Notifier Telegram Bot

This bot monitors websites and notifies you via Telegram, when they visually change.

The bot supports the following commands:
/help
Lists all commands and their descriptions
/start
Lists all commands and their descriptions
/list
Lists all entries including their areas
/listurls
Lists all entries including their websites
/info <name>
Shows more information about a specific entry
/myid
Returns your User ID
/add <name> <URL> [x y width height]
Adds a new website with an optional screenshot area to the list
/remove <name>
Removes an entry from the list
/update <name> <x> <y> <width> <height>
Updates the screenshot area of an entry
/setdelay <name> <delay>
Specifies a delay in seconds to wait after the website has been loaded
/setcaptureelement <name> [html element]
Specifies which HTML element to capture
/setclickelement <name> [html element]
Specifies which HTML element to click before taking the screenshot
/setwaitelement <name> [html element]
Specifies which HTML element to wait for before taking the screenshot
/fetch <name>
Takes a screenshot with the stored settings and sends it into this chat
/fetchurl <URL> [x y width height]
Takes a screenshot of the given website and settings and sends it into this chat
/diff <name>
Shows a picture highlighting the differences of the last website change, including extended information about the normalized cross correlation
/mute <name> <hours>
Prevents change notifications for the given entry and duration
/unmute <name>
Resumes notifications for the given entry
/listall
Lists all entries from all chats
/check
Performs a manual check if any monitored website changed
/getpermissions [id]
Returns the permission level of the author of the message, replied to or the user id provided
/setpermissions <level> [id]
Sets the permission level of the author of the message, replied to or the user id provided

Installation (Linux)

Prerequisites

For the bot to work, you first need the following things:

• ImageMagick (for cropping the screenshot using the convert tool and comparing the screenshots using compare)
• capture-website-cli to take the screenshots

1. Clone the repository: git clone https://github.com/iComputerfreak/NotifierBot
2. Change into the telegram bot source code directory: cd NotifierBot/NotifierBot
3. Build the code: swift build -c release
4. Copy the executable into the main directory: cp .build/release/Notifier ..
5. Switch to the parent directory: cd ..
6. Download the telegram.sh script: wget -O tools/telegram.sh https://raw.githubusercontent.com/fabianonline/telegram.sh/master/telegram
7. Make the telegram script executable: chmod +x tools/telegram.sh
8. Repeat steps 2 - 5 for the urlwatcher script:

cd urlwatcher
swift build -c release
cp .build/release/urlwatcher .
cd ..

9. Install the latest version of ImageMagick (version 7.1.1-36 or newer) by downloading the AppImage from ImageMagick.org
10. Move the downloaded magick file into tools.
11. You may have to install FUSE to run the AppImage. (see here)

If you completed all the steps above, your install directory should look like this:

$ tree -L 2
.
├── LICENSE
├── Notifier
├── NotifierBot
│   ├── Package.resolved
│   ├── Package.swift
│   ├── Sources
│   └── Tests
├── README.md
├── Shared
│   ├── Package.swift
│   ├── README.md
│   ├── Sources
│   └── Tests
├── tools
│   ├── magick
│   ├── screenshot.sh
│   └── telegram.sh
└── urlwatcher
    ├── Package.swift
    ├── Sources
    └── urlwatcher

Adding the urlwatch script to crontab

For the urlwatch script to be periodically executed, you have to create a cronjob for it.

1. Edit the crontab file: crontab -e
2. Add the following line at the end: */30 * * * * /path/to/your/install/directory/urlwatcher/urlwatcher
   This executes the script every 30 minutes. To execute it e.g. every hour, use 0 * * * * (every time the minute is zero).
3. Save the file

Setup

Create the BOT_TOKEN file

For the scripts and the bot to work, you have to put your bot token in a file called BOT_TOKEN in your installation directory.

1. cd to your installation directory
2. Create the file: echo YOUR_BOT_TOKEN > BOT_TOKEN

Give yourself admin permissions

1. Start the bot
2. Run the command /myid to retrieve your ID
3. Stop the bot
4. Add your ID to the permissions file: echo "YOUR_ID: admin" > /path/to/your/install/directory/NotifierBot/permissions.txt
5. Start the bot again and make sure, it worked by checking your permissions with the bot: /getpermissions YOUR_ID
6. If the bot returned your permission level as admin, everything worked and you now have admin permissions

Note: Modifying the permissions file requires a restart of the bot, but using /setpermissions <level> <userid> does not.

(Optional) Create a systemd service for the bot

1. Create the unit file: sudo nano /etc/systemd/system/notifier.service
2. Paste the following content (replace YOUR_USER_ACCOUNT with your linux user account name):

[Unit]
Description=Telegram Notifier Bot
After=network.target
StartLimitIntervalSec=0
[Service]
Type=simple
Restart=always
RestartSec=1
User=YOUR_USER_ACCOUNT
WorkingDirectory=/path/to/your/install/directory/NotifierBot
ExecStart=/path/to/your/install/directory/NotifierBot/Notifier

[Install]
WantedBy=multi-user.target

3. Start the service: sudo service notifier start
4. Optional: Enable automatic start on boot: sudo service notifier enable