small optimization of supporter count

core/models.py

@@ -316,6 +316,11 @@ class Campaign(models.Model):
         """nb: returns (distinct) supporter IDs, not supporter objects"""
         translist = self.transactions().filter(status=TRANSACTION_STATUS_ACTIVE).values_list('user', flat=True).distinct()
         return translist
+        
+    @property
+    def supporters_count(self):
+        # avoid transmitting the whole list if you don't need to; let the db do the count.
+        return self.transactions().filter(status=TRANSACTION_STATUS_ACTIVE).values_list('user', flat=True).distinct().count()
 
     def effective_premiums(self):
         """returns the available premiums for the Campaign including any default premiums"""

frontend/templates/manage_campaign.html

@@ -79,7 +79,7 @@ Please fix the following before launching your campaign:
                 
         <div class="pledged-info">
         	<div class="pledged-group">
-        		{{ work.last_campaign.supporters.count }} Ungluers have pledged ${{ work.last_campaign.current_total|intcomma }}
+        		{{ work.last_campaign.supporters_count }} Ungluers have pledged ${{ work.last_campaign.current_total|intcomma }}
         	</div>
         	<div class="status">
         		<img src="/static/images/images/icon-book-37by25-{{ work.percent_unglued }}.png"  title="book list status" alt="book list status" />

frontend/templates/pledge.html

@@ -37,7 +37,7 @@
                 
         <div class="pledged-info">
         	<div class="pledged-group">
-        		{{ work.last_campaign.supporters.count }} Ungluers have pledged ${{ work.last_campaign.current_total|intcomma }}
+        		{{ work.last_campaign.supporters_count }} Ungluers have pledged ${{ work.last_campaign.current_total|intcomma }}
         	</div>
         	<div class="status">
         		<img src="/static/images/images/icon-book-37by25-{{ work.percent_unglued }}.png"  title="book list status" alt="book list status" />

frontend/templates/work.html

@@ -181,10 +181,10 @@ $j(document).ready(function(){
                         {% if not work.first_ebook %}
                         <div class="pledged-info"><div class="pledged-group">
                         {% if status == 'ACTIVE' %}
-                            {% if work.last_campaign.supporters.count == 1 %}
+                            {% if work.last_campaign.supporters_count == 1 %}
                                 One Ungluer has 
                             {% else %} 
-                                {{ work.last_campaign.supporters.count }} Ungluers have 
+                                {{ work.last_campaign.supporters_count }} Ungluers have 
                             {% endif %}
                             pledged ${{ work.last_campaign.current_total|floatformat:0|intcomma }}<br />toward a ${{ work.last_campaign.target|floatformat:0|intcomma }} goal 
                         {% else %}

payment/tests.py

@@ -331,6 +331,7 @@ class TransactionTest(TestCase):
         results = p.query_campaign(c,campaign_total=True, summary=False)
         self.assertEqual(results[0].amount, D('12.34'))
         self.assertEqual(c.left,c.target-D('12.34'))
+        self.assertEqual(c.supporters_count, 1)
 
 class BasicGuiTest(TestCase):
     def setUp(self):