Allow callbacks to be removed

We’ve had a user who’s said:

> Seems configured callbacks cannot be removed once they’re set as the
> fields have a presence check. Is that intentional?

This means it’s not working as they expect. Rather than have to go and
change stuff in the database for them, let’s make it work as they’d
expect.

Only lets you clear the form if you remove both the token and the URL.

app/main/forms.py

@@ -826,7 +826,15 @@ class ServiceInboundNumberForm(StripWhitespaceForm):
     )
 
 
-class ServiceReceiveMessagesCallbackForm(StripWhitespaceForm):
+class CallbackForm(StripWhitespaceForm):
+
+    def validate(self):
+        return super().validate() or (
+            self.url.data == '' and self.bearer_token.data == ''
+        )
+
+
+class ServiceReceiveMessagesCallbackForm(CallbackForm):
     url = StringField(
         "URL",
         validators=[DataRequired(message='Can’t be empty'),
@@ -839,7 +847,7 @@ class ServiceReceiveMessagesCallbackForm(StripWhitespaceForm):
     )
 
 
-class ServiceDeliveryStatusCallbackForm(StripWhitespaceForm):
+class ServiceDeliveryStatusCallbackForm(CallbackForm):
     url = StringField(
         "URL",
         validators=[DataRequired(message='Can’t be empty'),

app/main/views/api_keys.py

@@ -208,9 +208,11 @@ def delivery_status_callback(service_id):
     )
 
     if form.validate_on_submit():
-        if delivery_status_callback:
-            if (delivery_status_callback.get('url') != form.url.data
-                    or form.bearer_token.data != dummy_bearer_token):
+        if delivery_status_callback and form.url.data:
+            if (
+                delivery_status_callback.get('url') != form.url.data or
+                form.bearer_token.data != dummy_bearer_token
+            ):
                 service_api_client.update_service_callback_api(
                     service_id,
                     url=form.url.data,
@@ -218,7 +220,12 @@ def delivery_status_callback(service_id):
                     user_id=current_user.id,
                     callback_api_id=delivery_status_callback.get('id')
                 )
-        else:
+        elif delivery_status_callback and not form.url.data:
+            service_api_client.delete_service_callback_api(
+                service_id,
+                delivery_status_callback['id'],
+            )
+        elif form.url.data:
             service_api_client.create_service_callback_api(
                 service_id,
                 url=form.url.data,
@@ -255,9 +262,11 @@ def received_text_messages_callback(service_id):
     )
 
     if form.validate_on_submit():
-        if received_text_messages_callback:
-            if (received_text_messages_callback.get('url') != form.url.data
-                    or form.bearer_token.data != dummy_bearer_token):
+        if received_text_messages_callback and form.url.data:
+            if (
+                received_text_messages_callback.get('url') != form.url.data or
+                form.bearer_token.data != dummy_bearer_token
+            ):
                 service_api_client.update_service_inbound_api(
                     service_id,
                     url=form.url.data,
@@ -265,7 +274,12 @@ def received_text_messages_callback(service_id):
                     user_id=current_user.id,
                     inbound_api_id=received_text_messages_callback.get('id')
                 )
-        else:
+        elif received_text_messages_callback and not form.url.data:
+            service_api_client.delete_service_inbound_api(
+                service_id,
+                received_text_messages_callback['id'],
+            )
+        elif form.url.data:
             service_api_client.create_service_inbound_api(
                 service_id,
                 url=form.url.data,

app/notify_client/service_api_client.py

@@ -332,6 +332,12 @@ class ServiceAPIClient(NotifyAdminAPIClient):
             )
         )['data']
 
+    @cache.delete('service-{service_id}')
+    def delete_service_inbound_api(self, service_id, callback_api_id):
+        return self.delete("/service/{}/inbound-api/{}".format(
+            service_id, callback_api_id
+        ))
+
     def get_reply_to_email_addresses(self, service_id):
         return self.get(
             "/service/{}/email-reply-to".format(
@@ -463,6 +469,12 @@ class ServiceAPIClient(NotifyAdminAPIClient):
             data['bearer_token'] = bearer_token
         return self.post("/service/{}/delivery-receipt-api/{}".format(service_id, callback_api_id), data)
 
+    @cache.delete('service-{service_id}')
+    def delete_service_callback_api(self, service_id, callback_api_id):
+        return self.delete("/service/{}/delivery-receipt-api/{}".format(
+            service_id, callback_api_id
+        ))
+
     @cache.delete('service-{service_id}')
     def create_service_callback_api(self, service_id, url, bearer_token, user_id):
         data = {