[docs] document NoSLQ engines MongoDB and redis

   private-engines

   recoll

   sql-engines

   nosql-engines

   search-indexer-engines

   command-line-engines

   searx.engines.xpath

===============

NoSQL databases

===============

.. sidebar:: further read

   - `NoSQL databases <https://en.wikipedia.org/wiki/NoSQL>`_

   - `redis.io <https://redis.io/>`_

   - `MongoDB <https://www.mongodb.com>`_

The following `NoSQL databases`_ are supported:

- :ref:`engine redis_server`

- :ref:`engine mongodb`

All of the engines above are just commented out in the :origin:`settings.yml

<searx/settings.yml>`, as you have to set various options and install

dependencies before using them.

By default, the engines use the ``key-value`` template for displaying results /

see :origin:`oscar <searx/templates/oscar/result_templates/key-value.html>` &

:origin:`simple <searx/templates/simple/result_templates/key-value.html>`

themes.  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}

Futhermore, 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`.

Configure the engines

=====================

`NoSQL databases`_ are used for storing arbitrary data without first defining

their structure.

Extra Dependencies

------------------

For using :ref:`engine redis_server` or :ref:`engine mongodb` you need to

install additional packages in Python's Virtual Environment of your SearxNG

instance.  To switch into the environment (:ref:`searx-src`) you can use

:ref:`searx.sh`::

  $ sudo utils/searx.sh shell

  (searx-pyenv)$ pip install ...

.. _engine redis_server:

Redis Server

------------

.. _redis: https://github.com/andymccurdy/redis-py#installation

.. sidebar:: info

   - ``pip install`` redis_

   - redis.io_

   - :origin:`redis_server.py <searx/engines/redis_server.py>`

Redis is an open source (BSD licensed), in-memory data structure (key value

based) store.  Before configuring the ``redis_server`` engine, you must install

the dependency redis_.

Select a database to search in and set its index in the option ``db``.  You can

either look for exact matches or use partial keywords to find what you are

looking for by configuring ``exact_match_only``.  You find an example

configuration below:

.. code:: yaml

  # Required dependency: redis

  - name: myredis

    shortcut : rds

    engine: redis_server

    exact_match_only: false

    host: '127.0.0.1'

    port: 6379

    enable_http: true

    password: ''

    db: 0

.. _engine mongodb:

MongoDB

-------

.. _pymongo: https://github.com/mongodb/mongo-python-driver#installation

.. sidebar:: info

   - ``pip install`` pymongo_

   - MongoDB_

   - :origin:`mongodb.py <searx/engines/mongodb.py>`

MongoDB_ is a document based database program that handles JSON like data.

Before configuring the ``mongodb`` engine, you must install the dependency

redis_.

In order to query MongoDB_, you have to select a ``database`` and a

``collection``.  Furthermore, you have to select a ``key`` that is going to be

searched.  MongoDB_ also supports the option ``exact_match_only``, so configure

it as you wish.  Below is an example configuration for using a MongoDB

collection:

.. code:: yaml

  # MongoDB engine

  # Required dependency: pymongo

  - name: mymongo

    engine: mongodb

    shortcut: md

    exact_match_only: false

    host: '127.0.0.1'

    port: 27017

    enable_http: true

    results_per_page: 20

    database: 'business'

    collection: 'reviews'  # name of the db collection

    key: 'name'            # key in the collection to search for

Acknowledgment

==============

This development was sponsored by `Search and Discovery Fund

<https://nlnet.nl/discovery>`_ of `NLnet Foundation <https://nlnet.nl/>`_.

  #   exact_match_only: false

  #   host: '127.0.0.1'

  #   port: 27017

  #   enable_http: true

  #   results_per_page: 20

  #   database: 'business'

  #   collection: 'reviews'  # name of the db collection

  # Required dependency: redis

  # - name: myredis

  #   shortcut : rds

  #   engine: redis_server

  #    exact_match_only: False

  #   exact_match_only: false

  #   host: '127.0.0.1'

  #   port: 6379

  #   enable_http: true

  #   password: ''

  #   db: 0