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Django4.0 文件上传-简单文件上传

考虑一个包含 ​FileField ​的表单:

from django import forms

class UploadFileForm(forms.Form):
    title = forms.CharField(max_length=50)
    file = forms.FileField()

处理这个表单的视图将在 ​request.FILES​ 中接收文件数据,它是一个字典,包含表单中每个 ​FileField ​(或 ​ImageField​,或其他 ​FileField ​子类)的键。所以上述表单中的数据将以 ​request.FILES['file']​ 的形式被访问。
注意 ​request.FILES​ 只有当请求方法是 ​POST​,至少有一个文件字段被实际发布,并且发布请求的 ​<form>​ 有 ​enctype="multipart/form-data"​ 属性时,才会包含数据。否则 ​request.FILES​ 将为空。
大多数情况下,你需要像将上传的文件绑定到表单中 里描述的那样将文件数据从 ​request ​传递给表单。示例如下:

from django.http import HttpResponseRedirect
from django.shortcuts import render
from .forms import UploadFileForm

# Imaginary function to handle an uploaded file.
from somewhere import handle_uploaded_file

def upload_file(request):
    if request.method == 'POST':
        form = UploadFileForm(request.POST, request.FILES)
        if form.is_valid():
            handle_uploaded_file(request.FILES['file'])
            return HttpResponseRedirect('/success/url/')
    else:
        form = UploadFileForm()
    return render(request, 'upload.html', {'form': form})

注意我们必须将 ​request.FILES​ 传入到表单的 构造方法中,只有这样文件数据才能绑定到表单中。
我们通常可能像这样处理上传文件:

def handle_uploaded_file(f):
    with open('some/file/name.txt', 'wb+') as destination:
        for chunk in f.chunks():
            destination.write(chunk)

使用 ​UploadedFile.chunks()​ 而不是 ​read()​ 是为了确保即使是大文件也不会将我们系统的内存占满。

通过模板来处理上传的文件

如果想要在 ​FileField ​上的 ​Model ​保存文件,使用 ​ModelForm ​会让这一过程变得简单。当调用 ​form.save()​ 时,文件对象将会被保存在对相应 ​FileField ​的 ​upload_to ​参数所指定的地方:

from django.http import HttpResponseRedirect
from django.shortcuts import render
from .forms import ModelFormWithFileField

def upload_file(request):
    if request.method == 'POST':
        form = ModelFormWithFileField(request.POST, request.FILES)
        if form.is_valid():
            # file is saved
            form.save()
            return HttpResponseRedirect('/success/url/')
    else:
        form = ModelFormWithFileField()
    return render(request, 'upload.html', {'form': form})

如果你准备手工构建对象,你可以指定来自 ​request.FILES​ 的文件对象到模型里的文件对象:

from django.http import HttpResponseRedirect
from django.shortcuts import render
from .forms import UploadFileForm
from .models import ModelWithFileField

def upload_file(request):
    if request.method == 'POST':
        form = UploadFileForm(request.POST, request.FILES)
        if form.is_valid():
            instance = ModelWithFileField(file_field=request.FILES['file'])
            instance.save()
            return HttpResponseRedirect('/success/url/')
    else:
        form = UploadFileForm()
    return render(request, 'upload.html', {'form': form})

如果您在请求之外手动构建对象,则可以将类似文件的对象分配给 ​FileField​:

from django.core.management.base import BaseCommand
from django.core.files.base import ContentFile

class MyCommand(BaseCommand):
    def handle(self, *args, **options):
        content_file = ContentFile(b'Hello world!', name='hello-world.txt')
        instance = ModelWithFileField(file_field=content_file)
        instance.save()

上传多个文件

如果你想使用一个表单字段上传多个文件,则需要设置字段的 ​widget的 ​multiple HTML​ 属性。

from django import forms

class FileFieldForm(forms.Form):
    file_field = forms.FileField(widget=forms.ClearableFileInput(attrs={'multiple': True}))

然后覆盖 ​FormView ​子类的 ​post ​方法来控制多个文件上传:

from django.views.generic.edit import FormView
from .forms import FileFieldForm

class FileFieldFormView(FormView):
    form_class = FileFieldForm
    template_name = 'upload.html'  # Replace with your template.
    success_url = '...'  # Replace with your URL or reverse().

    def post(self, request, *args, **kwargs):
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        files = request.FILES.getlist('file_field')
        if form.is_valid():
            for f in files:
                ...  # Do something with each file.
            return self.form_valid(form)
        else:
            return self.form_invalid(form)


Django4.0 处理HTTP请求-视图装饰器
Django4.0 文件上传-上传 Handlers
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Django4.0 模型和数据库

Django4.0 处理HTTP请求

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