Defer processing of transcripts to avoid timeouts

config/locales/server.en.yml

@@ -137,6 +137,7 @@ en:
           posted_in: "posted in %{name}"
           change_first_message: "Change first message..."
           change_last_message: "Change last message..."
+          loading: "Loading the transcript..."
 
       #######################################
       ########## TELEGRAM STRINGS ###########

lib/discourse_chat/provider/slack/slack_command_controller.rb

@@ -40,18 +40,19 @@ module DiscourseChat::Provider::SlackProvider
       channel ||= DiscourseChat::Channel.create!(provider: provider, data: { identifier: channel_id })
 
       if tokens[0] == 'post'
-        return process_post_request(channel, tokens, params[:channel_id], channel_id)
+        return process_post_request(channel, tokens, params[:channel_id], channel_id, params[:response_url])
       end
 
       return { text: ::DiscourseChat::Helper.process_command(channel, tokens) }
 
     end
 
-    def process_post_request(channel, tokens, slack_channel_id, channel_name)
+    def process_post_request(channel, tokens, slack_channel_id, channel_name, response_url)
       if SiteSetting.chat_integration_slack_access_token.empty?
         return { text: I18n.t("chat_integration.provider.slack.transcript.api_required") }
       end
 
+      Scheduler::Defer.later "Processing slack transcript request" do
         requested_messages = nil
         first_message_ts = nil
 
@@ -80,14 +81,22 @@ module DiscourseChat::Provider::SlackProvider
           transcript.set_first_message_by_index(-10) unless transcript.guess_first_message
         end
 
-      return transcript.build_slack_ui
+        http = Net::HTTP.new("slack.com", 443)
+        http.use_ssl = true
+        req = Net::HTTP::Post.new(URI(response_url), 'Content-Type' => 'application/json')
+        req.body = transcript.build_slack_ui.to_json
+        response = http.request(req)
+      end
+
+      return { text: I18n.t("chat_integration.provider.slack.transcript.loading") }
 
     end
 
     def interactive
       json = JSON.parse(params[:payload], symbolize_names: true)
+      process_interactive(json)
 
-      render json: process_interactive(json)
+      render nothing: true, status: 200
     end
 
     def process_interactive(json)
@@ -101,6 +110,7 @@ module DiscourseChat::Provider::SlackProvider
 
       error_message = { text: I18n.t("chat_integration.provider.slack.transcript.error") }
 
+      Scheduler::Defer.later "Processing slack transcript update" do
         return error_message unless transcript = SlackTranscript.new(channel_name: "##{json[:channel][:name]}", channel_id: json[:channel][:id])
         return error_message unless transcript.load_user_data
         return error_message unless transcript.load_chat_history
@@ -108,7 +118,12 @@ module DiscourseChat::Provider::SlackProvider
         return error_message unless transcript.set_first_message_by_ts(first_message)
         return error_message unless transcript.set_last_message_by_ts(last_message)
 
-      return transcript.build_slack_ui
+        http = Net::HTTP.new("slack.com", 443)
+        http.use_ssl = true
+        req = Net::HTTP::Post.new(URI(json[:response_url]), 'Content-Type' => 'application/json')
+        req.body = transcript.build_slack_ui.to_json
+        response = http.request(req)
+      end
     end
 
     def slack_token_valid?

spec/lib/discourse_chat/provider/slack/slack_command_controller_spec.rb

@@ -180,50 +180,63 @@ describe 'Slack Command Controller', type: :request do
           end
 
           it 'generates the transcript UI properly' do
+            command_stub = stub_request(:post, "https://slack.com/commands/1234")
+              .with(body: /attachments/)
+              .to_return(body: { ok: true }.to_json)
+
             post "/chat-integration/slack/command.json",
               text: "post",
+              response_url: 'https://hooks.slack.com/commands/1234',
               channel_name: 'general',
               channel_id: 'C6029G78F',
               token: token
 
-            json = JSON.parse(response.body)
-            expect(json["attachments"].length).to eq(2)
+            expect(command_stub).to have_been_requested
           end
 
           it 'can select by url' do
+            command_stub = stub_request(:post, "https://slack.com/commands/1234")
+              .with(body: /1501801629\.052212/)
+              .to_return(body: { ok: true }.to_json)
+
             post "/chat-integration/slack/command.json",
               text: "post https://sometestslack.slack.com/archives/C6029G78F/p1501801629052212",
+              response_url: 'https://hooks.slack.com/commands/1234',
               channel_name: 'general',
               channel_id: 'C6029G78F',
               token: token
 
-            json = JSON.parse(response.body)
-            expect(json["attachments"].length).to eq(2)
-            expect(json["attachments"][0]["ts"]).to eq("1501801629.052212")
+            expect(command_stub).to have_been_requested
           end
 
           it 'can select by count' do
+            command_stub = stub_request(:post, "https://slack.com/commands/1234")
+              .with(body: /1501801629\.052212/)
+              .to_return(body: { ok: true }.to_json)
+
             post "/chat-integration/slack/command.json",
               text: "post 4",
+              response_url: 'https://hooks.slack.com/commands/1234',
               channel_name: 'general',
               channel_id: 'C6029G78F',
               token: token
 
-            json = JSON.parse(response.body)
-            expect(json["attachments"].length).to eq(2)
-            expect(json["attachments"][0]["ts"]).to eq("1501801629.052212")
+            expect(command_stub).to have_been_requested
           end
 
           it 'can auto select' do
+            command_stub = stub_request(:post, "https://slack.com/commands/1234")
+              .with(body: /1501615820\.949638/)
+              .to_return(body: { ok: true }.to_json)
+
             post "/chat-integration/slack/command.json",
               text: "post",
+              response_url: 'https://hooks.slack.com/commands/1234',
               channel_name: 'general',
               channel_id: 'C6029G78F',
               token: token
 
-            json = JSON.parse(response.body)
-            expect(json["attachments"].length).to eq(2)
-            expect(json["attachments"][0]["ts"]).to eq("1501615820.949638")
+            expect(command_stub).to have_been_requested
           end
         end
 
@@ -232,6 +245,7 @@ describe 'Slack Command Controller', type: :request do
 
           post "/chat-integration/slack/command.json",
             text: "post 2",
+            response_url: 'https://hooks.slack.com/commands/1234',
             channel_name: 'general',
             channel_id: 'C6029G78F',
             token: token
@@ -246,6 +260,7 @@ describe 'Slack Command Controller', type: :request do
 
           post "/chat-integration/slack/command.json",
             text: "post 2",
+            response_url: 'https://hooks.slack.com/commands/1234',
             channel_name: 'general',
             channel_id: 'C6029G78F',
             token: token