Q:

Polling celery task and return on display

I am new to celery. I was following this example.
Views.py
def results(request):
    documents = Document.objects.all()
    if request.method == 'POST':
        form = DocumentForm(request.POST, request.FILES)
        if form.is_valid():
            data = form.cleaned_data['name']
            print 'data', data
            newdoc = Document(docfile=request.FILES['docfile'])
            newdoc.save()
        #send it to celery  
    documents = Document.objects.all()
    return render_to_response(
        'results.html',
        {'documents' : documents}, context_instance=RequestContext(request))

The user would upload a file which would be processed by an engine. In the meantime, i would want the results page to show all jobs that are already completed. I thought of using celery and modifying the tasks.py to process the files. After its completed, the file will be shown as a url for users to download it. 
I cannot think of a way to poll this tasks asynchronously to achieve this part. 
thanks. 

A:

You can use Django-celery-results. It is an easy and nice extension of celery that enable you to store your tasks results in django database.
install the extension using :
$ pip install -U django-celery-results

update settings.py :
CELERY_RESULT_BACKEND = 'django-db'

INSTALLED_APP = (
    ...
    ...
    django_celery_results
)

Create the Celery database tables by performing a database migrations:
$ python manage.py migrate django_celery_results

Then you can get the list of finished tasks from the database and display it in your view.
from django_celery_results.models import TaskResult
def tasks_view(request):
    tasks = TaskResult.objects.all()
    template = "tasks.html" 
    return render(request, template, {'tasks': tasks})

Define the template "templates/tasks.html" 
 <html>
    <head>
        <title>tasks</title>
    </head>
    <body>
    {% if tasks %}
    <ul>
    {% for task in tasks %}
        <li> {{task.id}} : {{ task.result }}</a></li>
    {% endfor %}
    </ul>
    <p>It works!</p>
   {% else %}
    <p>No tasks are available.</p>
   {% endif %}

    </body>
</html>

