How do I solve a Django NoReverseMatch Error?

Question

How do I solve a Django NoReverseMatch Error?

When I visit basic_list, I get the error "Reverse for 'manage_account' with keyword arguments '{'pk': ''}' not found. 1 pattern(s) tried: ['manage_account/(?P[0-9]+)/$']" but all the other links are working.

models.py

from django.db import models

class Wine(models.Model):
    name = models.CharField(max_length=300)
    year = models.IntegerField()
    objects = models.Manager()

    def __str__(self):
        return str(self.pk) + ": " + self.name

class Account(models.Model):
    username = models.CharField(max_length=20)
    password = models.CharField(max_length=20)
    objects = models.Manager()

    def __str__(self):
        return str(self.pk) + ": " + self.username

urls.py

from django.urls import path
from . import views

urlpatterns = [
    path('login', views.view_login, name='view_login'),
    path('basic_list', views.view_basic_list, name='view_basic_list'),
    path('manage_account/<int:pk>/', views.manage_account, name='manage_account'),
]

views.py

from django.shortcuts import render, redirect, get_object_or_404
from .models import *
from django.core.exceptions import ObjectDoesNotExist

def view_login(request):
    if request.method == 'POST':
        username = request.POST.get('username')
        password = request.POST.get('password')
        account = Account.objects.get(username=username)   
        if password == account.password:
            return redirect('view_basic_list')
        else:
            return render(request, 'myapp/login.html', {'warning': "Invalid login"})
    else:
        return render(request, 'myapp/login.html')

def view_basic_list(request):
    wine_objects = Wine.objects.all()
    return render(request, 'myapp/basic_list.html', {'Wines':wine_objects})

def manage_account(request, pk):
    a = get_object_or_404(Account, pk=pk)
    return render(request, 'myapp/manage_account.html', {'a': a})

basic_list.html

{% extends 'myapp/base.html' %}
{% load static %}

{% block content %}
        <div class="container">
            <div class="row">
                <div class="col-12">
                    <table class="table table-striped">
                        <thead>
                            <th scope="col"> Name </th>
                            <th scope="col"> Year </th>
                        </thead>
                        <tbody>
                            {% for d in wines %}
                            <tr>
                                <td> {{ d.name }} </td>
                                <td> {{ d.year }} </td>
                            </tr>
                            {% endfor %}
                        </tbody>
                    </table>
                    <a href="{% url 'manage_account' pk=a.pk %}" class="btn btn-primary" role="button" aria-pressed="true">Manage Account</a> 
                    <a href="login" class="btn btn-outline-primary" role="button" aria-pressed="true">Log Out</a> 
                </div>
            </div>
        </div> 
{% endblock %}

manage_account.html

{% extends 'myapp/base.html' %}
{% load static %}

{% block content %}
<div class="card mx-auto">
    <div class="card-header">                    
        <h4>My Account</h4>  
    </div>                                      

    <div class="card-body">
        <div class="mb-3">
            <h5>Username:</h5>                                
                <h6>{{a.username}}</h6>
        </div>
    </div>
</div>
{% endblock %}

The other URLs are working fine. http://127.0.0.1:8000/basic_list shows a NoReverseMatch error.

We are not allowed to use Django's built-in user models and authentication system.

What should I do? Sorry, I am new to Django. Any suggestions would be greatly appreciated.

Answer 1

The problem is that you are using an a variable which is not passed to the basic_list.html template that is used on the view_basic_list view.

You should also pass the pk variable of the account to view_basic_list view. And pass the account to the template:

def view_basic_list(request, pk):
    a = get_object_or_404(Account, pk=pk)
    wine_objects = Wine.objects.all()
    return render(request, 'myapp/basic_list.html', {'Wines':wine_objects, 'a': a})

Answer 2

did you try this?

<a href="/manage_account/{{a.pk}}/" class="btn btn-primary" role="button" aria-pressed="true">Manage Account</a>

This way is not dynamic, so if you change your urls.py, you also have to change the href from the template. But it should work.