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https://github.com/icelam/leetcode-daily-question-telegram-bot

Fetch question of today from Leetcode's GraphQL API and send it to Telegram channel @LeetcodeQustionOfToday
https://github.com/icelam/leetcode-daily-question-telegram-bot

aws-lambda aws-lambda-python serverless-framework telegram-bot telegram-python telegram-python-bot telegram-scheduled-message

Last synced: 25 days ago
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Fetch question of today from Leetcode's GraphQL API and send it to Telegram channel @LeetcodeQustionOfToday

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README 

        
# Leetcode Daily Question Telegram Bot



> **Warning**  

> End of Maintenance Notice (2023-10-29):  

> Visit [https://t.me/LeetcodeQustionOfToday/720](https://t.me/LeetcodeQustionOfToday/720) for more information.



Fetch question of today from Leetcode's GraphQL API and send it to Telegram channel.



![Mockup](./docs/mockup.png)



## Development Notes



### Tech Stack

* Python 3

* [Serverless](https://www.npmjs.com/package/serverless)

* AWS Lambda

* AWS CloudFormation - Used by Serverless when doing deployment

* AWS CloudWatch - Automatically Setup by Serverless when doing deployment

* AWS S3 - Used by Serverless when doing deployment



> **Note:**  

> Both Lambda, CloudWatch, and CloudFormation has free tier provided. However for AWS S3, it has only has free tier for limited time.

> 

> To check the tier limit, head to [https://aws.amazon.com/free/](https://aws.amazon.com/free/). It is recommended to setup a billing alert by following the documentation on [https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/tracking-free-tier-usage.html](https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/tracking-free-tier-usage.html). 



### Development Setup



#### Prerequisites

* Node.js 14 installed

* Python 3 installed

* `virtualenv` installed



#### Prepare `serverless` environment



##### NPM



```bash

npm install serverless@3 --global

npm install

```



##### Yarn



```bash

yarn global add serverless@3

yarn

```



#### Setup Python Virtual Environments



```bash

# Create a new virtual environment

virtualenv venv --python=python3



# Activate virtual environment created

. venv/bin/activate



# Install dependencies listed in requirements.txt

pip install -r requirements.txt

```



#### Setup Bot to send message



Save a copy of `.env`  and name it as `.env.local`, place your Telegram bot token and Telegram Chat ID in the configuration file.



> **Note:**

> Environment variables are used instead of `ConfigParser` provided by Python since [by default AWS Lambda will encrypt environment variables using KMS](https://docs.aws.amazon.com/whitepapers/latest/kms-best-practices/encrypting-lambda-environment-variables.html), and we don't want to store tokens using plain text.



##### 1. How to get a Telegram bot token



1. In Telegram, search for the user `@BotFather`.

2. Use the command `\newbot` and choose a name and username for your bot.

3. `@BotFather` will return you the token of the bot created. Remember to keep it safe!



##### 2. How to get a Telegram chat ID



1. Send a `/start` command to the telegram bot created in the previous step

2. Visit `https://api.telegram.org/bot/getUpdates`

3. Look at the API response, `result[0]['message']['chat']['id']` should contains ID of the chat. Remember to copy the `-` prefix if exists.



##### 3. Test if Bot token and Chat ID is correct or not



Open Terminal, run the following command. You will need to replace `` and `` with the one you get in previous steps.



```bash

curl -X POST "https://api.telegram.org/bot/sendMessage" -d "chat_id=&text=Hello World"

```



#### Deployment



##### Create named AWS profile (for first time deployment)



1. Create new user on AWS, with "Programmatic access"

2. Assign permission to user by "Attaching existing policies directly"

    * In the official Serverless blog, they have introduced [serverless-policy generator](https://github.com/dancrumb/generator-serverless-policy) to help you generate IAM policies.

3. Configure new AWS credientials to use newly created user

    ```bash

    aws configure --profile 

    ```



##### Deploy to Lambda



```bash

# Load environment variables

. load-environment-variables.sh



# Deploy to AWS Lambda using serverless cli

serverless deploy --aws-profile 

```



#### Settings



##### Add / Edit bot messages

All messages are stored in `app/messages.txt`, and will be randomly picked when handler is triggered. To update the message sets, simply edit and save the file. Re-deployment is needed for changes to take effect.



##### Add / Edit stickers

All sticker IDs are stored in `app/stickers.txt`, and will be randomly picked when handler is triggered. To update the sticker sets, you will need to get the sticker ID by sending stickers to the created bot. Visit `https://api.telegram.org/bot/getUpdates`, stickers ID can be found in the API reponse node `result[n]['message']['sticker']['file_id']`. Re-deployment is needed for changes to take effect.



##### Edit bot schedule



Open `serverless.yml`, edit `functions['cron']['schedule']`. Syntax reference: [https://docs.aws.amazon.com/lambda/latest/dg/services-cloudwatchevents-expressions.html](https://docs.aws.amazon.com/lambda/latest/dg/services-cloudwatchevents-expressions.html)



#### Test



##### Testing the handler



Run the following command inside virtual environment:

```bash

# Load environment variables

. load-environment-variables.sh



# Execute handler

serverless invoke local -f cron

```



#### Others



##### Delete deployed Lambda function



```bash

serverless remove --aws-profile 

```