StaleChat error

README.md

@@ -89,6 +89,9 @@ bot.extend Telegram::Bot::Client::TypedResponse
 bot.get_me.class # => Telegram::Bot::Types::User
 ```
 
+Any API request error will raise `Telegram::Bot::Error` with description in its message.
+Special `Telegram::Bot::StaleChat` is raised when bot can't post messages to the chat anymore.
+
 ### Controller
 
 ```ruby

lib/telegram/bot.rb

@@ -7,6 +7,25 @@ module Telegram
     class Error < StandardError; end
     class NotFound < Error; end
 
+    # Error class for events when chat is not available anymore for bot.
+    # While Telegram has same error codes for different messages and there is no
+    # official docs for this error codes it uses `description` to
+    # check response.
+    class StaleChat < Error
+      DESCRIPTIONS = [
+        'bot was kicked',
+        "can't write to",
+        'group chat is deactivated',
+      ].freeze
+
+      class << self
+        def match_response?(response)
+          description = response['description'].to_s
+          DESCRIPTIONS.any? { |x| description[x] }
+        end
+      end
+    end
+
     autoload :Client,             'telegram/bot/client'
     autoload :ClientStub,         'telegram/bot/client_stub'
     autoload :Middleware,         'telegram/bot/middleware'

lib/telegram/bot/client.rb

@@ -68,14 +68,17 @@ module Telegram
         client.debug_dev = nil
       end
 
-      def request(action, body = {})
+      def request(action, body = {}) # rubocop:disable PerceivedComplexity
         res = http_request("#{base_uri}#{action}", self.class.prepare_body(body))
         status = res.status
         return JSON.parse(res.body) if 300 > status
         result = JSON.parse(res.body) rescue nil # rubocop:disable RescueModifier
         err_msg = "#{res.reason}: #{result && result['description'] || '-'}"
-        # NotFound is raised only for valid responses from Telegram
-        raise NotFound, err_msg if 404 == status && result
+        if result
+          # NotFound is raised only for valid responses from Telegram
+          raise NotFound, err_msg if 404 == status
+          raise StaleChat, err_msg if StaleChat.match_response?(result)
+        end
         raise Error, err_msg
       end
 

spec/telegram/bot_spec.rb

@@ -2,4 +2,22 @@ RSpec.describe Telegram::Bot do
   it 'has a version number' do
     expect(described_class::VERSION).not_to be nil
   end
+
+  describe described_class::StaleChat do
+    describe '.match_response?' do
+      subject { ->(val) { described_class.match_response?(val) } }
+
+      it 'returns true for specific errors' do
+        expect(subject.call({})).to eq false
+        expect(subject.call('description' => 'test')).to eq false
+        expect(subject.call('description' => 'Error: bot was kicked from')).to eq true
+        expect(subject.call(
+          'description' => "Forbidden: can't write to private chat with deleted user"
+        )).to eq true
+        expect(subject.call(
+          'description' => 'Bad request: group chat is deactivated'
+        )).to eq true
+      end
+    end
+  end
 end