feat(firestore): add get() method

Author: AsifArmanRahman

firebase/firestore/__init__.py

@@ -17,6 +17,7 @@
 from google.cloud.firestore import Client
 from google.cloud.firestore_v1._helpers import *
 
+from ._utils import _from_datastore
 from firebase._exception import raise_detailed_error
 
 
@@ -194,6 +195,57 @@ def delete(self, token=None):
 
 			raise_detailed_error(response)
 
+	def get(self, field_paths=None, token=None):
+		""" Read data from a document in firestore.
+
+
+		:type field_paths: list
+		:param field_paths: (Optional) A list of field paths
+			(``.``-delimited list of field names) to filter data, and
+			return the filtered values only, defaults
+			to :data:`None`.
+
+		:type token: str
+		:param token: (Optional) Firebase Auth User ID Token, defaults
+			to :data:`None`.
+
+
+		:return: The whole data stored in the document unless filtered
+			to retrieve specific fields.
+		:rtype: dict
+		"""
+
+		path = self._path.copy()
+		self._path.clear()
+
+		if self._credentials:
+			db_ref = _build_db(self.__datastore, path)
+
+			result = db_ref.get(field_paths=field_paths)
+
+			return result.to_dict()
+
+		else:
+
+			mask = ''
+
+			if field_paths:
+				for field_path in field_paths:
+					mask = f"{mask}mask.fieldPaths={field_path}&"
+
+			req_ref = f"{self._base_url}/{'/'.join(path)}?{mask}key={self._api_key}"
+
+			if token:
+				headers = {"Authorization": "Firebase " + token}
+				response = self._requests.get(req_ref, headers=headers)
+
+			else:
+				response = self._requests.get(req_ref)
+
+			raise_detailed_error(response)
+
+			return _from_datastore(response.json())
+
 	def set(self, data, token=None):
 		""" Add data to a document in firestore.
 

firebase/firestore/_utils.py

@@ -0,0 +1,84 @@
+
+#   Copyright (c) 2022 Asif Arman Rahman
+#   Licensed under MIT (https://github.com/AsifArmanRahman/firebase/blob/main/LICENSE)
+
+# --------------------------------------------------------------------------------------
+
+
+from base64 import b64decode
+
+
+def _from_datastore(data):
+	""" Converts a map of Firestore ``data``-s to Python dictionary.
+
+
+	:type data: dict
+	:param data: A map of firestore data.
+
+
+	:return: A dictionary of native Python values converted
+		from the ``data``.
+	:rtype: dict
+	"""
+
+	data_to_restructure = data['fields']
+
+	for key, val in data_to_restructure.items():
+
+		if val.get('mapValue'):
+			data_to_restructure[key] = _from_datastore(val['mapValue'])
+
+		elif val.get('arrayValue'):
+			arr = []
+
+			for x in val['arrayValue']['values']:
+				arr.append(_decode_datastore(x))
+
+			data_to_restructure[key] = arr
+
+		else:
+			data_to_restructure[key] = _decode_datastore(val)
+
+	return data_to_restructure
+
+
+def _decode_datastore(value):
+	""" Converts a Firestore ``value`` to a native Python value.
+
+
+	:type value: dict
+	:param value: A Firestore data to be decoded / parsed /
+		converted.
+
+
+	:return: A native Python value converted from the ``value``.
+	:rtype: :data:`None` or :class:`bool` or :class:`bytes`
+		or :class:`int` or :class:`float` or :class:`str` or
+		:class:`dict`
+
+	:raises TypeError: For value types that are unsupported.
+	"""
+
+	if value.get('nullValue', False) is None:
+		return value['nullValue']
+
+	elif value.get('booleanValue') is not None:
+		return bool(value['booleanValue'])
+
+	elif value.get('bytesValue'):
+		return b64decode(value['bytesValue'].encode('utf-8'))
+
+	elif value.get('integerValue'):
+		return int(value['integerValue'])
+
+	elif value.get('doubleValue'):
+		return float(value['doubleValue'])
+
+	elif value.get('stringValue'):
+		return str(value['stringValue'])
+
+	elif value.get('mapValue'):
+		return _from_datastore(value['mapValue'])
+
+	else:
+		raise TypeError("Cannot convert to a Python Value", value, "Invalid type", type(value))