Inserting a 'hidden timestamp field' in a modelform?

Question

I have a simple form that allows a user to create a post. The fields are post_title, post_content, post_date. The post_title and post_content will be provided by the user, however the post_date will be autogenerated by the system and will give the current timestamp. Due to this, I will only show both title and content in the form. When I try and submit a request however, this gives me an IntegrityError saying NOT NULL constraint failed: main_app_post.post_date. I am fairly new at Django so I really have no idea what to do. I want it that whenever the user sends a Post request (and if it passes the validations), it will generate the current timestamp to post_date before saving it to the database. Any advices in regards of this? Thanks a lot!

models.py:

class Post(models.Model):
    post_title = models.CharField(max_length=100)
    post_content = models.TextField(max_length=400)
    post_date = models.DateTimeField()

    def __str__(self):
        return self.post_title

forms.py:

class PostForm(forms.ModelForm):
    class Meta:
        model = models.Post
        fields = ('post_title', 'post_content')

views.py:

    if request.method == 'POST':
        form = forms.PostForm(request.POST)

        if form.is_valid():
            post_title = form.cleaned_data['post_title']
            post_content = form.cleaned_data['post_content']
            post_date = datetime.datetime.now().timestamp()

            form.post_date = post_date
            form.save(commit=True)

score 1 · Accepted Answer · answered Sep 21 '20 at 16:58

1

set auto_now_add=True

class Post(models.Model):
    post_title = models.CharField(max_length=100)
    post_content = models.TextField(max_length=400)
    post_date = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.post_title

Refernce: Django auto_now and auto_now_add

answered Sep 21 '20 at 16:58

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Thank you so much sir! That was quite simple! :') – Dran Dev Sep 21 '20 at 17:06

score 1 · Answer 2 · answered Sep 21 '20 at 16:58

You can specify a default and make it non-editable, but in fact Django already has a solution for this: you can specify auto_now_add=True [Django-doc]:

class Post(models.Model):
    post_title = models.CharField(max_length=100)
    post_content = models.TextField(max_length=400)
    post_date = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.post_title

This will make the field non-editable, so it will not show up in a form by default, and furthermore it will use as default value the current timestamp. This thus means that the view and form no longer have to worry about this.

Inserting a 'hidden timestamp field' in a modelform?

2 Answers2