[enh] add MySQL engine

Slightly modified merge of [c00a33fe] from searx.

[c00a33fe] https://github.com/searx/searx/commit/c00a33feee0886dc2b42f4c7b43731210597e5b7

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

searx/engines/mysql_server.py

@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+# pylint: disable=missing-function-docstring
+"""MySQL database (offline)
+
+"""
+
+# import error is ignored because the admin has to install mysql manually to use
+# the engine
+import mysql.connector  # pylint: disable=import-error
+
+engine_type = 'offline'
+auth_plugin = 'caching_sha2_password'
+host = "127.0.0.1"
+database = ""
+username = ""
+password = ""
+query_str = ""
+limit = 10
+paging = True
+result_template = 'key-value.html'
+_connection = None
+
+def init(engine_settings):
+    global _connection  # pylint: disable=global-statement
+
+    if 'query_str' not in engine_settings:
+        raise ValueError('query_str cannot be empty')
+
+    if not engine_settings['query_str'].lower().startswith('select '):
+        raise ValueError('only SELECT query is supported')
+
+    _connection = mysql.connector.connect(
+        database = database,
+        user = username,
+        password = password,
+        host = host,
+        auth_plugin=auth_plugin,
+    )
+
+def search(query, params):
+    query_params = {'query': query}
+    query_to_run = query_str + ' LIMIT {0} OFFSET {1}'.format(limit, (params['pageno'] - 1) * limit)
+
+    with _connection.cursor() as cur:
+        cur.execute(query_to_run, query_params)
+
+        return _fetch_results(cur)
+
+def _fetch_results(cur):
+    results = []
+    for res in cur:
+        result = dict(zip(cur.column_names, map(str, res)))
+        result['template'] = result_template
+        results.append(result)
+
+    return results

searx/settings.yml

@@ -1225,6 +1225,16 @@ engines:
     # See : http://mymemory.translated.net/doc/usagelimits.php
     # api_key : ''
 
+# Required dependency: mysql-connector-python
+#  - name : mysql
+#    engine : mysql_server
+#    database : mydatabase
+#    username : user
+#    password : pass
+#    limit : 10
+#    query_str : 'SELECT * from mytable WHERE fieldname=%(query)s'
+#    shortcut : mysql
+
   - name : 1337x
     engine : 1337x
     shortcut : 1337x