Engine Library¶

Implementations of the framework for the SearXNG engines.

searx.enginelib.EngineCache
searx.enginelib.Engine
searx.enginelib.traits

There is a command line for developer purposes and for deeper analysis. Here is an example in which the command line is called in the development environment:

$ ./manage pyenv.cmd bash --norc --noprofile
(py3) python -m searx.enginelib --help

Hint

The long term goal is to modularize all implementations of the engine framework here in this Python package. ToDo:

move implementations of the SearXNG’s engines loader to a new module in the searx.enginelib namespace.

class searx.enginelib.EngineCache(engine_name: str, expire: int | None = None)[source]¶

Persistent (SQLite) key/value cache that deletes its values again after expire seconds (default/max: MAXHOLD_TIME). This class is a wrapper around ENGINES_CACHE (ExpireCacheSQLite).

In the git://searx/engines/demo_offline.py engine you can find an exemplary implementation of such a cache other examples are implemented in:

For introspection of the DB, jump into developer environment and run command to show cache state:

$ ./manage pyenv.cmd bash --norc --noprofile
(py3) python -m searx.enginelib cache state

cache tables and key/values
===========================
[demo_offline        ] 2025-04-22 11:32:50 count        --> (int) 4
[startpage           ] 2025-04-22 12:32:30 SC_CODE      --> (str) fSOBnhEMlDfE20
[duckduckgo          ] 2025-04-22 12:32:31 4dff493e.... --> (str) 4-128634958369380006627592672385352473325
[duckduckgo          ] 2025-04-22 12:40:06 3e2583e2.... --> (str) 4-263126175288871260472289814259666848451
[radio_browser       ] 2025-04-23 11:33:08 servers      --> (list) ['https://de2.api.radio-browser.info',  ...]
[soundcloud          ] 2025-04-29 11:40:06 guest_client_id --> (str) EjkRJG0BLNEZquRiPZYdNtJdyGtTuHdp
[wolframalpha        ] 2025-04-22 12:40:06 code         --> (str) 5aa79f86205ad26188e0e26e28fb7ae7
number of tables: 6
number of key/value pairs: 7

In the “cache tables and key/values” section, the table name (engine name) is at first position on the second there is the calculated expire date and on the third and fourth position the key/value is shown.

About duckduckgo: The vqd coode of ddg depends on the query term and therefore the key is a hash value of the query term (to not to store the raw query term).

In the “properties of ENGINES_CACHE” section all properties of the SQLiteAppl / ExpireCache and their last modification date are shown:

properties of ENGINES_CACHE
===========================
[last modified: 2025-04-22 11:32:27] DB_SCHEMA           : 1
[last modified: 2025-04-22 11:32:27] LAST_MAINTENANCE    :
[last modified: 2025-04-22 11:32:27] crypt_hash          : ca612e3566fdfd7cf7efe...
[last modified: 2025-04-22 11:32:30] CACHE-TABLE--demo_offline: demo_offline
[last modified: 2025-04-22 11:32:30] CACHE-TABLE--startpage: startpage
[last modified: 2025-04-22 11:32:31] CACHE-TABLE--duckduckgo: duckduckgo
[last modified: 2025-04-22 11:33:08] CACHE-TABLE--radio_browser: radio_browser
[last modified: 2025-04-22 11:40:06] CACHE-TABLE--soundcloud: soundcloud
[last modified: 2025-04-22 11:40:06] CACHE-TABLE--wolframalpha: wolframalpha

These properties provide information about the state of the ExpireCache and control the behavior. For example, the maintenance intervals are controlled by the last modification date of the LAST_MAINTENANCE property and the hash value of the password can be used to detect whether the password has been changed (in this case the DB entries can no longer be decrypted and the entire cache must be discarded).

class searx.enginelib.Engine[source]¶

Class of engine instances build from YAML settings.

Further documentation see General Engine Configuration.

Hint

This class is currently never initialized and only used for type hinting.

engine_type: str¶: Type of the engine (Search processors)

paging: bool¶: Engine supports multiple pages.

max_page: int = 0¶: If the engine supports paging, then this is the value for the last page that is still supported. 0 means unlimited numbers of pages.

time_range_support: bool¶: Engine supports search time range.

safesearch: bool¶: Engine supports SafeSearch

language_support: bool¶: Engine supports languages (locales) search.

language: str¶

For an engine, when there is language: ... in the YAML settings the engine does support only this one language:

- name: google french
  engine: google
  language: fr

region: str¶

For an engine, when there is region: ... in the YAML settings the engine does support only this one region:

.. code:: yaml

name: google belgium engine: google region: fr-BE

fetch_traits: Callable[[EngineTraits, bool], None]¶: Function to to fetch engine’s traits from origin.

traits: traits.EngineTraits¶: Traits of the engine.

categories: list[str]¶: Specifies to which categories the engine should be added.

name: str¶: Name that will be used across SearXNG to define this engine. In settings, on the result page ..

engine: str¶: Name of the python file used to handle requests and responses to and from this search engine (file name from git://searx/engines without .py).

enable_http: bool¶: Enable HTTP (by default only HTTPS is enabled).

shortcut: str¶: Code used to execute bang requests (!foo)

timeout: float¶: Specific timeout for search-engine.

display_error_messages: bool¶: Display error messages on the web UI.

proxies: dict[str, dict[str, str]]¶

Set proxies for a specific engine (YAML):

proxies :
  http:  socks5://proxy:port
  https: socks5://proxy:port

disabled: bool¶: To disable by default the engine, but not deleting it. It will allow the user to manually activate it in the settings.

inactive: bool¶: Remove the engine from the settings (disabled & removed).

about: dict[str, dict[str, str]]¶

Additional fields describing the engine.

about:
   website: https://example.com
   wikidata_id: Q306656
   official_api_documentation: https://example.com/api-doc
   use_official_api: true
   require_api_key: true
   results: HTML

using_tor_proxy: bool¶: Using tor proxy (true) or not (false) for this engine.

send_accept_language_header: bool¶: When this option is activated, the language (locale) that is selected by the user is used to build and send a Accept-Language header in the request to the origin search engine.

tokens: list[str]¶: A list of secret tokens to make this engine private, more details see Private Engines (tokens).

weight: int¶: Weighting of the results of this engine (weight).

setup(engine_settings: dict[str, Any]) → bool[source]¶

Dynamic setup of the engine settings.

With this method, the engine’s setup is carried out. For example, to check or dynamically adapt the values handed over in the parameter engine_settings. The return value (True/False) indicates whether the setup was successful and the engine can be built or rejected.

The method is optional and is called synchronously as part of the initialization of the service and is therefore only suitable for simple (local) exams/changes at the engine setting. The Engine.init method must be used for longer tasks in which values of a remote must be determined, for example.

init(engine_settings: dict[str, Any]) → bool | None[source]¶

Initialization of the engine.

The method is optional and asynchronous (in a thread). It is suitable, for example, for setting up a cache (for the engine) or for querying values (required by the engine) from a remote.

Whether the initialization was successful can be indicated by the return value True or even False.

If no return value is given from this init method (None), this is equivalent to True.
If an exception is thrown as part of the initialization, this is equivalent to False.

abstractmethod search(query: str, params: OfflineParamTypes) → EngineResults[source]¶: Search method of the offline engines

abstractmethod request(query: str, params: OnlineParamTypes) → None[source]¶: Method to build the parameters for the request of an online engine.

abstractmethod response(resp: SXNG_Response) → EngineResults[source]¶: Method to parse the response of an online engine.

searx.enginelib.ENGINES_CACHE: ExpireCacheSQLite = <searx.cache.ExpireCacheSQLite object>¶: Global searx.cache.ExpireCacheSQLite instance where the cached values from all engines are stored. The MAXHOLD_TIME is 7 days and the MAINTENANCE_PERIOD is set to two hours.

Engine traits¶

Engine’s traits are fetched from the origin engines and stored in a JSON file in the data folder. Most often traits are languages and region codes and their mapping from SearXNG’s representation to the representation in the origin search engine. For new traits new properties can be added to the class EngineTraits.

To load traits from the persistence EngineTraitsMap.from_data can be used.

class searx.enginelib.traits.EngineTraitsEncoder(*, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, sort_keys=False, indent=None, separators=None, default=None)[source]¶

Encodes EngineTraits to a serializable object, see json.JSONEncoder.

default(o: Any) → Any[source]¶: Return dictionary of a EngineTraits object.

class searx.enginelib.traits.EngineTraits(regions: dict[str, str] = <factory>, languages: dict[str, str] = <factory>, all_locale: str | None = None, data_type: ~typing.Literal['traits_v1'] = 'traits_v1', custom: dict[str, ~typing.Any] = <factory>)[source]¶

The class is intended to be instantiated for each engine.

regions: dict[str, str]¶

Maps SearXNG’s internal representation of a region to the one of the engine.

SearXNG’s internal representation can be parsed by babel and the value is send to the engine:

regions ={
    'fr-BE' : <engine's region name>,
}

for key, egnine_region regions.items():
   searxng_region = babel.Locale.parse(key, sep='-')
   ...

languages: dict[str, str]¶

Maps SearXNG’s internal representation of a language to the one of the engine.

SearXNG’s internal representation can be parsed by babel and the value is send to the engine:

languages = {
    'ca' : <engine's language name>,
}

for key, egnine_lang in languages.items():
   searxng_lang = babel.Locale.parse(key)
   ...

all_locale: str | None = None¶: To which locale value SearXNG’s all language is mapped (shown a “Default language”).

data_type: Literal['traits_v1'] = 'traits_v1'¶: Data type, default is ‘traits_v1’.

custom: dict[str, Any]¶: A place to store engine’s custom traits, not related to the SearXNG core.

get_language(searxng_locale: str, default: Any = None)[source]¶

Return engine’s language string that best fits to SearXNG’s locale.

Parameters:

searxng_locale – SearXNG’s internal representation of locale selected by the user.
default – engine’s default language

The best fits rules are implemented in searx.locales.get_engine_locale. Except for the special value all which is determined from EngineTraits.all_locale.

get_region(searxng_locale: str, default: Any = None) → Any[source]¶

Return engine’s region string that best fits to SearXNG’s locale.

Parameters:

searxng_locale – SearXNG’s internal representation of locale selected by the user.
default – engine’s default region

The best fits rules are implemented in searx.locales.get_engine_locale. Except for the special value all which is determined from EngineTraits.all_locale.

is_locale_supported(searxng_locale: str) → bool[source]¶

A locale (SearXNG’s internal representation) is considered to be supported by the engine if the region or the language is supported by the engine.

For verification the functions EngineTraits.get_region() and EngineTraits.get_language() are used.

copy()[source]¶: Create a copy of the dataclass object.

classmethod fetch_traits(engine: Engine | types.ModuleType) → EngineTraits | None[source]¶: Call a function fetch_traits(engine_traits) from engines namespace to fetch and set properties from the origin engine in the object engine_traits. If function does not exists, None is returned.

set_traits(engine: Engine | types.ModuleType)[source]¶

Set traits from self object in a Engine namespace.

Parameters:: engine – engine instance build by searx.engines.load_engine()

class searx.enginelib.traits.EngineTraitsMap[source]¶

A python dictionary to map EngineTraits by engine name.

ENGINE_TRAITS_FILE: Path = PosixPath('/home/runner/work/searxng/searxng/searx/data/engine_traits.json')¶: File with persistence of the EngineTraitsMap.

save_data()[source]¶: Store EngineTraitsMap in in file self.ENGINE_TRAITS_FILE

classmethod from_data() → EngineTraitsMap[source]¶: Instantiate EngineTraitsMap object from ENGINE_TRAITS

set_traits(engine: Engine | types.ModuleType)[source]¶

Set traits in a Engine namespace.

Parameters:: engine – engine instance build by searx.engines.load_engine()

Engine Library¶

Engine traits¶

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