searxng/docs/dev/engine_overview.rst
Markus Heiser 8f79dd7659 [doc] additional descriptions about categories & categories_as_tabs
Add missing documentation of PR [#634].  Related to checkbox "Document how to
categorize engines" in [#690].

Related:

- [#634] https://github.com/searxng/searxng/pull/634#issuecomment-1004757502
- [#690] https://github.com/searxng/searxng/issues/690
- https://github.com/searxng/searxng/issues/1604
- https://github.com/searxng/searxng/pull/1545

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2023-04-07 12:56:45 +02:00

18 KiB

Engine Overview

Further reading ..

  • configured engines
  • settings engine

SearXNG is a metasearch-engine, so it uses different search engines to provide better results.

Because there is no general search API which could be used for every search engine, an adapter has to be built between SearXNG and the external search engines. Adapters are stored under the folder searx/engines.

General Engine Configuration

It is required to tell SearXNG 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.

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

Common options in the engine module
argument type information
categories list categories, in which the engine is working
paging boolean support multiple pages
time_range_support boolean support search time range

engine_type

str

  • online [ref] <demo online engine> by default, other possibles values are:
  • offline [ref] <offline engines>
  • online_dictionary
  • online_currency
  • online_url_search

Engine settings.yml

For a more detailed description, see settings engine in the settings.yml.

Common options in the engine setup (settings.yml)
argument type information
name string name of search-engine
engine string name of searxng-engine (file name 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})

Overrides

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 SearXNG will not start with that engine (global names with a leading underline can be None).

Here is an very simple example of the global names in the namespace of engine's module:

# engine dependent config
categories = ['general']
paging = True
_non_overwritten_global = 'foo'
The naming of overrides is arbitrary / recommended overrides are:
argument type information

base_url

string

base-url, can be overwritten to use same engine on other URL

number_of_results int maximum number of results per request
language string ISO code of language and country like en_US
api_key string api-key if required by engine

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 (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 :pyonline <searx.search.processors.online.OnlineProcessor.get_params>
argument type default-value, information
url str ''
method str 'GET'
headers set {}
data set {}
cookies set {}
verify bool True
headers.User-Agent str a random User-Agent
category str current category, like 'general'
safesearch int 0, between 0 and 2 (normal, moderate, strict)
time_range Optional[str] None, can be day, week, month, year
pageno int current pagenumber

searxng_locale

str

SearXNG's locale selected by user. Specific language code like 'en', 'en-US', or 'all' if unspecified.

If the engine_type is :pyonline_dictionary <searx.search.processors.online_dictionary.OnlineDictionaryProcessor.get_params>, in addition to the online <engine request online> arguments:
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 :pyonline_currency <searx.search.processors.online_currency.OnlineCurrencyProcessor.get_params>, in addition to the online <engine request online> arguments:
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

Specify Request

The function :pydef request(query, params): <searx.engines.demo_online.request> always returns the params variable, the following parameters can be used to specify a search request:

argument type information
url str requested url
method str HTTP request method
headers set HTTP header information
data set HTTP data information
cookies set HTTP cookies
verify bool Performing SSL-Validity check
allow_redirects bool Follow redirects
max_redirects int maximum redirects, hard limit
soft_max_redirects int maximum redirects, soft limit. Record an error but don't stop the engine
raise_for_httperror bool True by default: raise an exception if the HTTP code of response is >= 300

Media Types

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.

Parameter of the default media type:
result-parameter information
url string, url of the result
title string, title of the result
content string, general result-text
publishedDate :pydatetime.datetime, time of publish
Parameter of the images media type:
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)

publishedDate

:pydatetime.datetime, time of publish (partly implemented)

img_src string, url to the result image
thumbnail_src string, url to a small-preview image
Parameter of the videos media type:
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)
publishedDate :pydatetime.datetime, time of publish
thumbnail string, url to a small-preview image
Parameter of the torrent media type:
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

publishedDate

:pydatetime.datetime, time of publish (not implemented yet)

seed int, number of seeder
leech int, number of leecher
filesize int, size of file in bytes
files int, number of files
magnetlink string, magnetlink of the result
torrentfile string, torrentfile of the result
Parameter of the map media type:
result-parameter information
template is set to map.html
========================= =====================================================
url string, url of the result
title string, title of the result
content string, general result-text
publishedDate :pydatetime.datetime, time of publish
latitude latitude of result (in decimal format)
longitude longitude of result (in decimal format)

boundingbox

boundingbox of result (array of 4. values [lat-min, lat-max, lon-min, lon-max])

geojson geojson of result (https://geojson.org/)
osm.type type of osm-object (if OSM-Result)
osm.id id of osm-object (if OSM-Result)
address.name name of object
address.road street name of object
address.house_number house number of object
address.locality city, place of object
address.postcode postcode of object
address.country country of object
Parameter of the paper media type / see BibTeX field types and BibTeX format
result-parameter Python type information
template :pystr is set to paper.html
title :pystr title of the result
content :pystr abstract
comments :pystr free text display in italic below the content
tags :pyList <list>[:pystr] free tag list
publishedDate :pydatetime <datetime.datetime> last publication date
type :pystr short description of medium type, e.g. book, pdf or html ...
authors :pyList <list>[:pystr] list of authors of the work (authors with a "s")
editor :pystr list of editors of a book
publisher :pystr name of the publisher
journal :pystr name of the journal or magazine the article was published in
volume :pystr volume number
pages :pystr page range where the article is
number :pystr number of the report or the issue number for a journal article
doi :pystr DOI number (like 10.1038/d41586-018-07848-2)
issn :pyList <list>[:pystr] ISSN number like 1476-4687
isbn :pyList <list>[:pystr] ISBN number like 9780201896831
pdf_url :pystr URL to the full article, the PDF version
html_url :pystr URL to full article, HTML version