Django: Assign current user as foreign key to comments model

Question

I have been working thorough the DjangoGirls tutorial and was trying to improve on the section on adding comments to an application - TutorialExtensions

I have added the comments to a simple photo blog application but what I was attempting to do was replace the author = models.CharField(max_length=200) with an alternative that would store the current/logged-in user who was commenting on the photo instance and then allow me to display on the photo_detail template.

I thought I was close using author = models.ForeignKey(User, related_name='Commenter') but this through up an error:

NOT NULL constraint failed: timeline_comment.author_id

Here is my models.py consisiting of a Photo model and Comments model:

class Photo(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, default=1)
    title = models.CharField(max_length=120)
    slug = models.SlugField(unique=True)
    image = ProcessedImageField(upload_to=upload_location, 
        null=True, 
        blank=False,
        processors=[Transpose(), ResizeToFit(1000, 1000, False)],
        format='JPEG',
        options={'quality': 50},
        width_field="width_field",
        height_field="height_field")
    height_field = models.IntegerField(default=0)
    width_field = models.IntegerField(default=0)
    description = models.TextField(max_length=1000)
    updated = models.DateTimeField(auto_now=True, auto_now_add=False)
    timestamp = models.DateTimeField(auto_now=False, auto_now_add=True)

class Comment(models.Model):
    post = models.ForeignKey('timeline.Photo', related_name='comments')
    author = models.CharField(max_length=200)
    text = models.TextField(max_length=1000)
    created_date = models.DateTimeField(default=timezone.now)

The related view:

def photo_detail(request, slug=None):
    if not request.user.is_authenticated():
        return HttpResponseRedirect("/accounts/login")

    instance = get_object_or_404(Photo, slug=slug)

    if request.method == "POST":
        form = CommentForm(request.POST)
        if form.is_valid():
            comment = form.save(commit=False)
            comment.post = instance
            comment.save()
            return redirect('timeline:detail', slug=instance.slug)
    else:
        form = CommentForm()

    share_string = quote_plus(instance.description)

    context = {
        "title": instance.title,
        "instance": instance,
        "share_string": share_string,
        "form": form,
    }

    return render(request, "photo_detail.html", context)   

My forms.py:

class CommentForm(forms.ModelForm):
    text = forms.CharField(widget=forms.Textarea, label='Leave a comment: ')
    class Meta:
        model = Comment
        fields = [
            "text",
        ]

Finally the template for the photo_detail view:

<div class="row">
    <div class="col-md-12" id="comments">
        <p>
            {% if instance.comments.count == 0 %}
            No Comments
            {% elif instance.comments.count == 1 %}
            {{ instance.comments.count }} Comment
            {% else %}
            {{ instance.comments.count }} Comments
            {% endif %}
        </p>
        <hr style="margin-top: 10px;">
            {% for comment in instance.comments.all %}
                <div class="comment">
                    <div class="date pull-right">{{ comment.created_date | timesince }} Ago</div>
                    <strong>{{ comment.author }}</strong>
                    <p>{{ comment.text|linebreaks }}</p>
                </div>
                <hr>
            {% empty %}
                <p>No comments here yet :(</p>
            {% endfor %}
    </div>
</div>

{% if user.is_superuser or user.is_authenticated %} 
<div class="row">
    <div class="col-md-12">
        <form method="POST" class="comment-form" action=''>
            {% csrf_token %}
            {{ form | crispy }}
            <button type="submit" class="comment-add btn btn-lg btn-purple">Add</button>
        </form>
    </div>
</div>
{% endif %}

Could anybody recommend the best approach for this? Any help would be very much appreciated! Thank You.

Answer 1

Using the ForeignKey is correct[1] - the missing piece is that you need to assign that in your view. After comment = form.save(commit=False) just add one line:

comment.author = request.user

and it will work.

[1] although you don't want the related_name as "Commenter" (because it refers to the way you access the comment from the user: the default is comment_set which makes more sense).