[fix] engines: Google-Web & Google-Video (random arc_id)

Both enghines have been reported ``TooManyRequests``, additionaly Google-Videos
thumbnails needed a review.

Based on the research from @unixfox [1] this patch generates every hour a new random
``arc_id``.

[1] https://github.com/searxng/searxng/issues/4435#issuecomment-2703279522

Closes:

- https://github.com/searxng/searxng/issues/4435
- https://github.com/searxng/searxng/issues/4431

Related:

- https://github.com/searxng/searxng/discussions/4434
- https://github.com/searxng/searxng/discussions/4429

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

1 files changed, 42 insertions, 11 deletions

diff --git a/searx/engines/google.py b/searx/engines/google.py
index 9fd037a4f..10081e92e 100644
--- a/searx/engines/google.py
+++ b/searx/engines/google.py
@@ -10,10 +10,14 @@ engines:
 - :ref:`google autocomplete`
 
 """
+from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
 import re
+import random
+import string
+import time
 from urllib.parse import urlencode
 from lxml import html
 import babel
@@ -64,11 +68,31 @@ filter_mapping = {0: 'off', 1: 'medium', 2: 'high'}
 # from the links not the links itself.
 suggestion_xpath = '//div[contains(@class, "EIaa9b")]//a'
 
-# UI_ASYNC = 'use_ac:true,_fmt:html' # returns a HTTP 500 when user search for
-#                                    # celebrities like '!google natasha allegri'
-#                                    # or '!google chris evans'
-UI_ASYNC = 'use_ac:true,_fmt:prog'
-"""Format of the response from UI's async request."""
+
+_arcid_range = string.ascii_letters + string.digits + "_-"
+_arcid_random: tuple[str, int] | None = None
+
+
+def ui_async(start: int) -> str:
+    """Format of the response from UI's async request.
+
+    - ``arc_id:<...>,use_ac:true,_fmt:prog``
+
+    The arc_id is random generated every hour.
+    """
+    global _arcid_random  # pylint: disable=global-statement
+
+    use_ac = "use_ac:true"
+    # _fmt:html returns a HTTP 500 when user search for celebrities like
+    # '!google natasha allegri' or '!google chris evans'
+    _fmt = "_fmt:prog"
+
+    # create a new random arc_id every hour
+    if not _arcid_random or (int(time.time()) - _arcid_random[1]) > 3600:
+        _arcid_random = (''.join(random.choices(_arcid_range, k=23)), int(time.time()))
+    arc_id = f"arc_id:srp_{_arcid_random[0]}_1{start:02}"
+
+    return ",".join([arc_id, use_ac, _fmt])
 
 
 def get_google_info(params, eng_traits):
@@ -258,8 +282,10 @@ def detect_google_sorry(resp):
 def request(query, params):
     """Google search request"""
     # pylint: disable=line-too-long
-    offset = (params['pageno'] - 1) * 10
+    start = (params['pageno'] - 1) * 10
+    str_async = ui_async(start)
     google_info = get_google_info(params, traits)
+    logger.debug("ARC_ID: %s", str_async)
 
     # https://www.google.de/search?q=corona&hl=de&lr=lang_de&start=0&tbs=qdr%3Ad&safe=medium
     query_url = (
@@ -272,7 +298,7 @@ def request(query, params):
                 'q': query,
                 **google_info['params'],
                 'filter': '0',
-                'start': offset,
+                'start': start,
                 # 'vet': '12ahUKEwik3ZbIzfn7AhXMX_EDHbUDBh0QxK8CegQIARAC..i',
                 # 'ved': '2ahUKEwik3ZbIzfn7AhXMX_EDHbUDBh0Q_skCegQIARAG',
                 # 'cs' : 1,
@@ -284,7 +310,7 @@ def request(query, params):
                 # 'sstk': 'AcOHfVkD7sWCSAheZi-0tx_09XDO55gTWY0JNq3_V26cNN-c8lfD45aZYPI8s_Bqp8s57AHz5pxchDtAGCA_cikAWSjy9kw3kgg'
                 # formally known as use_mobile_ui
                 'asearch': 'arc',
-                'async': UI_ASYNC,
+                'async': str_async,
             }
         )
     )
@@ -303,15 +329,20 @@ def request(query, params):
 # =26;[3,"dimg_ZNMiZPCqE4apxc8P3a2tuAQ_137"]a87;data:image/jpeg;base64,/9j/4AAQSkZJRgABA
 # ...6T+9Nl4cnD+gr9OK8I56/tX3l86nWYw//2Q==26;
 RE_DATA_IMAGE = re.compile(r'"(dimg_[^"]*)"[^;]*;(data:image[^;]*;[^;]*);')
+RE_DATA_IMAGE_end = re.compile(r'"(dimg_[^"]*)"[^;]*;(data:image[^;]*;[^;]*)$')
 
 
-def _parse_data_images(dom):
+def parse_data_images(text: str):
     data_image_map = {}
-    for img_id, data_image in RE_DATA_IMAGE.findall(dom.text_content()):
+
+    for img_id, data_image in RE_DATA_IMAGE.findall(text):
         end_pos = data_image.rfind('=')
         if end_pos > 0:
             data_image = data_image[: end_pos + 1]
         data_image_map[img_id] = data_image
+    last = RE_DATA_IMAGE_end.search(text)
+    if last:
+        data_image_map[last.group(1)] = last.group(2)
     logger.debug('data:image objects --> %s', list(data_image_map.keys()))
     return data_image_map
 
@@ -320,12 +351,12 @@ def response(resp) -> EngineResults:
     """Get response from google's search request"""
     # pylint: disable=too-many-branches, too-many-statements
     detect_google_sorry(resp)
+    data_image_map = parse_data_images(resp.text)
 
     results = EngineResults()
 
     # convert the text to dom
     dom = html.fromstring(resp.text)
-    data_image_map = _parse_data_images(dom)
 
     # results --> answer
     answer_list = eval_xpath(dom, '//div[contains(@class, "LGOjhe")]')