MessageContext

README.md

@@ -180,6 +180,45 @@ class Telegram::WebhookController < Telegram::Bot::UpdatesController
 end
 ```
 
+It's usual to support chain of messages like BotFather: after receiving command
+it asks you for additional argument. There is `MessageContext` for this:
+
+```ruby
+class Telegram::WebhookController < Telegram::Bot::UpdatesController
+  include Telegram::Bot::UpdatesController::MessageContext
+
+  def rename(*)
+    # set context for the next message
+    save_context :rename
+    reply_with :message, text: 'What name do you like?'
+  end
+
+  # register context handlers to handle this context
+  context_handler :rename do |message|
+    update_name message[:text]
+    reply_with :message, text: 'Renamed!'
+  end
+
+  # You can do it in other way:
+  def rename(name = nil, *)
+    if name
+      update_name message[:text]
+      reply_with :message, text: 'Renamed!'
+    else
+      save_context :rename
+      reply_with :message, text: 'What name do you like?'
+    end
+  end
+
+  # This will call #rename like if it is called with message '/rename %text%'
+  context_handler :rename
+
+  # If you have a lot of such methods you can use
+  context_to_action!
+  # It'll use context value as action name for all contexts which miss handlers.
+end
+```
+
 ### Routes
 
 Use `telegram_webhooks` helper to add routes. It will create routes for bots

lib/telegram/bot/updates_controller.rb

@@ -10,6 +10,7 @@ module Telegram
       require 'telegram/bot/updates_controller/session'
       require 'telegram/bot/updates_controller/log_subscriber'
       require 'telegram/bot/updates_controller/instrumentation'
+      autoload :MessageContext, 'telegram/bot/updates_controller/message_context'
 
       include AbstractController::Callbacks
       # Redefine callbacks with default terminator.
@@ -59,7 +60,7 @@ module Telegram
           match = text.match CMD_REGEX
           return unless match
           return if match[3] && username != true && match[3] != username
-          [match[1], text.split(' ').drop(1)]
+          [match[1], text.split.drop(1)]
         end
       end
 

lib/telegram/bot/updates_controller/message_context.rb

@@ -0,0 +1,102 @@
+module Telegram
+  module Bot
+    class UpdatesController
+      # Allows to store context in session and treat next message according to this context.
+      module MessageContext
+        extend ActiveSupport::Concern
+
+        include Session
+
+        included do
+          # As we use before_action context is cleared anyway,
+          # no matter we used it or not.
+          before_action :fetch_context
+          singleton_class.send :attr_reader, :context_handlers, :context_to_action
+          @context_handlers = {}
+        end
+
+        module ClassMethods
+          # Registers handler for context.
+          #
+          #     context_handler :rename do |message|
+          #       resource.update!(name: message['text'])
+          #     end
+          #
+          #     # To run other action with all the callbacks:
+          #     context_handler :rename do |message|
+          #       process(:rename, *m['text'].split)
+          #     end
+          #
+          #     # Or just
+          #     context_handler :rename, :your_action_to_call
+          #     context_handler :rename # to call :rename
+          #
+          #     # For messages without context use this instead of `message` method:
+          #     context_handle do |message|
+          #     end
+          #
+          def context_handler(context = nil, action = nil, &block)
+            context &&= context.to_sym
+            context_handlers[context] = block || action || context
+          end
+
+          # Use it to use context value as action name for all contexts
+          # which miss handlers.
+          # For security reasons it supports only action methods and will
+          # raise AbstractController::ActionNotFound if context is invalid.
+          def context_to_action!
+            @context_to_action = true
+          end
+        end
+
+        # Finds handler for current context and processes message with it.
+        def message(message)
+          handler = handler_for_context
+          return unless handler
+          if handler.respond_to?(:call)
+            instance_exec(message, &handler)
+          else
+            process(handler, *message['text'].split)
+          end
+        end
+
+        # Action to clear context.
+        def cancel
+          # Context is already cleared in before_action
+        end
+
+        private
+
+        # Context is read from the session to treat messages
+        # according to previous request.
+        attr_reader :context
+
+        # Fetches and removes context from session.
+        def fetch_context
+          val = session.delete(:context)
+          @context = val && val.to_sym
+          true # TODO: remove in Rails 5.0
+        end
+
+        # Save context for the next request.
+        def save_context(context)
+          session[:context] = context
+        end
+
+        def handler_for_context
+          self.class.context_handlers[context] || self.class.context_to_action && begin
+            action_name = context.to_s
+            unless action_method?(action_name)
+              raise AbstractController::ActionNotFound,
+                "The action '#{action_name}' could not be set from context " \
+                "for #{self.class.name}. " \
+                'context_to_action! supports only action methods for security reasons. ' \
+                'If you need to call this action use context_handler for it.'
+            end
+            action_name
+          end
+        end
+      end
+    end
+  end
+end

spec/telegram/bot/updates_controller/message_context_spec.rb

@@ -0,0 +1,109 @@
+RSpec.describe Telegram::Bot::UpdatesController::MessageContext do
+  include_context 'telegram/bot/updates_controller'
+  let(:controller_class) do
+    described_class = self.described_class
+    Class.new(Telegram::Bot::UpdatesController) do
+      include described_class
+
+      attr_accessor :filter_done
+      before_action only: :redirect do
+        self.filter_done = true
+      end
+
+      context_handler do |*args|
+        [:no_context, *args]
+      end
+
+      context_handler :block do |*args|
+        [:block_result, *args]
+      end
+
+      context_handler :redirect
+      context_handler :other_redirect, :redirect
+
+      def redirect(*args)
+        [:method_result, *args]
+      end
+
+      def action(*args)
+        [:action_result, *args]
+      end
+
+      private
+
+      def not_action
+        raise 'Should not be called!'
+      end
+    end
+  end
+
+  describe '#message' do
+    subject { -> { dispatch } }
+    let(:payload_type) { 'message' }
+    let(:payload) { {'text' => text} }
+    let(:text) { 'asd qwe zxc' }
+
+    context 'when context is not set' do
+      its(:call) { should eq [:no_context, payload] }
+      it { should_not change(controller, :filter_done) }
+      it { should_not change { session[:context] } }
+    end
+
+    context 'when context is handled by block' do
+      before { session[:context] = :block }
+      its(:call) { should eq [:block_result, payload] }
+      it { should_not change(controller, :filter_done) }
+      it { should change { session[:context] }.to nil }
+    end
+
+    context 'when context is handled by short redirect' do
+      before { session[:context] = :redirect }
+      its(:call) { should eq [:method_result, *text.split] }
+      it { should change(controller, :filter_done).to true }
+      it { should change { session[:context] }.to nil }
+    end
+
+    context 'when context is handled by custom redirect' do
+      before { session[:context] = :other_redirect }
+      its(:call) { should eq [:method_result, *text.split] }
+      it { should change(controller, :filter_done).to true }
+      it { should change { session[:context] }.to nil }
+    end
+
+    context 'when context is action`s name but not mapped' do
+      before { session[:context] = :action }
+      its(:call) { should eq nil }
+      it { should_not change(controller, :filter_done) }
+      it { should change { session[:context] }.to nil }
+    end
+
+    context 'when context_to_action is true' do
+      before { controller_class.context_to_action! }
+
+      context 'when context is action`s name but not mapped' do
+        before { session[:context] = :action }
+        its(:call) { should eq [:action_result, *text.split] }
+        it { should_not change(controller, :filter_done) }
+        it { should change { session[:context] }.to nil }
+      end
+
+      context 'when context is invalid' do
+        before { session[:context] = :invalid }
+        it 'raises error and clears context' do
+          expect do
+            should raise_error AbstractController::ActionNotFound
+          end.to change { session[:context] }.to nil
+        end
+      end
+
+      context 'when context is private method`s name' do
+        before { session[:context] = :not_action }
+        it 'raises error and clears context' do
+          expect do
+            should raise_error AbstractController::ActionNotFound
+          end.to change { session[:context] }.to nil
+        end
+      end
+    end
+  end
+end