Python 3.7.3 : Using the flask - part 004.

The goal of this tutorial is to interact with the database in order to use it with flask_sqlalchemy python module.
The db.Model is used to interact with the database.
A database doesn't need a primary key but if you using the flask-sqlalchemy you need to have it for each one table in order to connect it.
Let's see the database:

C:\Python373\my_flask>python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD6
4)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from server import db
>>> db.create_all()
>>> db.engine.table_names()
['user']

Let's add some data into database on user table:

C:\Python373\my_flask>python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD6
4)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from server import db
>>> from server import User
>>> first_user = User(username='catafest',email='catafest@yahoo.com')
>>> db.session.add(first_user)
>>> db.session.commit()
>>> test_user = User(username='test',email='test@test.com')
>>> db.session.add(test_user)
>>> db.session.commit()

Update is a simple issue.
Let's update the username test_user from test to user_test:

>>> test_user.username = 'user_test'
>>> db.session.commit()

The delete is simple like the add:

>>> db.session.delete(test_user)
>>> db.session.commit()

Let's use query:

>>> results=User.query.all()
>>> results[0].username
'catafest'
>>> results[0].email
'catafest@yahoo.com'
>>> results

The next step is an important issue because let you to see how result by content and query and filter by first result:

>>> q1 = User.query.filter_by(username='catafest')
>>> q1
...flask_sqlalchemy .basequery= ...
>>> print(q1)
SELECT user.id AS user_id, user.username AS user_username, user.email AS user_email
FROM user
WHERE user.username = ?
>>> q2 = User.query.filter_by(username='catafest').first()
>>> q2
< User 1 >
>>> print(q2)
< User 1 >
>>> print(q1.username)
Traceback (most recent call last):
  File "", line 1, in 
AttributeError: 'BaseQuery' object has no attribute 'username'
>>> print(q2.username)
catafest
>>> print(q2.username,q2.email)
catafest catafest@yahoo.com 

In this case because the first is limited to one result the print of q2 is the correct way.

Python 3.7.3 : Using the twitter python module - part 003.

Today I will speak about twitter python module with the new changes of the A.P.I.
This two tutorial will not work now because the twitter A.P.I is changed.
The reason I don't delete it is the similar flow programming and access the A.P.I.:

• Use the twitter python module - part 001.
• Use the twitter python module - part 002.

Let's start with the install of this python module with Python version 3.7.3:

C:\Python373>cd Scripts

C:\Python373\Scripts>pip install python-twitter
...
Installing collected packages: python-twitter
Successfully installed python-twitter-3.5

Let's test the GetSearch.
You need to create a twitter application to have access to the tokens and secret keys:

import os
import json
import twitter
from twitter import *
CONSUMER_KEY=""
CONSUMER_SECRET=""

ACCESS_TOKEN=""
ACCESS_TOKEN_SECRET=""
LANGUAGES="En"
at=input("ACCESS_TOKEN: ", )
ats=input("ACCESS_TOKEN_SECRET: ", )
ck=input("CONSUMER_KEY: ", )
cs=input("CONSUMER_SECRET: ", )
api = Api(ck, cs, at, ats)
def main():
    print("Search by query using the GetSearch ")
    r = api.GetSearch(raw_query="q=twitter%20&result_type=recent&since=1999-03-07&count=100")
    print(r)
if __name__ == '__main__':
    main()

The result will be something like this:

...
@GeorgePapa19 @realDonaldTrump Sure Did https://t.co/GblrSOsaJg'), Status(ID=115
5787444525993984, ScreenName=MD__PCY, Created=Mon Jul 29 10:29:34 +0000 2019, Te
xt='mal ako ni twitter https://t.co/lRA1BOyf6a'), Status(ID=1155787444517838849,
 ScreenName=Elyse95, Created=Mon Jul 29 10:29:34 +0000 2019, Text='????? ????? ?
??? ..??? ???? ????????? ????? ????? ????? ?????? ??? ???????? .. !!    ... http
s://t.co/weChoAPDnC. https://t.co/34D2nmtbOz'), Status(ID=1155787444517781504, S
creenName=chrichacham123, Created=Mon Jul 29 10:29:34 +0000 2019, Text='RT @John
JCrace: Project Blind Faith! https://t.co/2mpB0MC540'), Status(ID=11557874445134
72514, ScreenName=318520_mu, Created=Mon Jul 29 10:29:34 +0000 2019, Text='31-85
20 ????????\n???????? → ???twitter??????????????\n??...?\n\nhttps://t.co/oVET5Z9
wXq')]

Python 3.7.3 : Using the flask - part 003.

Another tutorial with python 3.7.3 and flask python module.
In the last tutorial, I speak about some tricks and tips.
Today, I will show some steps for fixing and run with flask-sqlalchemy.
The source code from my GitHub account can be updated with this source code.

app = Flask (__name__)
app.config['SECRET_KEY'] = 'abcdefg'
# set SQLAlchemy
basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'server.sqlite')
db = SQLAlchemy(app)
ma = Marshmallow(app)
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True)
    email = db.Column(db.String(120), unique=True)

    def __init__(self, username, email):
        self.username = username
        self.email = email

If you run it then you get this:

C:\Python373\my_flask>python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD6
4)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from server import db
C:\Python373\lib\site-packages\flask_sqlalchemy\__init__.py:835: FSADeprecationW
arning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be dis
abled by default in the future.  Set it to True or False to suppress this warnin
g.
  'SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and '

You will have a database file named server.sqlite.

#app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

Let's create and show the database:

C:\Python373\my_flask>python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD6
4)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from server import db
>>> db.create_all()
>>> db.engine.table_names()
['user']

A good approach is to create a config.py file and used into the application area.
The config.py file will have this source code:

SQLALCHEMY_TRACK_MODIFICATIONS = False
SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(basedir, 'server.sqlite')
DEBUG=True

The server.py has this source code:

...
app = Flask (__name__)
app.config.from_pyfile('config.py')
db = SQLAlchemy(app)
...

Python 3.7.3 : About pytweening python module.

This is a simple module of tweening and easing functions implemented in Python, see the GitHub webpage.

C:\Python373\Scripts>pip install pytweening
Collecting pytweening
Downloading https://files.pythonhosted.org/packages/b9/f8/c32a58d6e4dff8aa5c27
e907194d69f3b57e525c2e4af96f39c6e9c854d2/PyTweening-1.0.3.zip
Building wheels for collected packages: pytweening
Building wheel for pytweening (setup.py) ... done
Created wheel for pytweening: filename=PyTweening-1.0.3-cp37-none-any.whl size
=3821 sha256=6655c055d779982ff1259a5266bf1300c1cd02046e45e92cf18b20053a326531
Stored in directory: C:\Users\catafest\AppData\Local\pip\Cache\wheels\7b\92\30
\06e21159eed2709436bfb6d7c690959e578cf74f029643866e
Successfully built pytweening
Installing collected packages: pytweening
Successfully installed pytweening-1.0.3

Let's test it:

C:\Python373>python.exe
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD6
4)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pytweening
>>> dir(pytweening)
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__',
'__package__', '__path__', '__spec__', '__version__', '_checkRange', 'division',
 'easeInBack', 'easeInBounce', 'easeInCirc', 'easeInCubic', 'easeInElastic', 'ea
seInExpo', 'easeInOutBack', 'easeInOutBounce', 'easeInOutCirc', 'easeInOutCubic'
, 'easeInOutElastic', 'easeInOutExpo', 'easeInOutQuad', 'easeInOutQuart', 'easeI
nOutQuint', 'easeInOutSine', 'easeInQuad', 'easeInQuart', 'easeInQuint', 'easeIn
Sine', 'easeOutBack', 'easeOutBounce', 'easeOutCirc', 'easeOutCubic', 'easeOutEl
astic', 'easeOutExpo', 'easeOutQuad', 'easeOutQuart', 'easeOutQuint', 'easeOutSi
ne', 'getLine', 'getPointOnLine', 'linear', 'math']
>>> pytweening.linear(0.1)
0.1
>>> pytweening.easeInOutSine(0.1)
0.024471741852423234
>>> pytweening.easeInQuad(0.1)
0.010000000000000002
>>> pytweening.getLine(0, 0, 0.1, 0.1)
[(0, 0)]
>>> pytweening.getLine(0, 0, 1.1, 1.1)
[(0, 0), (1, 1)]

For example, this module can help with some math function:

• simple linear tweening - no easing, no acceleration;
• quadratic easing in/out - acceleration until halfway, then deceleration;
• cubic easing in/out - acceleration until halfway, then deceleration;
• quartic easing in/out - acceleration until halfway, then deceleration;
• sinusoidal easing in/out - accelerating until halfway, then decelerating;
• ...

Python 3.7.3 : Tonny I.D.E. for python programmers.

Today I tested the Thonny I.D.E. from thonny.org official webpage.
Yesterday I tried several editors for python programming language and did not work.
One of these is the spyder editor that does not work with python 3.7.3 - we have not discovered why.
The Mu is a simple Python editor for beginner programmers and has a strange working I.D.E. for good and fast development.
The PyCharm, it is developed by the Czech company JetBrains is not fully free ...

---

The Thonny I.D.E. is fast and comes with two good features:
Code completion and Highlights syntax errors.
The install steps are easy with a wizard application.
After that, you can test with any python source code.
The source code from the image is a simple example from this webpage.
Let's see a screenshot:

This is a video tutorial with this I.D.E. from Aivar Annamaa user:

Python 3.7.3 : Using the flask - part 002.

Let's see some tips for starting any project with flask python module.
Use these python modules to work with databases: flask-sqlalchemy and flask_marshmallow.
The Flask-SQLAlchemy is an extension for Flask that adds support for SQLAlchemy to your application.
The marshmallow is an ORM/ODM/framework-agnostic library for converting complex datatypes, such as objects, to and from native Python datatypes.
Let's install it:

C:\Python373>cd Scripts

C:\Python373\Scripts>pip install flask-sqlalchemy
Collecting flask_sqlalchemy
...
Successfully installed flask-sqlalchemy-2.4.0
C:\Python373\Scripts>pip install flask_marshmallow
Collecting flask_marshmallow
...
Successfully installed flask-marshmallow-0.10.1 marshmallow-2.19.5
C:\Python373\Scripts>pip install marshmallow-sqlalchemy
Collecting marshmallow-sqlalchemy
...
Successfully installed marshmallow-sqlalchemy-0.17.0

Use these python modules for login and authorization issues: flask-login
The Flask-Login provides user session management for Flask. It handles the common tasks of logging in, logging out, and remembering your users’ sessions over extended periods of time.
Flask-login doesn't actually have a user backend, it just handles the session machinery to help you to log in and logout users.
Flask-Login can work with user models that are based on any database system with four required items: is_authenticated, is_active, is_anonymous and get_id.
Let's install it:

C:\Python373\Scripts>pip install flask-login
Collecting flask-login
...
Successfully installed flask-login-0.4.1

This python module named python-dotenv let us to reads the key-value pair from .env file and adds them to an environment variable.

C:\Python373\Scripts>pip install python-dotenv
Collecting python-dotenv
...
Successfully installed python-dotenv-0.10.3

Flask-Login provides a UserMixin which makes it easy to create a user class, see example class User:

from flask_login import UserMixin
...
class User(UserMixin, db.Model):

Another tip is to use the get_or_404 and first_or_404 to avoid show errors on the webpage.
Reduce the passing of multiple variables to render_template, let's see the example:

from flask import render_template
...
return render_template('index.html', fn=name.first, ln=name.last, day=student.day, 
.... ')

This can de easy fix with this code to send value I want to pass:

context = {
'fn': name.first,
'ln': name.last,
'day': student.day,
...
}
return render_template('index.html', **context)

Use query to solve complex tasks.
Let's see a simple example of delete from a Student database class:

...
class Student(db.Model):
id=db.Column(db.Integer, primary_key=True)
...
country=db.Column(db.String(2))
...

Let's delete this with a query and return the number of deleted by delete_count:

del_ids= db.session.query(Student.id).filter(Student.country=='Ro')
delete_count=db.session.query(Student).filter(Student.id.in_(del_ids.subquery())).delete(synchronize_session=False)

I used two files in the main project named .env and .flaskenv:
The file .env comes with:

SQLALCHEMY_DATABASE_URI=sqlite:///db.sqlite3
SECRET_KEY = abcdef

The file .flaskenv has these lines of source code:

FLASK_ENV = development
FLASK_APP = my_flask_app

This can be used into a new file named settings.py:

import os 
SQLALCHEMY_DATABASE_URI = os.environ.get('SQLALCHEMY_DATABASE_URI')
SECRET_KEY = os.environ.get('SECRET_KEY')
SQLALCHEMY_TRACK_MODIFICATIONS = False

Using this the main flask application will start like this:

from flask import Flask
def create_my_app(config_file='settings.py'):
    app = Flask(__name__)
    app.config.from_pyfile(config_file)
    return app

There are plenty of tips and tricks that can be found based on the project in the bottle.
These are the most used.