SignalCommander

This provides a step-by-step guide on how to control your server using the Signal messaging app.

Currently, you can send a message containing a torrent link, and the server will download the torrent. Additionally, you can check the status and perform other operations on the torrent application. In addition, you can send LaTeX files in a zip file and convert them to a PDF.

1. Setup & Installation

First Download the Github repository and enter it:

git clone git@github.com:fridolinvii/SignalCommander.git
cd SignalCommander

1.1 Installing signal-cli

I follwed the description to install it from this GitHub repository: signal-cli and https://oren.github.io/articles/signal-terminal/. There are two option you can use signal-cli. Either you register a new phone number or you add it to your Linked devices on your phone.

Option 1: Register new number

You can register your number:

signal-cli -a [YOUR_NUMBER] register

You will recive a CODE per SMS and you can verify it with the command:

signal-cli -a [YOUR_NUMBER] verify [CODE]

Option 2: Linked devices

If you want to link signal-cli instead of register a new number run the following command

signal-cli link -n "[NAME]"

This will generate a link. Create a QR-Code from this link and scan it with you mobile device. Do not generate the QR-Code online, but rather generate it on your local machine if possible.

1.2 Signal Group

Create a signal Group. You can check all the groups you have access to with:

signal-cli listGroups

Find your Group name, and copy the Id into

nano .env

under the variable name

TARGET_GROUP_ID='["Id"]'

If you have multiple groups: TARGET_GROUP_ID='["Id1","Id2",...]'

1.3 Install torrent client

To install the torrent client use

sudo apt install transmission-cli transmission-daemon

1.4 Activate autostart transmission

Enable and start transmission-daemon

sudo systemctl enable transmission-daemon
sudo systemctl start transmission-daemon
sudo service transmission-daemon start

To check the status and error of transmission-daemon

systemctl status transmission-daemon

You need to do some additional changes. To do so stop the transmission-daemon

sudo systemctl stop transmission-daemon

Edit the file

sudo nano /etc/transmission-daemon/settings.json

find "rpc-authentication-required" and set it to false:

"rpc-authentication-required": false,

and start the transmission-daemon

sudo systemctl start transmission-daemon

1.5 Compatibility

Install LaTeX on the server (and any additional packages you want and need).

sudo apt install texlive-latex-base texlive-fonts-recommended -y
sudo apt install texlive-fonts-extra texlive-xetex texlive-science -y
sudo apt install texlive-lang-german texlive-latex-extra texlive-font-utils -y
sudo apt install latexmk -y
sudo apt install biber -y

1.6 Automation

If you send a message in the Group, you can run the script:

./signal_listening.sh

This will check for new Signal messages, filter the ones which were used in the Group, and are further processed. See further down for the commands.

If you want to automate the process:

crontab -e

and add a following line:

*/5 * * * * /[PATH]/signal_listening.sh >> /[PATH]/signal_listening_crontab.log 2>&1 &

Change the PATH accordingly. A logfile is created under the name signal_listening_crontab.log. Every 5min the bash-script is executed.

1.7 File Download Functionality

It is possible to download files. These are generated by a random link. In addition, the files are compressed into a 7z file with a random password. The Signal-Bot will send you the link and the password.

Note: The link and the 7z file are only available for a limited time.

• Local Download (no additional settings needed)
• Global Download with no SSH tunnel (PORT_LOCAL needs to be opened on your router, not recommended)
• Global Download with SSH tunnel (external server required, see installation guide here)
  • Be sure that you are using the same PORT_SSH and PORT_GLOBAL on your server!

Install 7z

sudo apt install p7zip-full

Enter the folder where your Signal-Bot is located. Create a virtual environment:

python -m venv venv

activate it:

source venv/bin/activate

and install the required packages

pip install flask gunicorn

2. Commands

In the Signal Group you created, you can send commands, which will be read and executed. You will recieve a txt file with with the report. Each message should only contain one command, or an error may arrise. If you don't recieve a message, either the command is unvalid or there is an error.

2.1 General Commands

Command	Description
help	Display available commands.

2.2 Torrent Commands

Command	Description
magnet:?xt=...	Download torrent using a magnet link.
status	Check the status of current torrents.
delete_all	Delete all torrents.
delete_1-3,5	Delete torrents 1-3, and 5.

2.3 LaTeX Commands

Only one zip file can be converted to a PDF at a time. Attach the zip file to the message and specify which file should be converted, e.g., main.tex.

Attachment	Text	Description
file.zip	main.tex	Convert main.tex from file.zip into a pdf
file.zip	main.tex log	Converts main.tex to pdf and sends log file

2.4 Show and Delete Files

Command	Description
files_	Show your files and folders.
files_delete_1	Delete file/folder number 1.
files_delete_1-3,5	Delete file/folder number 1-3, and 5.
files_delete_all	Delete all files and folders.

2.5 Download Files

Through an ssh tunnel, a download link is created.

Command	Description
download_1	Download file/folder number 1.
download_1-3,5	Download file/folder number 1-3, and 5.
download_status	Check Status of SSH and Gunicorn
download_stop	Stop sharing the link