Django-template-view

Django-template-view and M2M.py

m2m

class Post(models.Model):
    slug = models.SlugField(max_length=200, unique=True)
    likes = models.ManyToManyField(User, related_name='blogpost_like', blank=True)


post = get_object_or_404(Post, slug=slug)
if post.likes.filter(id=request.user.id).exists():
    post.likes.remove(request.user)
else:
    post.likes.add(request.user)
.....................................................................................

Group By >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.

q = Bank.objects.filter(status="no").values("month").annotate(duration_count=Count("duration"))
>> <QuerySet [
    {'month': 'may', 'duration_count': 1305}, 
    {'month': 'apr', 'duration_count': 237}, 
    {'month': 'aug', 'duration_count': 554}, 
    {'month': 'jan', 'duration_count': 132}, ...]

>> q.query.__str__()
>> 
SELECT month, COUNT(duration) AS `duration_count` 
FROM bank
WHERE status = no
GROUP BY month
ORDER BY NULL'


......................................................................................

select coalesce(age/id, 0) from bank;

`coalesce(age/id, 0)` --> will return default value if the calculation is null (divide by zero also gives Null)
age/null --> null
null/id --> null
id/null --> null

..........................................................................................

Round(1.732, 2) ---> 1.73

>> select Round(1.732, 2) from bank;

..........................................................................................
from django.db.models import Model, Count, Max, Min

Bank.objects.values("month").annotate(max_age=Max("age"), min_age=Min("age"))

>>
[{'month': 'may', 'max_age': 84, 'min_age': 20}, 
 {'month': 'apr', 'max_age': 80, 'min_age': 20}, 
 {'month': 'aug', 'max_age': 81, 'min_age': 21}, ...]

>>
SELECT month, MAX(age) AS `max_age`, MIN(age) AS `min_age`
FROM `bank` 
GROUP BY month 
ORDER BY NULL

...........................................................................................
Bank.objects.values("month").annotate(
    max_age=Max("age"), min_age=Min("age")
).filter(max_age__gt=70)
>>
SELECT month, MAX(age) AS `max_age`, MIN(age) AS `min_age` 
FROM bank 
GROUP BY month 
HAVING MAX(age) > 70 ORDER BY NULL
............................................................................................

Function Based View
------------------------------------------------------------------------------------------

from django.shortcuts import render, redirect, reverse
from django.views import View
from django.views.decorators.csrf import csrf_exempt
from django.utils.decorators import method_decorator
from django.contrib.auth.decorators import login_required


class UploadCsvPartsView(View):
    '''
       View that handles the upload csv feature of the admin interface.
    '''
    template_view = 'admin/base_upload_page.html'
    template_view_erros = 'admin/upload_page.html'
    insertion_method = 'insert_only'
    error_message = 'Errors were found, Please fix them.'

    @method_decorator([csrf_exempt, login_required])
    def dispatch(self, request, *args, **kwargs):
        return super().dispatch(request, *args, **kwargs)

    def get(self, request):
        """
        this method returns the rendered html for upload page
        """

        data = request.GET
        extra_params = dict()
        model_name = data['model_name']
        app_label = data['app_label']
        
        if not object_id and role not in [Utils.ROLE_CENTRAL_INV_MANAGER,
                                          Utils.ID_SUPERADMIN]:
            return HttpResponseForbidden()

        for key, value in data.items():
            if key not in ('model_name', 'app_label'):
                extra_params[key] = value
        return render(request, self.template_view, {'extra_params': extra_params,
                                                    'url_back': 'admin:%s_%s_changelist' % (app_label, model_name)})
      
       def post(self, request):
        '''
           This HTTP method gets the csv as a file object.
           It then created temp table to store the data with errors
           and other validation logic such as
           check if the file is not empty and there are some error free rows.
           It also returns a sample csv to download.
        '''
        data = request.POST
        model_name = data['model_name']
        app_label = data['app_label']
        
        if data.get('back'):
            try:
                obj.delete_temp_table(data['table'])
            except:
                pass
            return HttpResponseRedirect(
                reverse('admin:%s_%s_changelist' % (app_label, model_name)))
        
        
        else:
            print(request.path) // gives you the URL in Browser
            return render(request=request, 
                          template_name=self.template_view_erros,
                          context={'errors': errors, 'data': data, 'total': total_count,
                                   'url_back': 'admin:%s_%s_changelist' % (app_label, model_name),
                                   'url_save': reverse('save_upload_data')})

Now with some more Beauty
---------------------------------------------------------------------------------------------

from django.http import HttpRequest, HttpResponse
from django.shortcuts import redirect, render
from django.views.generic.base import TemplateView, View


class LogoutUserView(View):
    """GET requests to this view delete session data."""

    def get(self: View, request: HttpRequest) -> HttpResponse:
        """Logout a user, and delete their associated chatroom."""
        slug = request.session.get('slug')
        if slug:
            room = Room.objects.filter(slug=slug)
            if room is not None:
                room.delete()
            request.session.flush()
        return redirect('/')


class ChatRoomView(TemplateView):
    """Render a room if it exists, otherwise return a 404 page."""

    def get(self: View, request: HttpRequest, slug: str) -> HttpResponse:
        """Find a room that matches the provided slug."""
        room = Room.objects.filter(slug=slug).first()
        if room is not None:
            return render(request, 'room.html', context=dict(room=room))
        else:
            return render(request, '404.html', status=404, context=dict(room=slug))

          
 Similarly Api as Decent Look
 ===============================================================================
from django.http import HttpRequest, JsonResponse
from django.views.generic import View

from humanhash import humanize
  
  class RegisterUserView(View):
    """POST to this endpoint to register a user."""

    def post(self: View, request: HttpRequest) -> JsonResponse:
        """Create a user, provided the username."""
        try:
            payload = json.loads(request.body.decode())
        except json.JSONDecodeError:
            return error('You supplied incorrect data.')

        username = str(payload.get('username', ''))

        if request.session.get('registered'):
            return error('You are already registered.')

        if not 1 <= len(username) <= 100:
            return error('Username length must be between 1 and 100.')

        digest = uuid4().hex
        slug = humanize(digest)

        request.session['slug'] = slug
        request.session['registered'] = True
        request.session['username'] = username

        room = Room(uuid=digest, slug=slug)
        room.save()
        return JsonResponse({
            'success': True,
            'slug': slug
        })

 -------------------------------------------------------------------------------------------
 Updating the Only Fields that is really need to change
 
 if change:
        obj.updated_at = datetime.datetime.now()
        obj.updated_by = request.user.first_name
        obj.save(update_fields=['updated_at', 'updated_by'])