[enh] add hostname_replace plugin

* backport of https://github.com/searx/searx/pull/2724
* allow to remove result if the replacement is the boolean value false

searx/plugins/hostname_replace.py

@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import re
+from urllib.parse import urlunparse
+from searx import settings
+from searx.plugins import logger
+from flask_babel import gettext
+
+name = gettext('Hostname replace')
+description = gettext('Rewrite result hostnames or remove results based on the hostname')
+default_on = False
+preference_section = 'general'
+
+plugin_id = 'hostname_replace'
+
+replacements = {re.compile(p): r for (p, r) in settings[plugin_id].items()} if plugin_id in settings else {}
+
+logger = logger.getChild(plugin_id)
+parsed = 'parsed_url'
+
+
+def on_result(request, search, result):
+    if parsed not in result:
+        return True
+    for (pattern, replacement) in replacements.items():
+        if pattern.search(result[parsed].netloc):
+            if not replacement:
+                return False
+            result[parsed] = result[parsed]._replace(netloc=pattern.sub(replacement, result[parsed].netloc))
+            result['url'] = urlunparse(result[parsed])
+
+    return True