Related
The answer to this question is confusing me.
Multiple Models in Django Rest Framework?
the answer is to a question of sending multipule models in a response. I have the same use case.
the author of the answer has this:
def get(self, request, format=None, **kwargs):
cart = get_cart(request)
cart_serializer = CartSerializer(cart)
another_serializer = AnotherSerializer(another_object)
return Response({
'cart': cart_serializer.data,
'another': another_serializer.data,
'yet_another_field': 'yet another value',
})
but I am keeping with the documentation.
http://www.django-rest-framework.org/api-guide/serializers/#serializing-objects
EXAMPLE FROM DOCS
serializer = CommentSerializer(comment)
serializer.data
# {'email': 'leila#example.com', 'content': 'foo bar', 'created': '2016-01-27T15:17:10.375877'}
from rest_framework.renderers import JSONRenderer
json = JSONRenderer().render(serializer.data)
json
# b'{"email":"leila#example.com","content":"foo bar","created":"2016-01-27T15:17:10.375877"}'
so which one is it? Do I JSON or not JSON. This is what I currently have.
def get(self, request, format=None):
searchcityqueryset = SearchCity.objects.all()
neighborhoodqueryset = SearchNeighborhood.objects.all()
serializedsearchcity = SearchCitySerializer(searchcityqueryset)
serializedsearchneighborhood = SearchNeighborhoodSerializer(neighborhoodqueryset)
jsonsearchcity = JSONRenderer().render(serializedsearchcity.data)
jsonsearchneighborhood = JSONRenderer().render(serializedsearchneighborhood.data)
return Response({
'searchcity': jsonsearchcity,
'searchneighborhood': jsonsearchneighborhood,
})
You don't need to do it.
From the doc:
Unlike regular HttpResponse objects, you do not instantiate Response
objects with rendered content. Instead you pass in unrendered data,
which may consist of any Python primitives.
Also JSONRenderer is default renderer class, which will be used to render.
So you can simple do this:
return Response({
'cart': cart_serializer.data,
'another': another_serializer.data,
'yet_another_field': 'yet another value',
})
I'm working in Django 1.8 and having trouble finding the modern way to do this.
This is what I've got, based on Googling and this blog post:
results = PCT.objects.filter(code__startswith='a')
json_res = []
for result in results:
json_res.append(result.as_dict())
return HttpResponse(json.dumps(json_res), content_type='application/json')
However this gives me 'PCT' object has no attribute 'as_dict'.
Surely there must be a neater way by now?
I was wondering if it was possible to use JSONResponse but frustratingly, the docs give no example of how to use JSONRespose with a queryset, which must be the most common use case. I have tried this:
results = PCT.objects.filter(code__startswith='a')
return JsonResponse(results, safe=False)
This gives [<PCT: PCT object>, <PCT: PCT object>] is not JSON serializable.
Simplest solution without any additional framework:
results = PCT.objects.filter(code__startswith='a').values('id', 'name')
return JsonResponse({'results': list(results)})
returns {'results': [{'id': 1, 'name': 'foo'}, ...]}
or if you only need the values:
results = PCT.objects.filter(code__startswith='a').values_list('id', 'name')
return JsonResponse({'results': list(results)})
returns {'results': [[1, 'foo'], ...]}
use values() to return a querydict, and pass that to json.dumps
values = PCT.objects.filter(code__startswith='a').values()
return HttpResponse(json.dumps(values), content_type='application/json')
https://docs.djangoproject.com/en/1.8/ref/models/querysets/#values
Most of these answers are out of date. Here's what I use:
views.py (returns HTML)
from django.shortcuts import render
from django.core import serializers
def your_view(request):
data = serializers.serialize('json', YourModel.objects.all())
context = {"data":data}
return render(request, "your_view.html", context)
views.py (returns JSON)
from django.core import serializers
from django.http import HttpResponse
def your_view(request):
data = serializers.serialize('json', YourModel.objects.all())
return HttpResponse(data, content_type='application/json')
Take a look at Django's serialization framework. It allows not only the XML format, but also JSON and YAML.
The accepted answer, using JsonResponse, is nice and simple. However, it does not return complete objects.
An alternative is to use Django's serializers. Here's an example copied verbatim from the admin actions documentation:
...
response = HttpResponse(content_type="application/json")
serializers.serialize("json", queryset, stream=response)
return response
This is very similar to what happens in Django's JsonResponse, as can be seen in the source.
The main difference is that JsonResponse calls json.dumps() directly, and does not know how to handle querysets, whereas the example above uses serializers.serialize('json', ...), which does know how to handle querysets, and returns complete objects that can also be de-serialized later on.
If you want to save directly to file (using content-disposition: attachment to open a save dialog in the browser), you could use a FileResponse, for example:
...
data = serializers.serialize('json', queryset)
return FileResponse(
io.BytesIO(data.encode('utf-8')),
content_type='application/json',
as_attachment=True,
filename=f'{queryset.model.__name__.lower()}-objects.json'
)
I am trying to write a Django Rest Framework API handler that can receive a file as well as a JSON payload. I've set the MultiPartParser as the handler parser.
However, it seems I cannot do both. If I send the payload with the file as a multi part request, the JSON payload is available in a mangled manner in the request.data (first text part until the first colon as the key, the rest is the data). I can send the parameters in standard form parameters just fine - but the rest of my API accepts JSON payloads and I wanted to be consistent. The request.body cannot be read as it raises *** RawPostDataException: You cannot access body after reading from request's data stream
For example, a file and this payload in the request body:
{"title":"Document Title", "description":"Doc Description"}
Becomes:
<QueryDict: {u'fileUpload': [<InMemoryUploadedFile: 20150504_115355.jpg (image/jpeg)>, <InMemoryUploadedFile: Front end lead.doc (application/msword)>], u'{%22title%22': [u'"Document Title", "description":"Doc Description"}']}>
Is there a way to do this? Can I eat my cake, keep it and not gain any weight?
Edit:
It was suggested that this might be a copy of Django REST Framework upload image: "The submitted data was not a file". It is not. The upload and request is done in multipart, and keep in mind the file and upload of it is fine. I can even complete the request with standard form variables. But I want to see if I can get a JSON payload in there instead.
For someone who needs to upload a file and send some data, there is no straight fwd way you can get it to work. There is an open issue in json api specs for this. One possibility i have seen is to use multipart/related as shown here, but i think its very hard to implement it in drf.
Finally what i had implemented was to send the request as formdata. You would send each file as file and all other data as text.
Now for sending the data as text you can have a single key called data and send the whole json as string in value.
Models.py
class Posts(models.Model):
id = models.UUIDField(default=uuid.uuid4, primary_key=True, editable=False)
caption = models.TextField(max_length=1000)
media = models.ImageField(blank=True, default="", upload_to="posts/")
tags = models.ManyToManyField('Tags', related_name='posts')
serializers.py -> no special changes needed, not showing my serializer here as its too lengthy because of the writable ManyToMany Field implimentation.
views.py
class PostsViewset(viewsets.ModelViewSet):
serializer_class = PostsSerializer
parser_classes = (MultipartJsonParser, parsers.JSONParser)
queryset = Posts.objects.all()
lookup_field = 'id'
You will need custom parser as shown below for parsing json.
utils.py
from django.http import QueryDict
import json
from rest_framework import parsers
class MultipartJsonParser(parsers.MultiPartParser):
def parse(self, stream, media_type=None, parser_context=None):
result = super().parse(
stream,
media_type=media_type,
parser_context=parser_context
)
data = {}
# find the data field and parse it
data = json.loads(result.data["data"])
qdict = QueryDict('', mutable=True)
qdict.update(data)
return parsers.DataAndFiles(qdict, result.files)
The request example in postman
EDIT:
see this extended answer if you want to send each data as key value pair
I know this is an old thread, but I just came across this. I had to use MultiPartParser in order to get my file and extra data to come across together. Here's what my code looks like:
# views.py
class FileUploadView(views.APIView):
parser_classes = (MultiPartParser,)
def put(self, request, filename, format=None):
file_obj = request.data['file']
ftype = request.data['ftype']
caption = request.data['caption']
# ...
# do some stuff with uploaded file
# ...
return Response(status=204)
My AngularJS code using ng-file-upload is:
file.upload = Upload.upload({
url: "/api/picture/upload/" + file.name,
data: {
file: file,
ftype: 'final',
caption: 'This is an image caption'
}
});
I send JSON and an image to create/update a product object. Below is a create APIView that works for me.
Serializer
class ProductCreateSerializer(serializers.ModelSerializer):
class Meta:
model = Product
fields = [
"id",
"product_name",
"product_description",
"product_price",
]
def create(self,validated_data):
return Product.objects.create(**validated_data)
View
from rest_framework import generics,status
from rest_framework.parsers import FormParser,MultiPartParser
class ProductCreateAPIView(generics.CreateAPIView):
queryset = Product.objects.all()
serializer_class = ProductCreateSerializer
permission_classes = [IsAdminOrIsSelf,]
parser_classes = (MultiPartParser,FormParser,)
def perform_create(self,serializer,format=None):
owner = self.request.user
if self.request.data.get('image') is not None:
product_image = self.request.data.get('image')
serializer.save(owner=owner,product_image=product_image)
else:
serializer.save(owner=owner)
Example test:
def test_product_creation_with_image(self):
url = reverse('products_create_api')
self.client.login(username='testaccount',password='testaccount')
data = {
"product_name" : "Potatoes",
"product_description" : "Amazing Potatoes",
"image" : open("local-filename.jpg","rb")
}
response = self.client.post(url,data)
self.assertEqual(response.status_code,status.HTTP_201_CREATED)
#Nithin solution works but essentially it means you are sending JSON as strings and hence not using the actual application/json inside the multipart segments.
What we want is to make the backend accept data in the below format
------WebKitFormBoundaryrga771iuUYap8BB2
Content-Disposition: form-data; name="file"; filename="1x1_noexif.jpeg"
Content-Type: image/jpeg
------WebKitFormBoundaryrga771iuUYap8BB2
Content-Disposition: form-data; name="myjson"; filename="blob"
Content-Type: application/json
{"hello":"world"}
------WebKitFormBoundaryrga771iuUYap8BB2
Content-Disposition: form-data; name="isDownscaled"; filename="blob"
Content-Type: application/json
false
------WebKitFormBoundaryrga771iuUYap8BB2--
MultiPartParser works with the above format but will treat those jsons as files. So we simply unmarshal those jsons by putting them to data.
parsers.py
from rest_framework import parsers
class MultiPartJSONParser(parsers.MultiPartParser):
def parse(self, stream, *args, **kwargs):
data = super().parse(stream, *args, **kwargs)
# Any 'File' found having application/json as type will be moved to data
mutable_data = data.data.copy()
unmarshaled_blob_names = []
json_parser = parsers.JSONParser()
for name, blob in data.files.items():
if blob.content_type == 'application/json' and name not in data.data:
mutable_data[name] = json_parser.parse(blob)
unmarshaled_blob_names.append(name)
for name in unmarshaled_blob_names:
del data.files[name]
data.data = mutable_data
return data
settings.py
REST_FRAMEWORK = {
..
'DEFAULT_PARSER_CLASSES': [
..
'myproject.parsers.MultiPartJSONParser',
],
}
This should work now.
The final bit is testing. Since the test client that ships with Django and REST doesn't support multipart JSON, we work around that by wrapping any JSON data.
import io
import json
def JsonBlob(obj):
stringified = json.dumps(obj)
blob = io.StringIO(stringified)
blob.content_type = 'application/json'
return blob
def test_simple(client, png_3x3):
response = client.post(f'http://localhost/files/', {
'file': png_3x3,
'metadata': JsonBlob({'lens': 'Sigma 35mm'}),
}, format='multipart')
assert response.status_code == 200
If you're getting an error along the lines of Incorrect type. Expected pk value, received list., with #nithin's solution, it's because Django's QueryDict is getting in the way - it's specifically structured to use a list for each entry in the dictionary, and thus:
{ "list": [1, 2] }
when parsed by MultipartJsonParser yields
{ 'list': [[1, 2]] }
which trips up your serializer.
Here is an alternative which handles this case, specifically expecting the _data key for your JSON:
from rest_framework import parsers
import json
class MultiPartJSONParser(parsers.MultiPartParser):
def parse(self, stream, *args, **kwargs):
data = super().parse(stream, *args, **kwargs)
json_data_field = data.data.get('_data')
if json_data_field is not None:
parsed = json.loads(json_data_field)
mutable_data = {}
for key, value in parsed.items():
mutable_data[key] = value
mutable_files = {}
for key, value in data.files.items():
if key != '_data':
mutable_files[key] = value
return parsers.DataAndFiles(mutable_data, mutable_files)
json_data_file = data.files.get('_data')
if json_data_file:
parsed = parsers.JSONParser().parse(json_data_file)
mutable_data = {}
for key, value in parsed.items():
mutable_data[key] = value
mutable_files = {}
for key, value in data.files.items():
mutable_files[key] = value
return parsers.DataAndFiles(mutable_data, mutable_files)
return data
It is very simple to use a multipart post and a regular view, if this is an option.
You send the json as a field and files as files, then process in one view.
Here is a simple python client and a Django server:
Client - sending multiple files and an arbitrary json-encoded object:
import json
import requests
payload = {
"field1": 1,
"manifest": "special cakes",
"nested": {"arbitrary":1, "object":[1,2,3]},
"hello": "word" }
filenames = ["file1","file2"]
request_files = {}
url="example.com/upload"
for filename in filenames:
request_files[filename] = open(filename, 'rb')
r = requests.post(url, data={'json':json.dumps(payload)}, files=request_files)
Server - consuming the json and saving the files:
#csrf_exempt
def upload(request):
if request.method == 'POST':
data = json.loads(request.POST['json'])
try:
manifest = data['manifest']
#process the json data
except KeyError:
HttpResponseServerError("Malformed data!")
dir = os.path.join(settings.MEDIA_ROOT, "uploads")
os.makedirs(dir, exist_ok=True)
for file in request.FILES:
path = os.path.join(dir,file)
if not os.path.exists(path):
save_uploaded_file(path, request.FILES[file])
else:
return HttpResponseNotFound()
return HttpResponse("Got json data")
def save_uploaded_file(path,f):
with open(path, 'wb+') as destination:
for chunk in f.chunks():
destination.write(chunk)
I'd just like to add to #Pithikos's answer by modifying the parser to accept lists as well, in line with how DRF parses lists in serializers in utils/html#parse_html_list
class MultiPartJSONParser(parsers.MultiPartParser):
def parse(self, stream, *args, **kwargs):
data = super().parse(stream, *args, **kwargs)
# Any 'File' found having application/json as type will be moved to data
mutable_data = data.data.copy()
unmarshaled_blob_names = []
json_parser = parsers.JSONParser()
for name, blob in data.files.items():
if blob.content_type == 'application/json' and name not in data.data:
parsed = json_parser.parse(blob)
if isinstance(parsed, list):
# need to break it out into [0], [1] etc
for idx, item in enumerate(parsed):
mutable_data[name+f"[{str(idx)}]"] = item
else:
mutable_data[name] = parsed
unmarshaled_blob_names.append(name)
for name in unmarshaled_blob_names:
del data.files[name]
data.data = mutable_data
return data
The following code worked for me.
from django.core.files.uploadedfile import SimpleUploadedFile
import requests
from typing import Dict
with open(file_path, 'rb') as f:
file = SimpleUploadedFile('Your-Name', f.read())
data: Dict[str,str]
files: Dict[str,SimpleUploadedFile] = {'model_field_name': file}
requests.put(url, headers=headers, data=data, files=files)
requests.post(url, headers=headers, data=data, files=files)
'model_field_name' is the name of the FileField or ImageField in your Django model. You can pass other data as name or location as usual by using data parameter.
Hope this helps.
This work for me:
class FileUpload(APIView):
parser_classes = [MultiPartParser]
authentication_classes = [JWTAuthentication]
def post(self, request, filename, format=None):
file = request.data['file']
data = json.loads(request.POST['form'])
#.... just do.....
.
.
.
frontend part: example with fetch (vue frontend)
let data = await new FormData(); // creates a new FormData object
data.append("file", this.files); // add your file to form data
data.append('form',JSON.stringify(body)) //add your json
fetch(`https://endpoint/FileUpload/${body.nombre}`, {
method: 'POST',
body: data,
headers: {Authorization: `Bearer ${accessToken}`}
})
I hope this helps.
I am trying to serialize my form into the json format. My view:
form = CSVUploadForm(request.POST, request.FILES)
data_to_json={}
data_to_json = simplejson.dumps(form.__dict__)
return HttpResponse(data_to_json, mimetype='application/json')
I have the error <class 'django.forms.util.ErrorList'> is not JSON serializable. What to do to handle django forms?
Just in case anyone is new to Django, you can also do something like this:
from django.http import JsonResponse
form = YourForm(request.POST)
if form.is_valid():
data = form.cleaned_data
return JsonResponse(data)
else:
data = form.errors.as_json()
return JsonResponse(data, status=400)
JsonResponse: https://docs.djangoproject.com/en/dev/ref/request-response/#jsonresponse-objects
Form.cleaned_data: https://docs.djangoproject.com/en/dev/ref/forms/api/#django.forms.Form.cleaned_data
Form.errors.as_json(): https://docs.djangoproject.com/en/dev/ref/forms/api/#django.forms.Form.errors.as_json
You may want to look at the package called django-remote-forms:
A package that allows you to serialize django forms, including fields
and widgets into Python dictionary for easy conversion into JSON and
expose over API
Also see:
How to cast Django form to dict where keys are field id in template and values are initial values?
I want to serialize my queryset, and I want it in a format as this view outputs:
class JSONListView(ListView):
queryset = Users.objects.all()
def get(self, request, *args, **kwargs):
return HttpResponse(json.dumps({'data': [['bar','foo','bar','foo'],['foo','bar','foo','bar']]}, indent=4), content_type='application/json')
I simply don't know how to output the queryset instead of the manual data in the example.
I've tried
json.dumps({"data": self.get_queryset()})
and
serializers.serialize("json", {'data': self.get_queryset()})
but it won't work. What am I doing wrong? Do I need to make a custom JSON Encoder?
You can use JsonResponse with values. Simple example:
from django.http import JsonResponse
def some_view(request):
data = list(SomeModel.objects.values()) # wrap in list(), because QuerySet is not JSON serializable
return JsonResponse(data, safe=False) # or JsonResponse({'data': data})
Or another approach with Django's built-in serializers:
from django.core import serializers
from django.http import HttpResponse
def some_view(request):
qs = SomeModel.objects.all()
qs_json = serializers.serialize('json', qs)
return HttpResponse(qs_json, content_type='application/json')
In this case result is slightly different (without indent by default):
[
{
"model": "some_app.some_model",
"pk": 1,
"fields": {
"name": "Elon",
"age": 48,
...
}
},
...
]
I have to say, it is good practice to use something like marshmallow to serialize queryset.
...and a few notes for better performance:
use pagination if your queryset is big;
use objects.values() to specify list of required fields to avoid serialization and sending to client unnecessary model's fields (you also can pass fields to serializers.serialize);
It didn't work, because QuerySets are not JSON serializable.
1) In case of json.dumps you have to explicitely convert your QuerySet to JSON serializable objects:
class Model(model.Model):
def as_dict(self):
return {
"id": self.id,
# other stuff
}
And the serialization:
dictionaries = [ obj.as_dict() for obj in self.get_queryset() ]
return HttpResponse(json.dumps({"data": dictionaries}), content_type='application/json')
2) In case of serializers. Serializers accept either JSON serializable object or QuerySet, but a dictionary containing a QuerySet is neither. Try this:
serializers.serialize("json", self.get_queryset())
Read more about it here:
https://docs.djangoproject.com/en/dev/topics/serialization/
For a efficient solution, you can use .values() function to get a list of dict objects and then dump it to json response by using i.e. JsonResponse (remember to set safe=False).
Once you have your desired queryset object, transform it to JSON response like this:
...
data = list(queryset.values())
return JsonResponse(data, safe=False)
You can specify field names in .values() function in order to return only wanted fields (the example above will return all model fields in json objects).
To return the queryset you retrieved with queryset = Users.objects.all(), you first need to serialize them.
Serialization is the process of converting one data structure to another. Using Class-Based Views, you could return JSON like this.
from django.core.serializers import serialize
from django.http import JsonResponse
from django.views.generic import View
class JSONListView(View):
def get(self, request, *args, **kwargs):
qs = User.objects.all()
data = serialize("json", qs)
return JsonResponse(data)
This will output a list of JSON. For more detail on how this works, check out my blog article How to return a JSON Response with Django. It goes into more detail on how you would go about this.
If the goal is to build an API that allow you to access your models in JSON format I recommend you to use the django-restframework that is an enormously popular package within the Django community to achieve this type of tasks.
Django Rest Framework Website
Github
It include useful features such as Pagination, Defining Serializers, Nested models/relations and more. Even if you only want to do minor Javascript tasks and Ajax calls I would still suggest you to build a proper API using the Django Rest Framework instead of manually defining the JSON response.
Another way to turn queryset into JSON, is appending necessary elements to an empty list with loop. It provides to design customizable JSON.
queryset = Users.objects.all()
output = []
for query in queryset:
output.append('id': query.id, 'name': query.name, etc...)
return JSONResponse(output, safe=False)
Try this:
class JSONListView(ListView):
queryset = Users.objects.all()
def get(self, request, *args, **kwargs):
data = {}
data["users"] = get_json_list(queryset)
return JSONResponse(data)
def get_json_list(query_set):
list_objects = []
for obj in query_set:
dict_obj = {}
for field in obj._meta.get_fields():
try:
if field.many_to_many:
dict_obj[field.name] = get_json_list(getattr(obj, field.name).all())
continue
dict_obj[field.name] = getattr(obj, field.name)
except AttributeError:
continue
list_objects.append(dict_obj)
return list_objects
from django.http import JsonResponse
def SomeFunction():
dict1 = {}
obj = list( Mymodel.objects.values() )
dict1['data']=obj
return JsonResponse(dict1)
Try this code for Django