python django chap 11

Friends this is the continuation from its previous post so i kindly recommend you to read that post i have made this very simple even a complete beginner can learn it and if you are beginner in python then you need to learn python i have made that blog also for that click this link

HANDLING UPLOADED files

In the previous post we have learn to bind the request.FILES into the forms constructor now here we will learn common methods to handle the uploaded file as for example an uploaded file can be

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

Looping over UploadedFile.chunks() instead of using read() ensure that large file don't overwhelm your systems memory

HANDLING UPLOADED FILE WITH MODEL

If you are saving file on a Model with a FileField using a ModelForm the file object will be saved to the location specified by the upload_to argument of the corresponding FileField when calling form.save
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():
                                        form.save
                                         return HttpResponseRedirect('/success/url/')
                     else:
                            form = ModelFormWithFileField()
                   return render (request,'upload.html',{'form':form})

If you are constructing an object manually you can simply assign the file object from request.FILES to the file field in the model

from django.http import HttpResponseRedirect
from django.shortcuts import render
from .form import UploadFileForm
from .model 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})

Uploading Multiple Files

                   the multiple files can be uploaded with the one form field . Set the multiple HTML attribute of the fields Widget
 

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

Then override the post method of the FormView subclass to handle the multiple file uploads

from django.views.generics.edit import FormView
from .forms import FileFieldForm
class FileFieldView(FormView):
      form_class = FileFieldForm()
       template_name = 'upload.html' #you can 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)  

That's all for this post guys now you have the basic knowledge to start learning the advanced lessons on django more advanced lessons will be included in future posts

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