change: themes.simple.autocompleter.MinChars 4 -> 0

add: settings.server.autocomplete_limit

add settings.server.autocomplete_limit to SCHEMA

add limit to autocomplete.py

change: default value of autocomplete_limit 0-50

fix: pylint C0325 R1719 R1735

searx/autocomplete.py

@@ -18,6 +18,12 @@ from searx.exceptions import SearxEngineResponseException
 # a fetch_supported_languages() for XPath engines isn't available right now
 # _brave = ENGINES_LANGUAGES['brave'].keys()
 
+_autocomplete_limit = settings['server']['autocomplete_limit']
+_autocomplete_limit_enabled = bool(_autocomplete_limit)
+# Make sure _autocomplete_limit['overwrite'] is always a dict.
+if not hasattr(_autocomplete_limit, 'get'):
+    _autocomplete_limit['overwrite'] = {}
+
 
 def get(*args, **kwargs):
     if 'timeout' not in kwargs:
@@ -158,9 +164,24 @@ backends = {
 }
 
 
+def meet_limit(backend_name, query) -> bool:
+    if _autocomplete_limit_enabled:
+        backend_limit = _autocomplete_limit['overwrite'].get(
+            backend_name, _autocomplete_limit
+        )
+        limit_min = backend_limit.get("min", 0)
+        limit_max = backend_limit.get("max", 0x7FFFFFFF)
+
+        return limit_min <= len(query) <= limit_max
+
+    # If autocomplete_limit is not configured,
+    # allow all autocomplete requests.
+    return True
+
+
 def search_autocomplete(backend_name, query, lang):
     backend = backends.get(backend_name)
-    if backend is None:
+    if backend is None or not meet_limit(backend_name, query):
         return []
 
     try:

searx/settings.yml

@@ -47,6 +47,20 @@ server:
   base_url: false  # Possible values: false or "https://example.org/location".
   limiter: false  # rate limit the number of request on the instance, block some bots
 
+  # The autocompleter will only return suggestions when:
+  #   min < len(query) < max
+  # otherwise it will simply return a null list.
+  # {{ backend_name }} can be any existing autocomplete backends.
+  # The values settings in this section will overwrite the default
+  # value when use the corresponding backend.
+  autocomplete_limit:
+    min: 0
+    max: 50
+    # overwrite:
+    #   "{{ backend_name }}":
+    #     min: 4
+    #     max: 16
+
   # If your instance owns a /etc/searxng/settings.yml file, then set the following
   # values there.
 

searx/settings_defaults.py

@@ -170,6 +170,7 @@ SCHEMA = {
         'http_protocol_version': SettingsValue(('1.0', '1.1'), '1.0'),
         'method': SettingsValue(('POST', 'GET'), 'POST'),
         'default_http_headers': SettingsValue(dict, {}),
+        'autocomplete_limit': SettingsValue(dict, {"min":0, "max": 50}),
     },
     'redis': {
         'url': SettingsValue(str, 'unix:///usr/local/searxng-redis/run/redis.sock?db=0'),

searx/static/themes/simple/src/js/main/search.js

@@ -68,7 +68,7 @@
             "Content-type": "application/x-www-form-urlencoded",
             "X-Requested-With": "XMLHttpRequest"
           },
-          MinChars: 4,
+          MinChars: 0,
           Delay: 300,
           _Position: function () {},
           _Open: function () {