Add message chunking feature.

- Add `chunk($limit)` method.

Closes #127

Author: irazasyed

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to `telegram` will be documented in this file
 
 ## Unreleased
 
+- Add message chunking feature (`chunk($limit)`) in cases where the message is too long. Closes [#127](https://github.com/laravel-notification-channels/telegram/issues/127).
+
 ## 0.7.0 - 2021-10-28
 
 - Dropped PHP 7.1 support. PR [#118](https://github.com/laravel-notification-channels/telegram/pull/118).

README.md

@@ -242,8 +242,9 @@ Notification::route('telegram', 'TELEGRAM_CHAT_ID')
 
 - `to($chatId)`: (integer) Recipient's chat id.
 - `token($token)`: (string) Bot token if you wish to override the default token for a specific notification (optional).
-- `content('')`: (string) Notification message, supports markdown. For more information on supported markdown styles, check out these [docs](https://telegram-bot-sdk.readme.io/reference#section-formatting-options).
+- `content('', $limit = null)`: (string) Notification message, supports markdown. For more information on supported markdown styles, check out these [docs](https://telegram-bot-sdk.readme.io/reference#section-formatting-options).
 - `view($view, $data = [], $mergeData = [])`: (string) Blade template name with Telegram supported HTML or Markdown syntax content if you wish to use a view file instead of the `content()` method.
+- `chunk($limit = 4096)`: (integer) Message chars chunk size to send in parts (For long messages). Note: Chunked messages will be rate limited to one message per second to comply with rate limitation requirements from Telegram.
 - `button($text, $url)`: (string) Adds an inline "Call to Action" button. You can add as many as you want, and they'll be placed 2 in a row.
 - `buttonWithCallback($text, $callback_data)`: (string) Adds an inline button with callback. You can add as many as you want, and they'll be placed 2 in a row.
 - `disableNotification($disableNotification = true)`: (bool) Send the message silently.  Users will receive a notification with no sound.

src/TelegramChannel.php

@@ -2,6 +2,7 @@
 
 namespace NotificationChannels\Telegram;
 
+use Illuminate\Support\Collection;
 use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Notifications\Events\NotificationFailed;
 use Illuminate\Notifications\Notification;
@@ -25,8 +26,8 @@ class TelegramChannel
     /**
      * Channel constructor.
      *
-     * @param Telegram $telegram
-     * @param Dispatcher $dispatcher
+     * @param  Telegram    $telegram
+     * @param  Dispatcher  $dispatcher
      */
     public function __construct(Telegram $telegram, Dispatcher $dispatcher)
     {
@@ -37,8 +38,8 @@ public function __construct(Telegram $telegram, Dispatcher $dispatcher)
     /**
      * Send the given notification.
      *
-     * @param mixed        $notifiable
-     * @param Notification $notification
+     * @param  mixed         $notifiable
+     * @param  Notification  $notification
      *
      * @throws CouldNotSendNotification
      * @return null|array
@@ -55,7 +56,7 @@ public function send($notifiable, Notification $notification): ?array
             $to = $notifiable->routeNotificationFor('telegram', $notification)
                 ?? $notifiable->routeNotificationFor(self::class, $notification);
 
-            if (! $to) {
+            if (!$to) {
                 return null;
             }
 
@@ -68,8 +69,41 @@ public function send($notifiable, Notification $notification): ?array
 
         $params = $message->toArray();
 
-        try{
+        try {
             if ($message instanceof TelegramMessage) {
+                if ($message->shouldChunk()) {
+                    $replyMarkup = $message->getPayloadValue('reply_markup');
+
+                    if ($replyMarkup) {
+                        unset($params['reply_markup']);
+                    }
+
+                    $messages = $this->chunk($message->getPayloadValue('text'), $message->chunkSize);
+
+                    $payloads = collect($messages)->filter()->map(function ($text) use ($params) {
+                        return array_merge($params, ['text' => $text]);
+                    });
+
+                    if ($replyMarkup) {
+                        $lastMessage = $payloads->pop();
+                        $lastMessage['reply_markup'] = $replyMarkup;
+                        $payloads->push($lastMessage);
+                    }
+
+                    return $payloads->map(function ($payload) {
+                        $response = $this->telegram->sendMessage($payload);
+
+                        // To avoid rate limit of one message per second.
+                        sleep(1);
+
+                        if ($response) {
+                            return json_decode($response->getBody()->getContents(), true);
+                        }
+
+                        return $response;
+                    })->toArray();
+                }
+
                 $response = $this->telegram->sendMessage($params);
             } elseif ($message instanceof TelegramLocation) {
                 $response = $this->telegram->sendLocation($params);
@@ -89,7 +123,34 @@ public function send($notifiable, Notification $notification): ?array
             throw $exception;
         }
 
-
         return json_decode($response->getBody()->getContents(), true);
     }
+
+    /**
+     * Chunk the given string into an array of strings.
+     *
+     * @param  string  $value
+     * @param  int     $limit
+     *
+     * @return array
+     */
+    public function chunk(string $value, int $limit = 4096): array
+    {
+        if (mb_strwidth($value, 'UTF-8') <= $limit) {
+            return [$value];
+        }
+
+        if ($limit >= 4097) {
+            $limit = 4096;
+        }
+
+        $output = explode("%#TGMSG#%", wordwrap($value, $limit, '%#TGMSG#%'));
+
+        // Fallback for when the string is too long and wordwrap doesn't cut it.
+        if (count($output) <= 1) {
+            $output = mb_str_split($value, $limit, 'UTF-8');
+        }
+
+        return $output;
+    }
 }

src/TelegramMessage.php

@@ -13,8 +13,11 @@ class TelegramMessage implements JsonSerializable
 {
     use HasSharedLogic;
 
+    /** @var int Message Chunk Size */
+    public $chunkSize;
+
     /**
-     * @param string $content
+     * @param  string  $content
      *
      * @return self
      */
@@ -26,7 +29,7 @@ public static function create(string $content = ''): self
     /**
      * Message constructor.
      *
-     * @param string $content
+     * @param  string  $content
      */
     public function __construct(string $content = '')
     {
@@ -37,29 +40,58 @@ public function __construct(string $content = '')
     /**
      * Notification message (Supports Markdown).
      *
-     * @param string $content
+     * @param  string    $content
+     * @param  int|null  $limit
      *
      * @return $this
      */
-    public function content(string $content): self
+    public function content(string $content, int $limit = null): self
     {
         $this->payload['text'] = $content;
 
+        if ($limit) {
+            $this->chunkSize = $limit;
+        }
+
         return $this;
     }
 
     /**
      * Attach a view file as the content for the notification.
      * Supports Laravel blade template.
      *
-     * @param string $view
-     * @param array  $data
-     * @param array  $mergeData
+     * @param  string  $view
+     * @param  array   $data
+     * @param  array   $mergeData
      *
      * @return $this
      */
     public function view(string $view, array $data = [], array $mergeData = []): self
     {
         return $this->content(View::make($view, $data, $mergeData)->render());
     }
+
+    /**
+     * Chunk message to given size.
+     *
+     * @param  int  $limit
+     *
+     * @return $this
+     */
+    public function chunk(int $limit = 4096): self
+    {
+        $this->chunkSize = $limit;
+
+        return $this;
+    }
+
+    /**
+     * Should the message be chunked.
+     *
+     * @return bool
+     */
+    public function shouldChunk(): bool
+    {
+        return null !== $this->chunkSize;
+    }
 }