Reusing django templates?

Question

I find django's template language very limiting. Following along with django's DRY principle, I have a template that I'd like to use in many other templates. For example a patient list:

    {% for physician in physicians.all %}
        {% if physician.service_patients.count %}
            <div id="tabs-{{ forloop.counter }}">
                {% include "hospitalists/patient_list.html" %}
            </div>
        {% endif %}
    {% endfor %}

The problem is that the patient_list template is expecting a list of patients named patients. How can I rename physician.service_patients to patients before including the template?

Thanks, Pete

Answer 1

Use the with tag:

{% for physician in physicians.all %}
   {% if physician.service_patients.count %}
      {% with physician.service_patients as patients %}                   
         <div id="tabs-{{ forloop.counter }}">
            {% include "hospitalists/patient_list.html" %}
         </div>
      {% endwith %}
   {% endif %}
{% endfor %}

You might also upgrade to creating a custom tag:

{% for physician in physicians.all %}
   {% if physician.service_patients.count %}
      {% patient-list physician.service_patients %}
   {% endif %}
{% endfor %}

Although custom tags involve writing Python code, there are shortcuts that make it easy to use an existing template file as a tag: Django Inclusion Tags

Answer 2

When you have "functionality" (specifically an if-condition) inside a loop, you have an opportunity to move this into the view function.

First

This construct

{% for physician in physicians.all %}
    {% if physician.service_patients.count %}
    {% endif %}
{% endfor %}

Is so common that you have several ways to avoid it.

1. Change your model. Add a patients" method and use it instead of the default query set that you get with a on-to-many relationship. This method of your model has theif service_patients.count` test, removing it from your template.

   This eliminates the {% if %} from your template, reducing it to {% for %} and the actual HTML, which cannot easily the eliminated.

2. Change your view function. Write a few lines of code to create a list of physicians with service_patients instead of a simplistic collection of physicians. This code in your view function has the if service_patients.count test, removing it from your template.

   This eliminates the {% if %} from your template, reducing it to a {% for %} and the actual HTML, which cannot easily be eliminated.

The point is to get rid of the {% if %} so that you're simply cutting and pasting the {% for %} and the actual HTML. By keeping your template to just the HTML (which cannot be eliminated), the only overhead is the {% for %}

Second

It appears that you want to reuse an {% include %} construct in slightly different contexts.

It's not at all clear what the problem with this {% include %} file is. It is "expecting a list of patients named patients" seems superficially silly. Fix it, so it expects physician.patients.

Perhaps you want to use this same list twice. Once with a list called 'patients' and once with a list called 'physician.patients'. In this case, consider (a) simplifying or (b) writing a template tag.

It appears that you have a patient list that is sometimes a stand-alone page, and other times is repeated many times on a much more complex page. Repeating a list of details embedded in some longer list is not really the best page design. Django doesn't help you with this because -- frankly -- it's not easy for people to use. Hence option (a) -- consider redesigning this "patient list within a physician" list as too complex.

However, you can always write a template tags to create really complex pages.

Summary

There's a really good reason why the Django template language has limited functionality. All of your functionality should be either an essential feature of your model, or a feature of the current application that uses the model.

Presentation is simply the translation of objects (and querysets) into HTML. Nothing more