resolve send_signals conflict

standard/helpers.py

@@ -4,9 +4,9 @@
 from django.contrib.auth.models import get_hexdigest
 
 
-def duplicate_txn_id(ipn_obj):
-    """Returns True if a record with this transaction id exists."""
-    return ipn_obj._default_manager.filter(txn_id=ipn_obj.txn_id).count() > 0
+def duplicate_txn_id(ipn_obj, from_view='notify'):
+    "Returns True if a record with this transaction id exists."
+    return ipn_obj._default_manager.filter(txn_id=ipn_obj.txn_id, from_view=from_view).count() > 0
 
 def make_secret(form_instance, secret_fields=None):
     """
@@ -45,4 +45,4 @@ def check_secret(form_instance, secret):
     """
     # ### ToDo: add invoice & custom
     # secret_fields = ['business', 'item_name']
-    return make_secret(form_instance) == secret
+    return make_secret(form_instance) == secret

standard/ipn/views.py

@@ -5,18 +5,10 @@
 from paypal.standard.ipn.forms import PayPalIPNForm
 from paypal.standard.ipn.models import PayPalIPN
 
-
-@require_POST
-def ipn(request, item_check_callable=None):
+def handle_ipn_post(request, item_check_callable=None, from_view='notify'):
+    """Naive wrapper for ipn view, so we can set the view whence the ipn came from
     """
-    PayPal IPN endpoint (notify_url).
-    Used by both PayPal Payments Pro and Payments Standard to confirm transactions.
-    http://tinyurl.com/d9vu9d
-    
-    PayPal IPN Simulator:
-    https://developer.paypal.com/cgi-bin/devscr?cmd=_ipn-link-session
-    
-    """    
+
     form = PayPalIPNForm(request.POST)
     if form.is_valid():
         try:
@@ -27,6 +19,9 @@ def ipn(request, item_check_callable=None):
     else:
         ipn_obj.set_flag("Invalid form. (%s)" % form.errors)
 
+    # notify/return/cancel
+    ipn_obj.from_view = from_view
+
     ipn_obj.initialize(request)
     if not ipn_obj.flag:
         # Secrets should only be used over SSL.
@@ -35,5 +30,22 @@ def ipn(request, item_check_callable=None):
         else:
             ipn_obj.verify(item_check_callable)
 
+    return ipn_obj
+
+@require_POST
+def ipn(request, item_check_callable=None):
+    """
+    PayPal IPN endpoint (notify_url).
+    Used by both PayPal Payments Pro and Payments Standard to confirm transactions.
+    http://tinyurl.com/d9vu9d
+    
+    PayPal IPN Simulator:
+    https://developer.paypal.com/cgi-bin/devscr?cmd=_ipn-link-session
+    
+    """    
+
+    ipn_obj = handle_ipn_post(request, item_check_callable=item_check_callable, from_view='notify')
+
     ipn_obj.save()
-    return HttpResponse("OKAY")
+    return HttpResponse("OKAY")
+

standard/models.py

@@ -160,7 +160,10 @@ class PayPalStandardBase(models.Model):
     response = models.TextField(blank=True)  # What we got back.
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
-
+
+    # Where did it come from?
+    from_view = models.CharField(max_length=6, null=True, blank=True)
+
     class Meta:
         abstract = True
 
@@ -212,7 +215,7 @@ def verify(self, item_check_callable=None):
             if self.is_transaction():
                 if self.payment_status != "Completed":
                     self.set_flag("Invalid payment_status (%s). " % self.payment_status)
-                if duplicate_txn_id(self):
+                if duplicate_txn_id(self, self.from_view):
                     self.set_flag("Duplicate transaction ID (%s). " % self.txn_id)
                 if self.receiver_email != RECEIVER_EMAIL:
                     self.set_flag("Invalid receiver_email (%s). " % self.receiver_email)
@@ -241,19 +244,40 @@ def get_endpoint(self):
         else:
             return POSTBACK_ENDPOINT
 
+    def send_signals(self):
+        """Shout for the world to hear whether a txn was successful."""
+
+        # Don't do anything if we're not notifying!
+        if self.from_view != 'notify':
+            return
+
+        # Transaction signals:
+        if self.is_transaction():
+            if self.flag:
+                payment_was_flagged.send(sender=self)
+            else:
+                payment_was_successful.send(sender=self)
+        # Subscription signals:
+        else:
+            if self.is_subscription_cancellation():
+                subscription_cancel.send(sender=self)
+            elif self.is_subscription_signup():
+                subscription_signup.send(sender=self)
+            elif self.is_subscription_end_of_term():
+                subscription_eot.send(sender=self)
+            elif self.is_subscription_modified():
+                subscription_modify.send(sender=self) 
+
+
     def initialize(self, request):
         """Store the data we'll need to make the postback from the request object."""
         self.query = getattr(request, request.method).urlencode()
         self.ipaddress = request.META.get('REMOTE_ADDR', '')
 
-    def send_signals(self):
-        """After a transaction is completed use this to send success/fail signals"""
-        raise NotImplementedError
-
     def _postback(self):
         """Perform postback to PayPal and store the response in self.response."""
         raise NotImplementedError
 
     def _verify_postback(self):
         """Check self.response is valid andcall self.set_flag if there is an error."""
-        raise NotImplementedError
+        raise NotImplementedError

standard/signals.py

@@ -0,0 +1,25 @@
+"""
+Note that sometimes you will get duplicate signals emitted, depending on configuration of your systems. 
+If you do encounter this, you will need to add the "dispatch_uid" to your connect handlers:
+http://code.djangoproject.com/wiki/Signals#Helppost_saveseemstobeemittedtwiceforeachsave
+
+"""
+from django.dispatch import Signal
+
+# Sent when a payment is successfully processed.
+payment_was_successful = Signal()
+
+# Sent when a payment is flagged.
+payment_was_flagged = Signal()
+
+# Sent when a subscription was cancelled.
+subscription_cancel = Signal()
+
+# Sent when a subscription expires.
+subscription_eot = Signal()
+
+# Sent when a subscription was modified.
+subscription_modify = Signal()
+
+# Sent when a subscription ends.
+subscription_signup = Signal()