Limit Amount Of Files A User Can Upload

Question

I have a multi-file upload and want to limit users to 3 uploads each. My problem is that I need to know how many files a user has already created in the DB and how many they are currently uploading (they can upload multiple files at once, and can upload multiple times).

I have attempted many things, including:

Creating a validator (the validator was passed the actual file being added, not a model, so I couldn't access the model to get it's id to call if StudentUploadedFile.objects.filter(student_lesson_data=data.id).count() >= 4:).

Doing the validation in clean(self): (clean was only passed one instance at a time and the DB isn't updated till all files are cleaned, so I could count the files already in the DB but couldn't count how many were currently being uploaded).

Using a pre-save method (If the DB was updated between each file being passed to my pre-save method it would work, but the DB is only updated after all the files being uploaded have passed through my pre-save method).

My post-save attempt:

@receiver(pre_save, sender=StudentUploadedFile)
def upload_file_pre_save(sender, instance, **kwargs):

    if StudentUploadedFile.objects.filter(student_lesson_data=instance.data.id).count() >= 4:
        raise ValidationError('Sorry, you cannot upload more than three files')

edit:

models.py

class StudentUploadedFile(models.Model):
    student_lesson_data = models.ForeignKey(StudentLessonData, related_name='student_uploaded_file', on_delete=models.CASCADE)
    student_file = models.FileField(upload_to='module_student_files/', default=None)

views.py

class StudentUploadView(View):
    def get(self, request):
        files_list = StudentUploadedFile.objects.all()
        return render(self.request, 'users/modules.html', {'student_files': files_list})

    def post(self, request, *args, **kwargs):
        form = StudentUploadedFileForm(self.request.POST, self.request.FILES)
        form.instance.student_lesson_data_id = self.request.POST['student_lesson_data_id']

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

            # pass uploaded_file data and username so new file can be added to students file list using ajax
            # lesson_id is used to output newly added file to corresponding newly_added_files div
            data = {'is_valid': True, 'username': request.user.username, 'file_id': uploaded_file.id, 'file_name': uploaded_file.filename(),
            'lesson_id': uploaded_file.student_lesson_data_id, 'file_path': str(uploaded_file.student_file)}
        else:
            data = {'is_valid': False}
        return JsonResponse(data)

template.py

<form id='student_uploaded_file{{ item.instance.id }}'>
                                                {% csrf_token %}
                                                <a href="{% url 'download_student_uploaded_file' username=request.user.username file_path=item.instance.student_file %}" target='_blank'>{{ item.instance.filename }}</a>
                                                <a href="{% url 'delete_student_uploaded_file' username=request.user.username file_id=item.instance.id %}" class='delete' id='{{ item.instance.id }}'>Delete</a>
                                            </form>

js

$(function () {
    // open file explorer window
    $(".js-upload-photos").on('click', function(){
        // concatenates the id from the button pressed onto the end of fileupload class to call correct input element
        $("#fileupload" + this.id).click();
     });

    $('.fileupload_input').each(function() {
        $(this).fileupload({
            dataType: 'json',
            done: function(e, data) { // process response from server
            // add newly added files to students uploaded files list
            if (data.result.is_valid) {
                $("#newly_added_files" + data.result.lesson_id).prepend("<form id='student_uploaded_file" + data.result.file_id +
                "'><a href='/student_hub/" + data.result.username + "/download_student_uploaded_file/" +
                data.result.file_path + "' target='_blank'>" + data.result.file_name + "</a><a href='/student_hub/" + data.result.username +
                "/delete_student_uploaded_file/" + data.result.file_id + "/'  class='delete' id=" + data.result.file_id + ">Delete</a></form>")
            }
            }
        });
    });

UPDATE: forms.py

class StudentUploadedFileForm(forms.ModelForm):
    student_file = forms.FileField(widget=forms.ClearableFileInput(attrs={'multiple': True}))

view.py

class StudentUploadView(View):
    model = StudentUploadedFile
    max_files_per_lesson = 3

    def post(self, request, *args, **kwargs):
        lesson_data_id = request.POST['student_lesson_data_id']
        current_files_count = self.model.objects.filter(
            student_lesson_data_id=lesson_data_id
        ).count()
        avail = self.max_files_per_lesson - current_files_count
        file_list = request.FILES.getlist('student_file')
        print(len(file_list))
        if avail - len(file_list) < 0:
            return JsonResponse(data={
                'is_valid': False,
                'reason': f'Too many files: you can only upload {avail}.'
            })
        else:
            for f in file_list:
                print(f)
                
        data = {'test': True}
        return JsonResponse(data)

Thank you.

Answer 1

I've tried using a PyPi package and it works flawlessly. I'm gonna go out on a limb here and assume that you are open to editing the package code to fix any errors you encounter due to compatibility issues since most of the packages that haven't been updated in quite a while might face them.

To solve the problem of limiting the number of files a user can upload, django-multiuploader package would be of enormous help and would honestly do more than you ask for. And yes, it uses JQuery form for uploading multiple files.

How to use it?

Installation and pre-usage steps

Installation

pip install django-multiuploader
python3 manage.py syncdb
python3 manage.py migrate multiuploader

In your settings.py file :

MULTIUPLOADER_FILES_FOLDER = ‘multiuploader’ # - media location where to store files

MULTIUPLOADER_FILE_EXPIRATION_TIME = 3600  # - time, when the file is expired (and it can be cleaned with clean_files command).

MULTIUPLOADER_FORMS_SETTINGS =

{
'default': {
    'FILE_TYPES' : ["txt","zip","jpg","jpeg","flv","png"],
    'CONTENT_TYPES' : [
            'image/jpeg',
            'image/png',
            'application/msword',
            'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
            'application/vnd.ms-excel',
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
            'application/vnd.ms-powerpoint',
            'application/vnd.openxmlformats-officedocument.presentationml.presentation',
            'application/vnd.oasis.opendocument.text',
            'application/vnd.oasis.opendocument.spreadsheet',
            'application/vnd.oasis.opendocument.presentation',
            'text/plain',
            'text/rtf',
                ],
    'MAX_FILE_SIZE': 10485760,
    'MAX_FILE_NUMBER':5,
    'AUTO_UPLOAD': True,
},
'images':{
    'FILE_TYPES' : ['jpg', 'jpeg', 'png', 'gif', 'svg', 'bmp', 'tiff', 'ico' ],
    'CONTENT_TYPES' : [
        'image/gif',
        'image/jpeg',
        'image/pjpeg',
        'image/png',
        'image/svg+xml',
        'image/tiff',
        'image/vnd.microsoft.icon',
        'image/vnd.wap.wbmp',
        ],
    'MAX_FILE_SIZE': 10485760,
    'MAX_FILE_NUMBER':5,
    'AUTO_UPLOAD': True,
},
'video':{
    'FILE_TYPES' : ['flv', 'mpg', 'mpeg', 'mp4' ,'avi', 'mkv', 'ogg', 'wmv', 'mov', 'webm' ],
    'CONTENT_TYPES' : [
        'video/mpeg',
        'video/mp4',
        'video/ogg',
        'video/quicktime',
        'video/webm',
        'video/x-ms-wmv',
        'video/x-flv',
        ],
    'MAX_FILE_SIZE': 10485760,
    'MAX_FILE_NUMBER':5,
    'AUTO_UPLOAD': True,
},
'audio':{
    'FILE_TYPES' : ['mp3', 'mp4', 'ogg', 'wma', 'wax', 'wav', 'webm' ],
    'CONTENT_TYPES' : [
        'audio/basic',
        'audio/L24',
        'audio/mp4',
        'audio/mpeg',
        'audio/ogg',
        'audio/vorbis',
        'audio/x-ms-wma',
        'audio/x-ms-wax',
        'audio/vnd.rn-realaudio',
        'audio/vnd.wave',
        'audio/webm'
        ],
    'MAX_FILE_SIZE': 10485760,
    'MAX_FILE_NUMBER':5,
    'AUTO_UPLOAD': True,
}}

Take note of that MAX_FILE_NUMBER, right within their lies the answer to your question. Have a look at the source once you install this and try implementing it on your own if you want. It might be fun.

Refer for further instructions : django-multiuploader package on pypi