mirror of
https://github.com/encode/django-rest-framework.git
synced 2025-10-31 16:07:38 +03:00
125 lines
4.6 KiB
Markdown
125 lines
4.6 KiB
Markdown
---
|
|
source:
|
|
- metadata.py
|
|
---
|
|
|
|
# Metadata
|
|
|
|
> [The `OPTIONS`] method allows a client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without implying a resource action or initiating a resource retrieval.
|
|
>
|
|
> — [RFC7231, Section 4.3.7.][cite]
|
|
|
|
REST framework includes a configurable mechanism for determining how your API should respond to `OPTIONS` requests. This allows you to return API schema or other resource information.
|
|
|
|
There are not currently any widely adopted conventions for exactly what style of response should be returned for HTTP `OPTIONS` requests, so we provide an ad-hoc style that returns some useful information.
|
|
|
|
Here's an example response that demonstrates the information that is returned by default.
|
|
|
|
HTTP 200 OK
|
|
Allow: GET, POST, HEAD, OPTIONS
|
|
Content-Type: application/json
|
|
|
|
{
|
|
"name": "To Do List",
|
|
"description": "List existing 'To Do' items, or create a new item.",
|
|
"renders": [
|
|
"application/json",
|
|
"text/html"
|
|
],
|
|
"parses": [
|
|
"application/json",
|
|
"application/x-www-form-urlencoded",
|
|
"multipart/form-data"
|
|
],
|
|
"actions": {
|
|
"POST": {
|
|
"note": {
|
|
"type": "string",
|
|
"required": false,
|
|
"read_only": false,
|
|
"label": "title",
|
|
"max_length": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
## Setting the metadata scheme
|
|
|
|
You can set the metadata class globally using the `'DEFAULT_METADATA_CLASS'` settings key:
|
|
|
|
REST_FRAMEWORK = {
|
|
'DEFAULT_METADATA_CLASS': 'rest_framework.metadata.SimpleMetadata'
|
|
}
|
|
|
|
Or you can set the metadata class individually for a view:
|
|
|
|
class APIRoot(APIView):
|
|
metadata_class = APIRootMetadata
|
|
|
|
def get(self, request, format=None):
|
|
return Response({
|
|
...
|
|
})
|
|
|
|
The REST framework package only includes a single metadata class implementation, named `SimpleMetadata`. If you want to use an alternative style you'll need to implement a custom metadata class.
|
|
|
|
## Creating schema endpoints
|
|
|
|
If you have specific requirements for creating schema endpoints that are accessed with regular `GET` requests, you might consider reusing the metadata API for doing so.
|
|
|
|
For example, the following additional route could be used on a viewset to provide a linkable schema endpoint.
|
|
|
|
@action(methods=['GET'], detail=False)
|
|
def api_schema(self, request):
|
|
meta = self.metadata_class()
|
|
data = meta.determine_metadata(request, self)
|
|
return Response(data)
|
|
|
|
There are a couple of reasons that you might choose to take this approach, including that `OPTIONS` responses [are not cacheable][no-options].
|
|
|
|
---
|
|
|
|
# Custom metadata classes
|
|
|
|
If you want to provide a custom metadata class you should override `BaseMetadata` and implement the `determine_metadata(self, request, view)` method.
|
|
|
|
Useful things that you might want to do could include returning schema information, using a format such as [JSON schema][json-schema], or returning debug information to admin users.
|
|
|
|
## Example
|
|
|
|
The following class could be used to limit the information that is returned to `OPTIONS` requests.
|
|
|
|
class MinimalMetadata(BaseMetadata):
|
|
"""
|
|
Don't include field and other information for `OPTIONS` requests.
|
|
Just return the name and description.
|
|
"""
|
|
def determine_metadata(self, request, view):
|
|
return {
|
|
'name': view.get_view_name(),
|
|
'description': view.get_view_description()
|
|
}
|
|
|
|
Then configure your settings to use this custom class:
|
|
|
|
REST_FRAMEWORK = {
|
|
'DEFAULT_METADATA_CLASS': 'myproject.apps.core.MinimalMetadata'
|
|
}
|
|
|
|
# Third party packages
|
|
|
|
The following third party packages provide additional metadata implementations.
|
|
|
|
## DRF-schema-adapter
|
|
|
|
[drf-schema-adapter][drf-schema-adapter] is a set of tools that makes it easier to provide schema information to frontend frameworks and libraries. It provides a metadata mixin as well as 2 metadata classes and several adapters suitable to generate [json-schema][json-schema] as well as schema information readable by various libraries.
|
|
|
|
You can also write your own adapter to work with your specific frontend.
|
|
If you wish to do so, it also provides an exporter that can export those schema information to json files.
|
|
|
|
[cite]: https://tools.ietf.org/html/rfc7231#section-4.3.7
|
|
[no-options]: https://www.mnot.net/blog/2012/10/29/NO_OPTIONS
|
|
[json-schema]: https://json-schema.org/
|
|
[drf-schema-adapter]: https://github.com/drf-forms/drf-schema-adapter
|