[mod] isolation of botdetection from the limiter

This patch was inspired by the discussion around PR-2882 [2].  The goals of this
patch are:

1. Convert plugin searx.plugin.limiter to normal code [1]
2. isolation of botdetection from the limiter [2]
3. searx/{tools => botdetection}/config.py and drop searx.tools
4. in URL /config, 'limiter.enabled' is true only if the limiter is really
   enabled (Redis is available).

This patch moves all the code that belongs to botdetection into namespace
searx.botdetection and code that belongs to limiter is placed in namespace
searx.limiter.

Tthe limiter used to be a plugin at some point botdetection was added, it was
not a plugin.  The modularization of these two components was long overdue.
With the clear modularization, the documentation could then also be organized
according to the architecture.

[1] https://github.com/searxng/searxng/pull/2882
[2] https://github.com/searxng/searxng/pull/2882#issuecomment-1741716891

To test:

- check the app works without the limiter, check `/config`
- check the app works with the limiter and with the token, check `/config`
- make docs.live .. and read
  - http://0.0.0.0:8000/admin/searx.limiter.html
  - http://0.0.0.0:8000/src/searx.botdetection.html#botdetection

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

13 files changed, 402 insertions, 234 deletions

diff --git a/searx/botdetection/__init__.py b/searx/botdetection/__init__.py
index 74f6c426..d5716bcc 100644
--- a/searx/botdetection/__init__.py
+++ b/searx/botdetection/__init__.py
@@ -2,43 +2,22 @@
 # lint: pylint
 """.. _botdetection src:
 
-The :ref:`limiter <limiter src>` implements several methods to block bots:
-
-a. Analysis of the HTTP header in the request / can be easily bypassed.
-
-b. Block and pass lists in which IPs are listed / difficult to maintain, since
-   the IPs of bots are not all known and change over the time.
-
-c. Detection of bots based on the behavior of the requests and blocking and, if
-   necessary, unblocking of the IPs via a dynamically changeable IP block list.
-
-For dynamically changeable IP lists a Redis database is needed and for any kind
-of IP list the determination of the IP of the client is essential.  The IP of
-the client is determined via the X-Forwarded-For_ HTTP header
-
-.. _X-Forwarded-For:
-   https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
-
-X-Forwarded-For
-===============
-
-.. attention::
-
-   A correct setup of the HTTP request headers ``X-Forwarded-For`` and
-   ``X-Real-IP`` is essential to be able to assign a request to an IP correctly:
-
-   - `NGINX RequestHeader`_
-   - `Apache RequestHeader`_
-
-.. _NGINX RequestHeader:
-    https://docs.searxng.org/admin/installation-nginx.html#nginx-s-searxng-site
-.. _Apache RequestHeader:
-    https://docs.searxng.org/admin/installation-apache.html#apache-s-searxng-site
-
-.. autofunction:: searx.botdetection.get_real_ip
+Implementations used for bot detection.
 
 """
 
 from ._helpers import dump_request
 from ._helpers import get_real_ip
+from ._helpers import get_network
 from ._helpers import too_many_requests
+
+__all__ = ['dump_request', 'get_network', 'get_real_ip', 'too_many_requests']
+
+redis_client = None
+cfg = None
+
+
+def init(_cfg, _redis_client):
+    global redis_client, cfg  # pylint: disable=global-statement
+    redis_client = _redis_client
+    cfg = _cfg
diff --git a/searx/botdetection/_helpers.py b/searx/botdetection/_helpers.py
index f50250e8..365067c2 100644
--- a/searx/botdetection/_helpers.py
+++ b/searx/botdetection/_helpers.py
@@ -13,8 +13,8 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
 from searx import logger
+from . import config
 
 logger = logger.getChild('botdetection')
 
@@ -104,10 +104,10 @@ def get_real_ip(request: flask.Request) -> str:
     if not forwarded_for:
         _log_error_only_once("X-Forwarded-For header is not set!")
     else:
-        from .limiter import get_cfg  # pylint: disable=import-outside-toplevel, cyclic-import
+        from . import cfg  # pylint: disable=import-outside-toplevel, cyclic-import
 
         forwarded_for = [x.strip() for x in forwarded_for.split(',')]
-        x_for: int = get_cfg()['real_ip.x_for']  # type: ignore
+        x_for: int = cfg['real_ip.x_for']  # type: ignore
         forwarded_for = forwarded_for[-min(len(forwarded_for), x_for)]
 
     if not real_ip:
diff --git a/searx/botdetection/config.py b/searx/botdetection/config.py
new file mode 100644
index 00000000..d2710456
--- /dev/null
+++ b/searx/botdetection/config.py
@@ -0,0 +1,377 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+"""Configuration class :py:class:`Config` with deep-update, schema validation
+and deprecated names.
+
+The :py:class:`Config` class implements a configuration that is based on
+structured dictionaries.  The configuration schema is defined in a dictionary
+structure and the configuration data is given in a dictionary structure.
+"""
+from __future__ import annotations
+from typing import Any
+
+import copy
+import typing
+import logging
+import pathlib
+import pytomlpp as toml
+
+__all__ = ['Config', 'UNSET', 'SchemaIssue']
+
+log = logging.getLogger(__name__)
+
+
+class FALSE:
+    """Class of ``False`` singelton"""
+
+    # pylint: disable=multiple-statements
+    def __init__(self, msg):
+        self.msg = msg
+
+    def __bool__(self):
+        return False
+
+    def __str__(self):
+        return self.msg
+
+    __repr__ = __str__
+
+
+UNSET = FALSE('<UNSET>')
+
+
+class SchemaIssue(ValueError):
+    """Exception to store and/or raise a message from a schema issue."""
+
+    def __init__(self, level: typing.Literal['warn', 'invalid'], msg: str):
+        self.level = level
+        super().__init__(msg)
+
+    def __str__(self):
+        return f"[cfg schema {self.level}] {self.args[0]}"
+
+
+class Config:
+    """Base class used for configuration"""
+
+    UNSET = UNSET
+
+    @classmethod
+    def from_toml(cls, schema_file: pathlib.Path, cfg_file: pathlib.Path, deprecated: dict) -> Config:
+
+        # init schema
+
+        log.debug("load schema file: %s", schema_file)
+        cfg = cls(cfg_schema=toml.load(schema_file), deprecated=deprecated)
+        if not cfg_file.exists():
+            log.warning("missing config file: %s", cfg_file)
+            return cfg
+
+        # load configuration
+
+        log.debug("load config file: %s", cfg_file)
+        try:
+            upd_cfg = toml.load(cfg_file)
+        except toml.DecodeError as exc:
+            msg = str(exc).replace('\t', '').replace('\n', ' ')
+            log.error("%s: %s", cfg_file, msg)
+            raise
+
+        is_valid, issue_list = cfg.validate(upd_cfg)
+        for msg in issue_list:
+            log.error(str(msg))
+        if not is_valid:
+            raise TypeError(f"schema of {cfg_file} is invalid!")
+        cfg.update(upd_cfg)
+        return cfg
+
+    def __init__(self, cfg_schema: typing.Dict, deprecated: typing.Dict[str, str]):
+        """Construtor of class Config.
+
+        :param cfg_schema: Schema of the configuration
+        :param deprecated: dictionary that maps deprecated configuration names to a messages
+
+        These values are needed for validation, see :py:obj:`validate`.
+
+        """
+        self.cfg_schema = cfg_schema
+        self.deprecated = deprecated
+        self.cfg = copy.deepcopy(cfg_schema)
+
+    def __getitem__(self, key: str) -> Any:
+        return self.get(key)
+
+    def validate(self, cfg: dict):
+        """Validation of dictionary ``cfg`` on :py:obj:`Config.SCHEMA`.
+        Validation is done by :py:obj:`validate`."""
+
+        return validate(self.cfg_schema, cfg, self.deprecated)
+
+    def update(self, upd_cfg: dict):
+        """Update this configuration by ``upd_cfg``."""
+
+        dict_deepupdate(self.cfg, upd_cfg)
+
+    def default(self, name: str):
+        """Returns default value of field ``name`` in ``self.cfg_schema``."""
+        return value(name, self.cfg_schema)
+
+    def get(self, name: str, default: Any = UNSET, replace: bool = True) -> Any:
+        """Returns the value to which ``name`` points in the configuration.
+
+        If there is no such ``name`` in the config and the ``default`` is
+        :py:obj:`UNSET`, a :py:obj:`KeyError` is raised.
+        """
+
+        parent = self._get_parent_dict(name)
+        val = parent.get(name.split('.')[-1], UNSET)
+        if val is UNSET:
+            if default is UNSET:
+                raise KeyError(name)
+            val = default
+
+        if replace and isinstance(val, str):
+            val = val % self
+        return val
+
+    def set(self, name: str, val):
+        """Set the value to which ``name`` points in the configuration.
+
+        If there is no such ``name`` in the config, a :py:obj:`KeyError` is
+        raised.
+        """
+        parent = self._get_parent_dict(name)
+        parent[name.split('.')[-1]] = val
+
+    def _get_parent_dict(self, name):
+        parent_name = '.'.join(name.split('.')[:-1])
+        if parent_name:
+            parent = value(parent_name, self.cfg)
+        else:
+            parent = self.cfg
+        if (parent is UNSET) or (not isinstance(parent, dict)):
+            raise KeyError(parent_name)
+        return parent
+
+    def path(self, name: str, default=UNSET):
+        """Get a :py:class:`pathlib.Path` object from a config string."""
+
+        val = self.get(name, default)
+        if val is UNSET:
+            if default is UNSET:
+                raise KeyError(name)
+            return default
+        return pathlib.Path(str(val))
+
+    def pyobj(self, name, default=UNSET):
+        """Get python object refered by full qualiffied name (FQN) in the config
+        string."""
+
+        fqn = self.get(name, default)
+        if fqn is UNSET:
+            if default is UNSET:
+                raise KeyError(name)
+            return default
+        (modulename, name) = str(fqn).rsplit('.', 1)
+        m = __import__(modulename, {}, {}, [name], 0)
+        return getattr(m, name)
+
+
+# working with dictionaries
+
+
+def value(name: str, data_dict: dict):
+    """Returns the value to which ``name`` points in the ``dat_dict``.
+
+    .. code: python
+
+        >>> data_dict = {
+                "foo": {"bar": 1 },
+                "bar": {"foo": 2 },
+                "foobar": [1, 2, 3],
+            }
+        >>> value('foobar', data_dict)
+        [1, 2, 3]
+        >>> value('foo.bar', data_dict)
+        1
+        >>> value('foo.bar.xxx', data_dict)
+        <UNSET>
+
+    """
+
+    ret_val = data_dict
+    for part in name.split('.'):
+        if isinstance(ret_val, dict):
+            ret_val = ret_val.get(part, UNSET)
+        if ret_val is UNSET:
+            break
+    return ret_val
+
+
+def validate(
+    schema_dict: typing.Dict, data_dict: typing.Dict, deprecated: typing.Dict[str, str]
+) -> typing.Tuple[bool, list]:
+
+    """Deep validation of dictionary in ``data_dict`` against dictionary in
+    ``schema_dict``.  Argument deprecated is a dictionary that maps deprecated
+    configuration names to a messages::
+
+        deprecated = {
+            "foo.bar" : "config 'foo.bar' is deprecated, use 'bar.foo'",
+            "..."     : "..."
+        }
+
+    The function returns a python tuple ``(is_valid, issue_list)``:
+
+    ``is_valid``:
+      A bool value indicating ``data_dict`` is valid or not.
+
+    ``issue_list``:
+      A list of messages (:py:obj:`SchemaIssue`) from the validation::
+
+          [schema warn] data_dict: deprecated 'fontlib.foo': <DEPRECATED['foo.bar']>
+          [schema invalid] data_dict: key unknown 'fontlib.foo'
+          [schema invalid] data_dict: type mismatch 'fontlib.foo': expected ..., is ...
+
+    If ``schema_dict`` or ``data_dict`` is not a dictionary type a
+    :py:obj:`SchemaIssue` is raised.
+
+    """
+    names = []
+    is_valid = True
+    issue_list = []
+
+    if not isinstance(schema_dict, dict):
+        raise SchemaIssue('invalid', "schema_dict is not a dict type")
+    if not isinstance(data_dict, dict):
+        raise SchemaIssue('invalid', f"data_dict issue{'.'.join(names)} is not a dict type")
+
+    is_valid, issue_list = _validate(names, issue_list, schema_dict, data_dict, deprecated)
+    return is_valid, issue_list
+
+
+def _validate(
+    names: typing.List,
+    issue_list: typing.List,
+    schema_dict: typing.Dict,
+    data_dict: typing.Dict,
+    deprecated: typing.Dict[str, str],
+) -> typing.Tuple[bool, typing.List]:
+
+    is_valid = True
+
+    for key, data_value in data_dict.items():
+
+        names.append(key)
+        name = '.'.join(names)
+
+        deprecated_msg = deprecated.get(name)
+        # print("XXX %s: key %s //   data_value: %s" % (name, key, data_value))
+        if deprecated_msg:
+            issue_list.append(SchemaIssue('warn', f"data_dict '{name}': deprecated - {deprecated_msg}"))
+
+        schema_value = value(name, schema_dict)
+        # print("YYY %s: key %s // schema_value: %s" % (name, key, schema_value))
+        if schema_value is UNSET:
+            if not deprecated_msg:
+                issue_list.append(SchemaIssue('invalid', f"data_dict '{name}': key unknown in schema_dict"))
+                is_valid = False
+
+        elif type(schema_value) != type(data_value):  # pylint: disable=unidiomatic-typecheck
+            issue_list.append(
+                SchemaIssue(
+                    'invalid',
+                    (f"data_dict: type mismatch '{name}':" f" expected {type(schema_value)}, is: {type(data_value)}"),
+                )
+            )
+            is_valid = False
+
+        elif isinstance(data_value, dict):
+            _valid, _ = _validate(names, issue_list, schema_dict, data_value, deprecated)
+            is_valid = is_valid and _valid
+        names.pop()
+
+    return is_valid, issue_list
+
+
+def dict_deepupdate(base_dict: dict, upd_dict: dict, names=None):
+    """Deep-update of dictionary in ``base_dict`` by dictionary in ``upd_dict``.
+
+    For each ``upd_key`` & ``upd_val`` pair in ``upd_dict``:
+
+    0. If types of ``base_dict[upd_key]`` and ``upd_val`` do not match raise a
+       :py:obj:`TypeError`.
+
+    1. If ``base_dict[upd_key]`` is a dict: recursively deep-update it by ``upd_val``.
+
+    2. If ``base_dict[upd_key]`` not exist: set ``base_dict[upd_key]`` from a
+       (deep-) copy of ``upd_val``.
+
+    3. If ``upd_val`` is a list, extend list in ``base_dict[upd_key]`` by the
+       list in ``upd_val``.
+
+    4. If ``upd_val`` is a set, update set in ``base_dict[upd_key]`` by set in
+       ``upd_val``.
+    """
+    # pylint: disable=too-many-branches
+    if not isinstance(base_dict, dict):
+        raise TypeError("argument 'base_dict' is not a ditionary type")
+    if not isinstance(upd_dict, dict):
+        raise TypeError("argument 'upd_dict' is not a ditionary type")
+
+    if names is None:
+        names = []
+
+    for upd_key, upd_val in upd_dict.items():
+        # For each upd_key & upd_val pair in upd_dict:
+
+        if isinstance(upd_val, dict):
+
+            if upd_key in base_dict:
+                # if base_dict[upd_key] exists, recursively deep-update it
+                if not isinstance(base_dict[upd_key], dict):
+                    raise TypeError(f"type mismatch {'.'.join(names)}: is not a dict type in base_dict")
+                dict_deepupdate(
+                    base_dict[upd_key],
+                    upd_val,
+                    names
+                    + [
+                        upd_key,
+                    ],
+                )
+
+            else:
+                # if base_dict[upd_key] not exist, set base_dict[upd_key] from deepcopy of upd_val
+                base_dict[upd_key] = copy.deepcopy(upd_val)
+
+        elif isinstance(upd_val, list):
+
+            if upd_key in base_dict:
+                # if base_dict[upd_key] exists, base_dict[up_key] is extended by
+                # the list from upd_val
+                if not isinstance(base_dict[upd_key], list):
+                    raise TypeError(f"type mismatch {'.'.join(names)}: is not a list type in base_dict")
+                base_dict[upd_key].extend(upd_val)
+
+            else:
+                # if base_dict[upd_key] doesn't exists, set base_dict[key] from a deepcopy of the
+                # list in upd_val.
+                base_dict[upd_key] = copy.deepcopy(upd_val)
+
+        elif isinstance(upd_val, set):
+
+            if upd_key in base_dict:
+                # if base_dict[upd_key] exists, base_dict[up_key] is updated by the set in upd_val
+                if not isinstance(base_dict[upd_key], set):
+                    raise TypeError(f"type mismatch {'.'.join(names)}: is not a set type in base_dict")
+                base_dict[upd_key].update(upd_val.copy())
+
+            else:
+                # if base_dict[upd_key] doesn't exists, set base_dict[upd_key] from a copy of the
+                # set in upd_val
+                base_dict[upd_key] = upd_val.copy()
+
+        else:
+            # for any other type of upd_val replace or add base_dict[upd_key] by a copy
+            # of upd_val
+            base_dict[upd_key] = copy.copy(upd_val)
diff --git a/searx/botdetection/http_accept.py b/searx/botdetection/http_accept.py
index b78a8627..b1f52459 100644
--- a/searx/botdetection/http_accept.py
+++ b/searx/botdetection/http_accept.py
@@ -24,7 +24,7 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
+from . import config
 from ._helpers import too_many_requests
 
 
diff --git a/searx/botdetection/http_accept_encoding.py b/searx/botdetection/http_accept_encoding.py
index 60718a4c..e0c03cc7 100644
--- a/searx/botdetection/http_accept_encoding.py
+++ b/searx/botdetection/http_accept_encoding.py
@@ -25,7 +25,7 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
+from . import config
 from ._helpers import too_many_requests
 
 
diff --git a/searx/botdetection/http_accept_language.py b/searx/botdetection/http_accept_language.py
index 395d28bf..aaef81cc 100644
--- a/searx/botdetection/http_accept_language.py
+++ b/searx/botdetection/http_accept_language.py
@@ -21,7 +21,7 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
+from . import config
 from ._helpers import too_many_requests
 
 
diff --git a/searx/botdetection/http_connection.py b/searx/botdetection/http_connection.py
index ee0d80a2..a3287715 100644
--- a/searx/botdetection/http_connection.py
+++ b/searx/botdetection/http_connection.py
@@ -22,7 +22,7 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
+from . import config
 from ._helpers import too_many_requests
 
 
diff --git a/searx/botdetection/http_user_agent.py b/searx/botdetection/http_user_agent.py
index 17025f68..e2e02a9b 100644
--- a/searx/botdetection/http_user_agent.py
+++ b/searx/botdetection/http_user_agent.py
@@ -24,7 +24,7 @@ from ipaddress import (
 import flask
 import werkzeug
 
-from searx.tools import config
+from . import config
 from ._helpers import too_many_requests
 
 
diff --git a/searx/botdetection/ip_limit.py b/searx/botdetection/ip_limit.py
index 5ff3c87c..071978a3 100644
--- a/searx/botdetection/ip_limit.py
+++ b/searx/botdetection/ip_limit.py
@@ -13,8 +13,7 @@ and at least for a maximum of 10 minutes.
 
 The :py:obj:`.link_token` method can be used to investigate whether a request is
 *suspicious*.  To activate the :py:obj:`.link_token` method in the
-:py:obj:`.ip_limit` method add the following to your
-``/etc/searxng/limiter.toml``:
+:py:obj:`.ip_limit` method add the following configuration:
 
 .. code:: toml
 
@@ -46,13 +45,13 @@ from ipaddress import (
 
 import flask
 import werkzeug
-from searx.tools import config
 from searx import settings
 
 from searx import redisdb
 from searx.redislib import incr_sliding_window, drop_counter
 
 from . import link_token
+from . import config
 from ._helpers import (
     too_many_requests,
     logger,
diff --git a/searx/botdetection/ip_lists.py b/searx/botdetection/ip_lists.py
index 456ef436..5c904f4a 100644
--- a/searx/botdetection/ip_lists.py
+++ b/searx/botdetection/ip_lists.py
@@ -33,7 +33,7 @@ from ipaddress import (
     IPv6Address,
 )
 
-from searx.tools import config
+from . import config
 from ._helpers import logger
 
 logger = logger.getChild('ip_limit')
diff --git a/searx/botdetection/limiter.py b/searx/botdetection/limiter.py
deleted file mode 100644
index 9b3532f0..00000000
--- a/searx/botdetection/limiter.py
+++ /dev/null
@@ -1,145 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-# lint: pylint
-""".. _limiter src:
-
-Limiter
-=======
-
-.. sidebar:: info
-
-   The limiter requires a :ref:`Redis <settings redis>` database.
-
-Bot protection / IP rate limitation.  The intention of rate limitation is to
-limit suspicious requests from an IP.  The motivation behind this is the fact
-that SearXNG passes through requests from bots and is thus classified as a bot
-itself.  As a result, the SearXNG engine then receives a CAPTCHA or is blocked
-by the search engine (the origin) in some other way.
-
-To avoid blocking, the requests from bots to SearXNG must also be blocked, this
-is the task of the limiter.  To perform this task, the limiter uses the methods
-from the :py:obj:`searx.botdetection`.
-
-To enable the limiter activate:
-
-.. code:: yaml
-
-   server:
-     ...
-     limiter: true  # rate limit the number of request on the instance, block some bots
-
-and set the redis-url connection. Check the value, it depends on your redis DB
-(see :ref:`settings redis`), by example:
-
-.. code:: yaml
-
-   redis:
-     url: unix:///usr/local/searxng-redis/run/redis.sock?db=0
-
-"""
-
-from __future__ import annotations
-
-from pathlib import Path
-from ipaddress import ip_address
-import flask
-import werkzeug
-
-from searx.tools import config
-from searx import logger
-
-from . import (
-    http_accept,
-    http_accept_encoding,
-    http_accept_language,
-    http_user_agent,
-    ip_limit,
-    ip_lists,
-)
-
-from ._helpers import (
-    get_network,
-    get_real_ip,
-    dump_request,
-)
-
-logger = logger.getChild('botdetection.limiter')
-
-CFG: config.Config = None  # type: ignore
-
-LIMITER_CFG_SCHEMA = Path(__file__).parent / "limiter.toml"
-"""Base configuration (schema) of the botdetection."""
-
-LIMITER_CFG = Path('/etc/searxng/limiter.toml')
-"""Local Limiter configuration."""
-
-CFG_DEPRECATED = {
-    # "dummy.old.foo": "config 'dummy.old.foo' exists only for tests.  Don't use it in your real project config."
-}
-
-
-def get_cfg() -> config.Config:
-    global CFG  # pylint: disable=global-statement
-    if CFG is None:
-        CFG = config.Config.from_toml(LIMITER_CFG_SCHEMA, LIMITER_CFG, CFG_DEPRECATED)
-    return CFG
-
-
-def filter_request(request: flask.Request) -> werkzeug.Response | None:
-    # pylint: disable=too-many-return-statements
-
-    cfg = get_cfg()
-    real_ip = ip_address(get_real_ip(request))
-    network = get_network(real_ip, cfg)
-
-    if request.path == '/healthz':
-        return None
-
-    # link-local
-
-    if network.is_link_local:
-        return None
-
-    # block- & pass- lists
-    #
-    # 1. The IP of the request is first checked against the pass-list; if the IP
-    #    matches an entry in the list, the request is not blocked.
-    # 2. If no matching entry is found in the pass-list, then a check is made against
-    #    the block list; if the IP matches an entry in the list, the request is
-    #    blocked.
-    # 3. If the IP is not in either list, the request is not blocked.
-
-    match, msg = ip_lists.pass_ip(real_ip, cfg)
-    if match:
-        logger.warning("PASS %s: matched PASSLIST - %s", network.compressed, msg)
-        return None
-
-    match, msg = ip_lists.block_ip(real_ip, cfg)
-    if match:
-        logger.error("BLOCK %s: matched BLOCKLIST - %s", network.compressed, msg)
-        return flask.make_response(('IP is on BLOCKLIST - %s' % msg, 429))
-
-    # methods applied on /
-
-    for func in [
-        http_user_agent,
-    ]:
-        val = func.filter_request(network, request, cfg)
-        if val is not None:
-            return val
-
-    # methods applied on /search
-
-    if request.path == '/search':
-
-        for func in [
-            http_accept,
-            http_accept_encoding,
-            http_accept_language,
-            http_user_agent,
-            ip_limit,
-        ]:
-            val = func.filter_request(network, request, cfg)
-            if val is not None:
-                return val
-    logger.debug(f"OK {network}: %s", dump_request(flask.request))
-    return None
diff --git a/searx/botdetection/limiter.toml b/searx/botdetection/limiter.toml
deleted file mode 100644
index 9560ec8f..00000000
--- a/searx/botdetection/limiter.toml
+++ /dev/null
@@ -1,40 +0,0 @@
-[real_ip]
-
-# Number of values to trust for X-Forwarded-For.
-
-x_for = 1
-
-# The prefix defines the number of leading bits in an address that are compared
-# to determine whether or not an address is part of a (client) network.
-
-ipv4_prefix = 32
-ipv6_prefix = 48
-
-[botdetection.ip_limit]
-
-# To get unlimited access in a local network, by default link-lokal addresses
-# (networks) are not monitored by the ip_limit
-filter_link_local = false
-
-# activate link_token method in the ip_limit method
-link_token = false
-
-[botdetection.ip_lists]
-
-# In the limiter, the ip_lists method has priority over all other methods -> if
-# an IP is in the pass_ip list, it has unrestricted access and it is also not
-# checked if e.g. the "user agent" suggests a bot (e.g. curl).
-
-block_ip = [
-  # '93.184.216.34',  # IPv4 of example.org
-  # '257.1.1.1',      # invalid IP --> will be ignored, logged in ERROR class
-]
-
-pass_ip = [
-  # '192.168.0.0/16',      # IPv4 private network
-  # 'fe80::/10'            # IPv6 linklocal / wins over botdetection.ip_limit.filter_link_local
-]
-
-# Activate passlist of (hardcoded) IPs from the SearXNG organization,
-# e.g. `check.searx.space`.
-pass_searxng_org = true
\ No newline at end of file
diff --git a/searx/botdetection/link_token.py b/searx/botdetection/link_token.py
index 7ea15f5c..dcfee33d 100644
--- a/searx/botdetection/link_token.py
+++ b/searx/botdetection/link_token.py
@@ -99,15 +99,13 @@ def ping(request: flask.Request, token: str):
     The expire time of this ping-key is :py:obj:`PING_LIVE_TIME`.
 
     """
-    from . import limiter  # pylint: disable=import-outside-toplevel, cyclic-import
+    from . import redis_client, cfg  # pylint: disable=import-outside-toplevel, cyclic-import
 
-    redis_client = redisdb.client()
     if not redis_client:
         return
     if not token_is_valid(token):
         return
 
-    cfg = limiter.get_cfg()
     real_ip = ip_address(get_real_ip(request))
     network = get_network(real_ip, cfg)