Model support¶

Concepts¶

django-meta provides a mixin to handle metadata in your models.

Actual data are evaluated at runtime pulling values from model attributes and methods.

To use it, defines a _metadata attribute as a dictionary of tag/value pairs;

tag is the name of the metatag as used by meta.html template
value is a string that is evaluated in the following order:
- model method name called with the meta attribute as argument
- model method name called with no arguments
- model attribute name (evaluated at runtime)
- string literal (if none of the above exists)

If value is False or it is evaluated as False at runtime the tag is skipped.

To use this mixin you must invoke as_meta() on the model instance for example in the get_context_data().

Request¶

as_meta() accepts the request object that is saved locally and is available to methods by using the get_request method.

Public interface¶

ModelMeta.get_meta(request=None): returns the metadata attributes definition. Tipically these are set in _metadata attribute in the model;

ModelMeta.as_meta(request=None): returns the meta representation of the object suitable for use in the template;

ModelMeta.get_request(): returns the request object, if given as argument to as_meta;

ModelMeta.get_author(): returns the author object for the current instance. Default implementation does not return a valid object, this must be overidden in the application according to what is an author in the application domain;

ModelMeta.build_absolute_uri(url): create an absolute URL (i.e.: complete with protocol and domain); this is generated from the request object, if given as argument to as_meta;

Usage¶

Configure django-meta according to documentation

Add meta information to your model:

from django.db import models
from meta.models import ModelMeta

class MyModel(ModelMeta, models.Model):
    name = models.CharField(max_length=20)
    abstract = models.TextField()
    image = models.ImageField()
    ...

    _metadata = {
        'title': 'name',
        'description': 'abstract',
        'image': 'get_meta_image',
        ...
    }
    def get_meta_image(self):
        if self.image:
            return self.image.url

Push metadata in the context using as_meta method:

class MyView(DetailView):

    ...

    def get_context_data(self, **kwargs):
        context = super(MyView, self).get_context_data(self, **kwargs)
        context['meta'] = self.get_object().as_meta(self.request)
        return context

For Function Based View can just use as_meta() method for pass “meta” context variable:

def post(request, id):
    template = 'single_post.html'
    post = Post.objects.get(pk=id)
    context = {}
    context['post'] = post
    context['meta'] = post.as_meta()
    return render(request, template, context)

Include meta/meta.html template in your templates:

{% load meta %}

<html>
<head {% meta_namespaces %}>
    {% include "meta/meta.html" %}
</head>
<body>
</body>
</html>

Note¶

For Google+ support you must add {% render_block 'html_extra' %} in your template to add object type definition. See relevant Google+ snippets documentation (https://developers.google.com/+/web/snippet/)
For OpenGraph / Facebook support, edit your <head> tag to use meta_namespaces templatetags

Reference template¶

See below the basic reference template:

{% load meta %}

<html>
<head {% meta_namespaces %}>
    {% include "meta/meta.html" %}
</head>
<body>
{% block content %}
{% endblock content %}
</body>
</html>