问题
I have a Django application with a view that accepts a file to be uploaded. Using the Django REST framework I'm subclassing APIView and implementing the post() method like this:
class FileUpload(APIView):
permission_classes = (IsAuthenticated,)
def post(self, request, *args, **kwargs):
try:
image = request.FILES['image']
# Image processing here.
return Response(status=status.HTTP_201_CREATED)
except KeyError:
return Response(status=status.HTTP_400_BAD_REQUEST, data={'detail' : 'Expected image.'})
Now I'm trying to write a couple of unittests to ensure authentication is required and that an uploaded file is actually processed.
class TestFileUpload(APITestCase):
def test_that_authentication_is_required(self):
self.assertEqual(self.client.post('my_url').status_code, status.HTTP_401_UNAUTHORIZED)
def test_file_is_accepted(self):
self.client.force_authenticate(self.user)
image = Image.new('RGB', (100, 100))
tmp_file = tempfile.NamedTemporaryFile(suffix='.jpg')
image.save(tmp_file)
with open(tmp_file.name, 'rb') as data:
response = self.client.post('my_url', {'image': data}, format='multipart')
self.assertEqual(status.HTTP_201_CREATED, response.status_code)
But this fails when the REST framework attempts to encode the request
Traceback (most recent call last):
File "/home/vagrant/.virtualenvs/myapp/lib/python3.3/site-packages/django/utils/encoding.py", line 104, in force_text
s = six.text_type(s, encoding, errors)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 118: invalid start byte
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/vagrant/webapp/myproject/myapp/tests.py", line 31, in test_that_jpeg_image_is_accepted
response = self.client.post('my_url', { 'image': data}, format='multipart')
File "/home/vagrant/.virtualenvs/myapp/lib/python3.3/site- packages/rest_framework/test.py", line 76, in post
return self.generic('POST', path, data, content_type, **extra)
File "/home/vagrant/.virtualenvs/myapp/lib/python3.3/site-packages/rest_framework/compat.py", line 470, in generic
data = force_bytes_or_smart_bytes(data, settings.DEFAULT_CHARSET)
File "/home/vagrant/.virtualenvs/myapp/lib/python3.3/site-packages/django/utils/encoding.py", line 73, in smart_text
return force_text(s, encoding, strings_only, errors)
File "/home/vagrant/.virtualenvs/myapp/lib/python3.3/site-packages/django/utils/encoding.py", line 116, in force_text
raise DjangoUnicodeDecodeError(s, *e.args)
django.utils.encoding.DjangoUnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 118: invalid start byte. You passed in b'--BoUnDaRyStRiNg\r\nContent-Disposition: form-data; name="image"; filename="tmpyz2wac.jpg"\r\nContent-Type: image/jpeg\r\n\r\n\xff\xd8\xff[binary data omitted]' (<class 'bytes'>)
How can I make the test client send the data without attempting to decode it as UTF-8?
回答1:
When testing file uploads, you should pass the stream object into the request, not the data.
This was pointed out in the comments by @arocks
Pass { 'image': file} instead
But that didn't full explain why it was needed (and also didn't match the question). For this specific question, you should be doing
from PIL import Image
class TestFileUpload(APITestCase):
def test_file_is_accepted(self):
self.client.force_authenticate(self.user)
image = Image.new('RGB', (100, 100))
tmp_file = tempfile.NamedTemporaryFile(suffix='.jpg')
image.save(tmp_file)
tmp_file.seek(0)
response = self.client.post('my_url', {'image': tmp_file}, format='multipart')
self.assertEqual(status.HTTP_201_CREATED, response.status_code)
This will match a standard Django request, where the file is passed in as a stream object, and Django REST Framework handles it. When you just pass in the file data, Django and Django REST Framework interpret it as a string, which causes issues because it is expecting a stream.
And for those coming here looking to another common error, why file uploads just won't work but normal form data will: make sure to set format="multipart" when creating the request.
This also gives a similar issue, and was pointed out by @RobinElvin in the comments
It was because I was missing format='multipart'
回答2:
Python 3 users: make sure you open the file in mode='rb' (read,binary). Otherwise, when Django calls read on the file the utf-8 codec will immediately start choking. The file should be decoded as binary not utf-8, ascii or any other encoding.
# This won't work in Python 3
with open(tmp_file.name) as fp:
response = self.client.post('my_url',
{'image': fp},
format='multipart')
# Set the mode to binary and read so it can be decoded as binary
with open(tmp_file.name, 'rb') as fp:
response = self.client.post('my_url',
{'image': fp},
format='multipart')
回答3:
It's not so simple to understand how to do it if you want to use the PATCH method, but I found the solution in this question.
from django.test.client import BOUNDARY, MULTIPART_CONTENT, encode_multipart
with open(tmp_file.name, 'rb') as fp:
response = self.client.patch(
'my_url',
encode_multipart(BOUNDARY, {'image': fp}),
content_type=MULTIPART_CONTENT
)
回答4:
For those in Windows, the answer is a bit different. I had to do the following:
resp = None
with tempfile.NamedTemporaryFile(suffix='.jpg', delete=False) as tmp_file:
image = Image.new('RGB', (100, 100), "#ddd")
image.save(tmp_file, format="JPEG")
tmp_file.close()
# create status update
with open(tmp_file.name, 'rb') as photo:
resp = self.client.post('/api/articles/', {'title': 'title',
'content': 'content',
'photo': photo,
}, format='multipart')
os.remove(tmp_file.name)
The difference, as pointed in this answer (https://stackoverflow.com/a/23212515/72350), the file cannot be used after it was closed in Windows. Under Linux, @Meistro's answer should work.
回答5:
You can use Django built-in SimpleUploadedFile:
from django.core.files.uploadedfile import SimpleUploadedFile
class TestFileUpload(APITestCase):
...
def test_file_is_accepted(self):
...
tmp_file = SimpleUploadedFile(
"file.jpg", "file_content", content_type="image/jpg")
response = self.client.post(
'my_url', {'image': tmp_file}, format='multipart')
self.assertEqual(response.status_code, status.HTTP_201_CREATED)
来源：https://stackoverflow.com/questions/24201676/how-can-i-test-binary-file-uploading-with-django-rest-frameworks-test-client