Telegram_Bot_AWS_Python

A simple Template

This little proyect is about managing your Telegram bot using your pc and AWS Lambda service. I recommend you to read Telegram Bot API and understand how Telegram Server communicate with your Webhook (in this case Lambda AWS).

We will use 3 scripts:

• 2 Bot handlers: lambda_function.py and PCHandler.py. The first one runs on AWS Lambda service, and the second one runs on your PC. Both do exaclty the same thing, responding to Telegram Server chat updates, but in a different way. The big difference how they communicate with Telegram Server.

• 1 Switcher: Switcher.py. It is used to change who will handle the bot (lambda_function.py or PCHandler.py) This last script is also useful for debugging.

• 1 PrivateVariables: PrivateVariables.py. Here you will have to save your own private variables (ie: botToken, tableName of DynamoDB, etc).

If you have never played with Telegram Bot, i recommend you to practise first with CDHandler.py. Otherwise, if you understand how Telegram Bot works and what is inside Telegrams JSON updates or you simply are an impatient person :D, you can directly read my lambda_function.py.

1. lambda_function.py

So I guess that you have your Lambda AWS ready with an APIGateway configured. You only have to copy my code on your Lambda AWS and it will work. This lambda function is divided by 3 sections. The first 2 are mandatory, the last one is optional if you want to comunicate with a DynamoBD.

• REQUEST HANDLERS. First, I read the Lambda events that triggers him. In this case, Telegram HTTP requests from APIGateway, sent by Telegram Server, that contains an JSON serialized file. We just read them, convert it to python's JSON variable and send it to the right Handler function. In my case, I only accept 2 types of updates (you can find this updates inside JSON file): 'message' and 'callback_query'. Both have their own functions and generates the HTTP response depending on what they get. You should modify this functions depending on what you want to answer or what you want to do with the updates. I just give you some examples inside this handlers. Be careful with 'callback_query' example, because it use DynamoDB. If you don't want to use DynamoDB, you can simply save data on your script as a global variable. Keep in mind that if you do this, the info of this variable will be deleted each time you update your script and click 'save'.

• ANSWER GENERATORS. This two Handler functions described in previous chapter use other little functions to generate HTTP responses. They are sendMessage, sendKeyboard, sendPollSolution, sendVoice, sendVideo, sendAudio and sendPhoto. All of them generates an HTTPresponse that Handlers will return to AWS Lambda manager, so then he can return it to Telegram Server. It is mandatory to send an 'statusCode': '200', so Telegram Server knows that everything went OK, also when you don't want to answer anything to that update. You don't need to modify this functions if you want.

• DYNAMO COMUNICATION. The third section is used to save on DynamoDB the polls votes. You should first create a table on DynamoDB and give to your bot access permission to that table on AWS IAM (Roles).

NOTE: lambda_function.py doesn't use PrivateVariables.py. He uses Lambda AWS enviroment variables. It read them in this way:

botToken = os.environ['BOT_TOKEN']

2. PCHandler.py

This is the same script of lambda_function.py, but runs on your own PC, not in a server. I really made this script first, so it is like the lambda_function.py father. If you are curious of how you can handle your bot on your PC without servers, you can take a look to this script. This scripts doesn't need an exhaustive analysis because if you understood how the lambda function works, you will easily understand this version.

This scripts have the same 2 sections named before: REQUEST HANDLERS and ANSWER GENERATORS, it doens't have a DynamoBD comunication because of obvious reasons. The big difference between this script and the other one is the way he communicates with the server. I think you know it (otherwise you won't be reading this Repo), but i will explain it. Instead of receiving HTTPrequests, he polls Telegram server, asking if there is any update that he have to handle. The process of choosing a response is nearly the same. It only changes how you response to this updates. In this case, you make an HTTPrequest to get the updates and then you make another HTTPrequest to send a message/photo/video/etc. In lambda_function.py you gave the response on the HTTPresponse.

3. Switcher.py

This little script is not required, but I found it useful for debbugging and catching file_id's, so I share it with you.

It have 4 options:'Enable AWS bot', 'Disable AWS bot', 'Get updates', 'Clean updates'. You can perform multiple options at the same time, but be careful with the order. For example, 'Get updates' won't work correcly if you dont 'Disable AWS bot' first. You have to add on optionsChosen a list with the options you want to be executed.

• 'Enable AWS bot': As his name says, this options is to enable AWS handler. It will set the Webhook of your APIGateway. Remember to add your awsGatewayUrl on PrivateVariables.py.

• 'Disable AWS bot': This is the opposite of first option. He just disable the Webhook, enabling /getUpdates queries, so we can debug using this script.

• 'Get updates': In this option, we read the incoming updates and save them on a JSON file, called "results.json". Note that it overrides the file, so be careful with information loosing.

• 'Clean updates': Use this option if you want to tell Telegram Server that you have handled all pending updates, so he won't send them again.

An example of typical use is this:

optionsChosen = [options[1],options[2]]

I use this to disable the Telegram AWS handler, and then read incoming updates. I use to open a conversation with my bot and send him audios/voices/videos that I want to get his ID_FILE. They will appear on results.json.

4. PrivateVariables.py (hidden)

The mandatory private variables you should have here are:

• "botToken" = your bot token
• "awsGatewayUrl" = your AWSGateway URL

There are some private variables that I use on this Repo, but they are not mandatory. You can "hard code" them on your script.

• "idFileAudio" = your bot token
• "idFileVoice" = your AWSGateway URL

Then, on your AWS enviroment variables you should include this variables:

• "BOT_TOKEN" = your bot token
• "TABLE_NAME" = DynamoDB Table Name (this only is on AWS enviroment variables)

Important!: you dont have to quote (" ") your enviroment variables, they will be autoQuoted by AWS Lambda Service.

Thank you and I hope you found this Repo useful :)