[fix] make flask_babel.gettext() work in engine modules (L10n & threads)

incident:
  flask_babel.gettext() does not work in the engine modules.

cause:
  the request() and response() functions of the engine modules run in the
  processor, whose search() method runs in a thread and in the threads the
  context of the Flask app does not exist. The context of the Flask app is
  needed by the gettext() function for the L10n.

Solution:
  copy context of the Flask app into the threads. [1]

special case:
  We cannot equip the search() method of the processors with the decorator [1],
  because the decorator requires a context (Flask app) that does not yet exist
  at the time of the initialization of the processors (the initialization of the
  processors is part of the initialization of the Flask app).

[1] https://flask.palletsprojects.com/en/2.3.x/api/#flask.copy_current_request_context

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

1 files changed, 16 insertions, 50 deletions

diff --git a/searxng_extra/standalone_searx.py b/searxng_extra/standalone_searx.py
index d7964bd0..2ce9925c 100755
--- a/searxng_extra/standalone_searx.py
+++ b/searxng_extra/standalone_searx.py
@@ -1,12 +1,26 @@
 #!/usr/bin/env python
 # lint: pylint
-
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # (C) Copyright Contributors to the SearXNG project.
-# (C) Copyright Contributors to the searx project (2014 - 2021)
 
 """Script to run SearXNG from terminal.
 
+  DON'T USE THIS SCRIPT!!
+
+.. danger::
+
+   Be warned, using the ``standalone_searx.py`` won't give you privacy!
+
+   On the contrary, this script behaves like a SearXNG server: your IP is
+   exposed and tracked by all active engines (google, bing, qwant, ... ), with
+   every query!
+
+.. note::
+
+   This is an old and grumpy hack / SearXNG is a Flask application with
+   client/server structure, which can't be turned into a command line tool the
+   way it was done here.
+
 Getting categories without initiate the engine will only return `['general']`
 
 >>> import searx.engines
@@ -23,54 +37,6 @@ Example to use this script:
 
     $ python3 searxng_extra/standalone_searx.py rain
 
-.. danger::
-
-   Be warned, using the ``standalone_searx.py`` won't give you privacy!
-
-   On the contrary, this script behaves like a SearXNG server: your IP is
-   exposed and tracked by all active engines (google, bing, qwant, ... ), with
-   every query!
-
-Example to run it from python:
-
->>> import importlib
-... import json
-... import sys
-... import searx.engines
-... import searx.search
-... search_query = 'rain'
-... # initialize engines
-... searx.search.initialize()
-... # load engines categories once instead of each time the function called
-... engine_cs = list(searx.engines.categories.keys())
-... # load module
-... spec = importlib.util.spec_from_file_location(
-...     'utils.standalone_searx', 'searxng_extra/standalone_searx.py')
-... sas = importlib.util.module_from_spec(spec)
-... spec.loader.exec_module(sas)
-... # use function from module
-... prog_args = sas.parse_argument([search_query], category_choices=engine_cs)
-... search_q = sas.get_search_query(prog_args, engine_categories=engine_cs)
-... res_dict = sas.to_dict(search_q)
-... sys.stdout.write(json.dumps(
-...     res_dict, sort_keys=True, indent=4, ensure_ascii=False,
-...     default=sas.json_serial))
-{
-    "answers": [],
-    "infoboxes": [ {...} ],
-    "paging": true,
-    "results": [... ],
-    "number_of_results": 820000000.0,
-    "search": {
-        "lang": "all",
-        "pageno": 1,
-        "q": "rain",
-        "safesearch": 0,
-        "timerange": null
-    },
-    "suggestions": [...]
-}
-
 """  # pylint: disable=line-too-long
 
 import argparse