Synopsis
This module is an add-on for Django REST Framework that serves a django model respecting the Linked Data Platform convention.
It aims at enabling people with little development skills to serve their own data, to be used with a LDP application.
Building a Startin' Blox application? Read this: https://git.happy-dev.fr/startinblox/devops/doc
Requirements
- Django (known to work with django 1.11)
- Django Rest Framework
- pyld
- django-guardian
- djangorestframework-guardian
Installation
- Install this module and all its dependencies
$ pip install djangoldp
- Create a django project
$ django-admin startproject myldpserver
- Add DjangoLDP to INSTALLED_APPS
INSTALLED_APPS = [
...
# make sure all of your own apps are installed BEFORE DjangoLDP
'djangoldp.apps.DjangoldpConfig',
]
IMPORTANT: DjangoLDP will register any models which haven't been registered, with the admin. As such it is important to add your own apps above DjangoLDP, so that you can use custom Admin classes if you wish
- Create your django model inside a file myldpserver/myldpserver/models.py Note that container_path will be use to resolve instance iri and container iri In the future it could also be used to auto configure django router (e.g. urls.py)
from djangoldp.models import Model
class Todo(Model):
name = models.CharField(max_length=255)
deadline = models.DateTimeField()
4.1. Configure container path (optional) By default it will be "todos/" with an S for model called Todo
<Model>._meta.container_path = "/my-path/"
4.2. Configure field visibility (optional) Note that at this stage you can limit access to certain fields of models using
<Model>._meta.serializer_fields (<>list of field names to show>)
For example, if you have a model with a related field with type django.contrib.auth.models.User you don't want to show personal details or password hashes.
E.g.
from django.contrib.auth.models import User
User._meta.serializer_fields = ('username','first_name','last_name')
Note that this will be overridden if you explicitly set the fields= parameter as an argument to LDPViewSet.urls(), and filtered if you set the excludes= parameter.
- Add a url in your urls.py:
from django.conf.urls import url
from django.contrib import admin
from djangoldp.views import LDPViewSet
from .models import Todo
urlpatterns = [
url(r'^', include('djangoldp.urls')),
url(r'^admin/', admin.site.urls), # Optional
]
This creates 2 routes for each Model, one for the list, and one with an ID listing the detail of an object.
You could also only use this line in settings.py instead:
ROOT_URLCONF = 'djangoldp.urls'
- In the settings.py file, add your application name at the beginning of the application list, and add the following lines
STATIC_ROOT = os.path.join(os.path.dirname(BASE_DIR), 'static')
LDP_RDF_CONTEXT = 'https://cdn.happy-dev.fr/owl/hdcontext.jsonld'
DJANGOLDP_PACKAGES = []
SITE_URL = 'http://localhost:8000'
BASE_URL = SITE_URL
-
LDP_RDF_CONTEXT
tells DjangoLDP where our RDF ontology is defined, which will be returned as part of our views in the 'context' field. This is a web URL and you can visit the value to view the full ontology online -
DJANGOLDP_PACKAGES
defines which other DjangoLDP packages we're using in this installation -
SITE_URL
is the URL serving the site, e.g.https://example.com/
-
BASE_URL
may be different from SITE_URL, e.g.https://example.com/app/
- You can also register your model for the django administration site
from django.contrib import admin
from .models import Todo
admin.site.register(Todo)
-
You then need to have your WSGI server pointing on myldpserver/myldpserver/wsgi.py
-
You will probably need to create a super user
$ ./manage.py createsuperuser
- If you have no CSS on the admin screens :
$ ./manage.py collectstatic
Execution
To start the server, cd
to the root of your Django project and run :
$ python3 manage.py runserver
Custom Parameters to LDPViewSet
lookup_field
Can be used to use a slug in the url instead of the primary key.
LDPViewSet.urls(model=User, lookup_field='username')
nested_fields
list of ForeignKey, ManyToManyField, OneToOneField and their reverse relations. When a field is listed in this parameter, a container will be created inside each single element of the container.
In the following example, besides the urls /members/
and /members/<pk>/
, two other will be added to serve a container of the skills of the member: /members/<pk>/skills/
and /members/<pk>/skills/<pk>/
<Model>._meta.nested_fields=["skills"]
Custom Meta options on models
rdf_type
auto_author
This property allows to associate a model with the logged in user.
class MyModel(models.Model):
author_user = models.ForeignKey(settings.AUTH_USER_MODEL)
class Meta:
auto_author = 'author_user'
Now when an instance of MyModel
is saved, its author_user
property will be set to the current user.
permissions_classes
This allows you to add permissions for anonymous, logged in user, author ... in the url:
By default LDPPermissions
is used.
Specific permissin classes can be developed to fit special needs.
anonymous_perms, user_perms, owner_perms
Those allow you to set permissions from your model's meta.
You can give the following permission to them:
view
add
change
control
delete
inherit
With inherit, Users can herit from Anons. Also Owners can herit from Users.
Eg. with this model Anons can view, Auths can add & Owners can edit & delete.
Note that owner_perms
need a owner_field
meta that point the field with owner user.
from djangoldp.models import Model
class Todo(Model):
name = models.CharField(max_length=255)
deadline = models.DateTimeField()
user = models.ForeignKey(settings.AUTH_USER_MODEL)
class Meta:
anonymous_perms = ['view']
authenticated_perms = ['inherit', 'add']
owner_perms = ['inherit', 'change', 'control', 'delete']
owner_field = 'user'
Important note: If you need to give permissions to owner's object, don't forget to add auto_author in model's meta
view_set
In case of custom viewset, you can use
from djangoldp.models import Model
class Todo(Model):
name = models.CharField(max_length=255)
deadline = models.DateTimeField()
class Meta:
view_set = TodoViewSet
container_path
See 3.1. Configure container path (optional)
serializer_fields
from djangoldp.models import Model
class Todo(Model):
name = models.CharField(max_length=255)
deadline = models.DateTimeField()
class Meta:
serializer_fields = ['name']
Only name
will be serialized
Custom urls
To add customs urls who can not be add through the Model
class, it's possible de create a file named djangoldp_urls.py
. It will be executed like an urls.py
file
Pagination
To enable pagination feature just add this configuration to the server settings.py
:
REST_FRAMEWORK = {
'DEFAULT_PAGINATION_CLASS': 'djangoldp.pagination.LDPPagination',
'PAGE_SIZE': 20
}
Sources
To enable sources auto creation for all models, change djangoldp
by djangoldp.apps.DjangoldpConfig
, on INSTALLED_APPS
INSTALLED_APPS = [
'djangoldp.apps.DjangoldpConfig',
]
301 on domain mismatch
To enable 301 redirection on domain mismatch, add djangoldp.middleware.AllowOnlySiteUrl
on MIDDLEWARE
This ensure that your clients will use SITE_URL
and avoid mismatch betwen url & the id of a resource/container
MIDDLEWARE = [
'djangoldp.middleware.AllowOnlySiteUrl',
]
Notice tht it'll redirect only HTTP 200 Code.
License
Licence MIT