Allow running getUpdates without database connection

CHANGELOG.md

@@ -7,9 +7,12 @@ Exclamation symbols (:exclamation:) note something of importance e.g. breaking c
 :exclamation: After updating to this version, you will need to execute the [SQL migration script][unreleased-sql-migration] on your database.
 ### Added
 - Implemented new changes for Bot API 3.6 (streamable InputMediaVideo, connected website).
+- `Telegram::getLastUpdateId()` method, returns ID of the last update that was processed.
+- `Telegram::useGetUpdatesWithoutDatabase()` method, enables `Telegram::handleGetUpdates()` to run without a database.
 ### Changed
 - Updated Travis to use Trusty containers (for HHVM) and add PHP 7.2 to the tests.
 - Add debug log entry instead of throwing an exception for duplicate updates.
+- `Telegram::handleGetUpdates()` can now work without a database connection (not enabled by default).
 ### Deprecated
 ### Removed
 ### Fixed

README.md

@@ -186,7 +186,7 @@ The bot can handle updates with **Webhook** or **getUpdates** method:
 | ---- | :----: | :----: |
 | Description | Telegram sends the updates directly to your host | You have to fetch Telegram updates manually |
 | Host with https | Required | Not required |
-| MySQL | Not required | Required  |
+| MySQL | Not required | ([Not](#getupdates-without-database)) Required  |
 
 
 ## Webhook installation
@@ -257,9 +257,9 @@ $result = $telegram->setWebhook($hook_url, ['certificate' => '/path/to/certifica
 
 Edit [*unset.php*][unset.php] with your bot credentials and execute it.
 
-### getUpdates installation
+## getUpdates installation
 
-The MySQL database must be enabled for the getUpdates method!
+For best performance, the MySQL database should be enabled for the `getUpdates` method!
 
 Create [*getUpdatesCLI.php*][getUpdatesCLI.php] with the following contents:
 ```php
@@ -301,6 +301,13 @@ Lastly, run it!
 $ ./getUpdatesCLI.php
 ```
 
+### getUpdates without database
+
+If you choose to / or are obliged to use the `getUpdates` method without a database, you can replace the `$telegram->useMySQL(...);` line above with:
+```php
+$telegram->useGetUpdatesWithoutDatabase();
+```
+
 ## Support
 
 ### Types

src/Telegram.php

@@ -137,6 +137,21 @@ class Telegram
      */
     protected $run_commands = false;
 
+    /**
+     * Is running getUpdates without DB enabled
+     *
+     * @var bool
+     */
+    protected $getupdates_without_database = false;
+
+    /**
+     * Last update ID
+     * Only used when running getUpdates without a database
+     *
+     * @var integer
+     */
+    protected $last_update_id = null;
+
     /**
      * Telegram constructor.
      *
@@ -320,26 +335,33 @@ public function handleGetUpdates($limit = null, $timeout = null)
             throw new TelegramException('Bot Username is not defined!');
         }
 
-        if (!DB::isDbConnected()) {
+        if (!DB::isDbConnected() && !$this->getupdates_without_database) {
             return new ServerResponse(
                 [
                     'ok'          => false,
-                    'description' => 'getUpdates needs MySQL connection!',
+                    'description' => 'getUpdates needs MySQL connection! (This can be overridden - see documentation)',
                 ],
                 $this->bot_username
             );
         }
 
+        $offset = 0;
+
         //Take custom input into account.
         if ($custom_input = $this->getCustomInput()) {
             $response = new ServerResponse(json_decode($custom_input, true), $this->bot_username);
         } else {
-            //DB Query
-            $last_update = DB::selectTelegramUpdate(1);
-            $last_update = reset($last_update);
+            if (DB::isDbConnected()) {
+                //Get last update id from the database
+                $last_update = DB::selectTelegramUpdate(1);
+                $last_update = reset($last_update);
 
-            //As explained in the telegram bot api documentation
-            $offset = isset($last_update['id']) ? $last_update['id'] + 1 : null;
+                $this->last_update_id = isset($last_update['id']) ? $last_update['id'] : null;
+            }
+
+            if ($this->last_update_id !== null) {
+                $offset = $this->last_update_id + 1;    //As explained in the telegram bot API documentation
+            }
 
             $response = Request::getUpdates(
                 [
@@ -351,11 +373,24 @@ public function handleGetUpdates($limit = null, $timeout = null)
         }
 
         if ($response->isOk()) {
+            $results = $response->getResult();
+
             //Process all updates
             /** @var Update $result */
-            foreach ((array) $response->getResult() as $result) {
+            foreach ($results as $result) {
                 $this->processUpdate($result);
             }
+
+            if (!DB::isDbConnected() && !$custom_input && $this->last_update_id !== null && $offset === 0) {
+                //Mark update(s) as read after handling
+                Request::getUpdates(
+                    [
+                        'offset'  => $this->last_update_id + 1,
+                        'limit'   => 1,
+                        'timeout' => $timeout,
+                    ]
+                );
+            }
         }
 
         return $response;
@@ -415,6 +450,7 @@ protected function getCommandFromType($type)
     public function processUpdate(Update $update)
     {
         $this->update = $update;
+        $this->last_update_id = $update->getUpdateId();
 
         //If all else fails, it's a generic message.
         $command = 'genericmessage';
@@ -965,4 +1001,24 @@ public function isRunCommands()
     {
         return $this->run_commands;
     }
+
+    /**
+     * Switch to enable running getUpdates without a database
+     *
+     * @param bool $enable
+     */
+    public function useGetUpdatesWithoutDatabase($enable = true)
+    {
+        $this->getupdates_without_database = $enable;
+    }
+
+    /**
+     * Return last update id
+     *
+     * @return int
+     */
+    public function getLastUpdateId()
+    {
+        return $this->last_update_id;
+    }
 }