[mod] Revision of the favicon solution

All favicons implementations have been documented and moved to the Python
package:

    searx.favicons

There is a configuration (based on Pydantic) for the favicons and all its
components:

    searx.favicons.config

A solution for caching favicons has been implemented:

    searx.favicon.cache

If the favicon is already in the cache, the returned URL is a data URL [1]
(something like `data:image/png;base64,...`).  By generating a data url from
the FaviconCache, additional HTTP roundtripps via the favicon_proxy are saved:

    favicons.proxy.favicon_url

The favicon proxy service now sets a HTTP header "Cache-Control: max-age=...":

    favicons.proxy.favicon_proxy

The resolvers now also provide the mime type (data, mime):

    searx.favicon.resolvers

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs

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

docs/admin/settings/settings_search.rst

@@ -43,7 +43,8 @@
   - ``wikipedia``
 
 ``favicon_resolver``:
-  Favicon resolver, leave blank to turn off the feature by default.
+  :ref:`Favicon resolver <favicons>`, leave blank to turn off the feature by
+  default.
 
   - ``allesedv``
   - ``duckduckgo``

docs/conf.py

@@ -127,6 +127,7 @@ extensions = [
     "sphinx_tabs.tabs", # https://github.com/djungelorm/sphinx-tabs
     'myst_parser',  # https://www.sphinx-doc.org/en/master/usage/markdown.html
     'notfound.extension',  # https://github.com/readthedocs/sphinx-notfound-page
+    'sphinxcontrib.autodoc_pydantic',  # https://github.com/mansenfranzen/autodoc_pydantic
 ]
 
 autodoc_default_options = {

docs/src/searx.favicons.rst

@@ -0,0 +1,48 @@
+.. _favicons:
+
+========
+Favicons
+========
+
+.. contents::
+   :depth: 2
+   :local:
+   :backlinks: entry
+
+.. automodule:: searx.favicons
+   :members:
+
+.. _favicons.config:
+
+Favicons Config
+===============
+
+.. automodule:: searx.favicons.config
+   :members:
+
+.. _favicons.proxy:
+
+Favicons Proxy
+==============
+
+.. automodule:: searx.favicons.proxy
+   :members:
+
+.. _favicons.resolver:
+
+Favicons Resolver
+=================
+
+.. automodule:: searx.favicons.resolvers
+   :members:
+
+.. _favicons.cache:
+
+Favicons Cache
+==============
+
+.. automodule:: searx.favicons.cache
+   :members:
+
+
+

requirements-dev.txt

@@ -21,3 +21,4 @@ wlc==1.15
 coloredlogs==15.0.1
 docutils>=0.21.2
 parameterized==0.9.0
+autodoc_pydantic==2.2.0

requirements.txt

@@ -16,3 +16,6 @@ redis==5.0.8
 markdown-it-py==3.0.0
 fasttext-predict==0.9.2.2
 pytomlpp==1.0.13; python_version < '3.11'
+pydantic==2.8.2
+eval_type_backport; python_version < '3.9'
+typer-slim==0.12.5

searx/compat.py

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Compatibility with older versions"""
+
+# pylint: disable=unused-import
+
+__all__ = [
+    "tomllib",
+]
+
+import sys
+
+# TOML (lib) compatibility
+# ------------------------
+
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib

searx/favicon_resolver.py

@@ -1,105 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-"""This module implements functions needed for the favicon resolver.
-
-"""
-# pylint: disable=use-dict-literal
-
-from httpx import HTTPError
-
-from searx import settings
-
-from searx.network import get as http_get, post as http_post
-from searx.exceptions import SearxEngineResponseException
-
-
-def update_kwargs(**kwargs):
-    if 'timeout' not in kwargs:
-        kwargs['timeout'] = settings['outgoing']['request_timeout']
-    kwargs['raise_for_httperror'] = False
-
-
-def get(*args, **kwargs):
-    update_kwargs(**kwargs)
-    return http_get(*args, **kwargs)
-
-
-def post(*args, **kwargs):
-    update_kwargs(**kwargs)
-    return http_post(*args, **kwargs)
-
-
-def allesedv(domain):
-    """Favicon Resolver from allesedv.com"""
-
-    url = 'https://f1.allesedv.com/32/{domain}'
-
-    # will just return a 200 regardless of the favicon existing or not
-    # sometimes will be correct size, sometimes not
-    response = get(url.format(domain=domain))
-
-    # returns image/gif if the favicon does not exist
-    if response.headers['Content-Type'] == 'image/gif':
-        return []
-
-    return response.content
-
-
-def duckduckgo(domain):
-    """Favicon Resolver from duckduckgo.com"""
-
-    url = 'https://icons.duckduckgo.com/ip2/{domain}.ico'
-
-    # will return a 404 if the favicon does not exist and a 200 if it does,
-    response = get(url.format(domain=domain))
-
-    # api will respond with a 32x32 png image
-    if response.status_code == 200:
-        return response.content
-    return []
-
-
-def google(domain):
-    """Favicon Resolver from google.com"""
-
-    url = 'https://www.google.com/s2/favicons?sz=32&domain={domain}'
-
-    # will return a 404 if the favicon does not exist and a 200 if it does,
-    response = get(url.format(domain=domain))
-
-    # api will respond with a 32x32 png image
-    if response.status_code == 200:
-        return response.content
-    return []
-
-
-def yandex(domain):
-    """Favicon Resolver from yandex.com"""
-
-    url = 'https://favicon.yandex.net/favicon/{domain}'
-
-    # will always return 200
-    response = get(url.format(domain=domain))
-
-    # api will respond with a 16x16 png image, if it doesn't exist, it will be a 1x1 png image (70 bytes)
-    if response.status_code == 200:
-        if len(response.content) > 70:
-            return response.content
-    return []
-
-
-backends = {
-    'allesedv': allesedv,
-    'duckduckgo': duckduckgo,
-    'google': google,
-    'yandex': yandex,
-}
-
-
-def search_favicon(backend_name, domain):
-    backend = backends.get(backend_name)
-    if backend is None:
-        return []
-    try:
-        return backend(domain)
-    except (HTTPError, SearxEngineResponseException):
-        return []

searx/favicons/__init__.py

@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Implementations for providing the favicons in SearXNG"""
+
+from __future__ import annotations
+
+__all__ = ["init", "favicon_url", "favicon_proxy"]
+
+import pathlib
+from searx import logger
+from searx import get_setting
+from .proxy import favicon_url, favicon_proxy
+
+logger = logger.getChild('favicons')
+
+
+def is_active():
+    return bool(get_setting("search.favicon_resolver", False))
+
+
+def init():
+
+    # pylint: disable=import-outside-toplevel
+
+    from . import config, cache, proxy
+
+    cfg_file = pathlib.Path("/etc/searxng/favicons.toml")
+    if not cfg_file.exists():
+        if is_active():
+            logger.error(f"missing favicon config: {cfg_file}")
+        cfg_file = config.DEFAULT_CFG_TOML
+
+    logger.debug(f"load favicon config: {cfg_file}")
+    cfg = config.FaviconConfig.from_toml_file(cfg_file, use_cache=True)
+    cache.init(cfg.cache)
+    proxy.init(cfg.proxy)
+
+    del cache, config, proxy, cfg

searx/favicons/__main__.py

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Command line implementation"""
+
+import typer
+
+from . import cache
+from . import init
+
+init()
+app = typer.Typer()
+app.add_typer(cache.app, name="cache", help="commands related to the cache")
+app()

searx/favicons/cache.py

@@ -0,0 +1,476 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Implementations for caching favicons.
+
+:py:obj:`FaviconCacheConfig`:
+  Configuration of the favicon cache
+
+:py:obj:`FaviconCache`:
+  Abstract base class for the implementation of a favicon cache.
+
+:py:obj:`FaviconCacheSQLite`:
+  Favicon cache that manages the favicon BLOBs in a SQLite DB.
+
+:py:obj:`FaviconCacheNull`:
+  Fallback solution if the configured cache cannot be used for system reasons.
+
+----
+
+"""
+
+from __future__ import annotations
+from typing import Literal
+
+import abc
+import dataclasses
+import hashlib
+import logging
+import pathlib
+import sqlite3
+import tempfile
+import time
+import typer
+
+from pydantic import BaseModel
+
+from searx import sqlitedb
+from searx import logger
+from searx.utils import humanize_bytes, humanize_number
+
+CACHE: "FaviconCache"
+FALLBACK_ICON = b"FALLBACK_ICON"
+
+logger = logger.getChild('favicons.cache')
+app = typer.Typer()
+
+
+@app.command()
+def state():
+    """show state of the cache"""
+    print(CACHE.state().report())
+
+
+@app.command()
+def maintenance(force: bool = True, debug: bool = False):
+    """perform maintenance of the cache"""
+    root_log = logging.getLogger()
+    if debug:
+        root_log.setLevel(logging.DEBUG)
+    else:
+        root_log.handlers = []
+        handler = logging.StreamHandler()
+        handler.setFormatter(logging.Formatter("%(message)s"))
+        logger.addHandler(handler)
+        logger.setLevel(logging.DEBUG)
+
+    state_t0 = CACHE.state()
+    CACHE.maintenance(force=force)
+    state_t1 = CACHE.state()
+    state_delta = state_t0 - state_t1
+    print("The cache has been reduced by:")
+    print(state_delta.report("\n- {descr}: {val}").lstrip("\n"))
+
+
+def init(cfg: "FaviconCacheConfig"):
+    """Initialization of a global ``CACHE``"""
+
+    global CACHE  # pylint: disable=global-statement
+    if cfg.db_type == "sqlite":
+        if sqlite3.sqlite_version_info <= (3, 35):
+            logger.critical(
+                "Disable favicon caching completely: SQLite library (%s) is too old! (require >= 3.35)",
+                sqlite3.sqlite_version,
+            )
+            CACHE = FaviconCacheNull(cfg)
+        else:
+            CACHE = FaviconCacheSQLite(cfg)
+    elif cfg.db_type == "mem":
+        logger.error("Favicons are cached in memory, don't use this in production!")
+        CACHE = FaviconCacheMEM(cfg)
+    else:
+        raise NotImplementedError(f"favicons db_type '{cfg.db_type}' is unknown")
+
+
+class FaviconCacheConfig(BaseModel):
+    """Configuration of the favicon cache."""
+
+    db_type: Literal["sqlite", "mem"] = "sqlite"
+    """Type of the database:
+
+    ``sqlite``:
+      :py:obj:`.cache.FaviconCacheSQLite`
+
+    ``mem``:
+      :py:obj:`.cache.FaviconCacheMEM` (not recommended)
+    """
+
+    db_url: pathlib.Path = pathlib.Path(tempfile.gettempdir()) / "faviconcache.db"
+    """URL of the SQLite DB, the path to the database file."""
+
+    HOLD_TIME: int = 60 * 60 * 24 * 30  # 30 days
+    """Hold time (default in sec.), after which a BLOB is removed from the cache."""
+
+    LIMIT_TOTAL_BYTES: int = 1024 * 1024 * 50  # 50 MB
+    """Maximum of bytes (default) stored in the cache of all blobs.  Note: The
+    limit is only reached at each maintenance interval after which the oldest
+    BLOBs are deleted; the limit is exceeded during the maintenance period. If
+    the maintenance period is *too long* or maintenance is switched off
+    completely, the cache grows uncontrollably."""
+
+    BLOB_MAX_BYTES: int = 1024 * 20  # 20 KB
+    """The maximum BLOB size in bytes that a favicon may have so that it can be
+    saved in the cache.  If the favicon is larger, it is not saved in the cache
+    and must be requested by the client via the proxy."""
+
+    MAINTENANCE_PERIOD: int = 60 * 60
+    """Maintenance period in seconds / when :py:obj:`MAINTENANCE_MODE` is set to
+    ``auto``."""
+
+    MAINTENANCE_MODE: Literal["auto", "off"] = "auto"
+    """Type of maintenance mode
+
+    ``auto``:
+      Maintenance is carried out automatically as part of the maintenance
+      intervals (:py:obj:`MAINTENANCE_PERIOD`); no external process is required.
+
+    ``off``:
+      Maintenance is switched off and must be carried out by an external process
+      if required.
+    """
+
+
+@dataclasses.dataclass
+class FaviconCacheStats:
+    """Dataclass wich provides information on the status of the cache."""
+
+    favicons: int | None = None
+    bytes: int | None = None
+    domains: int | None = None
+    resolvers: int | None = None
+
+    field_descr = (
+        ("favicons", "number of favicons in cache", humanize_number),
+        ("bytes", "total size (approx. bytes) of cache", humanize_bytes),
+        ("domains", "total number of domains in cache", humanize_number),
+        ("resolvers", "number of resolvers", str),
+    )
+
+    def __sub__(self, other) -> FaviconCacheStats:
+        if not isinstance(other, self.__class__):
+            raise TypeError(f"unsupported operand type(s) for +: '{self.__class__}' and '{type(other)}'")
+        kwargs = {}
+        for field, _, _ in self.field_descr:
+            self_val, other_val = getattr(self, field), getattr(other, field)
+            if None in (self_val, other_val):
+                continue
+            if isinstance(self_val, int):
+                kwargs[field] = self_val - other_val
+            else:
+                kwargs[field] = self_val
+        return self.__class__(**kwargs)
+
+    def report(self, fmt: str = "{descr}: {val}\n"):
+        s = []
+        for field, descr, cast in self.field_descr:
+            val = getattr(self, field)
+            if val is None:
+                val = "--"
+            else:
+                val = cast(val)
+            s.append(fmt.format(descr=descr, val=val))
+        return "".join(s)
+
+
+class FaviconCache(abc.ABC):
+    """Abstract base class for the implementation of a favicon cache."""
+
+    @abc.abstractmethod
+    def __init__(self, cfg: FaviconCacheConfig):
+        """An instance of the favicon cache is build up from the configuration."""
+
+    @abc.abstractmethod
+    def __call__(self, resolver: str, authority: str) -> None | tuple[None | bytes, None | str]:
+        """Returns ``None`` or the tuple of ``(data, mime)`` that has been
+        registered in the cache.  The ``None`` indicates that there was no entry
+        in the cache."""
+
+    @abc.abstractmethod
+    def set(self, resolver: str, authority: str, mime: str | None, data: bytes | None) -> bool:
+        """Set data and mime-type in the cache.  If data is None, the
+        :py:obj:`FALLBACK_ICON` is registered. in the cache."""
+
+    @abc.abstractmethod
+    def state(self) -> FaviconCacheStats:
+        """Returns a :py:obj:`FaviconCacheStats` (key/values) with information
+        on the state of the cache."""
+
+    @abc.abstractmethod
+    def maintenance(self, force=False):
+        """Performs maintenance on the cache"""
+
+
+class FaviconCacheNull(FaviconCache):
+    """A dummy favicon cache that caches nothing / a fallback solution. The
+    NullCache is used when more efficient caches such as the
+    :py:obj:`FaviconCacheSQLite` cannot be used because, for example, the SQLite
+    library is only available in an old version and does not meet the
+    requirements."""
+
+    def __init__(self, cfg: FaviconCacheConfig):
+        return None
+
+    def __call__(self, resolver: str, authority: str) -> None | tuple[None | bytes, None | str]:
+        return None
+
+    def set(self, resolver: str, authority: str, mime: str | None, data: bytes | None) -> bool:
+        return False
+
+    def state(self):
+        return FaviconCacheStats(favicons=0)
+
+    def maintenance(self, force=False):
+        pass
+
+
+class FaviconCacheSQLite(sqlitedb.SQLiteAppl, FaviconCache):
+    """Favicon cache that manages the favicon BLOBs in a SQLite DB.  The DB
+    model in the SQLite DB is implemented using the abstract class
+    :py:obj:`sqlitedb.SQLiteAppl`.
+
+    The following configurations are required / supported:
+
+    - :py:obj:`FaviconCacheConfig.db_url`
+    - :py:obj:`FaviconCacheConfig.HOLD_TIME`
+    - :py:obj:`FaviconCacheConfig.LIMIT_TOTAL_BYTES`
+    - :py:obj:`FaviconCacheConfig.BLOB_MAX_BYTES`
+    - :py:obj:`MAINTENANCE_PERIOD`
+    - :py:obj:`MAINTENANCE_MODE`
+    """
+
+    DB_SCHEMA = 1
+
+    DDL_BLOBS = """\
+CREATE TABLE IF NOT EXISTS blobs (
+  sha256     TEXT,
+  bytes_c    INTEGER,
+  mime       TEXT NOT NULL,
+  data       BLOB NOT NULL,
+  PRIMARY KEY (sha256))"""
+
+    """Table to store BLOB objects by their sha256 hash values."""
+
+    DDL_BLOB_MAP = """\
+CREATE TABLE IF NOT EXISTS blob_map (
+    m_time     INTEGER DEFAULT (strftime('%s', 'now')),  -- last modified (unix epoch) time in sec.
+    sha256     TEXT,
+    resolver   TEXT,
+    authority  TEXT,
+    PRIMARY KEY (resolver, authority))"""
+
+    """Table to map from (resolver, authority) to sha256 hash values."""
+
+    DDL_CREATE_TABLES = {
+        "blobs": DDL_BLOBS,
+        "blob_map": DDL_BLOB_MAP,
+    }
+
+    SQL_DROP_LEFTOVER_BLOBS = (
+        "DELETE FROM blobs WHERE sha256 IN ("
+        " SELECT b.sha256"
+        "   FROM blobs b"
+        "   LEFT JOIN blob_map bm"
+        "     ON b.sha256 = bm.sha256"
+        "  WHERE bm.sha256 IS NULL)"
+    )
+    """Delete blobs.sha256 (BLOBs) no longer in blob_map.sha256."""
+
+    SQL_ITER_BLOBS_SHA256_BYTES_C = (
+        "SELECT b.sha256, b.bytes_c FROM blobs b"
+        "  JOIN blob_map bm "
+        "    ON b.sha256 = bm.sha256"
+        " ORDER BY bm.m_time ASC"
+    )
+
+    SQL_INSERT_BLOBS = (
+        "INSERT INTO blobs (sha256, bytes_c, mime, data) VALUES (?, ?, ?, ?)"
+        "    ON CONFLICT (sha256) DO NOTHING"
+    )  # fmt: skip
+
+    SQL_INSERT_BLOB_MAP = (
+        "INSERT INTO blob_map (sha256, resolver, authority) VALUES (?, ?, ?)"
+        "    ON CONFLICT DO UPDATE "
+        "   SET sha256=excluded.sha256, m_time=strftime('%s', 'now')"
+    )
+
+    def __init__(self, cfg: FaviconCacheConfig):
+        """An instance of the favicon cache is build up from the configuration."""  #
+
+        if cfg.db_url == ":memory:":
+            logger.critical("don't use SQLite DB in :memory: in production!!")
+        super().__init__(cfg.db_url)
+        self.cfg = cfg
+
+    def __call__(self, resolver: str, authority: str) -> None | tuple[None | bytes, None | str]:
+
+        sql = "SELECT sha256 FROM blob_map WHERE resolver = ? AND authority = ?"
+        res = self.DB.execute(sql, (resolver, authority)).fetchone()
+        if res is None:
+            return None
+
+        data, mime = (None, None)
+        sha256 = res[0]
+        if sha256 == FALLBACK_ICON:
+            return data, mime
+
+        sql = "SELECT data, mime FROM blobs WHERE sha256 = ?"
+        res = self.DB.execute(sql, (sha256,)).fetchone()
+        if res is not None:
+            data, mime = res
+        return data, mime
+
+    def set(self, resolver: str, authority: str, mime: str | None, data: bytes | None) -> bool:
+
+        if self.cfg.MAINTENANCE_MODE == "auto" and int(time.time()) > self.next_maintenance_time:
+            # Should automatic maintenance be moved to a new thread?
+            self.maintenance()
+
+        if data is not None and mime is None:
+            logger.error(
+                "favicon resolver %s tries to cache mime-type None for authority %s",
+                resolver,
+                authority,
+            )
+            return False
+
+        bytes_c = len(data or b"")
+        if bytes_c > self.cfg.BLOB_MAX_BYTES:
+            logger.info(
+                "favicon of resolver: %s / authority: %s to big to cache (bytes: %s) " % (resolver, authority, bytes_c)
+            )
+            return False
+
+        if data is None:
+            sha256 = FALLBACK_ICON
+        else:
+            sha256 = hashlib.sha256(data).hexdigest()
+
+        with self.connect() as conn:
+            if sha256 != FALLBACK_ICON:
+                conn.execute(self.SQL_INSERT_BLOBS, (sha256, bytes_c, mime, data))
+            conn.execute(self.SQL_INSERT_BLOB_MAP, (sha256, resolver, authority))
+
+        return True
+
+    @property
+    def next_maintenance_time(self) -> int:
+        """Returns (unix epoch) time of the next maintenance."""
+
+        return self.cfg.MAINTENANCE_PERIOD + self.properties.m_time("LAST_MAINTENANCE")
+
+    def maintenance(self, force=False):
+
+        # Prevent parallel DB maintenance cycles from other DB connections
+        # (e.g. in multi thread or process environments).
+
+        if not force and int(time.time()) < self.next_maintenance_time:
+            logger.debug("no maintenance required yet, next maintenance interval is in the future")
+            return
+        self.properties.set("LAST_MAINTENANCE", "")  # hint: this (also) sets the m_time of the property!
+
+        # do maintenance tasks
+
+        with self.connect() as conn:
+
+            # drop items not in HOLD time
+            res = conn.execute(
+                f"DELETE FROM blob_map"
+                f" WHERE cast(m_time as integer) < cast(strftime('%s', 'now') as integer) - {self.cfg.HOLD_TIME}"
+            )
+            logger.debug("dropped %s obsolete blob_map items from db", res.rowcount)
+            res = conn.execute(self.SQL_DROP_LEFTOVER_BLOBS)
+            logger.debug("dropped %s obsolete BLOBS from db", res.rowcount)
+
+            # drop old items to be in LIMIT_TOTAL_BYTES
+            total_bytes = conn.execute("SELECT SUM(bytes_c) FROM blobs").fetchone()[0] or 0
+            if total_bytes > self.cfg.LIMIT_TOTAL_BYTES:
+
+                x = total_bytes - self.cfg.LIMIT_TOTAL_BYTES
+                c = 0
+                sha_list = []
+                for row in conn.execute(self.SQL_ITER_BLOBS_SHA256_BYTES_C):
+                    sha256, bytes_c = row
+                    sha_list.append(sha256)
+                    c += bytes_c
+                    if c > x:
+                        break
+                if sha_list:
+                    conn.execute("DELETE FROM blobs WHERE sha256 IN ('%s')" % "','".join(sha_list))
+                    conn.execute("DELETE FROM blob_map WHERE sha256 IN ('%s')" % "','".join(sha_list))
+                    logger.debug("dropped %s blobs with total size of %s bytes", len(sha_list), c)
+
+    def _query_val(self, sql, default=None):
+        val = self.DB.execute(sql).fetchone()
+        if val is not None:
+            val = val[0]
+        if val is None:
+            val = default
+        return val
+
+    def state(self) -> FaviconCacheStats:
+        return FaviconCacheStats(
+            favicons=self._query_val("SELECT count(*) FROM blobs", 0),
+            bytes=self._query_val("SELECT SUM(bytes_c) FROM blobs", 0),
+            domains=self._query_val("SELECT count(*) FROM (SELECT authority FROM blob_map GROUP BY authority)", 0),
+            resolvers=self._query_val("SELECT count(*) FROM (SELECT resolver FROM blob_map GROUP BY resolver)", 0),
+        )
+
+
+class FaviconCacheMEM(FaviconCache):
+    """Favicon cache in process' memory.  Its just a POC that stores the
+    favicons in the memory of the process.
+
+    .. attention::
+
+       Don't use it in production, it will blow up your memory!!
+
+    """
+
+    def __init__(self, cfg):
+
+        self.cfg = cfg
+        self._data = {}
+        self._sha_mime = {}
+
+    def __call__(self, resolver: str, authority: str) -> None | tuple[bytes | None, str | None]:
+
+        sha, mime = self._sha_mime.get(f"{resolver}:{authority}", (None, None))
+        if sha is None:
+            return None
+        data = self._data.get(sha)
+        if data == FALLBACK_ICON:
+            data = None
+        return data, mime
+
+    def set(self, resolver: str, authority: str, mime: str | None, data: bytes | None) -> bool:
+
+        if data is None:
+            data = FALLBACK_ICON
+            mime = None
+
+        elif mime is None:
+            logger.error(
+                "favicon resolver %s tries to cache mime-type None for authority %s",
+                resolver,
+                authority,
+            )
+            return False
+
+        digest = hashlib.sha256(data).hexdigest()
+        self._data[digest] = data
+        self._sha_mime[f"{resolver}:{authority}"] = (digest, mime)
+        return True
+
+    def state(self):
+        return FaviconCacheStats(favicons=len(self._data.keys()))
+
+    def maintenance(self, force=False):
+        pass

searx/favicons/config.py

@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# pylint: disable=missing-module-docstring
+
+from __future__ import annotations
+
+import pathlib
+from pydantic import BaseModel
+
+from searx.compat import tomllib
+from .cache import FaviconCacheConfig
+from .proxy import FaviconProxyConfig
+
+CONFIG_SCHEMA: int = 1
+"""Version of the configuration schema."""
+
+TOML_CACHE: dict[str, "FaviconConfig"] = {}
+"""Cache config objects by TOML's filename."""
+
+DEFAULT_CFG_TOML = pathlib.Path(__file__).parent / "favicons.toml"
+
+
+class FaviconConfig(BaseModel):
+    """The class aggregates configurations of the favicon tools"""
+
+    cfg_schema: int
+    """Config's schema version.  The specification of the version of the schema
+    is mandatory, currently only version :py:obj:`CONFIG_SCHEMA` is supported.
+    By specifying a version, it is possible to ensure downward compatibility in
+    the event of future changes to the configuration schema"""
+
+    cache: FaviconCacheConfig = FaviconCacheConfig()
+    """Setup of the :py:obj:`.cache.FaviconCacheConfig`."""
+
+    proxy: FaviconProxyConfig = FaviconProxyConfig()
+    """Setup of the :py:obj:`.proxy.FaviconProxyConfig`."""
+
+    @classmethod
+    def from_toml_file(cls, cfg_file: pathlib.Path, use_cache: bool) -> "FaviconConfig":
+        """Create a config object from a TOML file, the ``use_cache`` argument
+        specifies whether a cache should be used.
+        """
+
+        cached = TOML_CACHE.get(str(cfg_file))
+        if use_cache and cached:
+            return cached
+
+        with cfg_file.open("rb") as f:
+
+            cfg = tomllib.load(f)
+            cfg = cfg.get("favicons", cfg)
+
+            schema = cfg.get("cfg_schema")
+            if schema != CONFIG_SCHEMA:
+                raise ValueError(
+                    f"config schema version {CONFIG_SCHEMA} is needed, version {schema} is given in {cfg_file}"
+                )
+
+            cfg = cls(**cfg)
+            if use_cache and cached:
+                TOML_CACHE[str(cfg_file.resolve())] = cfg
+
+            return cfg

searx/favicons/favicons.toml

@@ -0,0 +1,25 @@
+[favicons]
+
+cfg_schema = 1   # config's schema version no.
+
+[favicons.proxy]
+
+# max_age = 5184000             # 60 days / default: 7 days (604800 sec)
+
+# [favicons.proxy.resolver_map]
+#
+# The available favicon resolvers are registered here.
+#
+# "duckduckgo" = "searx.favicons.resolvers.duckduckgo"
+# "allesedv" = "searx.favicons.resolvers.allesedv"
+# "google" = "searx.favicons.resolvers.google"
+# "yandex" = "searx.favicons.resolvers.yandex"
+
+[favicons.cache]
+
+# db_url = "/var/cache/searxng/faviconcache.db"  # default: "/tmp/faviconcache.db"
+# HOLD_TIME = 5184000                            # 60 days / default: 30 days
+# LIMIT_TOTAL_BYTES = 2147483648                 # 2 GB / default: 50 MB
+# BLOB_MAX_BYTES = 40960                         # 40 KB / default 20 KB
+# MAINTENANCE_MODE = "off"                       # default: "auto"
+# MAINTENANCE_PERIOD = 600                       # 10min / default: 1h

searx/favicons/proxy.py

@@ -0,0 +1,237 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Implementations for a favicon proxy"""
+
+from __future__ import annotations
+
+from typing import Callable
+
+import importlib
+import base64
+import pathlib
+import urllib.parse
+
+import flask
+from httpx import HTTPError
+from pydantic import BaseModel
+
+from searx import get_setting
+
+from searx.webutils import new_hmac, is_hmac_of
+from searx.exceptions import SearxEngineResponseException
+
+from .resolvers import DEFAULT_RESOLVER_MAP
+from . import cache
+
+DEFAULT_FAVICON_URL = {}
+CFG: FaviconProxyConfig = None  # type: ignore
+
+
+def init(cfg: FaviconProxyConfig):
+    global CFG  # pylint: disable=global-statement
+    CFG = cfg
+
+
+def _initial_resolver_map():
+    d = {}
+    name: str = get_setting("search.favicon_resolver", None)  # type: ignore
+    if name:
+        func = DEFAULT_RESOLVER_MAP.get(name)
+        if func:
+            d = {name: f"searx.favicons.resolvers.{func.__name__}"}
+    return d
+
+
+class FaviconProxyConfig(BaseModel):
+    """Configuration of the favicon proxy."""
+
+    max_age: int = 60 * 60 * 24 * 7  # seven days
+    """HTTP header Cache-Control_ ``max-age``
+
+    .. _Cache-Control: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
+    """
+
+    secret_key: str = get_setting("server.secret_key")  # type: ignore
+    """By default, the value from :ref:`server.secret_key <settings server>`
+    setting is used."""
+
+    resolver_timeout: int = get_setting("outgoing.request_timeout")  # type: ignore
+    """Timeout which the resolvers should not exceed, is usually passed to the
+    outgoing request of the resolver.  By default, the value from
+    :ref:`outgoing.request_timeout <settings outgoing>` setting is used."""
+
+    resolver_map: dict[str, str] = _initial_resolver_map()
+    """The resolver_map is a key / value dictionary where the key is the name of
+    the resolver and the value is the fully qualifying name (fqn) of resolver's
+    function (the callable).  The resolvers from the python module
+    :py:obj:`searx.favicons.resolver` are available by default."""
+
+    def get_resolver(self, name: str) -> Callable | None:
+        """Returns the callable object (function) of the resolver with the
+        ``name``.  If no resolver is registered for the ``name``, ``None`` is
+        returned.
+        """
+        fqn = self.resolver_map.get(name)
+        if fqn is None:
+            return None
+        mod_name, _, func_name = fqn.rpartition('.')
+        mod = importlib.import_module(mod_name)
+        func = getattr(mod, func_name)
+        if func is None:
+            raise ValueError(f"resolver {fqn} is not implemented")
+        return func
+
+    favicon_path: str = get_setting("ui.static_path") + "/themes/{theme}/img/empty_favicon.svg"  # type: ignore
+    favicon_mime_type: str = "image/svg+xml"
+
+    def favicon(self, **replacements):
+        """Returns pathname and mimetype of the default favicon."""
+        return (
+            pathlib.Path(self.favicon_path.format(**replacements)),
+            self.favicon_mime_type,
+        )
+
+    def favicon_data_url(self, **replacements):
+        """Returns data image URL of the default favicon."""
+
+        cache_key = ", ".join(f"{x}:{replacements[x]}" for x in sorted(list(replacements.keys()), key=str))
+        data_url = DEFAULT_FAVICON_URL.get(cache_key)
+        if data_url is not None:
+            return data_url
+
+        fav, mimetype = CFG.favicon(**replacements)
+        # hint: encoding utf-8 limits favicons to be a SVG image
+        with fav.open("r", encoding="utf-8") as f:
+            data_url = f.read()
+
+        data_url = urllib.parse.quote(data_url)
+        data_url = f"data:{mimetype};utf8,{data_url}"
+        DEFAULT_FAVICON_URL[cache_key] = data_url
+        return data_url
+
+
+def favicon_proxy():
+    """REST API of SearXNG's favicon proxy service
+
+    ::
+
+        /favicon_proxy?authority=<...>&h=<...>
+
+    ``authority``:
+      Domain name :rfc:`3986` / see :py:obj:`favicon_url`
+
+    ``h``:
+      HMAC :rfc:`2104`, build up from the :ref:`server.secret_key <settings
+      server>` setting.
+
+    """
+    authority = flask.request.args.get('authority')
+
+    # malformed request or RFC 3986 authority
+    if not authority or "/" in authority:
+        return '', 400
+
+    # malformed request / does not have authorisation
+    if not is_hmac_of(
+        CFG.secret_key,
+        authority.encode(),
+        flask.request.args.get('h', ''),
+    ):
+        return '', 400
+
+    resolver = flask.request.preferences.get_value('favicon_resolver')  # type: ignore
+    # if resolver is empty or not valid, just return HTTP 400.
+    if not resolver or resolver not in CFG.resolver_map.keys():
+        return "", 400
+
+    data, mime = search_favicon(resolver, authority)
+
+    if data is not None and mime is not None:
+        resp = flask.Response(data, mimetype=mime)  # type: ignore
+        resp.headers['Cache-Control'] = f"max-age={CFG.max_age}"
+        return resp
+
+    # return default favicon from static path
+    theme = flask.request.preferences.get_value("theme")  # type: ignore
+    fav, mimetype = CFG.favicon(theme=theme)
+    return flask.send_from_directory(fav.parent, fav.name, mimetype=mimetype)
+
+
+def search_favicon(resolver: str, authority: str) -> tuple[None | bytes, None | str]:
+    """Sends the request to the favicon resolver and returns a tuple for the
+    favicon.  The tuple consists of ``(data, mime)``, if the resolver has not
+    determined a favicon, both values are ``None``.
+
+    ``data``:
+      Binary data of the favicon.
+
+    ``mime``:
+      Mime type of the favicon.
+
+    """
+
+    data, mime = (None, None)
+
+    func = CFG.get_resolver(resolver)
+    if func is None:
+        return data, mime
+
+    # to avoid superfluous requests to the resolver, first look in the cache
+    data_mime = cache.CACHE(resolver, authority)
+    if data_mime is not None:
+        return data_mime
+
+    try:
+        data, mime = func(authority, timeout=CFG.resolver_timeout)
+        if data is None or mime is None:
+            data, mime = (None, None)
+
+    except (HTTPError, SearxEngineResponseException):
+        pass
+
+    cache.CACHE.set(resolver, authority, mime, data)
+    return data, mime
+
+
+def favicon_url(authority: str) -> str:
+    """Function to generate the image URL used for favicons in SearXNG's result
+    lists.  The ``authority`` argument (aka netloc / :rfc:`3986`) is usually a
+    (sub-) domain name.  This function is used in the HTML (jinja) templates.
+
+    .. code:: html
+
+       <div class="favicon">
+          <img src="{{ favicon_url(result.parsed_url.netloc) }}">
+       </div>
+
+    The returned URL is a route to :py:obj:`favicon_proxy` REST API.
+
+    If the favicon is already in the cache, the returned URL is a `data URL`_
+    (something like ``data:image/png;base64,...``).  By generating a data url from
+    the :py:obj:`.cache.FaviconCache`, additional HTTP roundtripps via the
+    :py:obj:`favicon_proxy` are saved.  However, it must also be borne in mind
+    that data urls are not cached in the client (web browser).
+
+    .. _data URL: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs
+
+    """
+
+    resolver = flask.request.preferences.get_value('favicon_resolver')  # type: ignore
+    # if resolver is empty or not valid, just return nothing.
+    if not resolver or resolver not in CFG.resolver_map.keys():
+        return ""
+
+    data_mime = cache.CACHE(resolver, authority)
+
+    if data_mime == (None, None):
+        # we have already checked, the resolver does not have a favicon
+        theme = flask.request.preferences.get_value("theme")  # type: ignore
+        return CFG.favicon_data_url(theme=theme)
+
+    if data_mime is not None:
+        data, mime = data_mime
+        return f"data:{mime};base64,{str(base64.b64encode(data), 'utf-8')}"  # type: ignore
+
+    h = new_hmac(CFG.secret_key, authority.encode())
+    proxy_url = flask.url_for('favicon_proxy')
+    query = urllib.parse.urlencode({"authority": authority, "h": h})
+    return f"{proxy_url}?{query}"

searx/favicons/resolvers.py

@@ -0,0 +1,100 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Implementations of the favicon *resolvers* that are available in the favicon
+proxy by default.  A *resolver* is a function that obtains the favicon from an
+external source.  The *resolver* function receives two arguments (``domain,
+timeout``) and returns a tuple ``(data, mime)``.
+
+"""
+
+from __future__ import annotations
+
+__all__ = ["DEFAULT_RESOLVER_MAP", "allesedv", "duckduckgo", "google", "yandex"]
+
+from typing import Callable
+from searx import network
+from searx import logger
+
+DEFAULT_RESOLVER_MAP: dict[str, Callable]
+logger = logger.getChild('favicons.resolvers')
+
+
+def _req_args(**kwargs):
+    # add the request arguments from the searx.network
+    d = {"raise_for_httperror": False}
+    d.update(kwargs)
+    return d
+
+
+def allesedv(domain: str, timeout: int) -> tuple[None | bytes, None | str]:
+    """Favicon Resolver from allesedv.com / https://favicon.allesedv.com/"""
+    data, mime = (None, None)
+    url = f"https://f1.allesedv.com/32/{domain}"
+    logger.debug("fetch favicon from: %s", url)
+
+    # will just return a 200 regardless of the favicon existing or not
+    # sometimes will be correct size, sometimes not
+    response = network.get(url, **_req_args(timeout=timeout))
+    if response and response.status_code == 200:
+        mime = response.headers['Content-Type']
+        if mime != 'image/gif':
+            data = response.content
+    return data, mime
+
+
+def duckduckgo(domain: str, timeout: int) -> tuple[None | bytes, None | str]:
+    """Favicon Resolver from duckduckgo.com / https://blog.jim-nielsen.com/2021/displaying-favicons-for-any-domain/"""
+    data, mime = (None, None)
+    url = f"https://icons.duckduckgo.com/ip2/{domain}.ico"
+    logger.debug("fetch favicon from: %s", url)
+
+    # will return a 404 if the favicon does not exist and a 200 if it does,
+    response = network.get(url, **_req_args(timeout=timeout))
+    if response and response.status_code == 200:
+        # api will respond with a 32x32 png image
+        mime = response.headers['Content-Type']
+        data = response.content
+    return data, mime
+
+
+def google(domain: str, timeout: int) -> tuple[None | bytes, None | str]:
+    """Favicon Resolver from google.com"""
+    data, mime = (None, None)
+
+    # URL https://www.google.com/s2/favicons?sz=32&domain={domain}" will be
+    # redirected (HTTP 301 Moved Permanently) to t1.gstatic.com/faviconV2:
+    url = (
+        f"https://t1.gstatic.com/faviconV2?client=SOCIAL&type=FAVICON&fallback_opts=TYPE,SIZE,URL"
+        f"&url=https://{domain}&size=32"
+    )
+    logger.debug("fetch favicon from: %s", url)
+
+    # will return a 404 if the favicon does not exist and a 200 if it does,
+    response = network.get(url, **_req_args(timeout=timeout))
+    if response and response.status_code == 200:
+        # api will respond with a 32x32 png image
+        mime = response.headers['Content-Type']
+        data = response.content
+    return data, mime
+
+
+def yandex(domain: str, timeout: int) -> tuple[None | bytes, None | str]:
+    """Favicon Resolver from yandex.com"""
+    data, mime = (None, None)
+    url = f"https://favicon.yandex.net/favicon/{domain}"
+    logger.debug("fetch favicon from: %s", url)
+
+    # api will respond with a 16x16 png image, if it doesn't exist, it will be a
+    # 1x1 png image (70 bytes)
+    response = network.get(url, **_req_args(timeout=timeout))
+    if response and response.status_code == 200 and len(response.content) > 70:
+        mime = response.headers['Content-Type']
+        data = response.content
+    return data, mime
+
+
+DEFAULT_RESOLVER_MAP = {
+    "allesedv": allesedv,
+    "duckduckgo": duckduckgo,
+    "google": google,
+    "yandex": yandex,
+}

searx/preferences.py

@@ -13,7 +13,7 @@ from collections import OrderedDict
 import flask
 import babel
 
-from searx import settings, autocomplete, favicon_resolver
+from searx import settings, autocomplete, favicons
 from searx.enginelib import Engine
 from searx.plugins import Plugin
 from searx.locales import LOCALE_NAMES
@@ -409,7 +409,7 @@ class Preferences:
             'favicon_resolver': EnumStringSetting(
                 settings['search']['favicon_resolver'],
                 locked=is_locked('favicon_resolver'),
-                choices=list(favicon_resolver.backends.keys()) + ['']
+                choices=list(favicons.proxy.CFG.resolver_map.keys()) + ['']
             ),
             'image_proxy': BooleanSetting(
                 settings['server']['image_proxy'],

searx/static/themes/simple/img/empty_favicon.svg

@@ -1,5 +1,4 @@
 <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
-  <path fill="#fff" d="M0 0h24v24H0z"/>
   <path fill="#58f" d="M11 20.85a.92.92 0 0 1-1.1.93A10 10 0 0 1 2.06 13c-.06-.55.4-1 .95-1h3a1 1 0 0 1 1 1 3 3 0 0 0 3 3 1 1 0 0 1 1 1v3.85Zm6-1.92c0 .77.83 1.23 1.42.74a10 10 0 0 0 2.03-2.32c.39-.61-.09-1.35-.81-1.35H18a1 1 0 0 0-1 1v1.93ZM12 2a10 10 0 0 1 6.65 2.53c.61.55.17 1.47-.65 1.47h-.15A2.85 2.85 0 0 0 15 8.85c0 .33-.18.62-.47.77l-.08.04a1 1 0 0 1-.9 0l-.08-.04a.85.85 0 0 1-.47-.77A2.85 2.85 0 0 0 10.15 6H10a1 1 0 0 1-1-1V3.2c0-.44.28-.84.7-.94C10.45 2.1 11.22 2 12 2Z"/>
   <path fill="#58f" d="M3.42 10c-.63 0-1.1-.58-.9-1.18.6-1.8 1.7-3.36 3.12-4.53C6.2 3.82 7 4.26 7 5a3 3 0 0 0 3 3h.15c.47 0 .85.38.85.85 0 1.09.61 2.07 1.58 2.56l.08.04a3 3 0 0 0 2.68 0l.08-.04A2.85 2.85 0 0 0 17 8.85c0-.47.38-.85.85-.85h2.66c.4 0 .77.23.9.6a9.98 9.98 0 0 1 .52 4.6.94.94 0 0 1-.95.8H18a3 3 0 0 0-3 3v3.8c0 .44-.28.84-.7.94l-.2.04a.92.92 0 0 1-1.1-.93V17a3 3 0 0 0-3-3 1 1 0 0 1-1-1 3 3 0 0 0-3-3H3.42Z"/>
-</svg>
+</svg>

searx/templates/simple/macros.html

@@ -23,12 +23,7 @@
   {{- result_open_link(result.url, "url_wrapper") -}}
   {% if not rtl %}
     {%- if favicon_resolver != "" %}
-    <div class="favicon">
-      <img
-        alt="{{ result.parsed_url.netloc }}"
-        src="{{ favicon_proxify(result.parsed_url.netloc) }}"
-      >
-    </div>
+    <div class="favicon"><img loading="lazy" src="{{ favicon_url(result.parsed_url.netloc) }}"></div>
     {%- endif -%}
   {%- endif -%}
   {%- for part in get_pretty_url(result.parsed_url) -%}
@@ -36,12 +31,7 @@
   {%- endfor %}
   {% if rtl %}
     {%- if favicon_resolver != "" %}
-    <div class="favicon">
-      <img
-        alt="{{ result.parsed_url.netloc }}"
-        src="{{ favicon_proxify(result.parsed_url.netloc) }}"
-      >
-    </div>
+    <div class="favicon"><img loading="lazy" src="{{ favicon_url(result.parsed_url.netloc) }}"></div>
     {%- endif -%}
   {%- endif -%}
   {{- result_close_link() -}}

searx/templates/simple/preferences/favicon.html

@@ -3,7 +3,7 @@
   <div class="value">{{- '' -}}
     <select name="favicon_resolver" aria-labelledby="pref_favicon_resolver">{{- '' -}}
       <option value=""> - </option>
-      {%- for backend in favicon_backends -%}
+      {%- for backend in favicon_resolver_names -%}
         <option value="{{ backend }}"
           {%- if backend == favicon_resolver %} selected="selected" {%- endif -%}>
           {{- backend -}}

searx/webapp.py

@@ -123,7 +123,8 @@ from searx.locales import (
 
 # renaming names from searx imports ...
 from searx.autocomplete import search_autocomplete, backends as autocomplete_backends
-from searx.favicon_resolver import search_favicon, backends as favicon_backends
+from searx import favicons
+
 from searx.redisdb import initialize as redis_initialize
 from searx.sxng_locales import sxng_locales
 from searx.search import SearchWithPlugins, initialize as search_initialize
@@ -298,24 +299,6 @@ def morty_proxify(url: str):
     return '{0}?{1}'.format(settings['result_proxy']['url'], urlencode(url_params))
 
 
-def favicon_proxify(url: str):
-    # url is a FQDN (e.g. example.com, en.wikipedia.org)
-
-    resolver = request.preferences.get_value('favicon_resolver')
-
-    # if resolver is empty, just return nothing
-    if not resolver:
-        return ""
-
-    # check resolver is valid
-    if resolver not in favicon_backends:
-        return ""
-
-    h = new_hmac(settings['server']['secret_key'], url.encode())
-
-    return '{0}?{1}'.format(url_for('favicon_proxy'), urlencode(dict(q=url.encode(), h=h)))
-
-
 def image_proxify(url: str):
 
     if url.startswith('//'):
@@ -377,7 +360,6 @@ def get_client_settings():
     return {
         'autocomplete_provider': req_pref.get_value('autocomplete'),
         'autocomplete_min': get_setting('search.autocomplete_min'),
-        'favicon_resolver': req_pref.get_value('favicon_resolver'),
         'http_method': req_pref.get_value('method'),
         'infinite_scroll': req_pref.get_value('infinite_scroll'),
         'translations': get_translations(),
@@ -452,7 +434,7 @@ def render(template_name: str, **kwargs):
     # helpers to create links to other pages
     kwargs['url_for'] = custom_url_for  # override url_for function in templates
     kwargs['image_proxify'] = image_proxify
-    kwargs['favicon_proxify'] = favicon_proxify
+    kwargs['favicon_url'] = favicons.favicon_url
     kwargs['proxify'] = morty_proxify if settings['result_proxy']['url'] is not None else None
     kwargs['proxify_results'] = settings['result_proxy']['proxify_results']
     kwargs['cache_url'] = settings['ui']['cache_url']
@@ -895,42 +877,6 @@ def autocompleter():
     return Response(suggestions, mimetype=mimetype)
 
 
-@app.route('/favicon', methods=['GET'])
-def favicon_proxy():
-    """Return proxied favicon results"""
-    url = request.args.get('q')
-
-    # malformed request
-    if not url:
-        return '', 400
-
-    # malformed request / does not have authorisation
-    if not is_hmac_of(settings['server']['secret_key'], url.encode(), request.args.get('h', '')):
-        return '', 400
-
-    resolver = request.preferences.get_value('favicon_resolver')
-
-    # check if the favicon resolver is valid
-    if not resolver or resolver not in favicon_backends:
-        return '', 400
-
-    # parse query
-    raw_text_query = RawTextQuery(url, [])
-
-    resp = search_favicon(resolver, raw_text_query)
-
-    # return 404 if the favicon is not found
-    if not resp:
-        theme = request.preferences.get_value("theme")
-        # return favicon from /static/themes/simple/img/empty_favicon.svg
-        # we can't rely on an onerror event in the img tag to display a default favicon as this violates the CSP.
-        # using redirect to save network bandwidth (user will have this location cached).
-        return redirect(url_for('static', filename='themes/' + theme + '/img/empty_favicon.svg'))
-
-    # will always return a PNG image
-    return Response(resp, mimetype='image/png')
-
-
 @app.route('/preferences', methods=['GET', 'POST'])
 def preferences():
     """Render preferences page && save user preferences"""
@@ -1078,7 +1024,7 @@ def preferences():
         ],
         disabled_engines = disabled_engines,
         autocomplete_backends = autocomplete_backends,
-        favicon_backends = favicon_backends,
+        favicon_resolver_names = favicons.proxy.CFG.resolver_map.keys(),
         shortcuts = {y: x for x, y in engine_shortcuts.items()},
         themes = themes,
         plugins = plugins,
@@ -1092,6 +1038,9 @@ def preferences():
     )
 
 
+app.add_url_rule('/favicon_proxy', methods=['GET'], endpoint="favicon_proxy", view_func=favicons.favicon_proxy)
+
+
 @app.route('/image_proxy', methods=['GET'])
 def image_proxy():
     # pylint: disable=too-many-return-statements, too-many-branches
@@ -1403,6 +1352,7 @@ if not werkzeug_reloader or (werkzeug_reloader and os.environ.get("WERKZEUG_RUN_
     plugin_initialize(app)
     search_initialize(enable_checker=True, check_network=True, enable_metrics=settings['general']['enable_metrics'])
     limiter.initialize(app, settings)
+    favicons.init()
 
 
 def run():

setup.py

@@ -61,6 +61,7 @@ setup(
             'data/*.json',
             'data/*.txt',
             'data/*.ftz',
+            'favicons/*.toml',
             'infopage/*/*',
             'static/themes/simple/css/*',
             'static/themes/simple/css/*/*',

tests/unit/test_preferences.py

@@ -2,6 +2,7 @@
 # pylint: disable=missing-module-docstring, invalid-name
 
 from tests import SearxTestCase
+from searx import favicons
 from searx.locales import locales_initialize
 from searx.preferences import (
     EnumStringSetting,
@@ -14,6 +15,7 @@ from searx.preferences import (
 from searx.plugins import Plugin
 
 locales_initialize()
+favicons.init()
 
 
 class PluginStub(Plugin):  # pylint: disable=missing-class-docstring, too-few-public-methods