build: Migrate to flat project structure

This change updates the project structure to become flattened.
Previously, the simulator, frontend and API each lived into their own
directory.

With this change, all modules of the project live in the top-level
directory of the repository. This should improve discoverability of
modules of the project.

1 files changed, 77 insertions, 0 deletions

diff --git a/opendc-web/opendc-web-api/opendc/util/database.py b/opendc-web/opendc-web-api/opendc/util/database.py
new file mode 100644
index 00000000..dd26533d
--- /dev/null
+++ b/opendc-web/opendc-web-api/opendc/util/database.py
@@ -0,0 +1,77 @@
+import urllib.parse
+from datetime import datetime
+
+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}`.
+        """
+        return getattr(self.opendc_db, collection).find_one(query)
+
+    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}`.
+        """
+        cursor = getattr(self.opendc_db, collection).find(query)
+        return list(cursor)
+
+    def insert(self, obj, collection):
+        """Updates an existing object."""
+        bson = getattr(self.opendc_db, collection).insert(obj)
+
+        return bson
+
+    def update(self, _id, obj, collection):
+        """Updates an existing object."""
+        return getattr(self.opendc_db, collection).update({'_id': _id}, obj)
+
+    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 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()