We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Using single apostrophe causes a "search error"
<!-- PLEASE FILL THESE FIELDS, IT REALLY HELPS THE MAINTAINERS OF SEARX -->

**Version of Searx, commit number if you are using on master branch and stipulate if you forked Searx**
1.1.0-27-bf0a583f
<!-- If you are running on master branch using git execute this command
in order to fetch the latest commit ID:
```
git log -1
``` 
If you are using searx-docker then look at the bottom of the Searx page
and check for the version after "Powered by searx"

Please also stipulate if you are using a forked version of Searx and
include a link to the fork source code.
-->
**How did you install Searx?**
searx-docker. Specifically using docker-compose and running ``docker-compose up``.
Compose file:
```yaml
version: '3.3'
services:
    searx:
        volumes:
            - /mnt/storage1/configs/searx:/etc/searx
        ports:
            - 9999:8080
        environment:
            - BASE_URL=http://localhost:9999/
        image: searx/searx
        restart: unless-stopped
```
<!-- Did you install Searx using the official wiki or using searx-docker
or manually by executing the searx/webapp.py file? -->
**What happened?**
Using a single apostrophe in a word (for example, "What's") causes a search error
<!-- A clear and concise description of what the bug is. -->
**How To Reproduce**
Use any single apostrophe in a search query
<!-- How can we reproduce this issue? (as minimally and as precisely as possible) -->
**Expected behavior**
Should return results, instead of an error.
<!-- A clear and concise description of what you expected to happen. -->
**Screenshots & Logs**
https://imgur.com/a/E2b4mNX
https://paste.ee/p/e5gS8

**Additional context**
It's also somewhat infuriating that it also returns from a result page to the home page when this happens, meaning I have to retype my query (though that's another issue entirely).

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `searx/plugins/search_operators.py`
Content:
```
1 import shlex
2 import string
3 
4 from flask_babel import gettext
5 
6 name = gettext("Search operators")
7 description = gettext("""Filter results using hyphen, site: and -site:.
8 Please note that you might get less results with the additional filtering.""")
9 default_on = False
10 
11 
12 def on_result(request, search, result):
13     q = search.search_query.query
14     qs = shlex.split(q)
15     spitems = [x.lower() for x in qs if ' ' in x]
16     mitems = [x.lower() for x in qs if x.startswith('-')]
17     siteitems = [x.lower() for x in qs if x.startswith('site:')]
18     msiteitems = [x.lower() for x in qs if x.startswith('-site:')]
19     url, title, content = (
20         result["url"].lower(),
21         result["title"].lower(),
22         (result.get("content").lower() if result.get("content") else '')
23     )
24     if all((x not in title or x not in content) for x in spitems):
25         return False
26     if all((x in title or x in content) for x in mitems):
27         return False
28     if all(x not in url for x in siteitems):
29         return False
30     if all(x in url for x in msiteitems):
31         return False
32     return True
33
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/searx/plugins/search_operators.py b/searx/plugins/search_operators.py
--- a/searx/plugins/search_operators.py
+++ b/searx/plugins/search_operators.py
@@ -11,7 +11,11 @@
 
 def on_result(request, search, result):
     q = search.search_query.query
-    qs = shlex.split(q)
+    # WARN: shlex.quote is designed only for Unix shells and may be vulnerable
+    # to command injection on non-POSIX compliant shells (Windows)
+    # https://docs.python.org/3/library/shlex.html#shlex.quote
+    squote = shlex.quote(q)
+    qs = shlex.split(squote)
     spitems = [x.lower() for x in qs if ' ' in x]
     mitems = [x.lower() for x in qs if x.startswith('-')]
     siteitems = [x.lower() for x in qs if x.startswith('site:')]

{"golden_diff": "diff --git a/searx/plugins/search_operators.py b/searx/plugins/search_operators.py\n--- a/searx/plugins/search_operators.py\n+++ b/searx/plugins/search_operators.py\n@@ -11,7 +11,11 @@\n \n def on_result(request, search, result):\n     q = search.search_query.query\n-    qs = shlex.split(q)\n+    # WARN: shlex.quote is designed only for Unix shells and may be vulnerable\n+    # to command injection on non-POSIX compliant shells (Windows)\n+    # https://docs.python.org/3/library/shlex.html#shlex.quote\n+    squote = shlex.quote(q)\n+    qs = shlex.split(squote)\n     spitems = [x.lower() for x in qs if ' ' in x]\n     mitems = [x.lower() for x in qs if x.startswith('-')]\n     siteitems = [x.lower() for x in qs if x.startswith('site:')]\n", "issue": "Using single apostrophe causes a \"search error\"\n<!-- PLEASE FILL THESE FIELDS, IT REALLY HELPS THE MAINTAINERS OF SEARX -->\r\n\r\n**Version of Searx, commit number if you are using on master branch and stipulate if you forked Searx**\r\n1.1.0-27-bf0a583f\r\n<!-- If you are running on master branch using git execute this command\r\nin order to fetch the latest commit ID:\r\n```\r\ngit log -1\r\n``` \r\nIf you are using searx-docker then look at the bottom of the Searx page\r\nand check for the version after \"Powered by searx\"\r\n\r\nPlease also stipulate if you are using a forked version of Searx and\r\ninclude a link to the fork source code.\r\n-->\r\n**How did you install Searx?**\r\nsearx-docker. Specifically using docker-compose and running ``docker-compose up``.\r\nCompose file:\r\n```yaml\r\nversion: '3.3'\r\nservices:\r\n    searx:\r\n        volumes:\r\n            - /mnt/storage1/configs/searx:/etc/searx\r\n        ports:\r\n            - 9999:8080\r\n        environment:\r\n            - BASE_URL=http://localhost:9999/\r\n        image: searx/searx\r\n        restart: unless-stopped\r\n```\r\n<!-- Did you install Searx using the official wiki or using searx-docker\r\nor manually by executing the searx/webapp.py file? -->\r\n**What happened?**\r\nUsing a single apostrophe in a word (for example, \"What's\") causes a search error\r\n<!-- A clear and concise description of what the bug is. -->\r\n**How To Reproduce**\r\nUse any single apostrophe in a search query\r\n<!-- How can we reproduce this issue? (as minimally and as precisely as possible) -->\r\n**Expected behavior**\r\nShould return results, instead of an error.\r\n<!-- A clear and concise description of what you expected to happen. -->\r\n**Screenshots & Logs**\r\nhttps://imgur.com/a/E2b4mNX\r\nhttps://paste.ee/p/e5gS8\r\n\r\n**Additional context**\r\nIt's also somewhat infuriating that it also returns from a result page to the home page when this happens, meaning I have to retype my query (though that's another issue entirely).\n", "before_files": [{"content": "import shlex\nimport string\n\nfrom flask_babel import gettext\n\nname = gettext(\"Search operators\")\ndescription = gettext(\"\"\"Filter results using hyphen, site: and -site:.\nPlease note that you might get less results with the additional filtering.\"\"\")\ndefault_on = False\n\n\ndef on_result(request, search, result):\n    q = search.search_query.query\n    qs = shlex.split(q)\n    spitems = [x.lower() for x in qs if ' ' in x]\n    mitems = [x.lower() for x in qs if x.startswith('-')]\n    siteitems = [x.lower() for x in qs if x.startswith('site:')]\n    msiteitems = [x.lower() for x in qs if x.startswith('-site:')]\n    url, title, content = (\n        result[\"url\"].lower(),\n        result[\"title\"].lower(),\n        (result.get(\"content\").lower() if result.get(\"content\") else '')\n    )\n    if all((x not in title or x not in content) for x in spitems):\n        return False\n    if all((x in title or x in content) for x in mitems):\n        return False\n    if all(x not in url for x in siteitems):\n        return False\n    if all(x in url for x in msiteitems):\n        return False\n    return True\n", "path": "searx/plugins/search_operators.py"}], "after_files": [{"content": "import shlex\nimport string\n\nfrom flask_babel import gettext\n\nname = gettext(\"Search operators\")\ndescription = gettext(\"\"\"Filter results using hyphen, site: and -site:.\nPlease note that you might get less results with the additional filtering.\"\"\")\ndefault_on = False\n\n\ndef on_result(request, search, result):\n    q = search.search_query.query\n    # WARN: shlex.quote is designed only for Unix shells and may be vulnerable\n    # to command injection on non-POSIX compliant shells (Windows)\n    # https://docs.python.org/3/library/shlex.html#shlex.quote\n    squote = shlex.quote(q)\n    qs = shlex.split(squote)\n    spitems = [x.lower() for x in qs if ' ' in x]\n    mitems = [x.lower() for x in qs if x.startswith('-')]\n    siteitems = [x.lower() for x in qs if x.startswith('site:')]\n    msiteitems = [x.lower() for x in qs if x.startswith('-site:')]\n    url, title, content = (\n        result[\"url\"].lower(),\n        result[\"title\"].lower(),\n        (result.get(\"content\").lower() if result.get(\"content\") else '')\n    )\n    if all((x not in title or x not in content) for x in spitems):\n        return False\n    if all((x in title or x in content) for x in mitems):\n        return False\n    if all(x not in url for x in siteitems):\n        return False\n    if all(x in url for x in msiteitems):\n        return False\n    return True\n", "path": "searx/plugins/search_operators.py"}]}