analitics

Pages

Saturday, December 28, 2019

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.

Tuesday, December 24, 2019

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.

Monday, December 23, 2019

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:


Sunday, December 22, 2019

Python 3.7.5 : The new PyQt5 released.

The PyQt v5.14.0 has been released with support for Qt v5.14.0.
[mythcat@desk ~]$ pip3 install --upgrade PyQt5 --user
Collecting PyQt5
...
Installing collected packages: PyQt5-sip, PyQt5
Successfully installed PyQt5-5.14.0 PyQt5-sip-12.7.0
Let's see how can see the version:
[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.
>>> from PyQt5.Qt import PYQT_VERSION_STR
>>> print("PyQt version:", PYQT_VERSION_STR)
PyQt version: 5.14.0


Saturday, December 21, 2019

Python 3.7.5 : Simple web search with google python package.

This is a simple search on the web with python google package.
[mythcat@desk ~]$ pip3 install google --user
Collecting google
...
Installing collected packages: google
Successfully installed google-2.0.3
This is a simple example for search on web with this words: protv news 2019.
From the python package, I need to import just the search and used it.
The python package need a variable string named query.
The search wants to know the words from query and arguments, see the help:
Help on function search in module googlesearch:

search(query, tld='com', lang='en', tbs='0', safe='off', num=10, start=0, stop=None, 
domains=None, pause=2.0, tpe='', country='', extra_params=None, user_agent=None)
    Search the given query string using Google.
    
    :param str query: Query string. Must NOT be url-encoded.
    :param str tld: Top level domain.
    :param str lang: Language.
    :param str tbs: Time limits (i.e "qdr:h" => last hour,
        "qdr:d" => last 24 hours, "qdr:m" => last month).
    :param str safe: Safe search.
    :param int num: Number of results per page.
    :param int start: First result to retrieve.
    :param int stop: Last result to retrieve.
        Use None to keep searching forever.
    :param list domains: A list of web domains to constrain
        the search.
    :param float pause: Lapse to wait between HTTP requests.
        A lapse too long will make the search slow, but a lapse too short may
        cause Google to block your IP. Your mileage may vary!
    :param str tpe: Search type (images, videos, news, shopping, books, apps)
        Use the following values {videos: 'vid', images: 'isch',
        news: 'nws', shopping: 'shop', books: 'bks', applications: 'app'}
    :param str country: Country or region to focus the search on. Similar to
        changing the TLD, but does not yield exactly the same results.
        Only Google knows why...
    :param dict extra_params: A dictionary of extra HTTP GET
        parameters, which must be URL encoded. For example if you don't want
        Google to filter similar results you can set the extra_params to
        {'filter': '0'} which will append '&filter=0' to every query.
    :param str user_agent: User agent for the HTTP requests.
        Use None for the default.
    
    :rtype: generator of str
    :return: Generator (iterator) that yields found URLs.
        If the stop parameter is None the iterator will loop forever.
This is the script:
[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.
>>> from googlesearch import search
>>> query = "protv news 2019"
>>> my_results_list = []
>>> for url in search(query,        
...     tld = 'com',  
...     lang = 'en',       
...     num = 10,     
...     start = 0,    
...     stop = None,  
...     pause = 2.0,):
...     my_results_list.append(url)
...     print(url)
... 
https://stirileprotv.ro/protvnews/
https://stirileprotv.ro/
https://stirileprotv.ro/superbun/protv-news.html
https://www.facebook.com/ProTvNews/
https://www.youtube.com/playlist?list=PLCJaU-QvLGR_FSZw6yeqBJHDe9LgFDRdy
https://www.youtube.com/watch?v=HaiQtDlaNic
https://www.youtube.com/watch?v=hxMEgAANSl4
https://www.youtube.com/channel/UCbbDChpDluLkdnH8QMwN6qA
https://www.youtube.com/watch?v=5zuN9uWFcTE
https://protvplus.ro/tv-live/1-pro-tv
https://en.wikipedia.org/wiki/Pro_TV
https://pro-tv.com/news/page/2/
https://m.youtube.cat/channel/UCbbDChpDluLkdnH8QMwN6qA
...

Sunday, December 15, 2019

Python 3.7.5 : Simple intro in CSRF.

CSRF or Cross-Site Request Forgery is a technique used by cyber-criminals to force users into executing unwanted actions on a web application.
To protect against web form CSRF attacks, it's isn't sufficient for web applications to trust authenticated users, must be equipped with a unique identifier called a CSRF token similar to a session identifier.
Django 3.0 can be used with CSRF, see the documentation page.
The CSRF process is a simple one in Django framework.
However, it's highly recommended to use the CsrfViewMiddleware instead.
To activate the django.middleware.csrf.CsrfViewMiddleware in the settings.py file.
Basically, you can use the decorator method in the view.py file.
For example, see documentation:
@csrf_protect
However csrf_protect will check only POST requests.
This annotation CSRF tells Django I'm not handling CSRF properly and don't fail this.
If I don't use this annotation then the CSRF is on if the post request is on by default and I will receive a 403 error.
As the developer using templates you don't have to know anything about that and you can use this in your template HTML5 file.
{% csrf_token %}
I can use the token with my code if I want to send it to the website.
from django.middleware.csrf import get_token
Then this can be used in view.py with a hidden form field with the name csrfmiddlewaretoken present in all outgoing POST forms.
You can used in any forms tag area like: input ...

def my_csrf_form(request):
    response = """ ... type = "hidden" name = "csrfmiddlewaretoken" value = "__token__" ... """
This can be used with:
token = get_token(request)
response = response.replace('__token__', html.escape(token))
response += dumpdata('POST', request.POST)
return HttpResponse(response)
This will get a token for the current request and fill into value = "__token__".
Using my old example from GitHub.
First, I start the project:

[mythcat@desk projects]$ source django/env/bin/activate
(env) [mythcat@desk projects]$ ls
cache  django  kaggle  logs  OSMnx  pygal_ex  SantaClaus.py
(env) [mythcat@desk projects]$ cd django/
(env) [mythcat@desk django]$ ls
env  mysite  venv
(env) [mythcat@desk django]$ cd mysite/
I change the chart.html file with this before javascript script:
... {% csrf_token %} ... 
You can use it in javascript - jQuery like this, if you want:
var csrftoken = jQuery("[name=csrfmiddlewaretoken]").val();
The CSRF protection on Django on my form can bu used in view.py:
...
# use csrf_protect
from django.views.decorators.csrf import csrf_protect
from django.utils.decorators import method_decorator
...
# define view for chart 
class Test001ChartView(TemplateView):
    csrf_protected_method = method_decorator(csrf_protect)
I test it and works well.
The documentation tells us:
The CSRF protection cannot protect against man-in-the-middle attacks, so use HTTPS with HTTP Strict Transport Security. It also assumes validation of the HOST header and that there aren’t any cross-site scripting vulnerabilities on your site (because XSS vulnerabilities already let an attacker do anything a CSRF vulnerability allows and much worse).