[docs] revision of the article "Engine Overview"

This patch revision of the article "Engine Overview":

- add links & anchors
- improve formating of the tables

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
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Markus Heiser 2021-06-03 18:53:00 +02:00
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@ -1,12 +1,20 @@
.. _engines-dev:
===============
Engine overview
Engine Overview
===============
.. _metasearch-engine: https://en.wikipedia.org/wiki/Metasearch_engine
.. sidebar:: Further reading ..
- :ref:`general engine settings`
- :ref:`settings engine`
.. contents::
:depth: 3
:backlinks: entry
searx is a metasearch-engine_, so it uses different search engines to provide
better results.
@ -14,71 +22,92 @@ Because there is no general search API which could be used for every search
engine, an adapter has to be built between searx and the external search
engines. Adapters are stored under the folder :origin:`searx/engines`.
.. contents::
:depth: 3
:backlinks: entry
.. _general engine configuration:
general engine configuration
General Engine Configuration
============================
It is required to tell searx the type of results the engine provides. The
arguments can be set in the engine file or in the settings file
(normally ``settings.yml``). The arguments in the settings file override
the ones in the engine file.
arguments can be set in the engine file or in the settings file (normally
``settings.yml``). The arguments in the settings file override the ones in the
engine file.
It does not matter if an option is stored in the engine file or in the
settings. However, the standard way is the following:
It does not matter if an option is stored in the engine file or in the settings.
However, the standard way is the following:
.. _engine file:
engine file
Engine File
-----------
.. table:: Common options in the engine module
:width: 100%
======================= =========== ========================================================
argument type information
======================= =========== ========================================================
categories list pages, in which the engine is working
paging boolean support multible pages
time_range_support boolean support search time range
engine_type str ``online`` by default, other possibles values are
``offline``, ``online_dictionnary``, ``online_currency``
engine_type str - ``online`` :ref:`[ref] <demo online engine>` by
default, other possibles values are:
- ``offline`` :ref:`[ref] <offline engines>`
- ``online_dictionary``
- ``online_currency``
======================= =========== ========================================================
.. _engine settings:
settings.yml
------------
Engine ``settings.yml``
-----------------------
======================= =========== =============================================
For a more detailed description, see :ref:`settings engine` in the :ref:`settings.yml`.
.. table:: Common options in the engine setup (``settings.yml``)
:width: 100%
======================= =========== ===============================================
argument type information
======================= =========== =============================================
======================= =========== ===============================================
name string name of search-engine
engine string name of searx-engine
(filename without ``.py``)
enable_http bool enable HTTP
(by default only HTTPS is enabled).
engine string name of searx-engine (filename without ``.py``)
enable_http bool enable HTTP (by default only HTTPS is enabled).
shortcut string shortcut of search-engine
timeout string specific timeout for search-engine
display_error_messages boolean display error messages on the web UI
proxies dict set proxies for a specific engine
(e.g. ``proxies : {http: socks5://proxy:port,
https: socks5://proxy:port}``)
======================= =========== =============================================
======================= =========== ===============================================
.. _engine overrides:
overrides
Overrides
---------
A few of the options have default values in the engine, but are often
overwritten by the settings. If ``None`` is assigned to an option in the engine
file, it has to be redefined in the settings, otherwise searx will not start
with that engine.
.. sidebar:: engine's global names
The naming of overrides is arbitrary. But the recommended overrides are the
following:
Global names with a leading underline are *private to the engine* and will
not be overwritten.
A few of the options have default values in the namespace of engine's python
modul, but are often overwritten by the settings. If ``None`` is assigned to an
option in the engine file, it has to be redefined in the settings, otherwise
searx will not start with that engine.
Here is an very simple example of the global names in the namespace of engine's
module:
.. code:: python
# engine dependent config
categories = ['general']
paging = True
_non_overwritten_global = 'foo'
.. table:: The naming of overrides is arbitrary / recommended overrides are:
:width: 100%
======================= =========== ===========================================
argument type information
@ -90,31 +119,25 @@ language string ISO code of language and country like en_US
api_key string api-key if required by engine
======================= =========== ===========================================
example code
------------
.. code:: python
# engine dependent config
categories = ['general']
paging = True
.. _engine request:
making a request
Making a Request
================
To perform a search an URL have to be specified. In addition to specifying an
URL, arguments can be passed to the query.
passed arguments
----------------
.. _engine request arguments:
Passed Arguments (request)
--------------------------
These arguments can be used to construct the search query. Furthermore,
parameters with default value can be redefined for special purposes.
If the ``engine_type`` is ``online```:
.. table:: If the ``engine_type`` is ``online``
:width: 100%
====================== ============== ========================================================================
argument type default-value, information
@ -134,35 +157,42 @@ language str specific language code like ``'en_US'``, o
====================== ============== ========================================================================
If the ``engine_type`` is ``online_dictionnary```, in addition to the ``online`` arguments:
.. table:: If the ``engine_type`` is ``online_dictionary``, in addition to the
``online`` arguments:
:width: 100%
====================== ============ ========================================================================
====================== ============== ========================================================================
argument type default-value, information
====================== ============ ========================================================================
====================== ============== ========================================================================
from_lang str specific language code like ``'en_US'``
to_lang str specific language code like ``'en_US'``
query str the text query without the languages
====================== ============ ========================================================================
====================== ============== ========================================================================
If the ``engine_type`` is ``online_currency```, in addition to the ``online`` arguments:
.. table:: If the ``engine_type`` is ``online_currency```, in addition to the
``online`` arguments:
:width: 100%
====================== ============ ========================================================================
====================== ============== ========================================================================
argument type default-value, information
====================== ============ ========================================================================
====================== ============== ========================================================================
amount float the amount to convert
from str ISO 4217 code
to str ISO 4217 code
from_name str currency name
to_name str currency name
====================== ============ ========================================================================
====================== ============== ========================================================================
parsed arguments
----------------
Specify Request
---------------
The function ``def request(query, params):`` always returns the ``params``
variable. Inside searx, the following paramters can be used to specify a search
request:
The function :py:func:`def request(query, params):
<searx.engines.demo_online.request>` always returns the ``params`` variable, the
following parameters can be used to specify a search request:
.. table::
:width: 100%
=================== =========== ==========================================================================
argument type information
@ -180,45 +210,18 @@ raise_for_httperror bool True by default: raise an exception if the HTTP
=================== =========== ==========================================================================
example code
------------
.. code:: python
# search-url
base_url = 'https://example.com/'
search_string = 'search?{query}&page={page}'
# do search-request
def request(query, params):
search_path = search_string.format(
query=urlencode({'q': query}),
page=params['pageno'])
params['url'] = base_url + search_path
return params
.. _engine results:
.. _engine media types:
returned results
================
Media Types
===========
Searx is able to return results of different media-types. Currently the
following media-types are supported:
Each result item of an engine can be of different media-types. Currently the
following media-types are supported. To set another media-type as ``default``,
the parameter ``template`` must be set to the desired type.
- default_
- images_
- videos_
- torrent_
- map_
To set another media-type as default, the parameter ``template`` must be set to
the desired type.
default
-------
.. table:: Parameter of the **default** media type:
:width: 100%
========================= =====================================================
result-parameter information
@ -229,15 +232,15 @@ content string, general result-text
publishedDate :py:class:`datetime.datetime`, time of publish
========================= =====================================================
images
------
To use this template, the parameter:
.. table:: Parameter of the **images** media type:
:width: 100%
========================= =====================================================
result-parameter information
========================= =====================================================
------------------------- -----------------------------------------------------
template is set to ``images.html``
========================= =====================================================
url string, url to the result site
title string, title of the result *(partly implemented)*
content *(partly implemented)*
@ -247,13 +250,15 @@ img\_src string, url to the result image
thumbnail\_src string, url to a small-preview image
========================= =====================================================
videos
------
.. table:: Parameter of the **videos** media type:
:width: 100%
========================= =====================================================
result-parameter information
========================= =====================================================
------------------------- -----------------------------------------------------
template is set to ``videos.html``
========================= =====================================================
url string, url of the result
title string, title of the result
content *(not implemented yet)*
@ -261,15 +266,16 @@ publishedDate :py:class:`datetime.datetime`, time of publish
thumbnail string, url to a small-preview image
========================= =====================================================
torrent
-------
.. _magnetlink: https://en.wikipedia.org/wiki/Magnet_URI_scheme
.. table:: Parameter of the **torrent** media type:
:width: 100%
========================= =====================================================
result-parameter information
========================= =====================================================
------------------------- -----------------------------------------------------
template is set to ``torrent.html``
========================= =====================================================
url string, url of the result
title string, title of the result
content string, general result-text
@ -283,12 +289,13 @@ magnetlink string, magnetlink_ of the result
torrentfile string, torrentfile of the result
========================= =====================================================
map
---
.. table:: Parameter of the **map** media type:
:width: 100%
========================= =====================================================
result-parameter information
------------------------- -----------------------------------------------------
template is set to ``map.html``
========================= =====================================================
url string, url of the result
title string, title of the result