Add welcome_bot.py example

examples/README.md

@@ -13,3 +13,4 @@ you have to change are the target chats (username, id) and file paths for sendin
 - [**simple_echo.py**](https://github.com/pyrogram/pyrogram/blob/master/examples/simple_echo.py)
 - [**advanced_echo.py**](https://github.com/pyrogram/pyrogram/blob/master/examples/advanced_echo.py)
 - [**advanced_echo2.py**](https://github.com/pyrogram/pyrogram/blob/master/examples/advanced_echo2.py)
+- [**welcome_bot.py**](https://github.com/pyrogram/pyrogram/blob/master/examples/welcome_bot.py)

examples/welcome_bot.py

@@ -0,0 +1,52 @@
+from pyrogram import Client, Emoji
+from pyrogram.api import types
+
+"""
+This is the Welcome Bot in @PyrogramChat
+The code is commented to help you understand each part
+
+It also uses the Emoji module to easily add emojis in your text messages
+"""
+
+# Your Supergroup ID
+SUPERGROUP_ID = 1387666944
+
+
+def update_handler(client, update, users, chats):
+    # Supergroup messages are contained in the "UpdateNewChannelMessage" update type
+    if isinstance(update, types.UpdateNewChannelMessage):
+        message = update.message
+        # When a user joins, a "MessageService" is received
+        if isinstance(message, types.MessageService):
+            # Check if the message is sent to your SUPERGROUP_ID
+            if message.to_id.channel_id == SUPERGROUP_ID:
+                # A "MessageService" contains the "action" field.
+                # The action for user joins is "MessageActionChatAddUser" if the user
+                # joined using the username, otherwise is "MessageActionChatJoinedByLink" if
+                # the user joined a private group by link
+                if isinstance(message.action, (types.MessageActionChatAddUser, types.MessageActionChatJoinedByLink)):
+                    # Now send the welcome message. Extra info about a user (such as the first_name, username, ...)
+                    # are contained in the users dictionary and can be accessed by the user ID
+                    client.send_message(
+                        SUPERGROUP_ID,
+                        "{} Welcome to [Pyrogram](https://docs.pyrogram.ml/)'s "
+                        "group chat, [{}](tg://user?id={})!".format(
+                            Emoji.SPARKLES,  # Add an emoji
+                            users[message.from_id].first_name,
+                            users[message.from_id].id
+                        ),
+                        reply_to_message_id=message.id,
+                        disable_web_page_preview=True
+                    )
+
+
+def main():
+    client = Client("example")
+    client.set_update_handler(update_handler)
+
+    client.start()
+    client.idle()
+
+
+if __name__ == "__main__":
+    main()