Beginner Django: Authenticating/logging in a User - python

Hello! I'm having trouble with the authentication system. I've followed the documentation pretty closely, but I just can't seem to get this to work. The problem seems to be that when I call the authenticate method with my cleaned form data, it's not returning anything. It's clearly doing this in the web page (it just returns the render request at the bottom every time I submit the form), and I tried authenticating in the same way via the shell and am also returning True for 'user is None'.
I'm wondering if perhaps the problem is that I haven't included the proper middleware? My MIDDLEWARE_CLASSES are as follows:
MIDDLEWARE_CLASSES = (
'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',
)
It appears that I have everything necessary, but I'm just not sure.
In any case, here's the code for my view:
from django.shortcuts import render
from django.http import HttpResponseRedirect, HttpResponse
from django.contrib.auth.models import User
from django.contrib.auth.forms import AuthenticationForm
from django.contrib.auth import authenticate, login
def user_login(request):
if request.method == 'POST':
form = AuthenticationForm(request.POST)
if form.is_valid():
username = form.cleaned_data['username']
password = form.cleaned_data['password']
user = authenticate(username=username, password=password)
if user is not None:
if user.is_active:
login(request, user)
return HttpResponse("Good Job")
else:
return HttpResponse("Inactive User")
else:
return HttpResponse("Bad Job")
else:
form = AuthenticationForm()
return render(request, 'myapp/login_form.html', {
'form': form,
})
And here is my very simple login_form.html template:
<h1>Login</h1>
<form action="/login/" method="post">{% csrf_token %}
{{ form.as_p }}
<input type="submit" value="Submit" />
</form>
UPDATE: I have implemented the following solution:
changed the line
form = AuthenticationForm(request.POST)
to
form = AuthenticationForm(data = request.POST)
Now I am able to login via the superuser account, but username/password combinations for ordinary accounts are not recognized. If I submit the credentials for a regular user, the form is re-rendered plus the following message:
Please enter a correct username and password. Note that both fields may be case-sensitive.
Any ideas?
UPDATE 2
It turns out I had an error in my registration form such that it wasn't properly storing the password for new users registered via that form. I was doing password assignment in the constructor for a new User object, when instead you need to:
User.objects.create_user('username', 'email', 'password')
Rookie mistake! Thanks for the help.

Try form = AuthenticationForm(data = request.POST)
From the django git for AuthenticationForm:
def __init__(self, request=None, *args, **kwargs):
"""The 'request' parameter is set for custom auth use by subclasses.
The form data comes in via the standard 'data' kwarg.`
"""

Related

Is it possible to override LoginView in function based views, not as a class?

I understand that in order to override from django.contrib.auth.views.LoginView one has to use a subclass Class(LoginView) in views.py.
However, in my views.py I only have views declared with def my_view(request)
In old versions of Django I could just do
from django.contrib.auth.views import login, logout
def login_user(request):
result = login(request=request, template_name='Market/pages/login.html')
return result
What's the modern Django equivalent of this? The documentation has this example, that forces me rewrite the whole username/password logic into my view:
from django.contrib.auth import authenticate, login
def my_view(request):
username = request.POST['username']
password = request.POST['password']
user = authenticate(request, username=username, password=password)
if user is not None:
login(request, user)
# Redirect to a success page.
...
else:
# Return an 'invalid login' error message.
...
How can I use a view function (not class!) and still have the automatic managing of the submitted request?
You're missing the point. The reason behind the move to class-based views is that they are more configurable than function-based ones.
In this case, you don't even need to define your own view to get the result you want; you can just do it in the URL:
path('login/', views.LoginView.as_view(template_name='Market/pages/login.html'), name='login')

How to get logged in username in views.py in django

Actually i'am very new to django and python. In /templates/home.html, added {{ user.username }} it's showing currently logged in username
<p>Welcome {{ user.username }} !!!</p>
I want to get currently logged in username in views.py file. How to get username?
i tried different way but i am not get the result
user = User.objects.get(username=request.user.username)
username = request.GET['username']
def sample_view(request):
current_user = request.user
print(current_user)
Please tell me, How to achieve my result.
my views.py look like this. is there any problem on my views.py
#!python
#log/views.py
from django.shortcuts import render
from django.contrib.auth.decorators import login_required
from django.template import Context
from contextlib import contextmanager
# Create your views here.
# this login required decorator is to not allow to any
# view without authenticating
#login_required(login_url="login/")
def home(request):
return render(request,"home.html")
#dummy_user = {{ username }}
#user = User.objects.get(username=request.user.username)
#username = request.GET['username']
#print(usernam
#user = request.user
#print(user)
def sample_view(request):
current_user = {}
#current_user['loggeduser'] = request.user
#or
current_user['loggeduser'] = request.user.username
return render(request,"home.html",current_user)
# print(current_user.id)
Provided that you have enabled the authentication middleware, you don't need to do any of this. The fact that the username shows up in your template indicates that you have enabled it. Each view has access to a request.user that is an instance of a User model. So the following is very much redundant
user = User.objects.get(username=request.user.username)
Because you already have request.user.username!! if you wanted to find the user's email, you do request.user.email Or just do
user = request.user
and use the newly created variable (eg user.username)
Reference: https://docs.djangoproject.com/en/1.10/ref/request-response/#django.http.HttpRequest.user
From the AuthenticationMiddleware: An instance of AUTH_USER_MODEL
representing the currently logged-in user. If the user isn’t currently
logged in, user will be set to an instance of AnonymousUser. You can
tell them apart with is_authenticated, like so:

Best way to display invalid login details message--django forms

I want to display an error message to users along the lines of 'invalid username or password, please try again' for a login form in django if authentication fails, but im not sure what the best way to go about doing this is.
I've considered setting a context variable which will be passed into a template and then I could use CSS to present the message with the form. Something like below:
if user is not None:
if user.is_active:
# Redirect to a success page.
else:
# Return a 'disabled account' error message
else:
form = LoginForm()
incorrect_login = True
context = ('incorrect_login': incorrect_login, 'form':form)
return render(request, 'home/home.html', context)
# Return an 'invalid login' error message.
And the html:
<form action="." method="POST"> {%csrf_token%}
{%if incorrect_login%}
<table class='failed_login'>
{{form.as_table}}
</table>
{%else%}
<table class='successful_login'>
{{form.as_table}}
</table>
{%endif%}
<p><input type='submit' value='Submit'></p>
</form>
<!--Dont worry about the exact implementation of the html, its the basic idea im concerned with-->
However, I feel like this is a common problem and thus there is likely a better solution provided by django within the forms. I've looked into the docs on working with forms but im not sure how to approach, the main problem being that the errors stored in the form fields seem more about validating input type. Any help or a point in the right direction would be appreciated.
Django comes with built in authentication views, including one to log in. You should think about using the login view, or at least look at the code to see how it works.
One key thing is that a blank form is only created for GET requests. The problem in your view is that you always create a new form with form = LoginForm() when user is None. That means that the errors from the bound form (form = LoginForm(request.POST)) are not shown to the user.
Im going to share this approach with you, maybe it could help :
Views.py
from django.shortcuts import render, get_object_or_404
from django.http import HttpResponseRedirect
from django.views.generic import View
from django.core.urlresolvers import reverse
from django.contrib import messages
from django.contrib.auth import login, authenticate, logout
from ..form import UsersForm
class LoginView(View):
template_name = ['yourappname/login.html', 'yourappname/home.html']
def get(self, request, *args, **kwargs):
form = UsersForm()
if request.user.is_authenticated():
return render(request, self.template_name[1], t)
return render(request, self.template_name[0], t)
def post(self, request, *args, **kwargs):
username = request.POST['username']
password = request.POST['password']
user = authenticate(username = username, password = password)
if user is not None:
login(request, user)
if user.is_active:
return render(request, self.template_name[ 1 ])
else:
messages.add_message(
request, messages.ERROR, "Incorrect user or password"
)
return HttpResponseRedirect(reverse( 'yourappname:login' ))
As i see you already know the template interaction, sending by post the user and password and using django messages.
If you wish to manage the errors from the form you can use the clean method :
https://docs.djangoproject.com/en/1.9/ref/forms/validation/

Django custom login page

I have a custom Django login page. I want to throw an exception when username or password fields are empty. How can I do that?
My view.py log in method :
def user_login(request):
context = RequestContext(request)
if request.method == 'POST':
# Gather the username and password provided by the user.
# This information is obtained from the login form.
username = request.POST['username']
password = request.POST['password']
user = authenticate(username=username, password=password)
print("auth",str(authenticate(username=username, password=password)))
if user:
# Is the account active? It could have been disabled.
if user.is_active:
login(request, user)
return HttpResponseRedirect('/')
else:
return HttpResponse("xxx.")
else:
# Bad login details were provided. So we can't log the user in.
print ("Invalid login details: {0}, {1}".format(username, password))
return HttpResponse("Invalid login details supplied.")
else:
return render_to_response('user/profile.html', {}, context)
I tried this and it didn't work:
This is forms.py
def clean_username(self):
username = self.cleaned_data.get('username')
if not username:
raise forms.ValidationError('username does not exist.')
You can use login view, which is provided by Django. So your login.html should look like that example.
<form class="login" method="POST" action="/login/">
{% csrf_token %}
{{form.as_p}}
<li><input type="submit" class="logBut" value="Log in"/></li>
</form>
And remember urls.py !
url(r'^login/$','django.contrib.auth.views.login', {'template_name': '/login.html'}),
The correct approach is to use forms, instead of fetching the variables directly from request.POST. Django will then validate the form data, and display errors when the form is rendered in the template. If a form field is required, then Django will automatically display an error when the field is empty, you don't even need to write a clean_<field_name> method for this.
Django already has a built in login view. The easiest approach is to use this rather than writing your own. If you still want to write your own view, you will still find it useful to look at how Django does it.

How to allow users to change their own passwords in Django?

Can any one point me to code where users can change their own passwords in Django?
Django comes with a user
authentication system. It handles user
accounts, groups, permissions and
cookie-based user sessions. This
document explains how things work.
How to change Django passwords
See the Changing passwords section
Navigation to your project where manage.py file lies
$ python manage.py shell
type below scripts :
from django.contrib.auth.models import User
u = User.objects.get(username__exact='john')
u.set_password('new password')
u.save()
You can also use the simple manage.py command:
manage.py changepassword *username*
Just enter the new password twice.
from the Changing passwords section in the docs.
If you have the django.contrib.admin in your INSTALLED_APPS, you can visit: example.com/path-to-admin/password_change/ which will have a form to confirm your old password and enter the new password twice.
You can also just use the django.contrib.auth.views.password_change view in your URLconf. It uses a default form and template; supplying your own is optional.
This tutorial shows how to do it with function based views:
View file:
from django.contrib import messages
from django.contrib.auth import update_session_auth_hash
from django.contrib.auth.forms import PasswordChangeForm
from django.shortcuts import render, redirect
def change_password(request):
if request.method == 'POST':
form = PasswordChangeForm(request.user, request.POST)
if form.is_valid():
user = form.save()
update_session_auth_hash(request, user) # Important!
messages.success(request, 'Your password was successfully updated!')
return redirect('change_password')
else:
messages.error(request, 'Please correct the error below.')
else:
form = PasswordChangeForm(request.user)
return render(request, 'accounts/change_password.html', {
'form': form
})
Url file:
from django.conf.urls import url
from myproject.accounts import views
urlpatterns = [
url(r'^password/$', views.change_password, name='change_password'),
]
And finally, the template:
<form method="post">
{% csrf_token %}
{{ form }}
<button type="submit">Save changes</button>
</form>
Its without need to go to shell enter passwd and reenter passwd
python manage.py changepassword <username>
or
/manage.py changepassword <username>
Using shell
python manage.py shell
from django.contrib.auth.models import User
users=User.objects.filter(email='<user_email>')
#you can user username or etc to get users query set
#you can also use get method to get users
user=users[0]
user.set_password('__enter passwd__')
user.save()
exit()
urls.py:
urlpatterns = [
url(r'^accounts/', include('django.contrib.auth.urls')),
Template:
{% trans "Change password" %}
Documented at: https://docs.djangoproject.com/en/1.9/topics/auth/default/#using-the-views
Per the documentation, use:
from django.contrib.auth.hashers import makepassword
The main reason to do this is that Django uses hashed passwords to store in the database.
password=make_password(password,hasher='default')
obj=User.objects.filter(empid=emp_id).update(username=username,password=password)
I used this technique for the custom user model which is derived from the AbstractUser model. I am sorry if I technically misspelled the class and subclass, but the technique worked well.
Authentication is the one way and after that reset the password
from django.contrib.auth import authenticate
user = authenticate(username='username',password='passwd')
try:
if user is not None:
user.set_password('new password')
else:
print('user is not exist')
except:
print("do something here")
Once the url pattern is added as shown in Ciro Santilli's answer, a quick way to allow users to change passwords is to give them "staff access" for the admin functions. If you don't add them to any groups or give them special permissions, they can still change their password by going to the example.com/admin page. The staff access lets them go to the page even if it is blank; in the upper right corner they can click "change password" and use the admin funtionality.
This is the command i used, just in case you are having problem in that throw AttributeError: Manager isn't available; 'auth.User' has been swapped for 'users.User'.
python manage.py shell -c "from django.contrib.auth import get_user_model;
User = get_user_model();
u = User.objects.get(username='admin');
u.set_password('password123');
u.save()"
Very similar to #Ciro's answer, but more specific to the original question (without adding all the authentication views):
just add to urlpatterns in urls.py:
url('^change-password/$', auth_views.password_change, {'post_change_redirect': 'next_page'}, name='password_change'),
Note that post_change_redirect specifies the url to redirect after the password is changed.
Then, just add to your template:
Change Password
view.py
views.py
def changepassword(request):
if request.method == "POST":
user_id = request.POST['user_id']
oldpassword = request.POST['oldpassword']
newpassword = request.POST['newpassword']
user = User.objects.get(id=user_id)
if **user.check_password**(oldpassword):
**user.set_password(newpassword)**
user.save()
return redirect("app:login-user")
else:
messages.success(request,"Pervious Password Not Match")
return redirect("app:changepassword")
else:
return render(request,'app/changepassword.html')
url.py
path('changepassword',views.changepassword,name='changepassword'),

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