susantabiswas/FaceRecog

# ---- coding: utf-8 ----
# ===================================================
# Author: Susanta Biswas
# ===================================================
"""Description: Class to handle saving and retrieving facial data.
The data is saved on disk for peersistence, also an in-memory cache is 
used for quicker look ups.

For persistent storage a JSON file is used and for in memory cache,
native python set is used.
Cache doesn't allow duplicates. Without duplicates, entries for 
search are limited.

Cache is initialized with data loaded from DB. Then each addition 
of face data for a new user goes through two writes:
1. Addition to cache
2. Saved to disk DB.

Cache is always up to date with the latest facial data.

Usage: python -m face_recog.face_data_store
"""
# ===================================================

import sys

from face_recog.exceptions import DatabaseFileNotFound, InvalidCacheInitializationData
from face_recog.json_persistent_storage import JSONStorage
from face_recog.logger import LoggerFactory
from face_recog.simple_cache import SimpleCache

# Load the custom logger
logger = None
try:
    logger_ob = LoggerFactory(logger_name=__name__)
    logger = logger_ob.get_logger()
    logger.info("{} loaded...".format(__name__))
    # set exception hook for uncaught exceptions
    sys.excepthook = logger_ob.uncaught_exception_hook
except Exception as exc:
    raise exc


class FaceDataStore:
    """Class to handle saving and retrieving facial data.
    The data is saved on disk for peersistence, also an in-memory cache is
    used for quicker look ups.

    For persistent storage a JSON file is used and for in memory cache,
    native python set is used.
    Cache doesn't allow duplicates. Without duplicates, entries for
    search are limited.

    Cache is initialized with data loaded from DB. Then each addition
    of face data for a new user goes through two writes:
    1. Addition to cache
    2. Saved to disk DB.

    Cache is always up to date with the latest facial data.
    """

    def __init__(self, persistent_data_loc="data/facial_data.json") -> None:
        # persistent storage handler
        self.db_handler = JSONStorage(persistent_data_loc)
        saved_data = []
        try:
            # Initialize the cache handler with data from DB
            saved_data = self.db_handler.get_all_data()
            logger.info(
                "Data loaded from DB with {} entries...".format(len(saved_data))
            )
        except DatabaseFileNotFound:
            logger.info("No existing DB file found!!")
        try:
            self.cache_handler = SimpleCache(saved_data)
        except InvalidCacheInitializationData:
            raise InvalidCacheInitializationData

    def add_facial_data(self, facial_data):
        """Add facial data to the in memory cache and
        persistent storage.

        Args:
            facial_data (Dict): {'id':str, 'encoding':tuple(), 'name':str}
        """
        # add to cache and save on disk
        self.cache_handler.add_data(face_data=facial_data)
        self.db_handler.add_data(face_data=facial_data)

    def remove_facial_data(self, face_id: str = None):
        """Delete facial record with the matching face id.

        Args:
            face_id (str, optional): Face data identifier. Defaults to None.
        """
        self.cache_handler.delete_data(face_id=face_id)
        self.db_handler.delete_data(face_id=face_id)

    def get_all_facial_data(self):
        """Returns data of all the registered faces.

        Returns:
            List[Dict]: List of facial data
        """
        # Cache data is returned since it is always up to date
        # with CRUD operations.
        return self.cache_handler.get_all_data()


if __name__ == "__main__":

    # print("Saving 1 entry to DataStore...")
    # ob = FaceDataStore(persistent_data_loc="data/test_facial_data.json")
    # # Save data
    # face_data = {"name": "test2", "encoding": (-3.4, 0.3, -0.823, 1)}
    # ob.add_facial_data(face_data)
    # print(ob.get_all_facial_data())

    # print("Saving 2 entry to DataStore with existing DB(1 entry)...")
    # # Now we again create a DB and again add the same data
    # # cache will return only 2 entry but DB will have both
    # ob1 = FaceDataStore(persistent_data_loc="data/test_facial_data.json")
    # # Save data
    # face_data1 = {"name": "test1", "encoding": (-3.4, 0.3, -0.823, 1)}
    # face_data2 = {"name": "test2", "encoding": (-3.4, 0.3, -0.823, 1)}
    # ob1.add_facial_data(face_data1)
    # ob1.add_facial_data(face_data2)

    # print("DB data", ob1.db_handler.get_all_data())
    # print("Cache data", ob1.cache_handler.get_all_data())
    # print("API data", ob1.get_all_facial_data())

    # # remove entry
    # print("\n\nAfter Deletion ******")
    # ob1.remove_facial_data(face_id="test2")
    # print("DB data", ob1.db_handler.get_all_data())
    # print("Cache data", ob1.cache_handler.get_all_data())
    # print("API data", ob1.get_all_facial_data())

    # # remove the test file
    # os.remove("data/test_facial_data.json")
    # print("File: {} deleted!".format("data/test_facial_data.json"))
    pass