如何使用 S3Boto3Storage 在 django 中上传图像，其中路径是从 django 中的视图动态设置的

Question

I'm wanting to save images to an S3 bucket using the session_key as the directory inside the bucket, in django.

I have created a test page that uploads an image to a set location in the bucket but don't know how to use the session_key to set the upload location dynamically.

I've looked at the docs for django-storages and I can see a way to do this if it wasn't for the fact that I am using a ModelForm .

Here is the code I have (I have omitted my settings.py with the bucket name and credentials):

storage_backends.py

from storages.backends.s3boto3 import S3Boto3Storage

class TestS3MediaStorage(S3Boto3Storage):
    location = 'dev/'
    default_acl = 'public-read'
    file_overwrite = False

models.py

from .storage_backends import TestS3MediaStorage

class TestS3Upload(models.Model):
    uploaded_at = models.DateTimeField(auto_now_add=True)
    file = models.FileField(storage=TestS3MediaStorage())

forms.py

from .models import TestS3Upload

class TestS3UploadForm(forms.ModelForm):

    class Meta:
        model = TestS3Upload
        fields = ['file']

views.py

from django.shortcuts import render
from django.http import HttpResponse

from .forms import TestS3UploadForm

def test_s3_upload(request):

    # create session if it doesn't already exist
    if not request.session.session_key:
        request.session.create()

    # not quite sure how to use this to set upload destination
    session_key = request.session.session_key

    if request.method == 'POST':

        form = TestS3UploadForm(request.POST, request.FILES)

        if form.is_valid():
            form.save()
            return HttpResponse("upload successful!")
    else:
        form = TestS3UploadForm()

    return render(
        request,
        'uploader/test_s3_upload.html',
        {
            'form': form
        }
    )

test_s3_upload.html

<h1>Test S3 file upload</h1>
<form method="POST" enctype="multipart/form-data">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Upload photo to S3 Bucket</button>
</form>

When I run my code and upload an image, for example car.jpg , it uploads successfully but the path inside the S3 bucket is

<bucket-name>/dev/car.jpg

and i want

<bucket-name>/dev/<session-key>/car.jpg

The packages needed are boto3 and django-storages in case anyone who wants to help answer needs to know.

Answer 1

I have figured out a way to upload an image/file to s3 to a directory using the session key. It also works for uploading a file in general, not just s3.

First I added an attribute to the model to store the session key.

class TestS3Upload(models.Model):
    session_key = models.CharField(max_length=50, null=False, blank=False)
    ...

Then I included a hidden field on the modelform that I pre-populated with the session_key value in the view.

forms.py

class TestS3UploadForm(forms.ModelForm):

    class Meta:
        model = TestS3Upload
        fields = ['file', 'session_key']
        widgets = {'session_key': forms.HiddenInput()}

views.py

def test_s3_upload(request):
    # create session if it doesn't already exist
    if not request.session.session_key:
        request.session.create()

    session_key = request.session.session_key
    ...
    form = TestS3UploadForm(initial={'session_key': session_key})

Then I created a function in my models.py that returns a path using the session_key from the model and set the model's file field upload_to attribute to this function

...
import os

def upload_to_session_key_dir(instance, filename):
    return os.path.join(instance.session_key, filename)

class TestS3Upload(models.Model):
    session_key = models.CharField(max_length=50, null=False, blank=False)
    uploaded_at = models.DateTimeField(auto_now_add=True)

    file = models.FileField(upload_to=upload_to_session_key_dir)

When saving the form now it uploads the file inside a directory with the session_key.

final views.py

from django.shortcuts import render
from django.http import HttpResponse
from .forms import TestS3UploadForm
from .models import TestS3Upload

def test_s3_upload(request):

    # create session if it doesn't already exist
    if not request.session.session_key:
        request.session.create()

    session_key = request.session.session_key

    if request.method == 'POST':

        form = TestS3UploadForm(request.POST, request.FILES)

        if form.is_valid():
            form.save()

            filename = "{}/{}".format(session_key, form.cleaned_data['file'].name)
            s3_upload_path = TestS3Upload.objects.get(file=filename).file.url

            return HttpResponse("Image successfully uploaded to bucket at location: {}".format(s3_upload_path))
    else:
        form = TestS3UploadForm(initial={'session_key': session_key})

    return render(
        request,
        'upload/test_s3_upload.html',
        {
            'form': form
        }
    )

The template for the view test_s3_upload.html remained the same.