matching query does not exist Error in Django

Question

I have implemented a password recovery functionality in django. With my method, the new password will be sent to the email id entered. It works fine when given the correct email (e-mail id which exists in the database). But when given an email id which is not in the database, it gives the error:
'DoesNotExist at /forgotPassword/ UniversityDetails matching query does not exist.'

How can I resolve this issue?

forgotPassword.html()

def forgotPassword(request):
    if request.POST:
        email=request.POST.get("email")
        user = UniversityDetails.objects.get(email=email)
        if(not user):
            print "No user"
            return render_to_response("forgotPassword.html")
        else:
            newPassword = user.password
            send_mail('Password Recovery', 'The password for your site is '+ newPassword, '[email protected]',
    ['[email protected]'], fail_silently=False)   
            return render_to_response("passwordRecovery.html")
    return render_to_response('forgotPassword.html')

html

<form name="forgotPassword" method="POST" id="myFormid" action="http://10.1.0.90:8080/forgotPassword/">
<div style="float:center;width:100%;color:#0000A0">
 Enter your E-mail ID</label><br/> <input type="text" name="email" size="25" /> 
 <input type="submit" value="Submit" />
 </div> 

</form >

Solution 1

try:
    user = UniversityDetails.objects.get(email=email)
except UniversityDetails.DoesNotExist:
    user = None

I also see you're storing your passwords in plaintext (a big security no-no!). Consider using the built-in auth system instead.

Solution 2

As mentioned in Django docs, when get method finds no entry or finds multiple entries, it raises an exception, this is the expected behavior:

get() raises MultipleObjectsReturned if more than one object was found. The MultipleObjectsReturned exception is an attribute of the model class.

get() raises a DoesNotExist exception if an object wasn’t found for the given parameters. This exception is an attribute of the model class.

Using exceptions is a way to handle this problem, but I actually don't like the ugly try-except block. An alternative solution, and cleaner to me, is to use the combination of filter + first.

user = UniversityDetails.objects.filter(email=email).first()

When you do .first() to an empty queryset it returns None. This way you can have the same effect in a single line.

The only difference between catching the exception and using this method occurs when you have multiple entries, the former will raise an exception while the latter will set the first element, but as you are using get I may assume we won't fall on this situation.

Note that first method was added on Django 1.6.

Solution 3

I also had this problem. It was caused by the development server not deleting the django session after a debug abort in Aptana, with subsequent database deletion. (Meaning the id of a non-existent database record was still present in the session the next time the development server started)

To resolve this during development, I used

request.session.flush()

Solution 4

You can use this in your case, it will work fine.

user = UniversityDetails.objects.filter(email=email).first()

Solution 5

In case anybody is here and the other two solutions do not make the trick, check that what you are using to filter is what you expect:

user = UniversityDetails.objects.get(email=email)

is email a str, or a None? or an int?

View more solutions

Comments

[Love Putin]

Can not use this at all on decimal fields. Raises error: 'decimal.Decimal' object has no attribute 'first'.

[Martín De la Fuente]

You are supposed to use this method over a QuerySet @user12379095

[Love Putin]

Nope!! Not happening even on a qs.