Model and Object-Oriented Programming
Week 18 Hacks
Model and Object-Oriented Programming Hacks
Object Oriented Programming is a part of learning Python. The objective of this blog is to introduce OOP with the intention of PBL task to create a database. The foundations for a database is defining a Class and understanding instance data and methods. A database is often a focus of backend coding as it will store persistent data, that can be recalled after the immediate session is closed.
from datetime import date
import json
def calculate_age(born):
today = date.today()
return today.year - born.year - ((today.month, today.day) < (born.month, born.day))
dob = date(2004, 12, 31)
age = calculate_age(dob)
print(age)
# A gateway in necessary as a web server cannot communicate directly with Python.
# In this case, imports are focused on generating hash code to protect passwords.
from werkzeug.security import generate_password_hash, check_password_hash
from datetime import date
import json
class User:
def __init__(self, name, uid, password, dob, classOf):
self._name = name # variables with self prefix become part of the object,
self._uid = uid
self.set_password(password)
self._dob = dob
self._classOf = classOf
@property
def name(self):
return self._name
# a setter function, allows name to be updated after initial object creation
@name.setter
def name(self, name):
self._name = name
# a getter method, extracts email from object
@property
def uid(self):
return self._uid
# a setter function, allows name to be updated after initial object creation
@uid.setter
def uid(self, uid):
self._uid = uid
# check if uid parameter matches user id in object, return boolean
def is_uid(self, uid):
return self._uid == uid
# dob property is returned as string, to avoid unfriendly outcomes
@property
def dob(self):
dob_string = self._dob.strftime('%m-%d-%Y')
return dob_string
# dob should be have verification for type date
@dob.setter
def dob(self, dob):
self._dob = dob
@property
def classOf(self):
return self._classOf
# gradDate should be have verification for type date
@classOf.setter
def classOf(self, classOf):
self._classOf = classOf
# age is calculated and returned each time it is accessed
@property
def age(self):
today = date.today()
return today.year - self._dob.year - ((today.month, today.day) < (self._dob.month, self._dob.day))
# dictionary is customized, removing password for security purposes
@property
def dictionary(self):
dict = {
"name" : self.name,
"uid" : self.uid,
"dob" : self.dob,
"age" : self.age,
"classOf" : self.classOf
}
return dict
# update password, this is conventional setter
def set_password(self, password):
"""Create a hashed password."""
self._password = generate_password_hash(password, method='sha256')
# check password parameter versus stored/encrypted password
def is_password(self, password):
"""Check against hashed password."""
result = check_password_hash(self._password, password)
return result
# output content using json dumps, this is ready for API response
def __str__(self):
return json.dumps(self.dictionary)
# output command to recreate the object, uses attribute directly
def __repr__(self):
return f'User(name={self._name}, uid={self._uid}, password={self._password},dob={self._dob}, classOf={self._classOf})'
# define tester
def tester(users, uid, psw):
result = None
for user in users:
# test for match in database
if user.uid == uid and user.is_password(psw): # check for match
print("* ", end="")
result = user
# print using __str__ method
print(str(user))
return result
# add users
if __name__ == "__main__":
u1 = User(name='Lydia Cho', uid='lyds', password='123lyds', dob=date(2006, 4, 12), classOf='2024')
u2 = User(name='Alexa Carlson', uid='lex', password='lex321', dob=date(2006, 5, 16), classOf='2024')
u3 = User(name='Ava Carlson', uid='aves', password='aves543', dob=date(2006, 5, 16), classOf='2024')
u4 = User(name='Sri Kotturi', uid='sri', password='sri333', dob=date(2005, 12, 13), classOf='2024')
# def variable for users
users = [u1, u2, u3, u4]
# Find user
print("Test 1, find user 3")
u = tester(users, u3.uid, "aves543")
# Change user
print("Test 2, change user 3")
u.name = "Bubba (Lillia) C"
u.uid = "bubbs"
u.set_password("bubba4life")
u = tester(users, u.uid, "bubba4life")
print("JSON ready string:\n", u1, "\n")
print("Raw Variables of object:\n", vars(u1), "\n")
print("Raw Attributes and Methods of object:\n", dir(u1), "\n")
print("Representation to Re-Create the object:\n", repr(u1), "\n")