Django将变量作为参数传递给视图中的函数

Question

What I'm trying to do here is to pass the variable result to a template. My problem is that I need to pass the variable path as a parameter to the tumor_classification() function in order to get the value of result . The value of the 'path' is obtained from the save() function, as I overrode it. I tried to make the variable path as global, but it doesn't work (the 'path' remains null). How can I do this ? The following code shows my views.py file :

from django.http import HttpResponseRedirect
from django.core.urlresolvers import reverse
from django.views.generic import FormView, DetailView, ListView
from django.conf import settings

import os

from .forms import BrainImageForm
from .models import BrainImage
from .brain import *

global result

class BrainImageView(FormView):
    template_name = 'brain_image_form.html'
    form_class = BrainImageForm
    def form_valid(self, form):


        brain_image = BrainImage(
            image = self.get_form_kwargs().get('files')['image']
        )

        brain_image.save()
        global path
        path = brain_image.save() # this is the variable I need to pass to the function tumor_classification() below

        self.id = brain_image.id

        return HttpResponseRedirect(self.get_success_url())

    def get_success_url(self):

        return reverse('brain_image',kwargs = {'pk': self.id})

class BrainImageIndexView(ListView):

    model = BrainImage
    template_name = 'brain_image_view.html'
    context_object_name = 'images'

    def tumor_classification(image_address):

            path = settings.MEDIA_ROOT+'/'+image_address
            img = selectImage(path)
            segmented = segmentation(img)
            replaced = replace(img, segmented)
            extractFeatures(replaced)
            classif = createSVMClassifier(settings.BASE_DIR+'/main/datasets/input_features.csv', settings.BASE_DIR+'/main/datasets/benign_input_features.csv')
            result = classify(classif, "tumor_features.csv")

            return result   

    result = tumor_classification(path) # this is where I need to pass the 'path' variable
    queryset = BrainImage.objects.all()

Thank you !

Answer 1

If path is something which is required for a short period of time, you can store it in session. See sessions manual for reference. Session is something associated to currently logged in user.

request.session.put('path', path)

request.session.get('path', default='something)

However if user will call the view which creates BrainImage multiple times, than the path value in session or will be overwriten (the same happens with global)

The best way to handle that is to store the path in database, for example in your BrainImage . This way you can retrieve it in other views in a thread-safe, multisuser-safe and what's even more important persitent way.

Answer 2

usually that is done by overriding the get_context_data method in your view, so:

def get_context_data(self, **kwargs):
    context = super(BrainImageIndexView, self).get_context_data(**kwargs)
    context["result"] = self.something()
    return context

but what you want seems to be something a little different, you should move that def tumor_classification(image_address): in your model definition, change the signature to pick up the image address from the object itself and not as a parameter, and then in the template do something like

 {% for img in images %}
      {{ img.get_tumor_classification }}
 {% endfor %}

example of the method in the model:

class BrainImage(models.Model):
    ....
    def tumor_classification(self):
        image_address = self.image.path
        path = settings.MEDIA_ROOT+'/'+image_address
        img = selectImage(path)
        segmented = segmentation(img)
        replaced = replace(img, segmented)
        extractFeatures(replaced)
        classif = createSVMClassifier(settings.BASE_DIR+'/main/datasets/input_features.csv', settings.BASE_DIR+'/main/datasets/benign_input_features.csv')
        result = classify(classif, "tumor_features.csv")

        return result