# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
"""This module implements the engine loader.
Load and initialize the ``engines``, see :py:func:`load_engines` and register
:py:obj:`engine_shortcuts`.
usage::
load_engines( settings['engines'] )
"""
import sys
import copy
from typing import Dict, List, Optional
from os.path import realpath, dirname
from babel.localedata import locale_identifiers
from searx import logger, settings
from searx.data import ENGINES_LANGUAGES
from searx.network import get
from searx.utils import load_module, match_language, gen_useragent
logger = logger.getChild('engines')
ENGINE_DIR = dirname(realpath(__file__))
BABEL_LANGS = [
lang_parts[0] + '-' + lang_parts[-1] if len(lang_parts) > 1 else lang_parts[0]
for lang_parts in (lang_code.split('_') for lang_code in locale_identifiers())
]
ENGINE_DEFAULT_ARGS = {
"engine_type": "online",
"inactive": False,
"disabled": False,
"timeout": settings["outgoing"]["request_timeout"],
"shortcut": "-",
"categories": ["general"],
"supported_languages": [],
"language_aliases": {},
"paging": False,
"safesearch": False,
"time_range_support": False,
"enable_http": False,
"using_tor_proxy": False,
"display_error_messages": True,
"send_accept_language_header": False,
"tokens": [],
"about": {},
}
# set automatically when an engine does not have any tab category
OTHER_CATEGORY = 'other'
class Engine: # pylint: disable=too-few-public-methods
"""This class is currently never initialized and only used for type hinting."""
name: str
engine: str
shortcut: str
categories: List[str]
supported_languages: List[str]
about: dict
inactive: bool
disabled: bool
language_support: bool
paging: bool
safesearch: bool
time_range_support: bool
timeout: float
# Defaults for the namespace of an engine module, see :py:func:`load_engine`
categories = {'general': []}
engines: Dict[str, Engine] = {}
engine_shortcuts = {}
"""Simple map of registered *shortcuts* to name of the engine (or ``None``).
::
engine_shortcuts[engine.shortcut] = engine.name
:meta hide-value:
"""
def load_engine(engine_data: dict) -> Optional[Engine]:
"""Load engine from ``engine_data``.
:param dict engine_data: Attributes from YAML ``settings:engines/<engine>``
:return: initialized namespace of the ``<engine>``.
1. create a namespace and load module of the ``<engine>``
2. update namespace with the defaults from :py:obj:`ENGINE_DEFAULT_ARGS`
3. update namespace with values from ``engine_data``
If engine *is active*, return namespace of the engine, otherwise return
``None``.
This function also returns ``None`` if initialization of the namespace fails
for one of the following reasons:
- engine name contains underscore
- engine name is not lowercase
- required attribute is not set :py:func:`is_missing_required_attributes`
"""
# pylint: disable=too-many-return-statements
engine_name = engine_data.get('name')
if engine_name is None:
logger.error('An engine does not have a "name" field')
return None
if '_' in engine_name:
logger.error('Engine name contains underscore: "{}"'.format(engine_name))
return None
if engine_name.lower() != engine_name:
logger.warn('Engine name is not lowercase: "{}", converting to lowercase'.format(engine_name))
engine_name = engine_name.lower()
engine_data['name'] = engine_name
# load_module
engine_module = engine_data.get('engine')
if engine_module is None:
logger.error('The "engine" field is missing for the engine named "{}"'.format(engine_name))
return None
try:
engine = load_module(engine_module + '.py', ENGINE_DIR)
except (SyntaxError, KeyboardInterrupt, SystemExit, SystemError, ImportError, RuntimeError):
logger.exception('Fatal exception in engine "{}"'.format(engine_module))
sys.exit(1)
except BaseException:
logger.exception('Cannot load engine "{}"'.format(engine_module))
return None
update_engine_attributes(engine, engine_data)
set_language_attributes(engine)
update_attributes_for_tor(engine)
if not is_engine_active(engine):
return None
if is_missing_required_attributes(engine):
return None
set_loggers(engine, engine_name)
if not any(cat in settings['categories_as_tabs'] for cat in engine.categories):
engine.categories.append(OTHER_CATEGORY)
return engine
def set_loggers(engine, engine_name):
# set the logger for engine
engine.logger = logger.getChild(engine_name)
# the engine may have load some other engines
# may sure the logger is initialized
# use sys.modules.copy() to avoid "RuntimeError: dictionary changed size during iteration"
# see https://github.com/python/cpython/issues/89516
# and https://docs.python.org/3.10/library/sys.html#sys.modules
modules = sys.modules.copy()
for module_name, module in modules.items():
if (
module_name.startswith("searx.engines")
and module_name != "searx.engines.__init__"
and not hasattr(module, "logger")
):
module_engine_name = module_name.split(".")[-1]
module.logger = logger.getChild(module_engine_name)
def update_engine_attributes(engine: Engine, engine_data):
# set engine attributes from engine_data
for param_name, param_value in engine_data.items():
if param_name == 'categories':
if isinstance(param_value, str):
param_value = list(map(str.strip, param_value.split(',')))
engine.categories = param_value
elif hasattr(engine, 'about') and param_name == 'about':
engine.about = {**engine.about, **engine_data['about']}
else:
setattr(engine, param_name, param_value)
# set default attributes
for arg_name, arg_value in ENGINE_DEFAULT_ARGS.items():
if not hasattr(engine, arg_name):
setattr(engine, arg_name, copy.deepcopy(arg_value))
def set_language_attributes(engine: Engine):
# assign supported languages from json file
if engine.name in ENGINES_LANGUAGES:
engine.supported_languages = ENGINES_LANGUAGES[engine.name]
elif engine.engine in ENGINES_LANGUAGES:
# The key of the dictionary ENGINES_LANGUAGES is the *engine name*
# configured in settings.xml. When multiple engines are configured in
# settings.yml to use the same origin engine (python module) these
# additional engines can use the languages from the origin engine.
# For this use the configured ``engine: ...`` from settings.yml
engine.supported_languages = ENGINES_LANGUAGES[engine.engine]
if hasattr(engine, 'language'):
# For an engine, when there is `language: ...` in the YAML settings, the
# engine supports only one language, in this case
# engine.supported_languages should contains this value defined in
# settings.yml
if engine.language not in engine.supported_languages:
raise ValueError(
"settings.yml - engine: '%s' / language: '%s' not supported" % (engine.name, engine.language)
)
if isinstance(engine.supported_languages, dict):
engine.supported_languages = {engine.language: engine.supported_languages[engine.language]}
else:
engine.supported_languages = [engine.language]
# find custom aliases for non standard language codes
for engine_lang in engine.supported_languages:
iso_lang = match_language(engine_lang, BABEL_LANGS, fallback=None)
if (
iso_lang
and iso_lang != engine_lang
and not engine_lang.startswith(iso_lang)
and iso_lang not in engine.supported_languages
):
engine.language_aliases[iso_lang] = engine_lang
# language_support
engine.language_support = len(engine.supported_languages) > 0
# assign language fetching method if auxiliary method exists
if hasattr(engine, '_fetch_supported_languages'):
headers = {
'User-Agent': gen_useragent(),
'Accept-Language': "en-US,en;q=0.5", # bing needs to set the English language
}
engine.fetch_supported_languages = (
# pylint: disable=protected-access
lambda: engine._fetch_supported_languages(get(engine.supported_languages_url, headers=headers))
)
def update_attributes_for_tor(engine: Engine) -> bool:
if using_tor_proxy(engine) and hasattr(engine, 'onion_url'):
engine.search_url = engine.onion_url + getattr(engine, 'search_path', '')
engine.timeout += settings['outgoing'].get('extra_proxy_timeout', 0)
def is_missing_required_attributes(engine):
"""An attribute is required when its name doesn't start with ``_`` (underline).
Required attributes must not be ``None``.
"""
missing = False
for engine_attr in dir(engine):
if not engine_attr.startswith('_') and getattr(engine, engine_attr) is None:
logger.error('Missing engine config attribute: "{0}.{1}"'.format(engine.name, engine_attr))
missing = True
return missing
def using_tor_proxy(engine: Engine):
"""Return True if the engine configuration declares to use Tor."""
return settings['outgoing'].get('using_tor_proxy') or getattr(engine, 'using_tor_proxy', False)
def is_engine_active(engine: Engine):
# check if engine is inactive
if engine.inactive is True:
return False
# exclude onion engines if not using tor
if 'onions' in engine.categories and not using_tor_proxy(engine):
return False
return True
def register_engine(engine: Engine):
if engine.name in engines:
logger.error('Engine config error: ambiguous name: {0}'.format(engine.name))
sys.exit(1)
engines[engine.name] = engine
if engine.shortcut in engine_shortcuts:
logger.error('Engine config error: ambiguous shortcut: {0}'.format(engine.shortcut))
sys.exit(1)
engine_shortcuts[engine.shortcut] = engine.name
for category_name in engine.categories:
categories.setdefault(category_name, []).append(engine)
def load_engines(engine_list):
"""usage: ``engine_list = settings['engines']``"""
engines.clear()
engine_shortcuts.clear()
categories.clear()
categories['general'] = []
for engine_data in engine_list:
engine = load_engine(engine_data)
if engine:
register_engine(engine)
return engines
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