From 02997b2522b9c66072b16f1425c02e81e0085e3c Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Tue, 14 Jul 2020 21:10:56 +0200
Subject: Rename web-server to API

This change renames the web-server component to API in order to be more
descriptive of its role. The OpenDC API bridges between the frontend on
one side and the database and simulator on the other side.
---
 api/opendc/util/database.py | 92 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 api/opendc/util/database.py

(limited to 'api/opendc/util/database.py')

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()
-- 
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