TODO Add some context - (can probably relate to previous chapters) why are we doing this? Update this chapter with content from Django Templates and Template Extending A break after this chapter?
We have different pieces in place: the Post model is defined in models.py, we have post_list in views.py and the template added. But how will we actually make our posts appear in our HTML template? Because that is what we want to do. Take some content (models saved in the database) and display it nicely in our template, right?
This is exactly what views are supposed to do: connect models and templates. In our post_list view we will need to take the models we want to display and pass them to the template. In a view we decide what (model) will be displayed in a template.
OK, so how will we achieve this?
We need to open our blog/views.py. So far post_list view looks like this:
{% filename %}blog/views.py{% endfilename %}
from django.shortcuts import render
def post_list(request):
return render(request, 'blog/index.html', {})Remember when we talked about including code written in different files? Now is the moment when we have to include the model we have written in models.py. We will add the line from .models import Post like this:
{% filename %}blog/views.py{% endfilename %}
from django.shortcuts import render
from .models import PostThe dot before models means current directory or current application. Both views.py and models.py are in the same directory. This means we can use . and the name of the file (without .py). Then we import the name of the model (Post).
But what's next? To take actual blog posts from the Post model we need something called QuerySet.
You should already be familiar with how QuerySets work. We talked about them in Django ORM (QuerySets) chapter.
So now we want published blog posts sorted by published_date, right? We already did that in QuerySets chapter!
{% filename %}blog/views.py{% endfilename %}
Post.objects.filter(published_date__lte=timezone.now()).order_by('published_date')Now we put this piece of code inside the blog/views.py file by adding it to the function def post_list(request):
{% filename %}blog/views.py{% endfilename %}
from django.shortcuts import render
from django.utils import timezone
from .models import Post
def post_list(request):
posts = Post.objects.filter(published_date__lte=timezone.now()).order_by('published_date')
return render(request, 'blog/index.html', {})Please note that we create a variable for our QuerySet: posts. Treat this as the name of our QuerySet. From now on we can refer to it by this name.
Also, the code uses the timezone.now() function, so we need to add an import for timezone.
The last missing part is passing the posts QuerySet to the template. Don't worry – we will cover how to display it in a later chapter.
In the render function we have one parameter request (everything we receive from the user via the Internet) and another giving the template file ('blog/index.html'). The last parameter, {}, is a place in which we can add some things for the template to use. We need to give them names (we will stick to 'posts' right now). :) It should look like this: {'posts': posts}. Please note that the part before : is a string; you need to wrap it with quotes: ''.
So finally our blog/views.py file should look like this:
{% filename %}blog/views.py{% endfilename %}
from django.shortcuts import render
from django.utils import timezone
from .models import Post
def post_list(request):
posts = Post.objects.filter(published_date__lte=timezone.now()).order_by('published_date')
return render(request, 'blog/index.html', {'posts': posts})That's it! Time to go back to our template and display this QuerySet!
Want to read a little bit more about QuerySets in Django? You should look here: https://docs.djangoproject.com/en/1.9/ref/models/querysets/
TODO: This is moved from Django Templates chapter.
In the previous chapter we gave our template a list of posts in the posts variable. Now we will display it in HTML.
To print a variable in Django templates, we use double curly brackets with the variable's name inside, like this:
{% filename %}blog/templates/blog/post_list.html{% endfilename %}
{{ posts }}Try this in your blog/templates/blog/post_list.html template. Replace everything from the second <div> to the third </div> with {{ posts }}. Save the file, and refresh the page to see the results:
As you can see, all we've got is this:
{% filename %}blog/templates/blog/post_list.html{% endfilename %}
[<Post: My second post>, <Post: My first post>]This means that Django understands it as a list of objects. Remember from Introduction to Python how we can display lists? Yes, with for loops! In a Django template you do them like this:
{% for post in posts %}
{{ post }}
{% endfor %}Try this in your template.
It works! But we want them to be displayed like the static posts we created earlier in the Introduction to HTML chapter. You can mix HTML and template tags. Our body will look like this:
<div>
<h1><a href="/">Django Girls Blog</a></h1>
</div>
{% for post in posts %}
<div>
<p>published: {{ post.published_date }}</p>
<h1><a href="">{{ post.title }}</a></h1>
<p>{{ post.text|linebreaksbr }}</p>
</div>
{% endfor %}{% raw %}Everything you put between {% for %} and {% endfor %} will be repeated for each object in the list. Refresh your page:{% endraw %}
Have you noticed that we used a slightly different notation this time ({{ post.title }} or {{ post.text }})? We are accessing data in each of the fields defined in our Post model. Also, the |linebreaksbr is piping the posts' text through a filter to convert line-breaks into paragraphs.