In Django, how do you pass a ForeignKey into an instance of a Model?

Question

I am writing an application which stores "Jobs". They are defined as having a ForeignKey linked to a "User". I don't understand how to pass the ForeignKey into the model when creating it. My Model for Job worked fine without a ForeignKey, but now that I am trying to add users to the system I can't get the form to validate.

models.py:

from django.db import models
from django import forms
from django.contrib.auth.models import User

class Job(models.Model):
    user = models.ForeignKey(User)
    name = models.CharField(max_length=50, blank=True)
    pub_date = models.DateTimeField('date published', auto_now_add=True)
    orig_image = models.ImageField('uploaded image', upload_to='origImageDB/', blank=True)
    clean_image = models.ImageField('clean image', upload_to='cleanImageDB/', blank=True)
    fullsize_image = models.ImageField('fullsize image', upload_to='fullsizeImageDB/')
    fullsize_clean_image = models.ImageField('fullsize clean image', upload_to='fullsizeCleanImageDB/')
    regions = models.TextField(blank=True)
    orig_regions = models.TextField(blank=True)

class JobForm(forms.ModelForm):
    class Meta:
        model = Job

In views.py I was creating the objects as follows:

if request.method == 'POST':
    form = JobForm(request.POST, request.FILES)
    if form.is_valid():
        #Do something here

I understand that this passes the form data and the uploaded files to the form. However, I don't understand how to pass in a User to be set as the ForeignKey.

Thanks in advance to anyone who can help.

Cirro

Answer 1

A typical pattern in Django is:

1. exclude the user field from the model form
2. save the form with commit=False
3. set job.user
4. save to database

In your case:

class JobForm(forms.ModelForm):
    class Meta:
        model = Job
        exclude = ('user',)

if request.method == 'POST':
    form = JobForm(request.POST, request.FILES)
    job = form.save(commit=False)
    job.user = request.user
    job.save()
    # the next line isn't necessary here, because we don't have any m2m fields
    form.save_m2m()

See the Django docs on the model form save() method for more information.

Tyrolienne

Didn't realize the ModelForm save() function returned an instance of the model class specified in the form's Meta class model attribute. Thanks for this! – Elude

Answer 2

Try:

if request.method == 'POST':
    data = request.POST
    data['user'] = request.user
    form = JobForm(data, request.FILES)
    if form.is_valid():
        #Do something here

Hagar

This works fine except 'request.user' should be 'request.user.id'. Thank you. – Cirro

@Cirro Actually in Django 1.6.1 request.user works fine – Elude

request.POST is immutable – Xenophon