Support msteams workflows (#10)

* [message.rb]: response.body can be empty on workflow responses

* [complex_example.rb]: Use dynamic datetime in text

* [message.rb]: use helper to distinguish between webhook responses

Adds two helper functions that encapsulate the properties of a
successful connector based webhook and a workflow based webhook.

Up to now, workflow based webhooks lead to a response where there
response code is 202 and the response body is empty.
For connector based webhooks, the status code is 200 and the response
body is set to "1".

* [complex_example.rb]: Rubocop says to use '.to_s`

* [message.rb]: Add comment and use '.' to call functions

* Move funcs to identify response type into class Message

as per PR review

* Check whether sent msg is too large in dedicated method

- Minor formatting change to simplify 'return response' statement

* [message.rb] Use '&&' instead of 'and' more ruby-ish?

complex_example.rb

@@ -19,7 +19,7 @@
       weight: MsTeamsHermes::Style::FontWeight::BOLDER
     ),
     MsTeamsHermes::Components::TextBlock.new(
-      text: "Saturday, 1 January 2022"
+      text: Time.now.strftime("%A, %d %B %Y %H:%M:%S").to_s
     )
   ]
 )

lib/msteams_hermes/message.rb

@@ -3,6 +3,15 @@
 require "net/http"
 require "json"
 
+##
+# Module to encapsulate the logic that decides whether a given response
+# is of type workflow or connector type webhook.
+# Both types must be considered differently to support both types of
+# MSTeams webhooks.
+##
+module MsTeamsWebhookType
+end
+
 module MsTeamsHermes
   ##
   # A class representing Microsoft's webhook message object
@@ -62,15 +71,12 @@ def deliver
 
         response = http.request(req)
 
-        # For details see:
-        # https://learn.microsoft.com/en-us/microsoftteams/platform/webhooks-and-connectors/how-to/connectors-using?tabs=cURL%2Ctext1#send-messages-using-curl-and-powershell
-        if response.body != "1"
-          raise MessageBodyTooLargeError, body_json.bytesize if response.body.include? MSTEAMS_MESSAGE_413_ERROR_TOKEN
+        return response if response_from_mst_workflow_webhook?(response) ||
+                           response_from_mst_connector_webhook?(response)
 
-          raise UnknownError, response.body
-        end
+        raise MessageBodyTooLargeError, body_json.bytesize if message_too_large?(response)
 
-        response
+        raise UnknownError, response.body
       end
     end
     # rubocop:enable Metrics/AbcSize
@@ -93,5 +99,21 @@ def body_json
         ]
       }.to_json
     end
+
+    private
+
+    def response_from_mst_workflow_webhook?(response)
+      response.code == "202" && response.body.empty?
+    end
+
+    def response_from_mst_connector_webhook?(response)
+      # For details see:
+      # https://learn.microsoft.com/en-us/microsoftteams/platform/webhooks-and-connectors/how-to/connectors-using?tabs=cURL%2Ctext1#send-messages-using-curl-and-powershell
+      response.code == "200" && response.body == "1"
+    end
+
+    def message_too_large?(response)
+      response.body.include? MSTEAMS_MESSAGE_413_ERROR_TOKEN
+    end
   end
 end