Django not able to display form error - django

Question

I am using Learning Website Development with Django book.
I have downloaded the source code from the fallowing path Source code in github. I am able to run the application in my windows machine.
However for some reason whenever login or registration from contains errors after submit, these errors are not shown in the html page.
Kindly let me know what is the issue. One obeseration what I saw in the browser console is
Following line of code displays error message
def register_page(request):
form = RegistrationForm(request.POST or None)
print request.method
if request.method == 'POST' and form.is_valid():
user = User.objects.create_user(
username=form.cleaned_data['username'],
password=form.cleaned_data['password1'],
email=form.cleaned_data['email']
)
return HttpResponseRedirect('/register/success/')
else:
form = RegistrationForm()
variables = RequestContext(request, {'form': form})
print variables
return render_to_response('registration/register.html', variables)
registration page html code:
{% extends "base.html" %}
{% block title %}User Registration{% endblock %}
{% block head %}User Registration{% endblock %}
{% block content %}
print "ddd"
{% if form.has_errors %}
<p>Your username and password didn't match.
Please try again.</p>
{% endif %}
<form method="post" action="">
{% csrf_token %}
{{ form.as_p }}
<input type="submit" value="register" />
</form>
{% endblock %}
Login page code:
{% extends "base.html" %}
{% block title %}User Login{% endblock %}
{% block head %}User Login{% endblock %}
{% block content %}
{% if form.has_errors %}
<p>Your username and password didn't match.
Please try again.</p>
{% endif %}
<form method="post" action="">
{% csrf_token %}
<p><label for="id_username">Username:</label>
{{ form.username }}</p>
<p><label for="id_password">Password:</label>
{{ form.password }}</p>
<input type="submit" value="login" />
<input type="hidden" name="next" value="/" />
</form>
{% endblock %}
form.py
import re
from django.core.exceptions import ObjectDoesNotExist
from django.contrib.auth.models import User
from django import forms
class RegistrationForm(forms.Form):
print forms.Form;
username = forms.CharField(
label='Username',
max_length=30
)
email = forms.EmailField(
label='Email'
)
password1 = forms.CharField(
label='Password',
widget=forms.PasswordInput()
)
password2 = forms.CharField(
label='Password (Again)',
widget=forms.PasswordInput()
)
# password validation:
def cleaned_password2(self):
# all valid values are accessible trough self.clean_data
if 'password1' in self.cleaned_data:
password1 = self.cleaned_data['password1']
password2 = self.cleaned_data['password2']
if password1 == password2:
return password2
raise forms.ValidationError('Passwords do not match.')
# username validation
def cleaned_username(self):
username = self.cleaned_data['username']
if not re.search(r'^\w+$', username):
raise forms.ValidationError('Username can only contain alphanumeric characters and the underscore.')
try:
User.objects.get(username=username)
except ObjectDoesNotExist:
return username
raise forms.ValidationError('Username is already taken.')
class BookmarkSaveForm(forms.Form):
url = forms.URLField(
label='URL',
widget=forms.TextInput(attrs={'size': 64})
)
title = forms.CharField(
label='Title',
widget=forms.TextInput(attrs={'size': 64})
)
tags = forms.CharField(
label='Tags',
widget=forms.TextInput(attrs={'size': 64})
)
http://localhost:8000/static/style.css Failed to load resource: the server responded with a status of 404 (Not Found)

Answer 1

The code is simply wrong.
By combining the method == 'POST' and form.is_valid() into one check, they're ensuring that a new - empty - form is created if either of those things are false. What they should be doing is only creating an empty form if method does not equal "POST"; if the form is not valid, they need to return that invalid form to the template, as it contains the errors.
So you need to follow the normal pattern, with two separate if statements:
def register_page(request):
if request.method == 'POST':
form = RegistrationForm(request.POST)
if form.is_valid():
user = User.objects.create_user(
username=form.cleaned_data['username'],
password=form.cleaned_data['password1'],
email=form.cleaned_data['email']
)
return HttpResponseRedirect('/register/success/')
else:
form = RegistrationForm()
variables = RequestContext(request, {'form': form})

Answer 2

I Remenber i got the same problem, the thing i did is:
Use self.add_error to attach errors to a specific field in the form. Call add_error() instead of forms.ValidationError(), like this:
password validation:
def cleaned_password2(self):
# all valid values are accessible trough self.clean_data
if 'password1' in self.cleaned_data:
password1 = self.cleaned_data['password1']
password2 = self.cleaned_data['password2']
if password1 == password2:
return password2
msg = 'Passwords do not match.'
self.add_error('password1',msg)