Add basic “slash command” functionality to the slack provider

Based on the existing slack plugin. Currently does not implement creating new rules or deleting rules.

config/settings.yml

@@ -20,6 +20,8 @@ plugins:
     default: 400
   chat_integration_slack_icon_url:
     default: ''
+  chat_integration_slack_incoming_webhook_token:
+    default: ''
   chat_integration_slack_access_token:
     default: ''
 

lib/discourse_chat/provider/slack/slack_command_controller.rb

@@ -2,9 +2,95 @@ module DiscourseChat::Provider::SlackProvider
   class SlackCommandController < DiscourseChat::Provider::HookController
     requires_provider ::DiscourseChat::Provider::SlackProvider::PROVIDER_NAME
 
-    def say_hello
+    before_filter :slack_token_valid?, only: :command
 
-    	render json: {hello: "world"}
+    skip_before_filter :check_xhr,
+                       :preload_json,
+                       :verify_authenticity_token,
+                       :redirect_to_login_if_required,
+                       only: :command
+
+    def command
+      text = process_command(params)
+
+      render json: { text: text }
+    end
+
+    def process_command(params)
+      guardian = DiscourseChat::Manager.guardian
+
+      tokens = params[:text].split(" ")
+
+      # channel name fix
+      channel =
+        case params[:channel_name]
+        when 'directmessage'
+          "@#{params[:user_name]}"
+        when 'privategroup'
+          params[:channel_id]
+        else
+          "##{params[:channel_name]}"
+        end
+
+      cmd = tokens.shift if tokens.size >= 1
+
+      error_text = I18n.t("chat_integration.provider.slack.error")
+
+      case cmd
+      when "watch", "follow", "mute"
+        return error_text if tokens.empty?
+        # If the first token in the command is a tag, this rule applies to all categories
+        category_name = tokens[0].start_with?('tag:') ? nil : tokens.shift
+
+        if category_name 
+          category = Category.find_by(slug: category_name)
+          unless category
+            cat_list = (CategoryList.new(guardian).categories.map(&:slug)).join(', ')
+            return I18n.t("chat_integration.provider.slack.not_found.category", name: category_name, list:cat_list)
+          end
+        else
+          category = nil # All categories
+        end
+
+        tags = []
+        # Every remaining token must be a tag. If not, abort and send help text
+        while tokens.size > 0
+          token = tokens.shift
+          if token.start_with?('tag:')
+            tag_name = token.sub(/^tag:/, '')
+          else
+            return error_text # Abort and send help text  
+          end
+
+          tag = Tag.find_by(name: tag_name)
+          unless tag # If tag doesn't exist, abort
+            return I18n.t("chat_integration.provider.slack.not_found.tag", name: tag_name)
+          end
+          tags.push(tag)
+        end
+
+        return "You want to watch post in #{category.nil? ? '(all)':category.name} with tags #{tags.map(&:name)}. Sorry, I can't do that yet"
+
+      when "remove"
+        return "You want to remove a rule. Sorry, I don't know how to do that yet"
+      when "status"
+        return DiscourseChat::Helper.status_for_channel(DiscourseChat::Provider::SlackProvider::PROVIDER_NAME, channel)
+      when "help"
+        return I18n.t("chat_integration.provider.slack.help")
+      else
+        return error_text
+      end
+      
+    end
+
+    def slack_token_valid?
+      params.require(:token)
+
+      if SiteSetting.chat_integration_slack_incoming_webhook_token.blank? ||
+         SiteSetting.chat_integration_slack_incoming_webhook_token != params[:token]
+
+        raise Discourse::InvalidAccess.new
+      end
     end
   end
 
@@ -14,7 +100,7 @@ module DiscourseChat::Provider::SlackProvider
   end
 
   SlackEngine.routes.draw do
-  	get "command" => "slack_command#say_hello"
+    post "command" => "slack_command#command"
   end
 
 end