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searx/engines/postgresql.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""PostgreSQL is a powerful and robust open source database.  Before configuring
+the PostgreSQL engine, you must install the dependency ``psychopg2``.
+
+Example
+=======
+
+Below is an example configuration:
+
+.. code:: yaml
+
+   - name: my_database
+     engine: postgresql
+     database: my_database
+     username: searxng
+     password: password
+     query_str: 'SELECT * from my_table WHERE my_column = %(query)s'
+
+Implementations
+===============
+
+"""
+
+try:
+    import psycopg2  # type: ignore
+except ImportError:
+    # import error is ignored because the admin has to install postgresql
+    # manually to use the engine.
+    pass
+
+from searx.result_types import EngineResults
+
+engine_type = 'offline'
+
+host = "127.0.0.1"
+"""Hostname of the DB connector"""
+
+port = "5432"
+"""Port of the DB connector"""
+
+database = ""
+"""Name of the database."""
+
+username = ""
+"""Username for the DB connection."""
+
+password = ""
+"""Password for the DB connection."""
+
+query_str = ""
+"""SQL query that returns the result items."""
+
+limit = 10
+paging = True
+_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 = psycopg2.connect(
+        database=database,
+        user=username,
+        password=password,
+        host=host,
+        port=port,
+    )
+
+
+def search(query, params) -> EngineResults:
+    query_params = {'query': query}
+    query_to_run = query_str + ' LIMIT {0} OFFSET {1}'.format(limit, (params['pageno'] - 1) * limit)
+
+    with _connection:
+        with _connection.cursor() as cur:
+            cur.execute(query_to_run, query_params)
+            return _fetch_results(cur)
+
+
+def _fetch_results(cur) -> EngineResults:
+    res = EngineResults()
+    try:
+        titles = [column_desc.name for column_desc in cur.description]
+        for row in cur:
+            kvmap = dict(zip(titles, map(str, row)))
+            res.add(res.types.KeyValue(kvmap=kvmap))
+
+    # no results to fetch
+    except psycopg2.ProgrammingError:
+        pass
+
+    return res