Django - Iterate over model instance field names and values in template

Question

I'm trying to create a basic template to display the selected instance's field values, along with their names. Think of it as just a standard output of the values of that instance in table format, with the field name (verbose_name specifically if specified on the field) in the first column and the value of that field in the second column.

For example, let's say we have the following model definition:

class Client(Model):
    name = CharField(max_length=150)
    email = EmailField(max_length=100, verbose_name="E-mail")

I would want it to be output in the template like so (assume an instance with the given values):

Field Name      Field Value
----------      -----------
Name            Wayne Koorts
E-mail          [email protected]

What I'm trying to achieve is being able to pass an instance of the model to a template and be able to iterate over it dynamically in the template, something like this:

<table>
    {% for field in fields %}
        <tr>
            <td>{{ field.name }}</td>
            <td>{{ field.value }}</td>
        </tr>
    {% endfor %}
</table>

Is there a neat, "Django-approved" way to do this? It seems like a very common task, and I will need to do it often for this particular project.

Answer 1

model._meta.get_all_field_names() will give you all the model's field names, then you can use model._meta.get_field() to work your way to the verbose name, and getattr() to get the value from the model.

Answer 2

Yeah it's not pretty, you'll have to make your own wrapper. Take a look at builtin databrowse app, which has all the functionality you need really.

Answer 3

I've come up with the following method, which works for me because in every case the model will have a ModelForm associated with it.

def GetModelData(form, fields):
    """
    Extract data from the bound form model instance and return a
    dictionary that is easily usable in templates with the actual
    field verbose name as the label, e.g.

    model_data{"Address line 1": "32 Memory lane",
               "Address line 2": "Brainville",
               "Phone": "0212378492"}

    This way, the template has an ordered list that can be easily
    presented in tabular form.
    """
    model_data = {}
    for field in fields:
        model_data[form[field].label] = eval("form.data.%s" % form[field].name)
    return model_data

@login_required
def clients_view(request, client_id):
    client = Client.objects.get(id=client_id)
    form = AddClientForm(client)

    fields = ("address1", "address2", "address3", "address4",
              "phone", "fax", "mobile", "email")
    model_data = GetModelData(form, fields)

    template_vars = RequestContext(request,
        {
            "client": client,
            "model_data": model_data
        }
    )
    return render_to_response("clients-view.html", template_vars)

Here is an extract from the template I am using for this particular view:

<table class="client-view">
    <tbody>
    {% for field, value in model_data.items %}
        <tr>
            <td class="field-name">{{ field }}</td><td>{{ value }}</td>
        </tr>
    {% endfor %}
    </tbody>
</table>

The nice thing about this method is that I can choose on a template-by-template basis the order in which I would like to display the field labels, using the tuple passed in to GetModelData and specifying the field names. This also allows me to exclude certain fields (e.g. a User foreign key) as only the field names passed in via the tuple are built into the final dictionary.

I'm not going to accept this as the answer because I'm sure someone can come up with something more "Djangonic" :-)

Update: I'm choosing this as the final answer because it is the simplest out of those given that does what I need. Thanks to everyone who contributed answers.

Answer 4

Here's another approach using a model method. This version resolves picklist/choice fields, skips empty fields, and lets you exclude specific fields.

def get_all_fields(self):
    """Returns a list of all field names on the instance."""
    fields = []
    for f in self._meta.fields:

        fname = f.name        
        # resolve picklists/choices, with get_xyz_display() function
        get_choice = 'get_'+fname+'_display'
        if hasattr( self, get_choice):
            value = getattr( self, get_choice)()
        else:
            try :
                value = getattr(self, fname)
            except User.DoesNotExist:
                value = None

        # only display fields with values and skip some fields entirely
        if f.editable and value and f.name not in ('id', 'status', 'workshop', 'user', 'complete') :

            fields.append(
              {
               'label':f.verbose_name, 
               'name':f.name, 
               'value':value,
              }
            )
    return fields

Then in your template:

{% for f in app.get_all_fields %}
    <dt>{{f.label|capfirst}}</dt>
    <dd>
    {{f.value|escape|urlize|linebreaks}}
    </dd>
{% endfor %}

Answer 5

This may be considered a hack but I've done this before using modelform_factory to turn a model instance into a form.

The Form class has a lot more information inside that's super easy to iterate over and it will serve the same purpose at the expense of slightly more overhead. If your set sizes are relatively small I think the performance impact would be negligible.

The one advantage besides convenience of course is that you can easily turn the table into an editable datagrid at a later date.

Answer 6

You can use Django's to-python queryset serializer.

Just put the following code in your view:

from django.core import serializers
data = serializers.serialize( "python", SomeModel.objects.all() )

And then in the template:

{% for instance in data %}
    {% for field, value in instance.fields.items %}
        {{ field }}: {{ value }}
    {% endfor %}
{% endfor %}

Its great advantage is the fact that it handles relation fields.

Answer 7

Finally found a good solution to this on the dev mailing list (http://groups.google.com/group/django-developers/browse_thread/thread/44cd834438cfda77/557f53697658ab04?lnk=gst&q=template+model#557f53697658ab04):

In the view add:

from django.forms.models import model_to_dict

def show(request, object_id):
    object = FooForm(data=model_to_dict(Foo.objects.get(pk=object_id)))
    return render_to_response('foo/foo_detail.html', {'object': object})

in the template add:

{% for field in object %}
    <li><b>{{ field.label }}:</b> {{ field.data }}</li>
{% endfor %}