Django session and Dojo dnd.

[voss]

I have a Dojo drag-and-drop and hope to store the dropped items and their information in a Django session. Using the example below, how do I pass "detail" in this code to a view so that the dropped info can be stored in a session?

Thank you!


        var source1 = new dojo.dnd.Source("itemListNode");
        var source2 = new dojo.dnd.Target("selectedListNode");

        dojo.connect( source1, "onDndDrop",
                              function(source, nodes, copy, target){
                                            for( i=0; i < nodes.length; i++){
                                                          item = this.getItem(nodes[i].id);
                                                          detail = item.data;
                                                          .....................................
                                                          .....................................
                                            }
                               }
        )

[henzk]

Hi,

i haven't tested the code and never used dojo before, but sth. like
this should work:

var source1 = new dojo.dnd.Source("itemListNode");
var source2 = new dojo.dnd.Target("selectedListNode");
dojo.connect( source1, "onDndDrop",
function(source, nodes, copy, target){

//gather items and details
var details = [];

for( i=0; i < nodes.length; i++){

var item = this.getItem(nodes[i].id);
details.push(item.data);
}
//send details to server via AJAX POST request
dojo.xhrPost({
url: "/save_details/",
content: {details: JSON.stringify(details)},
// The success handler
load: function(response) {
alert('ok');
},
// The error handler
error: function() {
alert("error");
}
});
});

Explanation:

- changed 'item' to 'var item' ... without the 'var' item will be
global, which is probably not what you want.
- to get around making multiple requests to the server(one for each
dropped node), put the detail of each node in the details array.
- then json-encode and send this array to your django view (assumed to
be at '/save_details/')
- in the view, access the list as
json.loads(request.POST.get('details', '[]')) and place it into
request.session

As mentioned, the code is completely untested.

Good luck!

Yours,

Hendrik Speidel

[voss]

Hello Hendrik,

Thank you for your help! I can get the 'ok' in the alert with your code. However, how do I show the response in the alert? For some reason I am unable to pass the message back from the view; I keep getting an empty alert(response).

My view looks like:
 
   def new_session(request):
      if not request.is_ajax() or not request.method=='POST':
          return HttpResponseNotAllowed(['POST'])
   
      else:
          request.session['key'] = json.loads(request.POST.get('details', '[]'))
          return HttpResponse(request.session['key'])

I've also tried "return HttpResponse('ok')", but the 'ok' still didn't get passed to the load function. What do I do wrong? Any hints would be much appreciated!

    voss

[voss]

Hi Hendrik,

I forgot to mention in my previous message that the debug shows the following:

code 400, message Bad request syntax ("\x16\x03\x01\x00\x8b\x01\x00\x00\x87\x03\x01O\xcc\xd8\xc0\x18hZ\x7f\xa3h\xb9l\xaf\xdb\xfbp}(\xc1\xc6\xa5g\x18\xe5!\x87\xd4\xe2`_'\x90\x00\x00H\x00\xff\xc0")

Thank you!

    voss



On Saturday, June 2, 2012 8:46:38 AM UTC-5, henzk wrote:

[henzk]

Hi Voss,

i forgot about django's CSRF protection.

You can use the csrf_exempt decorator on the view function to disable django's CSRF protection - however, i wouldn't recommend that.

There is a script at https://docs.djangoproject.com/en/dev/ref/contrib/csrf/ 

To use the script with dojo instead of jquery, you will need to adapt it a little:

-copy the getCookie function to your code

then, every time you make a POST request to your application using dojo.xhrPost, add this to the arguments object:

headers: {'X-CSRFToken': getCookie('csrftoken')}

If you are still getting HTTP 400 errors, verify that the request looks sane in firebug and check that it contains a X_HTTP_REQUESTED_WITH header set to XMLHttpRequest (but i am pretty sure dojo adds this one automatically).

hendrik

[voss]

Hello Hendrik,

Thank you for the explanation. It is *very* helpful!

   voss

[voss]

Hello Hendrik,

To simplify things and to do some tests, I started with disabling the csrf protection. Here is my JS:

                    dojo.xhrPost( {
                        url: "/test/",
                        content: {details: JSON.stringify(details)},
                        load: function(response){
                            alert(response);
                            },

                        error: function(){
                            alert("error");
                            }
                    });

In views.py, I have:

                    @csrf_exempt
                    def new_session(request):
                        if request.is_ajax():
                            return HttpResponse('ok')


In theory, I should see the 'ok' alert, but, instead, I got "null". The debug message shows:

[07/Jun/2012 10:31:06] code 400, message Bad request syntax ('\x16\x03\x01\x00\x8f\x01\x00\x00\x8b\x03\x01O\xd0\xc9:}m\x9e\x04\xbf_:$`\x96v\xca\x1b\x92\xb8\xc7?M\x0f\xbdc\x8e\xfb+\x84E\x8c?\x00\x00H\x00\xff\xc0')
[07/Jun/2012 10:31:06] "??O??:}m??_:$`?v????M?c??+?E??H??" 400 -

This error message looks similar to that before the csrf_exempt decorator was added, which suggests to me that the problem may not be in the csrf protection. Am I right? Any thoughts would be greatly appreciated!

    voss


On Monday, June 4, 2012 8:21:15 PM UTC-5, henzk wrote:

[Hendrik Speidel]

Hi Voss,

i guess you are right ... it may not be related to CSRF-Protection at all.
Are you using the django development server? I have found some references for '\x16\x03\x01' using google, e.g.
http://wishmesh.com/2010/05/apache-logs-contains-x16x03x01-when-accessing-site-via-https/

It seems that this is related to browsers that speak HTTPS to a (misconfigured) HTTP server.

Can you verify that this happens also when using the django devserver on port 8000?
Another thing you could try is to get rid of the is_ajax check.
In either case you should return a response for non-ajax requests also ... otherwise you will provoke a HTTP500 in these cases.

hendrik

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[voss]

Hi Hendrik,

Thank you for your prompt reply. I really appreciate it!

Yes, I am using the django development server, and it is on port 8000.  I, too, read that the https can cause the '\x16\x03\x01' problem, but I don't see how this can happen in my case because I did not create any https'.

Although it may not be csrf, do you think csrfmiddlewaretoken: '{{ csrf_token }}' could be the missing piece (see http://stackoverflow.com/questions/9085068/django-jquery-get-to-post)? It seems to make sense to me because {% csrf_token %} is required for a normal post request. If so, how do I use it in dojo.xhrPost? I tried 

                    dojo.xhrPost( {
                        url: "/test/",
                        content: {
                            details: JSON.stringify(details)

                            csrfmiddlewaretoken: '{{ csrf_token }}'

                        },
                        load: function(response){
                            alert(response);
                            },
                        error: function(){
                            alert("error");
                            }
                    });

, but it did not change anything. I also commented out the is_ajax line, but I got the same debug message.


    voss

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[Hendrik Speidel]

Hi Voss,

you were missing a comma after "details: JSON.stringify(details)"
However, i don't think that was the cause of the problem. When using csrf_exempt you do not need to include the csrf token.

I have now created a test project and it's working here. The project is called 'testp' and the app is called 'testa'

#testp.urls
from django.conf.urls import patterns, include, url

urlpatterns = patterns('',
    url(r'^dojo/$', 'testa.views.dojo'),
    url(r'^test/$', 'testa.views.new_session'),
)

#testa.views
from django.views.decorators.csrf import csrf_exempt
from django.shortcuts import render
from django.http import HttpResponse

def dojo(request):
    return render(request, 'dojo.html')

@csrf_exempt
def new_session(request):
    if request.is_ajax():
        return HttpResponse('ok')

    else:
        return HttpResponse('only AJAX requests are allowed!')

#dojo.html
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/dojo/1.7.2/dojo/dojo.js"></script>
<script>
    var details = [1,2,3,4,5]

    dojo.xhrPost( {
        url: "/test/",
        content: {details: JSON.stringify(details)},
        load: function(response){
            alert(response);
            },
        error: function(){
            alert("error");
            }
    });

</script>
</head>
<body>

If i visit localhost:8000/dojo/ it alerts 'ok'

Maybe you can deduce your error by comparing this to your setup.
Also, do you have a debugging tool like firebug? It really helps me out quite often.

Good luck!

hendrik

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[voss]

Hello Hendrik,

Your code works on my machine, too!! I don't know what is wrong with my code. I will definitely compare it carefully to yours. Hopefully, I will find the cause soon.

By the way, I do have firebug running all the time, but it does not show any errors.

Once again, thank you so much for all your help! Your help is very much appreciated.
   voss

[voss]

Hi Hendrik,

THANK YOU, THANK YOU, and THANK YOU!! I found it!! I made a mistake when defining the url, and that's why I kept getting the "code 400" error.

Your test code is extremely beneficial! I can't thank you enough for all your help!

   voss

[Hendrik Speidel]

Hi Voss,

you're welcome. Great that you got it working.

hendrik

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