从 Django 获取 JSON 响应

Question

EDIT: As asked, the thing that I'm trying to obtain is the following:

POST with the file from template --> File process in the view, generate an id --> id displays in template

I'm new to Django, and I'm trying to get the server to send a response to the same page, with a certain number. It's currently responding with a ValueError, and the template doesn't get the response. Here is my code.

views.py

def index(request):
dB = LegacyDatabase()
ints = None
if request.POST:
    form = UploadFileForm(request.POST, request.FILES)
    if form.is_valid():
        files = Upload(model=request.FILES['file_upload'])
        try:
            ints = dBconnection(dB, request.FILES['file_upload'].name)
        except IntegrityError:
            ints = dBGetExistingValue(dB, request.FILES['file_upload'].name)
        files.save()
        a = []
        a.append(["sessionid", ints])
        sess= dict(a)

        return JsonResponse(sess)
return render(request, "main/index.html")

urls.py from django.conf.urls import url

from phast.views import index

urlpatterns = [
  url(r'^$', index, name='main'),
]

index.html

   <form method="post" class = "sessionid">
    <input type="text" id = "demo" readonly>
  </form>
  <script>

    var xhttp = new XMLHttpRequest();
      xhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
      console.log(JSON.parse(xhttp.responseText));
      }
    };
  </script>

 <form class="dropzone" id="mydropzone" enctype="multipart/form-data">  {% csrf_token %} </form>

dropzone creation

var myDropzone = new Dropzone("#mydropzone", {
  url : '{% url phast.views.index %}'
});

Can you please help me?

EDIT: As asked, here is the error that the development server returns.

Internal Server Error: /
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/rubinhus/Development/django/phastload/phast/views.py", line 66, in index
    return render(request, "main/index.html", JsonResponse(sess))
  File "/usr/local/lib/python2.7/dist-packages/django/shortcuts.py", line 30, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/usr/local/lib/python2.7/dist-packages/django/template/loader.py", line 68, in render_to_string
    return template.render(context, request)
  File "/usr/local/lib/python2.7/dist-packages/django/template/backends/django.py", line 64, in render
    context = make_context(context, request, autoescape=self.backend.engine.autoescape)
  File "/usr/local/lib/python2.7/dist-packages/django/template/context.py", line 267, in make_context
    context.push(original_context)
  File "/usr/local/lib/python2.7/dist-packages/django/template/context.py", line 59, in push
    return ContextDict(self, *dicts, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/template/context.py", line 18, in __init__
    super(ContextDict, self).__init__(*args, **kwargs)
ValueError: dictionary update sequence element #0 has length 19; 2 is required

Answer 1

By what I see:

The trace back says in line 66 of views.py:

return render(request, "main/index.html", JsonResponse(sess))

This is the last line of your code and rest all are inbuilt of django. So you should instead concentrate on this line.

My approach would be to check the 66th line of views.py and debug whats going on there. If you don't see similar code in line 66 of views.py I bet you haven't restarted your django process. How are you running the server? If any process is supervising it restart that process.

EDIT

Template Context Django docs

If context is provided, it must be a dict. If it isn't provided, the engine will render the template with an empty context.

You were providing a JsonResponse to it. It is a repsponse which will contain status code of the request, headers d body as well.

so replacing return JsonResponse(sess) with render(request, "main/index.html", context=sess) should work.