5. Plugins

5.1. List of plugins

Plugins can also be installed on QGIS Server. They can add new features or alter existing ones from QGIS Server.

Some plugins designed for server can be found on the official QGIS repository.

5.2. Location of plugins

By default, on Debian based systems, QGIS Server will look for plugins located in /usr/lib/qgis/plugins. The default value is displayed when QGIS Server is starting, in the logs. It’s possible to set a custom path by defining the environment variable QGIS_PLUGINPATH in the web server configuration.

5.3. Installation

5.3.1. Manually with a ZIP

To install the HelloWorld example plugin for testing the server, using a specific folder, you first have to create a directory to hold server plugins. This will be specified in the virtual host configuration and passed on to the server through an environment variable:

mkdir -p /var/www/qgis-server/plugins
cd /var/www/qgis-server/plugins
wget https://github.com/elpaso/qgis-helloserver/archive/master.zip
unzip master.zip
mv qgis-helloserver-master HelloServer

5.3.2. With a command line tool

If you need to install and regularly upgrade plugins which are stored in the QGIS plugin repository, you may use the QGIS-Plugin-Manager. It’s a tool to help you manage plugins from the command line.

The installation is using pip. Installing in a virtual environment is a good practice but not required:

pip3 install qgis-plugin-manager

Then, you can use the qgis-plugin-manager executable from the command line:

cd /var/www/qgis-server/plugins
qgis-plugin-manager list

QGIS server version 3.19.0
List all plugins in /var/www/qgis-server/plugins

------------------------------------------------------------------------------------------------------------------------------------------------------
|  Folder                  |  Name            |  Version  |  Experimental  |  QGIS min  |  QGIS max  |  Author                  |  Action ⚠          |
------------------------------------------------------------------------------------------------------------------------------------------------------
|wfsOutputExtension        |wfsOutputExtension|1.6.2      |                |3.0         |            |3Liz                      |                    |
|qgis_server_render_geojson|GeoJson Renderer  |v0.4       |                |3.4         |            |Matthias Kuhn (OPENGIS.ch)|                    |
|DataPlotly                |Data Plotly       |3.7.1      |                |3.4         |3.98        |Matteo Ghetta (Faunalia)  |Upgrade to 3.8.1    |
------------------------------------------------------------------------------------------------------------------------------------------------------

We suggest you to read the full documentation in the readme file to know how to install or upgrade plugins with this tool.

5.4. HTTP Server configuration

5.4.1. Apache

To be able to use server plugins, FastCGI needs to know where to look. So, we have to modify the Apache configuration file to indicate the QGIS_PLUGINPATH environment variable to FastCGI:

FcgidInitialEnv QGIS_PLUGINPATH "/var/www/qgis-server/plugins"

Moreover, a basic HTTP authorization is necessary to play with the HelloWorld plugin previously introduced. So we have to update the Apache configuration file a last time:

# Needed for QGIS HelloServer plugin HTTP BASIC auth
<IfModule mod_fcgid.c>
    RewriteEngine on
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</IfModule>

Then, restart Apache:

systemctl restart apache2

5.5. How to use a plugin

Test the server with the HelloWorld plugin:

wget -q -O - "http://localhost/cgi-bin/qgis_mapserv.fcgi?SERVICE=HELLO"
 HelloServer!

You can have a look at the default GetCapabilities of the QGIS server at:

http://localhost/cgi-bin/qgis_mapserv.fcgi?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetCapabilities