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Python

Abhiram Challapalli
Abhiram Challapalli
5,605 Points

getting an error while creating step_details

when i try to save a step in the course, i am getting an error - Django Basics > Step Details

you can download the screenshots using the below Urls

step_details_page link

error_page_link

please let me know if you need additional information..........

Also, i suspect that the url could be the issue.

urlpatterns = [
    url(r'^$', views.course_list),
    url(r'(?P<pk>\d+)/(?P<pk>\d+)/$', views.step_details),  #SUSPECTING THAT THIS URL COULD BE THE ISSUE
    url(r'(?P<pk>\d+)/$', views.course_details),
]
TypeError at /admin/courses/course/3/change/

__str__ returned non-string (type NoneType)

Request Method:     POST
Request URL:    http://127.0.0.1:8000/admin/courses/course/3/change/
Django Version:     1.11.5
Exception Type:     TypeError
Exception Value:    

__str__ returned non-string (type NoneType)

Exception Location:     C:\Users\AsusGo\AppData\Local\Programs\Python\Python36\lib\site-packages\django\utils\encoding.py in force_text, line 76
Python Executable:  C:\Users\AsusGo\AppData\Local\Programs\Python\Python36\python.exe
Python Version:     3.6.2
Python Path:    

['C:\\Users\\AsusGo\\Documents\\treehouse_django',
 'C:\\Users\\AsusGo\\Documents\\treehouse_django',
 'C:\\Users\\AsusGo\\AppData\\Local\\Programs\\Python\\Python36\\python36.zip',
 'C:\\Users\\AsusGo\\AppData\\Local\\Programs\\Python\\Python36\\DLLs',
 'C:\\Users\\AsusGo\\AppData\\Local\\Programs\\Python\\Python36\\lib',
 'C:\\Users\\AsusGo\\AppData\\Local\\Programs\\Python\\Python36',
 'C:\\Users\\AsusGo\\AppData\\Local\\Programs\\Python\\Python36\\lib\\site-packages']

Url patterns

from django.conf.urls import url

from . import views

urlpatterns = [
    url(r'^$', views.course_list),
    url(r'(?P<pk>\d+)/(?P<pk>\d+)/$', views.step_details),
    url(r'(?P<pk>\d+)/$', views.course_details),
]

models.py

    class Step(models.Model):
    title = models.CharField(max_length = 255)
    description = models.TextField()
    order = models.IntegerField(default=0)
    course = models.ForeignKey(Course)

    class Meta:
        ordering = ['order', ]


    def __str__(self):
        self.title

Views.py

def step_details(request, course_pk, step_pk):
    step = get_object_or_404(Step, course_id = course_pk, pk=step_pk)
    return render(request, 'courses/step_details.html', {'step':step})

step_details.html

{% extends "layout.html"%}


{% block title%} {{step.title}} - {{ step.course.title }} {% endblock title %}

{% block content %}
  <article>
    <h2> {{ step.course.title }} </h2>
    {{ step.description }}
    {{ step.content|linebreaks }}
    {{ step.course.created_at }}

{##}
{#    <section>#}
{#      {% for step in course.step_set.all %}#}
{#        <h3> {{ step.title}}</h3>#}
{#      {{step.description}}#}
{#      {% endfor %}#}
{#    </section>#}
  </article>
{% endblock %}

admin.py

from django.contrib import admin

# Register your models here.

from .models import Course, Step

class StepInline(admin.TabularInline):
    model = Step

class CourseAdmin(admin.ModelAdmin):
    inlines = [StepInline,]

admin.site.register(Course, CourseAdmin)
admin.site.register(Step)

Regards, Abhiram.

1 Answer

Tom Slutsky
Tom Slutsky
12,453 Points

might be indentation in models.py ?

Abhiram Challapalli
Abhiram Challapalli
5,605 Points

thanks for your response...

I am sorry but it is not the indentation.. I must have removed it while pasting the code.

class Course(models.Model):
       created_at = models.DateTimeField(auto_now_add=True)
       title = models.CharField(max_length=255)
       description = models.TextField()

       def __str__(self):
             return self.title

class Step(models.Model):
      title = models.CharField(max_length = 255)
      description = models.TextField()
      order = models.IntegerField(default=0)
      course = models.ForeignKey(Course)

    class Meta:
          ordering = ['order', ]

The course part is working... i am getting an error while saving the step.

could the issue be with the url

urlpatterns = [
    url(r'^$', views.course_list),
    url(r'(?P<pk>\d+)/(?P<pk>\d+)/$', views.step_details),  #SUSPECTING THAT THIS URL COULD BE THE ISSUE
    url(r'(?P<pk>\d+)/$', views.course_details),
]