1 files changed, 92 insertions, 0 deletions
diff --git a/api/opendc/util/database.py b/api/opendc/util/database.py
new file mode 100644
index 00000000..80cdcbab
--- /dev/null
+++ b/api/opendc/util/database.py
@@ -0,0 +1,92 @@
+import json
+import urllib.parse
+from datetime import datetime
+
+from bson.json_util import dumps
+from pymongo import MongoClient
+
+DATETIME_STRING_FORMAT = '%Y-%m-%dT%H:%M:%S'
+CONNECTION_POOL = None
+
+
+class Database:
+    """Object holding functionality for database access."""
+    def __init__(self):
+        self.opendc_db = None
+
+    def initialize_database(self, user, password, database, host):
+        """Initializes the database connection."""
+
+        user = urllib.parse.quote_plus(user)
+        password = urllib.parse.quote_plus(password)
+        database = urllib.parse.quote_plus(database)
+        host = urllib.parse.quote_plus(host)
+
+        client = MongoClient('mongodb://%s:%s@%s/default_db?authSource=%s' % (user, password, host, database))
+        self.opendc_db = client.opendc
+
+    def fetch_one(self, query, collection):
+        """Uses existing mongo connection to return a single (the first) document in a collection matching the given
+        query as a JSON object.
+
+        The query needs to be in json format, i.e.: `{'name': prefab_name}`.
+        """
+        bson = getattr(self.opendc_db, collection).find_one(query)
+
+        return self.convert_bson_to_json(bson)
+
+    def fetch_all(self, query, collection):
+        """Uses existing mongo connection to return all documents matching a given query, as a list of JSON objects.
+
+        The query needs to be in json format, i.e.: `{'name': prefab_name}`.
+        """
+        results = []
+        cursor = getattr(self.opendc_db, collection).find(query)
+        for doc in cursor:
+            results.append(self.convert_bson_to_json(doc))
+        return results
+
+    def insert(self, obj, collection):
+        """Updates an existing object."""
+        bson = getattr(self.opendc_db, collection).insert(obj)
+
+        return self.convert_bson_to_json(bson)
+
+    def update(self, _id, obj, collection):
+        """Updates an existing object."""
+        bson = getattr(self.opendc_db, collection).update({'_id': _id}, obj)
+
+        return self.convert_bson_to_json(bson)
+
+    def delete_one(self, query, collection):
+        """Deletes one object matching the given query.
+
+        The query needs to be in json format, i.e.: `{'name': prefab_name}`.
+        """
+        getattr(self.opendc_db, collection).delete_one(query)
+
+    def delete_all(self, query, collection):
+        """Deletes all objects matching the given query.
+
+        The query needs to be in json format, i.e.: `{'name': prefab_name}`.
+        """
+        getattr(self.opendc_db, collection).delete_many(query)
+
+    @staticmethod
+    def convert_bson_to_json(bson):
+        """Converts a BSON representation to JSON and returns the JSON representation."""
+        json_string = dumps(bson)
+        return json.loads(json_string)
+
+    @staticmethod
+    def datetime_to_string(datetime_to_convert):
+        """Return a database-compatible string representation of the given datetime object."""
+        return datetime_to_convert.strftime(DATETIME_STRING_FORMAT)
+
+    @staticmethod
+    def string_to_datetime(string_to_convert):
+        """Return a datetime corresponding to the given string representation."""
+        return datetime.strptime(string_to_convert, DATETIME_STRING_FORMAT)
+
+
+DB = Database()