searxng/docs/dev/engines/offline/sql-engines.rst
Markus Heiser 5720844fcd [doc] rearranges Settings & Engines docs for better readability
We have built up detailed documentation of the *settings* and the *engines* over
the past few years.  However, this documentation was still spread over various
chapters and was difficult to navigate in its entirety.

This patch rearranges the Settings & Engines documentation for better
readability.

To review new ordered docs::

   make docs.clean docs.live

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2023-07-01 22:45:19 +02:00

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ReStructuredText

.. _sql engines:
===========
SQL Engines
===========
.. sidebar:: further read
- `SQLite <https://www.sqlite.org/index.html>`_
- `PostgreSQL <https://www.postgresql.org>`_
- `MySQL <https://www.mysql.com>`_
.. contents::
:depth: 2
:local:
:backlinks: entry
.. sidebar:: info
Initial sponsored by `Search and Discovery Fund
<https://nlnet.nl/discovery>`_ of `NLnet Foundation <https://nlnet.nl/>`_.
With the *SQL engines* you can bind SQL databases into SearXNG. The following
Relational Database Management System (RDBMS) are supported:
- :ref:`engine sqlite`
- :ref:`engine postgresql`
- :ref:`engine mysql_server`
All of the engines above are just commented out in the :origin:`settings.yml
<searx/settings.yml>`, as you have to set the required attributes for the
engines, e.g. ``database:`` ...
.. code:: yaml
- name: ...
engine: {sqlite|postgresql|mysql_server}
database: ...
result_template: {template_name}
query_str: ...
By default, the engines use the ``key-value`` template for displaying results /
see :origin:`simple <searx/templates/simple/result_templates/key-value.html>`
theme. If you are not satisfied with the original result layout, you can use
your own template, set ``result_template`` attribute to ``{template_name}`` and
place the templates at::
searx/templates/{theme_name}/result_templates/{template_name}
If you do not wish to expose these engines on a public instance, you can still
add them and limit the access by setting ``tokens`` as described in section
:ref:`private engines`.
Extra Dependencies
==================
For using :ref:`engine postgresql` or :ref:`engine mysql_server` you need to
install additional packages in Python's Virtual Environment of your SearXNG
instance. To switch into the environment (:ref:`searxng-src`) you can use
:ref:`searxng.sh`::
$ sudo utils/searxng.sh instance cmd bash
(searxng-pyenv)$ pip install ...
Configure the engines
=====================
The configuration of the new database engines are similar. You must put a valid
SQL-SELECT query in ``query_str``. At the moment you can only bind at most one
parameter in your query. By setting the attribute ``limit`` you can define how
many results you want from the SQL server. Basically, it is the same as the
``LIMIT`` keyword in SQL.
Please, do not include ``LIMIT`` or ``OFFSET`` in your SQL query as the engines
rely on these keywords during paging. If you want to configure the number of
returned results use the option ``limit``.
.. _engine sqlite:
SQLite
------
.. sidebar:: info
- :origin:`sqlite.py <searx/engines/sqlite.py>`
.. automodule:: searx.engines.sqlite
:members:
.. _engine postgresql:
PostgreSQL
----------
.. _psycopg2: https://www.psycopg.org/install
.. sidebar:: info
- :origin:`postgresql.py <searx/engines/postgresql.py>`
- ``pip install`` `psycopg2-binary <psycopg2>`_
.. automodule:: searx.engines.postgresql
:members:
.. _engine mysql_server:
MySQL
-----
.. sidebar:: info
- :origin:`mysql_server.py <searx/engines/mysql_server.py>`
- ``pip install`` :pypi:`mysql-connector-python <mysql-connector-python>`
.. automodule:: searx.engines.mysql_server
:members: