Installation on Debian
=====================

Have a Debian server
-----------------------

Ensure you have a Debian server up and running before proceeding.

Add the Taler repository to the apt sources list
---------------------------------------------------

To add the Taler repository to your apt sources, run:

.. code-block:: bash

   echo 'deb [signed-by=/etc/apt/keyrings/taler-systems.gpg] https://deb.taler.net/apt/debian bookworm main' | sudo tee /etc/apt/sources.list.d/taler.list

Import the Taler Systems SA public key and install packages
--------------------------------------------------------------

You must import the Taler Systems SA package signing key and then update/upgrade packages:

.. code-block:: bash

   wget -O /etc/apt/keyrings/taler-systems.gpg https://taler.net/taler-systems.gpg
   sudo apt update
   sudo apt upgrade -y
   sudo apt install postgresql nginx taler-merchant certbot python3-certbot-nginx -y

Configure the Taler merchant database
----------------------------------------

For the Taler merchant backend, configure the PostgreSQL database by running:

.. code-block:: bash

   taler-merchant-dbconfig

Start the Taler merchant services
------------------------------------

Enable and start the Taler merchant services:

.. code-block:: bash

   systemctl enable --now taler-merchant.target

Check that Taler merchant is running
---------------------------------------

Verify that the merchant service is active:

.. code-block:: bash

   systemctl status taler-merchant-httpd.service

If you see **active (running)**, the Backend is installed successfully. Press **q** to exit the status screen.

Configure a DNS record
-------------------------

Create a new DNS record with your domain registrar:

- **Type**: A
- **Name**: backend (or a subdomain of your choice, in this tutorial we are using **tutorial**)
- **Value**: Your server’s IP address

Return to this guide after the DNS record is set up.

Create HTTPS certificates
----------------------------

Use Certbot to request an SSL/TLS certificate. Replace ``your.domain`` with your domain:

.. code-block:: bash

   sudo certbot certonly --webroot -w /var/www/html -d your.domain

Follow the prompts to provide an email address and accept the terms of service.

Set up Taler merchant in Nginx
---------------------------------

Open the Nginx configuration file for Taler merchant:

.. code-block:: bash

   nano /etc/nginx/sites-available/taler-merchant

Replace ``your.domain`` with your domain name as needed:

.. code-block:: bash

   server {
       listen 80;
       listen [::]:80;

       server_name your.domain;

       access_log /var/log/nginx/merchant.log;
       error_log /var/log/nginx/merchant.err;
       location / {
           proxy_pass http://unix:/var/run/taler-merchant/httpd/merchant-http.sock;
           proxy_redirect off;
           proxy_set_header Host $host;
           proxy_set_header X-Forwarded-Host "your.domain";
           proxy_set_header X-Forwarded-Proto "http";
       }
   }

   server {
       listen 443 ssl;
       listen [::]:443 ssl;

       server_name your.domain;

       ssl_certificate /etc/letsencrypt/live/your.domain/fullchain.pem;
       ssl_certificate_key /etc/letsencrypt/live/your.domain/privkey.pem;

       access_log /var/log/nginx/merchant.log;
       error_log /var/log/nginx/merchant.err;
       location / {
           proxy_pass http://unix:/var/run/taler-merchant/httpd/merchant-http.sock;
           proxy_redirect off;
           proxy_set_header Host $host;
           proxy_set_header X-Forwarded-Host "your.domain";
           proxy_set_header X-Forwarded-Proto "https";
       }
   }

Activate the Nginx configuration
------------------------------------

Create a symbolic link and test your configuration:

.. code-block:: bash

   sudo ln -s /etc/nginx/sites-available/taler-merchant /etc/nginx/sites-enabled/
   sudo nginx -t
   sudo systemctl reload nginx

You should see:

``nginx: configuration file /etc/nginx/nginx.conf test is successful``.

Set up Taler merchant in Apache
-------------------------------

In case you prefer Apache, you can set up Taler merchant with it. Firstly, we need to check that it is installed:

.. code-block:: bash

   sudo apt install apache2 -y

Open the Apache configuration file for Taler merchant:

.. code-block:: bash

   nano /etc/apache2/sites-available/taler-merchant.conf

Replace ``your.domain`` with your domain name as needed:

.. code-block:: apache2

    <VirtualHost *:80>
        ServerName your.domain

        ErrorLog /var/log/apache2/merchant-error.log
        CustomLog /var/log/apache2/merchant-access.log combined

        ProxyPreserveHost On
        ProxyRequests Off

        ProxyPass / unix:/var/run/taler-merchant/httpd/merchant-http.sock|http://localhost/
        ProxyPassReverse / unix:/var/run/taler-merchant/httpd/merchant-http.sock|http://localhost/

        RequestHeader set X-Forwarded-Proto "http"
        RequestHeader set X-Forwarded-Host "your.domain"
    </VirtualHost>

    <VirtualHost *:443>
        ServerName your.domain

        ErrorLog /var/log/apache2/merchant-error.log
        CustomLog /var/log/apache2/merchant-access.log combined

        SSLEngine On
        SSLCertificateFile /etc/letsencrypt/live/your.domain/fullchain.pem
        SSLCertificateKeyFile /etc/letsencrypt/live/your.domain/privkey.pem

        ProxyPreserveHost On
        ProxyRequests Off

        ProxyPass / unix:/var/run/taler-merchant/httpd/merchant-http.sock|http://localhost/
        ProxyPassReverse / unix:/var/run/taler-merchant/httpd/merchant-http.sock|http://localhost/

        RequestHeader set X-Forwarded-Proto "https"
        RequestHeader set X-Forwarded-Host "your.domain"
    </VirtualHost>

Activate the Apache configuration
-----------------------------------

Make sure apache has modules enabled:

.. code-block:: bash

   sudo a2enmod proxy proxy_http headers ssl
   sudo systemctl restart apache2

Finally, activate the configuration and restart Apache:

.. code-block:: bash

   sudo a2ensite taler-merchant
   sudo systemctl reload apache2

You could also run test the configuration with:

.. code-block:: bash

   sudo apache2ctl configtest

If you see ``Syntax OK``, the configuration is correct.

Access the Taler merchant
-----------------------------

Open your browser and navigate to the domain you entered before. You should see the Taler merchant interface if everything is configured correctly.