MultipleObjectsReturned at /course/eyime/user_library/

Question

I am building a website where users can buy courses and the courses will display on their users library, a site similar to gumroad, but i am getting this error when i clicked on the payment option on my code.

Here is the error messages i am getting MultipleObjectsReturned at /course/eyime/user_library/

get() returned more than one UserLibrary -- it returned 2!

here is the Views.py codes

@login_required
def user_library(request, username):
    user = get_object_or_404(User, username=username)
    my_library = UserLibrary.objects.filter(user=user)

    if request.method == 'POST':
        course_id = request.POST['course_id']
        course_price = request.POST['course_price']
        course = UserLibrary.objects.get(courses__id=course_id)
        """for c in course.courses.all():
            print(c.name)"""
        context = {
            'course': course,
            'course_price': course_price,
            'email': request.user.email,
            'phone': request.user.phone_number,
        }
        return render(request, 'courses/content/pay_for_courses.html', context)

    return render(request, 'courses/content/user_library.html', {'my_library': my_library})

here is the html codes for payment of the courses

{% extends "jtalks/base.html" %}
{% load static %}

{% block title %}Payment With Paystack{% endblock %}

{% block content %}
    <div class='container' onload="payWithPaystack()">
        <div class='row justify-content-md-center'>
            <div class='col-md-auto'>
                <div id="output">

                </div>

                <div id="success">

                </div>

                <div id="display_info" style="display: none">
                    <p>Click <a href="{% url 'courses:print_course_pdf' course.id %}" target="_blank">Here</a> to print receipt of your purchase</p>
                    <p id="home">Go Back Home <a href="{% url 'jtalks:jtalks-home' %}">Homepage</a></p>
                </div>
            </div>
        </div>
    </div>
{% endblock content %}


{% block js %}
    <script src="https://js.paystack.co/v1/inline.js"></script>
    <script>
        window.onload=function(){
            payWithPaystack();
        };

        function payWithPaystack(){
            var price = '{{ course_price }}';
            var handler = PaystackPop.setup({
                key: 'pk_test_ce8979497f703eb955ab5ceb19fc54cdcb615e0d',
                email:'{{email}}',
                amount: parseInt(price) * 100,
                currency: "NGN",
                metadata: {
                    custom_fields: [
                        {
                            display_name: "Mobile Number",
                            variable_name: "mobile_number",
                            value: "{{phone}}",
                            course_id: "{{ course.id }}"
                        }
                    ]
                },

                callback: function(response){
                    var ref = response.reference;
                    var course_random_id = '{{ course.order_id }}'
                    var course_id = '{{ course.id }}'
                    //console.log(order_id)
                    
                    // $('div#home').show();
                    $.ajax({
                        method: "GET",
                        url: "/course/pay_for_courses/",
                        data: {
                            'id': course_id,
                            'reference': ref,
                        },
                        dataType: "json",

                        success: function (data) {
                            if (data.message == "Your Payment was successfully received") {
                                $('#output').html(data.message)
                                $('#success').html(`<p>Transaction reference is : <h2>${ref}</h2> and your order id is <h2>${course_random_id}</h2></p>`);
                                $("#display_info").show();
                            } else if (data.message == "Your Payment Failed!!!") {
                                $('#output').html(data.message)
                                $("#success").html(`<a href="{% url 'courses:user_library' %}" class="button">Back To Your Library</a>`)
                            }
                        },
                    });
                },

                onClose: function(){
                    alert('window closed');
                }
            });

            handler.openIframe();
        }
    </script>
{% endblock js %}

and here is the html codes for users library

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

{% block content %}
  <div>
    <center>Welcome to your library, {{ request.user.username }}</center>
  </div>
  <div class="container-fluid">
    <div class="row">
      <div class="col-6">
        <h1>Wish List</h1>
        <h3>Courses you are yet to pay for will show up here</h3>
        <div class="user_library" style="display: flex; flex-direction: row; flex-wrap: wrap;">
          {% for library in my_library %}
          {% if not library.paid %}
            {% for course in library.courses.all %}
              <div class="card" style="width: 18rem;">
                <img src="{{ course.content_file.url }}" class="card-img-top" alt="{{ course.name }}">
                <div class="card-body">
                  <h5 class="card-title">{{ course.name }}</h5>
                  <p class="card-text">{{ course.overview|slice:":50" }}...</p>
                </div>
                <ul class="list-group list-group-flush">
                  <li class="list-group-item">An item</li>
                  <li class="list-group-item">A second item</li>
                  <li class="list-group-item">A third item</li>
                </ul>
                <div class="card-body">
                  <a href="{% url 'courses:course_detail' course.id course.slug %}" class="btn btn-primary">Course Details</a>
                  <form method="post">
                    {% csrf_token %}
                    <input type="hidden" name="course_id" value="{{ course.id }}">
                    <input type="hidden" name="course_price" value="{{ course.price }}">
                    <input type="submit" class="btn btn-primary" value="Pay &#8358;{{ course.price}}">
                  </form>
                </div>
              </div>
            {% endfor %}
          {% endif %}
        {% endfor %}
        </div>
        
      </div>
      
      <div class="col-6">
        <h1>Paid Courses</h1>
        <h3>All courses you have successfully paid for will show here</h3>
        <div class="user_library" style="display: flex; flex-direction: row; flex-wrap: wrap;">
        {% for library in my_library %}
          {% if library.paid %}
            {% for course in library.courses.all %}
              <div class="card" style="width: 18rem;">
                <img src="{{ course.content_file.url }}" class="card-img-top" alt="{{ course.name }}">
                <div class="card-body">
                  <h5 class="card-title">{{ course.name }}</h5>
                  <p class="card-text">{{ course.overview|slice:":50" }}...</p>
                </div>
                <ul class="list-group list-group-flush">
                  <li class="list-group-item">An item</li>
                  <li class="list-group-item">A second item</li>
                  <li class="list-group-item">A third item</li>
                </ul>
                <div class="card-body">
                  <a href="{% url 'courses:course_detail' course.id course.slug %}" class="btn btn-primary">Course Details</a>
                  <a id="download_pdf" href="/media/pdf_courses/{{ course.slug }}.pdf" class="btn btn-primary" download>Download PDF</a>
                </div>
                
                <div>
                  <video width="300" height="240" controls controlsList="nodownload">
                    <source src="{{ MEDIA_URL}}{{ course.course_video }}" type="video/mp4">
                    Your browser does not support the video tag.
                  </video>
                </div>
              </div>
            {% endfor %}
          {% endif %}
        {% endfor %}
        </div>
      </div>
  </div>
  </div>
{% endblock %}

{% block js %}
  <script src="{% static 'jtalks/home.js' %}"></script>
{% endblock js %}

Answer 1

It seems that this line is returning 2 records instead of one:

course = UserLibrary.objects.get(courses__id=course_id)

Use filter instead of get and iterate through the course variable in a template tag such as:

{% for c in course %} and access c's fields instead.