Python 3.7.5 : Django security issues - part 002.

The project can be found at this Github project.
Let's start with my default project and activate the env:

[mythcat@desk ~]$ cd projects/
[mythcat@desk projects]$ cd django/
[mythcat@desk django]$ source env/bin/activate

Let's install this python module:

(env) [mythcat@desk django]$ pip3 install django-axes --user

Make these changes into settings.py:

(env) [mythcat@desk django]$ cd mysite/
(env) [mythcat@desk mysite]$ ls
db.sqlite3  manage.py  mysite  test001
(env) [mythcat@desk mysite]$ cd mysite/
(env) [mythcat@desk mysite]$ vim settings.py 

Into your settings.py add axes:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'test001',
    'rest_framework',
    'axes'
] 

Add this source code in settings.py:

AUTHENTICATION_BACKENDS = [
    # AxesBackend should be the first backend in the AUTHENTICATION_BACKENDS list.
    'axes.backends.AxesBackend',

    # Django ModelBackend is the default authentication backend.
    'django.contrib.auth.backends.ModelBackend',
] 

Add axes.middleware.AxesMiddleware into MIDDLEWARE area:

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'axes.middleware.AxesMiddleware',
] 

Check the configuration with this command:

(env) [mythcat@desk mysite]$ cd ..
(env) [mythcat@desk mysite]$ python manage.py check
System check identified no issues (0 silenced).

Use this command to sync the database:

(env) [mythcat@desk mysite]$ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, axes, contenttypes, sessions, test001
Running migrations:
  Applying axes.0001_initial... OK
  Applying axes.0002_auto_20151217_2044... OK
  Applying axes.0003_auto_20160322_0929... OK
  Applying axes.0004_auto_20181024_1538... OK
  Applying axes.0005_remove_accessattempt_trusted... OK
  Applying axes.0006_remove_accesslog_trusted... OK

Once Axes is is installed and configured, you can login and logout of your application via the django.contrib.auth views.
This python package can be integrated with some popular 3rd party packages such as Django Allauth, Django REST Framework, and other tools.
I will come with additional information about this python package in the future.

Python 3.7.5 : Django security issues - part 001.

Django like any website development and framework implementation requires security settings and configurations.
Today I will present some aspects of this topic and then I will come back with other information.
1. First, check your security vulnerabilities by the following command:

[mythcat@desk django]$ source env/bin/activate
(env) [mythcat@desk django]$ cd mysite
(env) [mythcat@desk mysite]$ python3 manage.py check --deploy
...
  File "/home/mythcat/projects/django/mysite/mysite/settings.py", line 14
    <<<<<<< HEAD
     

This shows us the bad changes in source code, is added by GitHub features.
Let's run it again:

(env) [mythcat@desk mysite]$ python3 manage.py check --deploy
System check identified some issues:

WARNINGS:
?: (security.W004) You have not set a value for the SECURE_HSTS_SECONDS setting. 

If your entire site is served only over SSL, you may want to consider setting a value and 

enabling HTTP Strict Transport Security. Be sure to read the documentation first; enabling

 HSTS carelessly can cause serious, irreversible problems.
?: (security.W008) Your SECURE_SSL_REDIRECT setting is not set to True. Unless your site 

should be available over both SSL and non-SSL connections, you may want to either set this 

setting True or configure a load balancer or reverse-proxy server to redirect all connections to HTTPS.
?: (security.W012) SESSION_COOKIE_SECURE is not set to True. Using a secure-only session cookie makes 

it more difficult for network traffic sniffers to hijack user sessions.
?: (security.W016) You have 'django.middleware.csrf.CsrfViewMiddleware' in your MIDDLEWARE, but you have

 not set CSRF_COOKIE_SECURE to True. Using a secure-only CSRF cookie makes it more difficult for network

 traffic sniffers to steal the CSRF token.
?: (security.W018) You should not have DEBUG set to True in deployment.
?: (security.W020) ALLOWED_HOSTS must not be empty in deployment.
?: (security.W022) You have not set the SECURE_REFERRER_POLICY setting. Without this, your site 

will not send a Referrer-Policy header. You should consider enabling this header to protect user privacy.

System check identified 7 issues (0 silenced).

This output show us the security warnning problems.
2. Use the Observatory by Mozilla site to scan the security status of your Django website.
3. Django has built-in security against most forms of CSRF threats, but The CSRF protection cannot protect against man-in-the-middle attacks.
Use HTTPS with HTTP Strict Transport Security by add these lines in your settings.py file.

CSRF_COOKIE_SECURE = True #to avoid transmitting the CSRF cookie over HTTP accidentally.
SESSION_COOKIE_SECURE = True #to avoid transmitting the session cookie over HTTP accidentally.

4. A Cross-site Scripting (XSS) allows an attacker to inject a script into the content of a website or application.
In your settings.py use this:

django.middleware.security.SecurityMiddleware
...
SECURE_BROWSER_XSS_FILTER = True
SECURE_CONTENT_TYPE_NOSNIFF = True

5. You can create fake admin login page using django-admin-honeypot to attempt unauthorized access.
6. Use SSL Redirect on your settings.py file.

SECURE_SSL_REDIRECT = True

7. Add Content Security Policy (CSP) to your Django website with the installed django-csp, add following lines to your settings.py file:

# Content Security Policy
CSP_DEFAULT_SRC = ("'none'", )
CSP_STYLE_SRC = ("'self'", )
CSP_SCRIPT_SRC = ("'self'", )
CSP_IMG_SRC = ("'self'", )
CSP_FONT_SRC = ("'self'", )
# Google Tag Manager or Google Analytics should be allowed in your CSP policy. 
CSP_DEFAULT_SRC = ("'none'", )
CSP_STYLE_SRC = ("'self'", "fonts.googleapis.com", "'sha256-/3kWSXHts8LrwfemLzY9W0tOv5I4eLIhrf0pT8cU0WI='")
CSP_SCRIPT_SRC = ("'self'", "ajax.googleapis.com", "www.googletagmanager.com", "www.google-analytics.com")
CSP_IMG_SRC = ("'self'", "data:", "www.googletagmanager.com", "www.google-analytics.com")
CSP_FONT_SRC = ("'self'", "fonts.gstatic.com")
CSP_CONNECT_SRC = ("'self'", )
CSP_OBJECT_SRC = ("'none'", )
CSP_BASE_URI = ("'none'", )
CSP_FRAME_ANCESTORS = ("'none'", )
CSP_FORM_ACTION = ("'self'", )
CSP_INCLUDE_NONCE_IN = ('script-src',)

The HTTP Strict Transport Security can be set into your settings.py file:

SECURE_HSTS_SECONDS = 86400  # 1 day
SECURE_HSTS_INCLUDE_SUBDOMAINS = True
SECURE_HSTS_PRELOAD = True

8. Use records login attempts to your Django powered site and prevents attackers from brute forcing using the django-axes.
This tutorial solves most of the security issues of any website built with Django and not just related to this framework.

Python 3.7.5 : About asterisk operators in Python.

The asterisk known as the star operator is used in Python with more than one meaning attached to it.
Today I will show you some simple examples of how can be used.
Let's start with these issues.
You can merge two or more dictionaries by unpacking them in a new one:

>>> a = {'u': 1}
>>> b = {'v': 2}
>>> ab = {**a, **b, 'c':'d'}
>>> ab
{'u': 1, 'v': 2, 'c': 'd'}

Create multiple assignments:

>>> *x, y = 1, 2, 3, 4
>>> x
[1, 2, 3]

You can split into lists and generate sets:

>>> *a, = "Python"
>>> a
['P', 'y', 't', 'h', 'o', 'n']
>>> print(a)
['P', 'y', 't', 'h', 'o', 'n']
>>> *a,
('P', 'y', 't', 'h', 'o', 'n')
>>> zeros = (0,) * 8
>>> print(zeros)
(0, 0, 0, 0, 0, 0, 0, 0)

For numeric data types is used as multiplication operator:

>>> 2 * 3
6

You can use in mathematical function as an exponent:

>>> 3**2
9

You can create a sequences of strings using it like a repetition operator:

>>> t = 'Bye!'
>>> t * 4 
'Bye!Bye!Bye!Bye!'
>>> p = [0,1]
>>> p * 4 
[0, 1, 0, 1, 0, 1, 0, 1]
>>> r = (0,1)
>>> r * 4
(0, 1, 0, 1, 0, 1, 0, 1)

You can used into definition with arguments: *args and **kwargs:

def set_zero(*args):
    result = 0

The *args will give you all function parameters as a tuple.
The **kwargs will give you all keyword arguments except for those corresponding to a formal parameter as a dictionary.
See the PEP 3102 about Keyword-Only Arguments.

Python 3.7.5 : The this python package.

The this python package is simple to use:

[mythcat@desk ~]$ python3 
Python 3.7.5 (default, Dec 15 2019, 17:54:26) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

Python 3.7.5 : Post class and migration process.

Today I will solve some issues with the Django framework like:

• create a new class for posts;
• explain how the migration process works.
• use the database with Django shell;

Let's activate the environment:

[mythcat@desk django]$ source env/bin/activate

I used my old project django-chart, see my old tutorials.
Let's add some source code to the models.py to create a class for the post into my website:

...
# Post data 
from django.utils import timezone
from django.contrib.auth.models import User
...
#create a post
class Post(models.Model):
  title = models.CharField(max_length = 100)
  content = models.TextField()
  date_posted = models.DateTimeField(default = timezone.now)
  #if the user is deleted their posts is deleted 
  author = models.ForeignKey(User, on_delete = models.CASCADE)

Let's use the migration process to update the database:

(env) [mythcat@desk django]$ cd mysite/
(env) [mythcat@desk mysite]$ python3 manage.py makemigrations
Migrations for 'test001':
  test001/migrations/0003_post.py
  - Create model Post

Before to run the migrate command I will show what happened with this migration output from SQL view.
This is great to solve issues and see the exact SQL code generated.
I have in the output of command makemigrations the application name test001 and the migration number 0003.
I will use all of this information output to show how you can see the SQL code:

(env) [mythcat@desk mysite]$ python3 manage.py sqlmigrate test001 0003
BEGIN;
--
-- Create model Post
--
CREATE TABLE "test001_post" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, 
"title" varchar(100) NOT NULL, "content" text NOT NULL, "date_posted" datetime NOT NULL, 
"author_id" integer NOT NULL REFERENCES "auth_user" ("id") DEFERRABLE INITIALLY DEFERRED);
CREATE INDEX "test001_post_author_id_fed29ee6" ON "test001_post" ("author_id");
COMMIT;

This print SQL code that it's going to run when I will use the next command:

(env) [mythcat@desk mysite]$ python3 manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions, test001
Running migrations:
  Applying test001.0003_post... OK

The migration process solves issues linked to changes in the database.
Let's use the Django shell to see the User changes into the database:

(env) [mythcat@desk mysite]$ python3 manage.py shell
Python 3.7.5 (default, Dec 15 2019, 17:54:26) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from test001.models import Post
>>> from django.contrib.auth.models import User
>>> User.objects.all()
...
>>> User.objects.first()
...
>>> User.objects.filter(username='catalin')
...
>>> User.objects.filter(username='catalin').first()
...
>>> user = User.objects.filter(username='catalin').first()
>>> user
...
>>> user.id
1
>>> user.pk
1
>>> Post.objects.all()
...

Let's add a post to the database and show it:

>>> post_1=Post(title='First title', content='The first content!',author=user)
>>> post_1.save()
>>> Post.objects.all()
...

I can see the posts and information about the user with the Django shell.

>>> post = Post.objects.first()
>>> post.content
'The first content!'
>>> post.date_posted
...
>>> post.author
...
>>> post.author.email
...
>>> user.post_set.all()
...

You need to add to views.py the new model changes:

...
from .models import Post
...
def posts(request):
  context = {
  'posts':Post.objects.all()
  }
  return render(request, 'test001/posts.html', context)
...

Into the templates folder, I created the file named posts.html to load the data to HTML5.

{% extends 'base.html' %}
{% block content %}
  {% for post in posts %}
  <article>
  <div>{{ post.title }}</div>
  <div>{{ post.content }}</div>
  <div>{{ post.author }}</div>
  <div>{{ post.date_posted|date:"F d, Y" }}</div>
  </article>
  {% endfor %}
{% endblock content %}

To see these changes into the website I add the route to this HTML5 file posts.html into urls.py file:

app_name = 'test001'
urlpatterns = [
...
    path('posts/',posts, name = 'posts'),
...
]

Now I can run the server and see the output from the database into posts URL.

(env) [mythcat@desk mysite]$ python3 manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
January 06, 2020 - 17:52:29
Django version 3.0.1, using settings 'mysite.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
...

This is the output of my running server...

Python 3.7.5 : Set json with settings in Django project.

[mythcat@desk django]$ source env/bin/activate
(env) [mythcat@desk django]$ cd mysite/
(env) [mythcat@desk mysite]$ ls
db.sqlite3  manage.py  mysite  test001
(env) [mythcat@desk mysite]$ pwd
/home/mythcat/projects/django/mysite

Create a file named config.json in the folder django:

(env) [mythcat@desk mysite]$ vim /home/mythcat/projects/django/config.json

Open your settings.py file from your Django project and copy your secret key from this file to config.json, see:

{ 
  "SECRET_KEY":"your_secret_key_from_settings.py"
}

Change your settings.py file with these changes:

...
import json 
...
with open('/home/mythcat/projects/django/config.json') as config_file:
    config = json.load(config_file)
...
# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = config['SECRET_KEY']

This allows us to get the SECRET_KEY from the config.json file.
We can add many variables into file config.json, like EMAIL_USER and EMAIL_PASS.
You need to have a validate JSON file and the settings.py will change from this:

EMAIL_HOST_USER = os.environ.get('EMAIL_USER')
...

to this source code for EMAIL_USER variable:

EMAIL_HOST_USER = config.get('EMAIL_USER')
...

Python 3.7.5 : Testing cryptography python package - part 001.

There are many python packets that present themselves as useful encryption and decryption solutions. I recommend before you test them, use them and spend time with them to focus on the correct study of cryptology because many disadvantages and problems can arise in the correct and safe writing of the source code.
Today I will show you a simple example with cryptography python package.
Let's install this with pip3 tool:

[mythcat@desk projects]$ pip3 install cryptography --user

You can read more about this python package on the documentation website.
Let's try a simple method of encryption and decryption.
I will show you how to solve this issue with the class cryptography.hazmat.primitives.ciphers.aead.AESGCM:
The AES-GCM construction is composed of the AES block cipher utilizing Galois Counter Mode (GCM).
The GCM (Galois Counter Mode) is a mode of operation for block ciphers.
An AEAD (authenticated encryption with additional data) mode is a type
of block cipher mode that simultaneously encrypts the message as well as authenticating it.
The Value of AESGCM key must be 128, 192, or 256 bits, see the size of the key:

[mythcat@desk projects]$ python3
Python 3.7.5 (default, Dec 15 2019, 17:54:26) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> from cryptography.hazmat.primitives.ciphers.aead import AESGCM
>>> aad = None
>>> key = 'catafestcatafestcatafestcatafest'
>>> aesgcm = AESGCM(key.encode('utf-8'))
>>> nonce = '12345678'
>>> data_binary = b'Hello world!'
>>> 
>>> cipher_text = aesgcm.encrypt(nonce.encode('utf-8'), data_binary, aad)
>>> print(cipher_text)
b'0\xab\xd2!mXe\xc3/\xdb\x15\xcaoT\x0f\x1d\xbb&\xc4\x92\xdf\\ZTMD\xa2\x9f'
>>> data_text = aesgcm.decrypt(nonce.encode('utf-8'), cipher_text, aad)
>>> print(data_text)
b'Hello world!'

Python 3.7.5 : Testing the PyMongo package - part 001.

MongoDB and PyMongo are not my priorities for the new year 2020 but because they are quite evolved I thought to start presenting it within my free time.
The PyMongo python package is a Python distribution containing tools for working with MongoDB.
The full documentation can be found on this webpage.
You can see my tutorial about how to install the MongoDB into Fedora 31 on this webpage.
I used that webpage install to test this python package, see the result:

[mythcat@desk mongo_test]$ mongo
...
MongoDB server version: 4.2.2-rc1
> use admin 
switched to db admin
> show dbs
> db.auth('admin', 'admin')
1
> show dbs
admin   0.000GB
config  0.000GB
local   0.000GB

Let's install it with pip3 tool:

[mythcat@desk projects]$ pip3 install pymongo --user
Collecting pymongo
...
Successfully installed pymongo-3.10.0

Let's start with a simple example:

[mythcat@desk projects]$ mkdir mongo_test
[mythcat@desk projects]$ cd mongo_test/
[mythcat@desk mongo_test]$ vim mongo001.py

If you have already created the admin user, to run the next spython script you need to change the role like this:

> use admin;
switched to db admin
> db.grantRolesToUser('admin', [{ role: 'root', db: 'admin' }])

The script show you how to use a simple connection to the MongoDB:

import pymongo
from pymongo import MongoClient, errors

MONGO_URI = 'mongodb://admin:admin767779@127.0.0.1:27017/admin'
client = pymongo.MongoClient(MONGO_URI)
print("Server info : ")
print(client.server_info())
print("Databases : " + str(client.list_database_names()))
print("Connect to : admin database!")
db = client['admin']
db2 = client.config
print(db)
print(db2)
print("Collection admin : ")
collection = db['admin']
collection2 = db.config
print(collection)
print(collection2)
print("try call find_one method")
try:
    one_doc= collection2.find_one()
    print ("find_one():", one_doc)
except errors.ServerSelectionTimeoutError as err:
    print ("find_one() ERROR:", err)

print("Client close!")
client.close()

The output is this:

[mythcat@desk mongo_test]$ python3 mongo001.py 
Server info : 
{'version': '4.2.2-rc1', 'gitVersion': 'a0bbbff6ada159e19298d37946ac8dc4b497eadf', 'modules': [],
 'allocator': 'tcmalloc', 'javascriptEngine': 'mozjs', 'sysInfo': 'deprecated', 'versionArray': [4, 2, 2, -49],
 'openssl': {'running': 'OpenSSL 1.1.1d FIPS  10 Sep 2019', 'compiled': 'OpenSSL 1.1.1 FIPS  11 Sep 2018'},
 'buildEnvironment': {'distmod': 'rhel80', 'distarch': 'x86_64', 'cc': '/opt/mongodbtoolchain/v3/bin/gcc:
 gcc (GCC) 8.2.0', 'ccflags': '-fno-omit-frame-pointer -fno-strict-aliasing -ggdb -pthread -Wall -Wsign-compare
 -Wno-unknown-pragmas -Winvalid-pch -Werror -O2 -Wno-unused-local-typedefs -Wno-unused-function
 -Wno-deprecated-declarations -Wno-unused-const-variable -Wno-unused-but-set-variable
 -Wno-missing-braces -fstack-protector-strong -fno-builtin-memcmp', 'cxx': '/opt/mongodbtoolchain/v3/bin/g++:
 g++ (GCC) 8.2.0', 'cxxflags': '-Woverloaded-virtual -Wno-maybe-uninitialized -fsized-deallocation -std=c++17',
 'linkflags': '-pthread -Wl,-z,now -rdynamic -Wl,--fatal-warnings -fstack-protector-strong -fuse-ld=gold -Wl,
--build-id -Wl,--hash-style=gnu -Wl,-z,noexecstack -Wl,--warn-execstack -Wl,-z,relro', 'target_arch':
 'x86_64', 'target_os': 'linux'}, 'bits': 64, 'debug': False, 'maxBsonObjectSize': 16777216, 'storageEngines':
 ['biggie', 'devnull', 'ephemeralForTest', 'wiredTiger'], 'ok': 1.0}
Databases : ['admin', 'config', 'local']
Connect to : admin database!
Database(MongoClient(host=['127.0.0.1:27017'], document_class=dict, tz_aware=False, connect=True), 'admin')
Database(MongoClient(host=['127.0.0.1:27017'], document_class=dict, tz_aware=False, connect=True), 'config')
Collection admin : 
Collection(Database(MongoClient(host=['127.0.0.1:27017'], document_class=dict, tz_aware=False, connect=True),
 'admin'), 'admin')
Collection(Database(MongoClient(host=['127.0.0.1:27017'], document_class=dict, tz_aware=False, connect=True),
 'admin'), 'config')
try call find_one method
find_one(): None
Client close!

Python 3.7.5 : Testing the Falcon framework - part 001.

I start the new year with this python framework named Falcon.
The Falcon is a low-level, high-performance Python framework for building HTTP APIs, app backends, and higher-level frameworks.
The main reason was the speed of this python framework, see this article about falcon benchmark.
You can see is more faster like Flask and Django.
The instalation is easy with pip tool, you can read also the documenation webpage:

[mythcat@desk projects]$ mkdir falcon_test
[mythcat@desk projects]$ cd falcon_test/
[mythcat@desk falcon_test]$ pip3 install falcon --user
Collecting falcon
...
Successfully installed falcon-2.0.0

Falcon also fully supports CPython 2.7 and 3.5+.
If you want to install the latest beta or release candidate use:

[mythcat@desk falcon_test]$ pip3 install --pre falcon --user

The Falcon framework is easy to use.
First, I created a folder named test001 for my falcon application script named app.py:

[mythcat@desk falcon_test]$ mkdir test001
[mythcat@desk falcon_test]$ cd test001/
[mythcat@desk test001]$ vim app.py

In this python script I used python packages json and falcon with a class named req_class:

import json
import falcon

class req_class:
    def on_get(self,req,resp):
        print("on_get class")
my_falcon_api = falcon.API()
my_falcon_api.add_route('/test',req_class())

The url route is set to test.
To test the falcon framework we need the Gunicorn python package.
The Gunicorn is working on my Fedora Linux distro and I'm not sure if working Gunicorn on Windows.
You can try on Windows O.S. the waitress python package.

[mythcat@desk falcon_test]$ pip3 install gunicorn --user
Collecting gunicorn
...
Successfully installed gunicorn-20.0.4

To test this simple Falcon application use this command line where the app python script and my falcon variable A.P.I. named my_falcon_api is used.

[mythcat@desk test001]$ gunicorn app:my_falcon_api
[2020-01-02 18:57:48 +0200] [4401] [INFO] Starting gunicorn 20.0.4
[2020-01-02 18:57:48 +0200] [4401] [INFO] Listening at: http://127.0.0.1:8000 (4401)
[2020-01-02 18:57:48 +0200] [4401] [INFO] Using worker: sync
[2020-01-02 18:57:48 +0200] [4404] [INFO] Booting worker with pid: 4404
on_get class
on_get class

Open in the browser this URL with the route I set: http://127.0.0.1:8000/test.
You will don't see anything in the browser but will see the python output of the print function for my request.

News : The Python 2.7 no longer support from Python team.

The 1st of January 2020 will mark the sunset of Python 2.7.
It’s clear that Python 3 is more popular these days.
You can learn more about the popularity of both on Google Trends.
Python 3.0 was released in December 2008.
The main goal was to fix problems existing in Python 2.
Since the 1st January 2020, Python 2 will no longer receive any support whatsoever from the core Python team.
Migrating to Python 3 is recommended, including some of the top libraries, such as machine learning.

Python 3.7.5 : Fix to python language the GitHub project.

I created a GitHub project with Django and I saw is detect like tcl programming language:

You need to create a file named .gitattributes in the root folder of my repository.
Use this source code to tell GitHub is a python project:

* linguist-vendored
*.py linguist-vendored=false

Now the project will be target with python language.

Python 3.7.5 : Is Django the best web framework?

This is the question for today in order to lineup the Django features with any web framework from my point of view.
Let's start with a brief introduction to this framework:
Django was created in the fall of 2003, when the web programmers at the Lawrence Journal-World newspaper, Adrian Holovaty and Simon Willison, began using Python to build applications. Jacob Kaplan-Moss was hired early in Django’s development shortly before Simon Willison's internship ended.[16] It was released publicly under a BSD license in July 2005. The framework was named after guitarist Django Reinhardt.[17], see wikipedia.
The Python which is a high-level programming language interpreted with general-purpose and together with the Django web framework creates a solution in fulfilling the objectives of web programming.
The problem of most of those who do not know closely the programming of this framework remains unknown and can be difficult to understand only from examples and tutorials.
Here are some of the difficulties that I personally encountered and had to solve them step by step.

1. understand how to use the link system between the python files created by Django;
2. how to use the templates and how to update them with the Django specific syntax;
3. understanding the way of displaying and resolving specific errors in Django;
4. using and setting the settings.py file;
5. understanding of how the web framework interacts with web technologies;

After solving these problems you will see the true power of this framework:

1. the development is easier with good and lower development costs and so are the additions and upgrades;
2. security is very good, see security documentation and deployment checklist;
3. is an open-source framework and updated by developers who use it;
4. most used and crowd tested and used to develop DropBox, Quora, Google, and Reddit;
5. comes with extensive documentation;
6. a large and community;

The official page of this web framework can be found on this webpage.

Python 3.7.5 : About Django REST framework.

First, let's activate my Python virtual environment:

[mythcat@desk django]$ source env/bin/activate

I update my django version 3.0 up to 3.0.1.

(env) [mythcat@desk django]$ pip3 install --upgrade django --user
Collecting django
...
      Successfully uninstalled Django-3.0
Successfully installed django-3.0.1

The next step comes with installation of Python modules for Django and Django REST:

(env) [mythcat@desk django]$ pip3 install djangorestframework --user
Collecting djangorestframework
...
Installing collected packages: djangorestframework
Successfully installed djangorestframework-3.11.0

Into my folder mysite I run this commands

(env) [mythcat@desk django]$ cd mysite/
(env) [mythcat@desk mysite]$ python3 manage.py makemigrations
No changes detected
(env) [mythcat@desk mysite]$ python3 manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions, test001
Running migrations:
  No migrations to apply.

To pass information over to an HTTP GET request, the information object must be translated into valid response data.
The Django implements serializers for this.
Serializers provide deserialization, allowing parsed data to be converted back into complex types and allow complex data such as querysets and model instances to be converted to native Python datatypes that can then be easily rendered into JSON, XML or other content types.
Let's create the mysite/serializers.py:

(env) [mythcat@desk mysite]$ cd mysite/
(env) [mythcat@desk mysite]$ vim serializers.py 

The code for this python script is this:

from django.contrib.auth.models import User, Group
from rest_framework import serializers

class UserSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = User
        fields = ['url', 'username', 'email', 'groups']

class GroupSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Group
        fields = ['url', 'name']

The next changes will be on urls.py and views.py.
My urls.py file from the Django-chart project is this:

from django.contrib import admin
from django.urls import path
from test001.views import home_page
from test001.views import Test001ChartView
#
from django.urls import include, path
from rest_framework import routers
from test001 import views

router = routers.DefaultRouter()
router.register(r'users', views.UserViewSet)
router.register(r'groups', views.GroupViewSet)

app_name = 'test001'
urlpatterns = [
    path('admin/', admin.site.urls),
    #path('', home_page, name ='home'),
    path('', Test001ChartView.as_view(), name = 'home'), 
    # Use automatic URL routing
    # Can also include login URLs for the browsable API
    path('', include(router.urls)),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

My views.py file is this:

from django.http import HttpResponse
from django.shortcuts import render
# snippet 
from django.shortcuts import get_object_or_404
# for chart 
from django.views.generic import TemplateView
from .models import Test001, Snippet
#
#def home_page(request):
#    return HttpResponse('Home page!')

# django framework
from django.contrib.auth.models import User, Group
from rest_framework import viewsets
from mysite.serializers import UserSerializer, GroupSerializer

def home_page(request):
    return render(request, 'test001/home.html',{
        'name':'CGF',
        'html_items': ['a','b','c','d','e']
    })


# define view for chart 
class Test001ChartView(TemplateView):
    template_name = 'test001/chart.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["qs"] = Test001.objects.all()
        return context


def snippet_detail(request, id):
    snippet = get_object_or_404(Snippet, id=id)
    return render(request, 'test001/snippets_detail.html', {'snippet': snippet})

class UserViewSet(viewsets.ModelViewSet):
    """
    API endpoint  allows users to be viewed or edited.
    """
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer

class GroupViewSet(viewsets.ModelViewSet):
    """
    API endpoint  allows groups to be viewed or edited.
    """
    queryset = Group.objects.all()
    serializer_class = GroupSerializer

The settings module for this my project is stored in mysite/settings.py and I add this:

INSTALLED_APPS = [
    ...
    'rest_framework',
]

I run the django project and works well:

python3 manage.py runserver

The http://127.0.0.1:8000/users/ page come with this output: