[enh] add mongodb offline engine

Cherry-Pick: https://github.com/searx/searx/commit/198aad43
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/mongodb.py

@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+# pylint: disable=missing-function-docstring
+"""MongoDB engine (Offline)
+
+"""
+
+import re
+from pymongo import MongoClient  # pylint: disable=import-error
+
+engine_type = 'offline'
+
+# mongodb connection variables
+host = '127.0.0.1'
+port = 27017
+username = ''
+password = ''
+database = None
+collection = None
+key = None
+
+# engine specific variables
+paging = True
+results_per_page = 20
+exact_match_only = False
+result_template = 'key-value.html'
+
+_client = None
+
+def init(_):
+    connect()
+
+def connect():
+    global _client  # pylint: disable=global-statement
+    kwargs = { 'port': port }
+    if username:
+        kwargs['username'] = username
+    if password:
+        kwargs['password'] = password
+    _client = MongoClient(host, **kwargs)[database][collection]
+
+def search(query, params):
+    results = []
+    if exact_match_only:
+        q = { '$eq': query }
+    else:
+        _re = re.compile('.*{0}.*'.format(re.escape(query)), re.I | re.M )
+        q = { '$regex': _re }
+
+    query = _client.find(
+        {key: q}
+    ).skip(
+        ( params['pageno'] -1 ) * results_per_page
+    ).limit(
+        results_per_page
+    )
+
+    results.append({ 'number_of_results': query.count() })
+    for r in query:
+        del r['_id']
+        r = { str(k):str(v) for k,v in r.items() }
+        r['template'] = result_template
+        results.append(r)
+
+    return results

searx/settings.yml

@@ -811,6 +811,19 @@ engines:
     engine: mixcloud
     shortcut: mc
 
+  # MongoDB engine
+  # Required dependency: pymongo
+  # - name: mymongo
+  #   engine: mongodb
+  #   shortcut: md
+  #   exact_match_only: false
+  #   host: '127.0.0.1'
+  #   port: 27017
+  #   results_per_page: 20
+  #   database: 'business'
+  #   collection: 'reviews'  # name of the db collection
+  #   key: 'name'  # key in the collection to search for
+
   - name: npm
     engine: json_engine
     paging: true