Django request.GET.get() 每两次返回 None

Question

I'm trying to use some ajax request to echange between django views and the templates but i'm experiencing a strange behavior with the request.GET.
Django sends an error saying that the data in parameter of the json.loads(data) shouldn't be NoneType as the result of request.GET.get('selects') seems to be None ; but if I try to debug this code, it seems that request.GET.get('selects') returns None every two times.

When requesting request.GET.get('selects') in the console, I get:
None the first time
and '[{"pk":"57226796-0960-428a-88aa-ba4120ad34b4"}]' the second time,
then None again
then '[{"pk":"57226796-0960-428a-88aa-ba4120ad34b4"}]' at the third attempt.
every odd attempt return None.... what do I wrong ?

views.py

class AjaxRenameView(View):

    def get(self,request):
        #import pdb; pdb.set_trace()
        selects=request.GET.get('selects', None)
        selects=json.loads(selects)
        pks = [ pk['pk'] for pk in selects]
        if len(pks)==1:
            folder=Folder.objects.filter(pk=pks[0])
            spotler=Spotler.objects.filter(pk=pks[0])
            if folder:
                form=FolderRenameForm(instance=folder)
                title=_('rename folder')
            elif spotler :
                form=SpotlerRenameForm(instance=folder)
                title=_('rename project')

            context={'form':form,'title':title,'submit':_('rename'),'has_error':False}
            html_form = render_to_string('includes/modal_form.html',
                context,
                request=request,
            )
            return JsonResponse({'html_form': html_form})

        return JsonResponse({'has_error':True, 'message':_('an error has occured while renaming')}, safe=False)

    def post(self,request):
        pass

folder.js

  //...
  function ajaxAction(selects,url,next){
    // when clicked on item of menu (rename, share, move...)
    $.ajax({
      type:"GET",
      data:{'selects':JSON.stringify(selects),'next':next},
      url: url,
      dataType:"json",
      beforeSend: function () {
        $("#Modal .modal-content").empty();
      },
      success: function (data) {
        $("#Modal .modal-content").html(data.html_form);
      }
    });//ajax
  }//function ajaxAction
//...

console

(Pdb) request.GET.dict()
{'selects': '[{"pk":"57226796-0960-428a-88aa-ba4120ad34b4"}]', 'next': '/fr/wf/myfiles/'}
(Pdb) request.GET.get('selects')
(Pdb) request.GET.get('selects')
'[{"pk":"57226796-0960-428a-88aa-ba4120ad34b4"}]'
(Pdb) request.GET.get('selects')
(Pdb) request.GET.get('selects')
'[{"pk":"57226796-0960-428a-88aa-ba4120ad34b4"}]'

Answer 1

well I finally found it. the click() event that triggered the ajax call was related to the href attribute of an element. And as I didn't halt the execution of the function, the link was activated and a call to the django view without parameters was send... the ajax call with return false; or e.preventDefault();

I modified the ajax call a little bit :

function ajaxActionMenu(pk_list,url){
  $.ajax({
    type:'GET',
    data:{'pk_list':JSON.stringify(pk_list)},
    url: url,
    dataType:'json',
    success:function(data){
      jQuery.each(data, function(index,value){
        $("#Modal .modal-body .nav").append('<a class="nav-link" href="'+value["url"]+'">'+value["menuitem"]+'</a>');
      });
    },
    complete: function(){
      $("#Modal .modal-body .nav").on("click",".nav-link",function(e){
        e.preventDefault(); // prevent the activation of the href link
        var urlLink=$(this).attr("href");
        ajaxAction(pk_list,urlLink);
        $("#Modal").modal("show");
      });

    }
  });
}