我在模型中有图像字段类型的文件...我想检查用户上传的文件是否为图像，如果我想将其图像转换为“ jpeg”格式以减小尺寸和安全性..我该怎么做？
相关视图：
class StoreCreateAPIView(generics.CreateAPIView):
parser_classes = (MultiPartParser, FormParser)
permission_classes = [IsAuthenticated, IsSuperUserOrAdmin]
def post(self, request, *args, **kwargs):
if request.method == 'POST':
file_serial = ProductSerializer(data=request.data, context={"request": request})
if file_serial.is_valid():
file_serial.save(author_id=request.user.id)
型号：
def validate_image(image):
if not image.is_image():
raise ValidationError('File should be image.')
file_size = image.file.size
limit_kb = 200
if file_size > limit_kb * 1024:
raise ValidationError("Max size of file is {} KB".format(limit_kb))
# save the uploaded file in user directory
def upload_to_custom_p(instance, filename):
name = instance.title
user_id = str(instance.author.id)
filename = filename.lower()
return 'Product/img/user_{0}/{1}/{2}'.format(user_id, name, filename)
class Product(models.Model):
product_id = models.AutoField(primary_key=True)
author = models.ForeignKey(User, on_delete=models.CASCADE, db_index=True)
title = models.CharField(max_length=200)
full_description = models.TextField(null=True, blank=True)
created_date = models.DateTimeField(auto_now_add=True)
updated_date = models.DateTimeField(auto_now=True)
publish = models.BooleanField(default=False)
draft = models.BooleanField(default=False)
slug = models.SlugField(allow_unicode=True, null=True, blank=True)
image = models.FileField(upload_to=upload_to_custom_p, null=True, blank=True,validators=[validate_image])
custom_path：
# save the uploaded file in user directory
def upload_to_custom_p(instance, filename):
name = instance.title
user_id = str(instance.author.id)
filename = filename.lower()
return 'Product/img/user_{0}/{1}/{2}'.format(user_id, name, filename)
p p p p p p
错误日志：
(uenv) [deb@arch academy]$ python3 manage.py runserver
Performing system checks...
/upload/upload/aa.mp4
System check identified no issues (0 silenced).
July 22, 2018 - 15:52:01
Django version 2.0.7, using settings 'academy.settings'
Starting ASGI/Channels version 2.1.1 development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
2018-07-22 15:52:01,540 - INFO - server - HTTP/2 support not enabled (install the http2 and tls Twisted extras)
2018-07-22 15:52:01,541 - INFO - server - Configuring endpoint tcp:port=8000:interface=127.0.0.1
2018-07-22 15:52:01,543 - INFO - server - Listening on TCP address 127.0.0.1:8000
Internal Server Error: /api/v1/store/view/make/
Traceback (most recent call last):
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/ImageFile.py", line 481, in _save
fh = fp.fileno()
io.UnsupportedOperation: fileno
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/serializers.py", line 940, in create
instance = ModelClass.objects.create(**validated_data)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/db/models/query.py", line 417, in create
obj.save(force_insert=True, using=self.db)
File "/home/deb/PycharmProjects/ac2/academy/api/v1/store/models.py", line 42, in save
image.save(image_io, format='JPEG')
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/Image.py", line 1950, in save
save_handler(self, fp, filename)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 762, in _save
ImageFile._save(im, fp, [("jpeg", (0, 0)+im.size, 0, rawmode)], bufsize)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/ImageFile.py", line 496, in _save
fp.write(d)
TypeError: string argument expected, got 'bytes'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 35, in inner
response = get_response(request)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/core/handlers/base.py", line 128, in _get_response
response = self.process_exception_by_middleware(e, request)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/core/handlers/base.py", line 126, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/views/generic/base.py", line 69, in view
return self.dispatch(request, *args, **kwargs)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/views.py", line 483, in dispatch
response = self.handle_exception(exc)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/views.py", line 443, in handle_exception
self.raise_uncaught_exception(exc)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/views.py", line 480, in dispatch
response = handler(request, *args, **kwargs)
File "/home/deb/PycharmProjects/ac2/academy/api/v1/store/views.py", line 269, in post
file_serial.save(author_id=request.user.id)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/serializers.py", line 214, in save
self.instance = self.create(validated_data)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/serializers.py", line 957, in create
raise TypeError(msg)
TypeError: Got a `TypeError` when calling `Product.objects.create()`. This may be because you have a writable field on the serializer class that is not a valid argument to `Product.objects.create()`. You may need to make the field read-only, or override the ProductSerializer.create() method to handle this correctly.
Original exception was:
Traceback (most recent call last):
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/ImageFile.py", line 481, in _save
fh = fp.fileno()
io.UnsupportedOperation: fileno
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/rest_framework/serializers.py", line 940, in create
instance = ModelClass.objects.create(**validated_data)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/django/db/models/query.py", line 417, in create
obj.save(force_insert=True, using=self.db)
File "/home/deb/PycharmProjects/ac2/academy/api/v1/store/models.py", line 42, in save
image.save(image_io, format='JPEG')
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/Image.py", line 1950, in save
save_handler(self, fp, filename)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 762, in _save
ImageFile._save(im, fp, [("jpeg", (0, 0)+im.size, 0, rawmode)], bufsize)
File "/home/deb/PycharmProjects/ac2/uenv/lib/python3.6/site-packages/PIL/ImageFile.py", line 496, in _save
fp.write(d)
TypeError: string argument expected, got 'bytes'
[2018/07/22 15:52:32] HTTP POST /api/v1/store/view/make/ 500 [0.42, 127.0.0.1:52918]
答案 0 :(得分：3)
建议使用
ImageField，如果您只想上传 图片，它会自动验证上传的对象是否为有效图片。
覆盖Product模型的保存方法，并使用Image包的PIL类将其转换为JPEG
from django.core.files.base import ContentFile
from PIL import Image
from io import BytesIO
class Product(models.Model):
# attribute lies here
...
def save(self, *args, **kwargs):
if self.image:
filename = "%s.jpg" % self.image.name.split('.')[0]
image = Image.open(self.image)
# for PNG images discarding the alpha channel and fill it with some color
if image.mode in ('RGBA', 'LA'):
background = Image.new(image.mode[:-1], image.size, '#fff')
background.paste(image, image.split()[-1])
image = background
image_io = BytesIO()
image.save(image_io, format='JPEG', quality=100)
# change the image field value to be the newly modified image value
self.image.save(filename, ContentFile(image_io.getvalue()), save=False)
super(Product, self).save(*args, **kwargs)