.chat_integration_telegram_secret != params[:token]
+
+        raise Discourse::InvalidAccess.new
+      end
     end
   end
 
@@ -14,6 +85,6 @@ module DiscourseChat::Provider::TelegramProvider
   end
 
   TelegramEngine.routes.draw do
-  	get "command" => "telegram_command#say_hello"
+  	post "command/:token" => "telegram_command#command"
   end
 end

lib/discourse_chat/provider/telegram/telegram_initializer.rb

@@ -0,0 +1,15 @@
+Rails.logger.error("LOADED")
+DiscourseEvent.on(:site_setting_saved) do |sitesetting|
+  isEnabledSetting =  sitesetting.name == 'chat_integration_telegram_enabled' 
+  isAccessToken =  sitesetting.name == 'chat_integration_telegram_access_token' 
+
+  if (isEnabledSetting or isAccessToken)
+    enabled = isEnabledSetting ? sitesetting.value == 't' : SiteSetting.chat_integration_telegram_enabled
+    # Rails.logger.error("JOB ENQUEUED"+sitesetting.value+SiteSetting.chat_integration_telegram_enabled.to_s)
+    if enabled
+      Scheduler::Defer.later("Setup Telegram Webhook") do
+        DiscourseChat::Provider::TelegramProvider.setup_webhook()
+      end
+    end
+  end
+end

lib/discourse_chat/provider/telegram/telegram_provider.rb

@@ -3,10 +3,107 @@ module DiscourseChat
     module TelegramProvider
       PROVIDER_NAME = "telegram".freeze
       PROVIDER_ENABLED_SETTING = :chat_integration_telegram_enabled
-      CHANNEL_PARAMETERS = []
+      CHANNEL_PARAMETERS = [
+                        {key: "name", regex: '^\S+'},
+                        {key: "chat_id", regex: '^(-?[0-9]+|@\S+)$'}
+                       ]
+
+      def self.setup_webhook 
+        newSecret = SecureRandom.hex
+        SiteSetting.chat_integration_telegram_secret = newSecret
+
+        message = {
+          url: Discourse.base_url+'/chat-integration/telegram/command/'+newSecret,
+        }
+
+        response = self.do_api_request('setWebhook', message)
+
+        if not response['ok'] == true
+          # If setting up webhook failed, disable provider
+          SiteSetting.chat_integration_telegram_enabled = false
+          Rails.logger.error("Failed to setup telegram webhook. Message data= "+message.to_json+ " response="+response.to_json)
+        end
+
+      end
+
+      def self.sendMessage(message)
+        return self.do_api_request('sendMessage', message)
+      end
+
+      def self.do_api_request(methodName, message)
+        http = Net::HTTP.new("api.telegram.org", 443)
+        http.use_ssl = true
+
+        access_token = SiteSetting.chat_integration_telegram_access_token
+
+        uri = URI("https://api.telegram.org/bot#{access_token}/#{methodName}")
+
+        req = Net::HTTP::Post.new(uri, 'Content-Type' =>'application/json')
+        req.body = message.to_json
+        response = http.request(req)
+
+        responseData = JSON.parse(response.body)
+
+        return responseData
+      end
+
+      def self.message_text(post)
+        display_name = "@#{post.user.username}"
+        full_name = post.user.name || ""
+
+        if !(full_name.strip.empty?) && (full_name.strip.gsub(' ', '_').casecmp(post.user.username) != 0) && (full_name.strip.gsub(' ', '').casecmp(post.user.username) != 0)
+          display_name = "#{full_name} @#{post.user.username}"
+        end
+
+        topic = post.topic
+
+        category = ''
+        if topic.category
+          category = (topic.category.parent_category) ? "[#{topic.category.parent_category.name}/#{topic.category.name}]": "[#{topic.category.name}]"
+        end
+
+        tags = ''
+        if topic.tags.present?
+          tags = topic.tags.map(&:name).join(', ')
+        end
+
+        return I18n.t(
+            "chat_integration.provider.telegram.message",
+            user: display_name,
+            post_url: "https://meta.discourse.org",
+            title: CGI::escapeHTML(topic.title),
+            post_excerpt: post.excerpt(SiteSetting.chat_integration_telegram_excerpt_length, text_entities: true, strip_links: true, remap_emoji: true),
+          )
+
+      end
+
+      def self.trigger_notification(post, channel)
+        chat_id = channel.data['chat_id']
+
+        message = {
+          chat_id: chat_id,
+          text: message_text(post),
+          parse_mode: "html",
+          disable_web_page_preview: true,
+        }
+
+        response = sendMessage(message)
+
+        if not response['ok'] == true
+          error_key = nil
+          if response['description'].include? 'chat not found'
+            error_key = 'chat_integration.provider.telegram.channel_not_found'
+          elsif response['description'].include? 'Forbidden'
+            error_key = 'chat_integration.provider.telegram.forbidden'
+          end
+          raise ::DiscourseChat::ProviderError.new info: {error_key: error_key, message: message, response_body:response}  
+        end
+
+      end
 
     end
   end
 end
 
-require_relative "telegram_command_controller.rb"
+require_relative "telegram_command_controller.rb"
+require_relative "telegram_initializer.rb"