python - Django Ajax requests - 500 INTERNAL SERVER ERROR with "matching query does not exist." error -

i encountered problem while building django based site; need run few template updates using ajax @ start:

 $(document).ready(function () {         var trees = ['1','2','3','4','5','6']         (i = 0; < trees.length; i++) {             $.ajax({                 'url': '/structure/showtrees',                 'data': {                     number:trees[i]                 },                 'type': 'get',                 'success': function (data) {                     $("#phylo"+i).html(data);                 }             });         };     }); 

this redirected through urls.py this: django.conf.urls import patterns, url

from structure import views django.conf import settings  urlpatterns = patterns('',     ...,     ..., url(r'^showtrees', views.rendertrees, name='render')  ) 

within "views.py" target function:

def rendertrees(request): print(request.session) number = request.session.get['number'] tree = open('static/home/images/00'+number+'_tree.xml').read()  return render(request, 'tree'+number+'.html', {'tree':tree,'num':number}) 

i have "print(session)" there marker, never diplayed. during page load get:

get http://localhost:8000/structure/showtrees?number=1 500 internal server error        464ms 

and response

doesnotexist @ /structure/showtrees structure matching query not exist. 

i searching , searching , couldn't find answer problem.

edit: full traceback here:

    doesnotexist @ /structure/showtrees structure matching query not exist.  request method: request url: http://localhost:8000/structure/showtrees?number=1 django version: 1.8.4 python executable: /usr/bin/python3 python version: 3.4.3 python path: ['/vagrant/protwis', '/usr/lib/python3.4', '/usr/lib/python3.4/plat-x86_64-linux-gnu', ' /usr/lib/python3.4/lib-dynload', '/usr/local/lib/python3.4/dist-packages', '/usr/lib/python3/dist-packages' ] server time: fri, 25 sep 2015 19:05:08 +0200 installed applications: ('django.contrib.admin',  'django.contrib.auth',  'django.contrib.contenttypes',  'django.contrib.sessions',  'django.contrib.messages',  'django.contrib.staticfiles',  'debug_toolbar',  'rest_framework',  'rest_framework_swagger',  'django_nvd3',  'common',  'api',  'documentation',  'news',  'pages',  'home',  'protein',  'family',  'residue',  'alignment',  'similaritysearch',  'similaritymatrix',  'structure',  'ligand',  'interaction',  'mutation',  'phylogenetic_trees',  'sitesearch',  'build_gpcr') installed middleware: ('debug_toolbar.middleware.debugtoolbarmiddleware',  'django.contrib.sessions.middleware.sessionmiddleware',  'django.middleware.common.commonmiddleware',  'django.middleware.csrf.csrfviewmiddleware',  'django.contrib.auth.middleware.authenticationmiddleware',  'django.contrib.auth.middleware.sessionauthenticationmiddleware',  'django.contrib.messages.middleware.messagemiddleware',  'django.middleware.clickjacking.xframeoptionsmiddleware')  traceback: file "/usr/local/lib/python3.4/dist-packages/django/core/handlers/base.py" in get_response   132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs) file "/vagrant/protwis/structure/views.py" in structuredetails   64.     crystal = structure.objects.get(pdb_code__index=pdbname) file "/usr/local/lib/python3.4/dist-packages/django/db/models/manager.py" in manager_method   127.                 return getattr(self.get_queryset(), name)(*args, **kwargs) file "/usr/local/lib/python3.4/dist-packages/django/db/models/query.py" in   334.                 self.model._meta.object_name  exception type: doesnotexist @ /structure/showtrees exception value: structure matching query not exist. request information: get: number = '1'  post: no post data  files: no files data  cookies: djdt = 'hide' csrftoken = 'fh9xuekpoau6drwd8thhgbece7yxmqms' sessionid = 'lf0wjer4wyyp98ez9y5ngbcawb1xxbak' 

the url calling /structure/showtrees, in urls.py file provided, have defined /showtrees. causing error. fix that, change js call /showtrees or insert urls.py file inside new app called structure
seems using structure.objects.get , somewhere , django raises doesnotexists exception. check structure object exists on db.
problem on line :

crystal = structure.objects.get(pdb_code__index=pdbname) 

check filters on queryset.