Add javascript login function allow service A to log user to service B via javascript

CORS need to be correctly configured if not this can lead to security issues.
Please do not put Access-Control-Allow-Origin: "*".
You can use django-cors-headers to properly configure CORS

cas_server/static/cas_server/cas.js

@@ -0,0 +1,53 @@
+function cas_login(cas_server_login, service, login_service){
+  url = cas_server_login + '?service=' + encodeURIComponent(service);
+  $.ajax({
+    type: 'GET',
+    url:url,
+    beforeSend: function (request) {   
+      request.setRequestHeader("X-AJAX", "1");
+    },
+    xhrFields: {
+      withCredentials: true
+    },
+    success: function(data, textStatus, request){
+      if(data.status == 'success'){
+        $.ajax({
+          type: 'GET',
+          url: data.url,
+          xhrFields: {
+            withCredentials: true
+          },
+        });
+      } else {
+        if(data.detail == "login required"){
+          window.location.href = cas_server_login + '?service=' + encodeURIComponent(login_service);
+        } else {
+          alert('error: ' + data.messages[1].message);
+        }
+      }
+    },
+    error: function (request, textStatus, errorThrown) {},
+  });
+}
+
+function cas_logout(cas_server_logout){
+  $.ajax({
+    type: 'GET',
+    url:cas_server_logout,
+    beforeSend: function (request) {   
+      request.setRequestHeader("X-AJAX", "1");
+    },
+    xhrFields: {
+      withCredentials: true
+    },
+    error: function (request, textStatus, errorThrown) {},
+    success: function(data, textStatus, request){
+      if(data.status == 'error'){
+        alert('error: ' + data.messages[1].message);
+      }
+    },
+  });
+}
+    
+
+   

cas_server/utils.py

@@ -14,11 +14,12 @@ from .default_settings import settings
 
 from django.utils.importlib import import_module
 from django.core.urlresolvers import reverse
-from django.http import HttpResponseRedirect
+from django.http import HttpResponseRedirect, HttpResponse
+from django.contrib import messages
 
 import random
 import string
-
+import json
 
 try:
     from urlparse import urlparse, urlunparse, parse_qsl
@@ -27,6 +28,13 @@ except ImportError:
     from urllib.parse import urlparse, urlunparse, parse_qsl, urlencode
 
 
+def JsonResponse(request, data):
+    data["messages"] = []
+    for msg in messages.get_messages(request):
+        data["messages"].append({'message': msg.message, 'level': msg.level_tag})
+    return HttpResponse(json.dumps(data), content_type="application/json")
+
+
 def import_attr(path):
     """transform a python module.attr path to the attr"""
     if not isinstance(path, str):
@@ -42,6 +50,12 @@ def redirect_params(url_name, params=None):
     return HttpResponseRedirect(url + "?%s" % params)
 
 
+def reverse_params(url_name, params=None, **kwargs):
+    url = reverse(url_name, **kwargs)
+    params = urlencode(params if params else {})
+    return url + "?%s" % params
+
+
 def update_url(url, params):
     """update params in the `url` query string"""
     if not isinstance(url, bytes):

cas_server/views.py

@@ -13,6 +13,7 @@
 from .default_settings import settings
 
 from django.shortcuts import render, redirect
+from django.core.urlresolvers import reverse
 from django.http import HttpResponse, HttpResponseRedirect
 from django.contrib import messages
 from django.utils.decorators import method_decorator
@@ -30,6 +31,7 @@ import cas_server.utils as utils
 import cas_server.forms as forms
 import cas_server.models as models
 
+from utils import JsonResponse
 from .models import ServiceTicket, ProxyTicket, ProxyGrantingTicket
 from .models import ServicePattern
 
@@ -93,6 +95,7 @@ class LogoutView(View, LogoutMixin):
         self.request = request
         self.service = request.GET.get('service')
         self.url = request.GET.get('url')
+        self.ajax = 'HTTP_X_AJAX' in request.META
 
     def get(self, request, *args, **kwargs):
         """methode called on GET request on this view"""
@@ -108,9 +111,17 @@ class LogoutView(View, LogoutMixin):
         # else redirect to login page
         else:
             if settings.CAS_REDIRECT_TO_LOGIN_AFTER_LOGOUT:
-
                 messages.add_message(request, messages.SUCCESS, _(u'Successfully logout'))
+                if self.ajax:
+                    url = reverse("cas_server:login")
+                    data = {'status': 'success', 'detail': 'logout', 'url': url}
+                    return JsonResponse(request, data)
+                else:
                     return redirect("cas_server:login")
+            else:
+                if self.ajax:
+                    data = {'status': 'success', 'detail': 'logout'}
+                    return JsonResponse(request, data)
                 else:
                     return render(request, settings.CAS_LOGOUT_TEMPLATE)
 
@@ -129,6 +140,7 @@ class LoginView(View, LogoutMixin):
     renew = None
     gateway = None
     method = None
+    ajax = None
 
     renewed = False
     warned = False
@@ -146,6 +158,7 @@ class LoginView(View, LogoutMixin):
         self.renew = True if request.POST.get('renew') else False
         self.gateway = request.POST.get('gateway')
         self.method = request.POST.get('method')
+        self.ajax = 'HTTP_X_AJAX' in request.META
 
     def check_lt(self):
         # save LT for later check
@@ -223,6 +236,7 @@ class LoginView(View, LogoutMixin):
         self.renew = True if request.GET.get('renew') else False
         self.gateway = request.GET.get('gateway')
         self.method = request.GET.get('method')
+        self.ajax = 'HTTP_X_AJAX' in request.META
 
     def get(self, request, *args, **kwargs):
         """methode called on GET request on this view"""
@@ -265,6 +279,10 @@ class LoginView(View, LogoutMixin):
                     _(u"Authentication has been required by service %(name)s (%(url)s)") %
                     {'name': service_pattern.name, 'url': self.service}
                 )
+                if self.ajax:
+                    data = {"status": "error", "detail": "confirmation needed"}
+                    return JsonResponse(request, data)
+                else:
                     return render(
                         self.request,
                         settings.CAS_WARN_TEMPLATE,
@@ -277,28 +295,39 @@ class LoginView(View, LogoutMixin):
             else:
                 # redirect, using method ?
                 list(messages.get_messages(self.request))  # clean messages before leaving django
-                return HttpResponseRedirect(
+                redirect_url = self.user.get_service_url(
-                    self.user.get_service_url(self.service, service_pattern, renew=self.renew)
+                    self.service,
+                    service_pattern,
+                    renew=self.renew
                 )
+                if not self.ajax:
+                    return HttpResponseRedirect(redirect_url)
+                else:
+                    data = {"status": "success", "detail": "auth", "url": redirect_url}
+                    return JsonResponse(self.request, data)
         except ServicePattern.DoesNotExist:
+            error = 1
             messages.add_message(
                 self.request,
                 messages.ERROR,
                 _(u'Service %(url)s non allowed.') % {'url': self.service}
             )
         except models.BadUsername:
+            error = 2
             messages.add_message(
                 self.request,
                 messages.ERROR,
                 _(u"Username non allowed")
             )
         except models.BadFilter:
+            error = 3
             messages.add_message(
                 self.request,
                 messages.ERROR,
                 _(u"User charateristics non allowed")
             )
         except models.UserFieldNotDefined:
+            error = 4
             messages.add_message(
                 self.request,
                 messages.ERROR,
@@ -307,11 +336,19 @@ class LoginView(View, LogoutMixin):
             )
 
         # if gateway is set and auth failed redirect to the service without authentication
-        if self.gateway:
+        if self.gateway and not self.ajax:
             list(messages.get_messages(self.request))  # clean messages before leaving django
             return HttpResponseRedirect(self.service)
 
-        return render(self.request, settings.CAS_LOGGED_TEMPLATE, {'session': self.request.session})
+        if not self.ajax:
+            return render(
+                self.request,
+                settings.CAS_LOGGED_TEMPLATE,
+                {'session': self.request.session}
+            )
+        else:
+            data = {"status": "error", "detail": "auth", "code": error}
+            return JsonResponse(self.request, data)
 
     def authenticated(self):
         """Processing authenticated users"""
@@ -322,11 +359,23 @@ class LoginView(View, LogoutMixin):
             )
         except models.User.DoesNotExist:
             self.logout()
+            if self.ajax:
+                data = {
+                    "status": "error",
+                    "detail": "login required",
+                    "url": utils.reverse_params("cas_server:login", params=self.request.GET)
+                }
+                return JsonResponse(self.request, data)
+            else:
                 return utils.redirect_params("cas_server:login", params=self.request.GET)
 
         # if login agains a service is self.requestest
         if self.service:
             return self.service_login()
+        else:
+            if self.ajax:
+                data = {"status": "success", "detail": "logged"}
+                return JsonResponse(self.request, data)
             else:
                 return render(
                     self.request,
@@ -339,7 +388,7 @@ class LoginView(View, LogoutMixin):
         if self.service:
             try:
                 service_pattern = ServicePattern.validate(self.service)
-                if self.gateway:
+                if self.gateway and not self.ajax:
                     # clean messages before leaving django
                     list(messages.get_messages(self.request))
                     return HttpResponseRedirect(self.service)
@@ -363,6 +412,14 @@ class LoginView(View, LogoutMixin):
                     messages.ERROR,
                     _(u'Service %s non allowed') % self.service
                 )
+        if self.ajax:
+            data = {
+                "status": "error",
+                "detail": "login required",
+                "url": utils.reverse_params("cas_server:login",  params=self.request.GET)
+            }
+            return JsonResponse(self.request, data)
+        else:
             return render(self.request, settings.CAS_LOGIN_TEMPLATE, {'form': self.form})
 
     def common(self):