Following Django-Rest-Framework Doc about Custom metadata I need to add an attribute (myatt) to determine_metadata() method, like this for example:
def determine_metadata(self, request, view):
metadata = OrderedDict()
metadata['name'] = view.get_view_name()
metadata['description'] = view.get_view_description()
metadata['myatt'] = 'blablabla'
metadata['renders'] = [renderer.media_type for renderer in view.renderer_classes]
metadata['parses'] = [parser.media_type for parser in view.parser_classes]
if hasattr(view, 'get_serializer'):
actions = self.determine_actions(request, view)
if actions:
metadata['actions'] = actions
return metadata
I edited the metadata.py file in rest-framework directory just to test it and worked. However in the correct way, I know that I shall override the determine_metadata() method to accomplish what I want.
My problem is that I don't know where and how shall I override it.
Can you help me?
You can create a MyCustomMetadata class which will add an extra attribute to the metadata.
This class will inherit from SimpleMetadata class which is the default metadata class in DRF. Then, we will override the determine_metadata() function in it. We first call the super() to get the original metadata returned by DRF, then we add our extra attribute to the metadata.
my_app/metadata.py
from rest_framework.metadata import SimpleMetadata
class MyCustomMetadata(SimpleMetadata):
def determine_metadata(self, request, view):
metadata = super(MyCustomMetadata, self).determine_metadata(request, view)
metadata['myatt'] = 'blablabla' # add extra attribute to metadata
return metadata # return the metadata with the extra attribute set in it
Now, we need to define MyCustomMetadata class in our settings which will be used by DRF then.
settings.py
REST_FRAMEWORK = {
...
'DEFAULT_METADATA_CLASS': 'my_app.metadata.MyCustomMetadata'
}
Related
Hi I am implementing test cases for my models.
I am using Mongoengine0.9.0 + Django 1.8
My models.py
class Project(Document):
# commented waiting for org-group to get finalize
project_name = StringField()
org_group = ListField(ReferenceField(OrganizationGroup, required=False))
My Serializers.py
class ProjectSerializer(DocumentSerializer):
class Meta:
model = Project
depth = 1
test.py file
def setUp(self):
# Every test needs access to the request factory.
self.factory = RequestFactory()
self.user = User.objects.create_user(
username='jacob', email='jacob#jacob.com', password='top_secret')
def test_post_put_project(self):
"""
Ensure we can create new clients in mongo database.
"""
org_group = str((test_utility.create_organization_group(self)).id)
url = '/project-management/project/'
data = {
"project_name": "googer",
"org_group": [org_group],
}
##import pdb; pdb.set_trace()
factory = APIRequestFactory()
user = User.objects.get(username='jacob')
view = views.ProjectList.as_view()
# Make an authenticated request to the view...
request = factory.post(url, data=data,)
force_authenticate(request, user=user)
response = view(request)
self.assertEqual(response.status_code, 200)
When I am running test cases I am getting this error
(Only lists and tuples may be used in a list field: ['org_group'])
The complete Stack Trace is
ValidationError: Got a ValidationError when calling Project.objects.create().
This may be because request data satisfies serializer validations but not Mongoengine`s.
You may need to check consistency between Project and ProjectSerializer.
If that is not the case, please open a ticket regarding this issue on https://github.com/umutbozkurt/django-rest-framework-mongoengine/issues
Original exception was: ValidationError (Project:None) (Only lists and tuples may be used in a list field: ['org_group'])
Not getting why we cant pass object like this.
Same thing when I am posting as an request to same method It is working for me but test cases it is failing
The tests should be running using multipart/form-data, which means that they don't support lists or nested data.
You can override this with the format argument, which I'm guessing you probably want to set to json. Most likely your front-end is using JSON, or a parser which supports lists, which explains why you are not seeing this.
In Django REST Framework (DRF), how do I support de-Serializing base64 encoded binary data?
I have a model:
class MyModel(Model):
data = models.FileField(...)
and I want to be able to send this data as base64 encoded rather than having to multi-part form data or a "File Upload". Looking at the Parsers, only FileUploadParser and MultiPartParser seem to parse out the files.
I would like to be able to send this data in something like JSON (ie send the binary data in the data rather than the files:
{
'data':'...'
}
I solved it by creating a new Parser:
def get_B64_JSON_Parser(fields):
class Impl(parsers.JSONParser):
media_type = 'application/json+b64'
def parse(self, *args, **kwargs):
ret = super(Impl, self).parse(*args, **kwargs)
for field in fields:
ret[field] = SimpleUploadedFile(name=field, content=ret[field].decode('base64'))
return ret
return Impl
which I then use in the View:
class TestModelViewSet(viewsets.ModelViewSet):
parser_classes = [get_B64_JSON_Parser(('data_file',)),]
This is an old question, but for those looking for an up-to-date solution, there is a plugin for DRF (drf_base64) that handles this situation. It allows reading files encoded as base64 strings in the JSON request.
So given a model like:
class MyModel(Model):
data = models.FileField(...)
and an expected json like:
{
"data": "data:image/png;base64,iVBORw0KGgoA ....",
...
}
The (des) serialization can be handled just importing from drf_base modules instead of the drf itself.
from drf_base64.serializers import ModelSerializer
from .models import MyModel
class MyModel(ModelSerializer):
class Meta:
model = MyModel
Just remember that is posible to get a base64 encoded file in javascript with the FileReader API.
There's probably something clever you can do at the serialiser level but the first thing that comes to mind is to do it in the view.
Step 1: Write the file. Something like:
fh = open("/path/to/media/folder/fileToSave.ext", "wb")
fh.write(fileData.decode('base64'))
fh.close()
Step 2: Set the file on the model. Something like:
instance = self.get_object()
instance.file_field.name = 'folder/fileToSave.ext' # `file_field` was `data` in your example
instance.save()
Note the absolute path at Step 1 and the path relative to the media folder at Step 2.
This should at least get you going.
Ideally you'd specify this as a serialiser field and get validation and auto-assignment to the model instance for free. But that seems complicated at first glance.
I'm using django tastypie to publish a model with a Related (ToOne) field to another model resource. The uri is:
/api/map/?format=json
I want to let the client include a full_pages url parameter to get the full related page resource: /api/map/?full_pages=1&format=json
I don't really understand the Relationship Fields docs, but I made a get_full callable:
def get_full(bundle):
if bundle.request.GET.get('full_pages', 0):
return True
return False
I tried passing the callable to the full argument of ToOneField:
from tastypie.contrib.gis import resources as gis_resources
class MapResource(gis_resources.ModelResource):
page = fields.ToOneField('pages.api.PageResource', 'page', full=get_full)
But when I check with pdb, get_full is never invoked.
So then I tried creating a custom FillableToOneField with a full attribute:
class FillableToOneField(fields.ToOneFIeld):
full = get_full
class MapResource(ModelResource):
page = FillableToOneField('pages.api.PageResource', 'page')
Again, get_full is never invoked.
Is there a better, easier way to do this?
After reading Amyth's answer and django-boundaryservice code, I got this to work by defaulting full to True and altering it in the dehydrate method on the Related PageResource:
class MapResource(gis_resources.ModelResource):
page = fields.ToOneField('pages.api.PageResource', 'page', full=True)
pages.api:
class PageResource(ModelResource):
...
def dehydrate(self, bundle):
if not bundle.request.GET.get('full_pages'):
bundle = bundle.data['resource_uri']
return bundle
You can simply achieve this under the dehydrate method as follows.
class MapResource(ModelResource):
page = fields.ToOneField('pages.api.PageResource', 'page')
def dehydrate(self, bundle):
if bundle.request.Get.get('full_pages'):
self.page.full = True
return bundle
and have them send a request as /api/map/?full_pages=True&format=json
Full Disclosure: Cross posted to Tastypie Google Group
I have a situation where I have limited control over what is being sent to my api. Essentially there are two webservices that I need to be able to accept POST data from. Both use plain POST actions with urlencoded data (basic form submission essentially).
Thinking about it in "curl" terms it's like:
curl --data "id=1&foo=2" http://path/to/api
My problem is that I can't update records using POST. So I need to adjust the model resource (I believe) such that if an ID is specified, the POST acts as a PUT instead of a POST.
api.py
class urlencodeSerializer(Serializer):
formats = ['json', 'jsonp', 'xml', 'yaml', 'html', 'plist', 'urlencoded']
content_types = {
'json': 'application/json',
'jsonp': 'text/javascript',
'xml': 'application/xml',
'yaml': 'text/yaml',
'html': 'text/html',
'plist': 'application/x-plist',
'urlencoded': 'application/x-www-form-urlencoded',
}
# cheating
def to_urlencoded(self,content):
pass
# this comes from an old patch on github, it was never implemented
def from_urlencoded(self, data,options=None):
""" handles basic formencoded url posts """
qs = dict((k, v if len(v)>1 else v[0] )
for k, v in urlparse.parse_qs(data).iteritems())
return qs
class FooResource(ModelResource):
class Meta:
queryset = Foo.objects.all() # "id" = models.AutoField(primary_key=True)
resource_name = 'foo'
authorization = Authorization() # only temporary, I know.
serializer = urlencodeSerializer()
urls.py
foo_resource = FooResource
...
url(r'^api/',include(foo_resource.urls)),
)
In #tastypie on Freenode, Ghost[], suggested that I overwrite post_list() by creating a function in the model resource like so, however, I have not been successful in using this as yet.
def post_list(self, request, **kwargs):
if request.POST.get('id'):
return self.put_detail(request,**kwargs)
else:
return super(YourResource, self).post_list(request,**kwargs)
Unfortunately this method isn't working for me. I'm hoping the larger community could provide some guidance or a solution for this problem.
Note: I cannot overwrite the headers that come from the client (as per: http://django-tastypie.readthedocs.org/en/latest/resources.html#using-put-delete-patch-in-unsupported-places)
I had a similar problem on user creation where I wasn't able to check if the record already existed. I ended up creating a custom validation method which validated if the user didn't exist in which case post would work fine. If the user did exist I updated the record from the validation method. The api still returns a 400 response but the record is updated. It feels a bit hacky but...
from tastypie.validation import Validation
class MyValidation(Validation):
def is_valid(self, bundle, request=None):
errors = {}
#if this dict is empty validation passes.
my_foo = foo.objects.filter(id=1)
if not len(my_foo) == 0: #if object exists
foo[0].foo = 'bar' #so existing object updated
errors['status'] = 'object updated' #this will be returned in the api response
return errors
#so errors is empty if object does not exist and validation passes. Otherwise object
#updated and response notifies you of this
class FooResource(ModelResource):
class Meta:
queryset = Foo.objects.all() # "id" = models.AutoField(primary_key=True)
validation = MyValidation()
With Cathal's recommendation I was able to utilize a validation function to update the records I needed. While this does not return a valid code... it works.
from tastypie.validation import Validation
import string # wrapping in int() doesn't work
class Validator(Validation):
def __init__(self,**kwargs):
pass
def is_valid(self,bundle,request=None):
if string.atoi(bundle.data['id']) in Foo.objects.values_list('id',flat=True):
# ... update code here
else:
return {}
Make sure you specify the validation = Validator() in the ModelResource meta.
I am writing an application in Django, which uses [year]/[month]/[title-text] in the url to identitfy news items. To manage the items I have defined a number of urls, each starting with the above prefix.
urlpatterns = patterns('msite.views',
(r'^(?P<year>[\d]{4})/(?P<month>[\d]{1,2})/(?P<slug>[\w]+)/edit/$', 'edit'),
(r'^(?P<year>[\d]{4})/(?P<month>[\d]{1,2})/(?P<slug>[\w]+)/$', 'show'),
(r'^(?P<year>[\d]{4})/(?P<month>[\d]{1,2})/(?P<slug>[\w]+)/save$', 'save'),
)
I was wondering, if there is a mechanism in Django, which allows me to preprocess a given request to the views edit, show and save. It could parse the parameters e.g. year=2010, month=11, slug='this-is-a-title' and extract a model object out of them.
The benefit would be, that I could define my views as
def show(news_item):
'''does some stuff with the news item, doesn't have to care
about how to extract the item from request data'''
...
instead of
def show(year, month, slug):
'''extract the model instance manually inside this method'''
...
What is the Django way of solving this?
Or in a more generic way, is there some mechanism to implement request filters / preprocessors such as in JavaEE and Ruby on Rails?
You need date based generic views and create/update/delete generic views maybe?
One way of doing this is to write a custom decorator. I tested this in one of my projects and it worked.
First, a custom decorator. This one will have to accept other arguments beside the function, so we declare another decorator to make it so.
decorator_with_arguments = lambda decorator: lambda * args, **kwargs: lambda func: decorator(func, *args, **kwargs)
Now the actual decorator:
#decorator_with_arguments
def parse_args_and_create_instance(function, klass, attr_names):
def _function(request, *args, **kwargs):
model_attributes_and_values = dict()
for name in attr_names:
value = kwargs.get(name, None)
if value: model_attributes_and_values[name] = value
model_instance = klass.objects.get(**model_attributes_and_values)
return function(model_instance)
return _function
This decorator expects two additional arguments besides the function it is decorating. These are respectively the model class for which the instance is to be prepared and injected and the names of the attributes to be used to prepare the instance. In this case the decorator uses the attributes to get the instance from the database.
And now, a "generic" view making use of a show function.
def show(model_instance):
return HttpResponse(model_instance.some_attribute)
show_order = parse_args_and_create_instance(Order, ['order_id'])(show)
And another:
show_customer = parse_args_and_create_instance(Customer, ['id'])(show)
In order for this to work the URL configuration parameters must contain the same key words as the attributes. Of course you can customize this by tweaking the decorator.
# urls.py
...
url(r'^order/(?P<order_id>\d+)/$', 'show_order', {}, name = 'show_order'),
url(r'^customer/(?P<id>\d+)/$', 'show_customer', {}, name = 'show_customer'),
...
Update
As #rebus correctly pointed out you also need to investigate Django's generic views.
Django is python after all, so you can easily do this:
def get_item(*args, **kwargs):
year = kwargs['year']
month = kwargs['month']
slug = kwargs['slug']
# return item based on year, month, slug...
def show(request, *args, **kwargs):
item = get_item(request, *args, **kwargs)
# rest of your logic using item
# return HttpResponse...