When Django handles a file upload, the file data ends up placed in\nrequest.FILES (for more on the\nrequest object see the documentation for request and response objects). This document explains how files are stored on disk\nand in memory, and how to customize the default behavior.
Consider a form containing a FileField:
forms.pyfrom django import forms\n\n\nclass UploadFileForm(forms.Form):\n title = forms.CharField(max_length=50)\n file = forms.FileField()\nA view handling this form will receive the file data in\nrequest.FILES, which is a dictionary\ncontaining a key for each FileField (or\nImageField, or other FileField\nsubclass) in the form. So the data from the above form would\nbe accessible as request.FILES['file'].
Note that request.FILES will only\ncontain data if the request method was POST, at least one file field was\nactually posted, and the <form> that posted the request has the attribute\nenctype="multipart/form-data". Otherwise, request.FILES will be empty.
Most of the time, you’ll pass the file data from request into the form as\ndescribed in Binding uploaded files to a form. This would look something like:
views.pyfrom django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import UploadFileForm\n\n# Imaginary function to handle an uploaded file.\nfrom somewhere import handle_uploaded_file\n\n\ndef upload_file(request):\n if request.method == "POST":\n form = UploadFileForm(request.POST, request.FILES)\n if form.is_valid():\n handle_uploaded_file(request.FILES["file"])\n return HttpResponseRedirect("/success/url/")\n else:\n form = UploadFileForm()\n return render(request, "upload.html", {"form": form})\nNotice that we have to pass request.FILES into the form’s constructor; this is how file\ndata gets bound into a form.
Here’s a common way you might handle an uploaded file:
\ndef handle_uploaded_file(f):\n with open("some/file/name.txt", "wb+") as destination:\n for chunk in f.chunks():\n destination.write(chunk)\nLooping over UploadedFile.chunks() instead of using read() ensures that\nlarge files don’t overwhelm your system’s memory.
There are a few other methods and attributes available on UploadedFile\nobjects; see UploadedFile for a complete reference.
If you’re saving a file on a Model with a\nFileField, using a ModelForm\nmakes this process much easier. The file object will be saved to the location\nspecified by the upload_to argument of the\ncorresponding FileField when calling\nform.save():
from django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import ModelFormWithFileField\n\n\ndef upload_file(request):\n if request.method == "POST":\n form = ModelFormWithFileField(request.POST, request.FILES)\n if form.is_valid():\n # file is saved\n form.save()\n return HttpResponseRedirect("/success/url/")\n else:\n form = ModelFormWithFileField()\n return render(request, "upload.html", {"form": form})\nIf you are constructing an object manually, you can assign the file object from\nrequest.FILES to the file field in the\nmodel:
from django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import UploadFileForm\nfrom .models import ModelWithFileField\n\n\ndef upload_file(request):\n if request.method == "POST":\n form = UploadFileForm(request.POST, request.FILES)\n if form.is_valid():\n instance = ModelWithFileField(file_field=request.FILES["file"])\n instance.save()\n return HttpResponseRedirect("/success/url/")\n else:\n form = UploadFileForm()\n return render(request, "upload.html", {"form": form})\nIf you are constructing an object manually outside of a request, you can assign\na File like object to the\nFileField:
from django.core.management.base import BaseCommand\nfrom django.core.files.base import ContentFile\n\n\nclass MyCommand(BaseCommand):\n def handle(self, *args, **options):\n content_file = ContentFile(b"Hello world!", name="hello-world.txt")\n instance = ModelWithFileField(file_field=content_file)\n instance.save()\nIf you want to upload multiple files using one form field, create a subclass\nof the field’s widget and set its allow_multiple_selected class attribute\nto True.
In order for such files to be all validated by your form (and have the value of\nthe field include them all), you will also have to subclass FileField. See\nbelow for an example.
forms.pyfrom django import forms\n\n\nclass MultipleFileInput(forms.ClearableFileInput):\n allow_multiple_selected = True\n\n\nclass MultipleFileField(forms.FileField):\n def __init__(self, *args, **kwargs):\n kwargs.setdefault("widget", MultipleFileInput())\n super().__init__(*args, **kwargs)\n\n def clean(self, data, initial=None):\n single_file_clean = super().clean\n if isinstance(data, (list, tuple)):\n result = [single_file_clean(d, initial) for d in data]\n else:\n result = [single_file_clean(data, initial)]\n return result\n\n\nclass FileFieldForm(forms.Form):\n file_field = MultipleFileField()\nThen override the form_valid() method of your\nFormView subclass to handle multiple file\nuploads:
views.pyfrom django.views.generic.edit import FormView\nfrom .forms import FileFieldForm\n\n\nclass FileFieldFormView(FormView):\n form_class = FileFieldForm\n template_name = "upload.html" # Replace with your template.\n success_url = "..." # Replace with your URL or reverse().\n\n def form_valid(self, form):\n files = form.cleaned_data["file_field"]\n for f in files:\n ... # Do something with each file.\n return super().form_valid(form)\nWhen a user uploads a file, Django passes off the file data to an upload\nhandler – a small class that handles file data as it gets uploaded. Upload\nhandlers are initially defined in the FILE_UPLOAD_HANDLERS setting,\nwhich defaults to:
[\n "django.core.files.uploadhandler.MemoryFileUploadHandler",\n "django.core.files.uploadhandler.TemporaryFileUploadHandler",\n]\nTogether MemoryFileUploadHandler and\nTemporaryFileUploadHandler provide Django’s default file upload\nbehavior of reading small files into memory and large ones onto disk.
You can write custom handlers that customize how Django handles files. You\ncould, for example, use custom handlers to enforce user-level quotas, compress\ndata on the fly, render progress bars, and even send data to another storage\nlocation directly without storing it locally. See Writing custom upload handlers\nfor details on how you can customize or completely replace upload behavior.
\nBefore you save uploaded files, the data needs to be stored somewhere.
\nBy default, if an uploaded file is smaller than 2.5 megabytes, Django will hold\nthe entire contents of the upload in memory. This means that saving the file\ninvolves only a read from memory and a write to disk and thus is very fast.
\nHowever, if an uploaded file is too large, Django will write the uploaded file\nto a temporary file stored in your system’s temporary directory. On a Unix-like\nplatform this means you can expect Django to generate a file called something\nlike /tmp/tmpzfp6I6.upload. If an upload is large enough, you can watch\nthis file grow in size as Django streams the data onto disk.
These specifics – 2.5 megabytes; /tmp; etc. – are «reasonable defaults»\nwhich can be customized as described in the next section.
There are a few settings which control Django’s file upload behavior. See\nFile Upload Settings for details.
\nSometimes particular views require different upload behavior. In these cases,\nyou can override upload handlers on a per-request basis by modifying\nrequest.upload_handlers. By default, this list will contain the upload\nhandlers given by FILE_UPLOAD_HANDLERS, but you can modify the list\nas you would any other list.
For instance, suppose you’ve written a ProgressBarUploadHandler that\nprovides feedback on upload progress to some sort of AJAX widget. You’d add\nthis handler to your upload handlers like this:
request.upload_handlers.insert(0, ProgressBarUploadHandler(request))\nUsing list.insert(), as shown above, ensures that the progress bar handler\nis placed at the beginning of the list. Since upload handlers are executed in\norder, this placement guarantees that the progress bar handler runs before the\ndefault handlers, allowing it to track progress across the entire upload.
If you want to replace the upload handlers completely, you can assign a new\nlist:
\nrequest.upload_handlers = [ProgressBarUploadHandler(request)]\n