From e047c9025ce02f661bdb5cb3c035fb32c241aea5 Mon Sep 17 00:00:00 2001
From: Mike Ryan <mike@fadedink.co.uk>
Date: Mon, 19 Dec 2011 23:21:20 +0000
Subject: [PATCH] Added support for Buy Now button with product/price options.
 See:
 https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_html_buynow_buttons#id08A2G0Y06X4

    fields = {'item_name': 'name',
              'item_options': (('10.00', 'Ten dollars'),
                               ('20.00', 'Twenty dollars')),
              ...
             }
---
 paypal/standard/forms.py   | 10 ++++++++-
 paypal/standard/widgets.py | 42 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/paypal/standard/forms.py b/paypal/standard/forms.py
index e9992a5..63a7da4 100644
--- a/paypal/standard/forms.py
+++ b/paypal/standard/forms.py
@@ -4,7 +4,8 @@
 from django.conf import settings
 from django.utils.safestring import mark_safe
 from paypal.standard.conf import *
-from paypal.standard.widgets import ValueHiddenInput, ReservedValueHiddenInput
+from paypal.standard.widgets import (ValueHiddenInput, ReservedValueHiddenInput,
+    ItemOptionsInput)
 from paypal.standard.conf import (POSTBACK_ENDPOINT, SANDBOX_POSTBACK_ENDPOINT, 
     RECEIVER_EMAIL)
 
@@ -59,6 +60,7 @@ class PayPalPaymentsForm(forms.Form):
     item_name = forms.CharField(widget=ValueHiddenInput())
     item_number = forms.CharField(widget=ValueHiddenInput())
     quantity = forms.CharField(widget=ValueHiddenInput())
+    item_options = forms.ChoiceField(widget=ItemOptionsInput())
     
     # Subscription Related.
     a1 = forms.CharField(widget=ValueHiddenInput())  # Trial 1 Price
@@ -99,6 +101,12 @@ def __init__(self, button_type="buy", *args, **kwargs):
         super(PayPalPaymentsForm, self).__init__(*args, **kwargs)
         self.button_type = button_type
 
+        # If item_options have been specified, populate the item_options select
+        # with the given choices.
+        item_options = kwargs['initial'].get('item_options', ())
+        if item_options:
+            self.fields['item_options'].choices = item_options
+
     def render(self):
         return mark_safe(u"""<form action="%s" method="post">
     %s
diff --git a/paypal/standard/widgets.py b/paypal/standard/widgets.py
index 51aea94..46011f0 100644
--- a/paypal/standard/widgets.py
+++ b/paypal/standard/widgets.py
@@ -28,4 +28,44 @@ def render(self, name, value, attrs=None):
         final_attrs = self.build_attrs(attrs, type=self.input_type)
         if value != '':
             final_attrs['value'] = force_unicode(value)
-        return mark_safe(u'<input%s />' % flatatt(final_attrs))
\ No newline at end of file
+        return mark_safe(u'<input%s />' % flatatt(final_attrs))
+
+class ItemOptionsInput(ValueHiddenInput):
+    """ Displays a list of options on the PayPal button. Each option has a
+        different price.
+
+        choices is a tuple of amount/name pairs:
+            (('10.00', 'Ten Dollars'),
+             ('20.00', 'Twenty Dollars'))
+    """
+    def render(self, name, value, attrs=None, choices=()):
+        if not self.choices:
+            return ''
+
+        hiddens = []
+        options = []
+        count = 0
+        hidden = """<input type="hidden" name="option_select%(count)s" value="%(name)s">
+                    <input type="hidden" name="option_amount%(count)s" value="%(amount)s">
+                 """
+        option = '<option value="%(name)s">%(name)s</option>'
+
+        for amount, opt_name in self.choices:
+            vars = {'count': count, 'amount': amount, 'name': opt_name}
+            options.append(option % vars)
+            hiddens.append(hidden % vars)
+            count += 1
+
+        output = """<table><tr><td>
+                    <input type="hidden" name="on0" value="%(name)s">%(name)s
+                    </td></tr><tr><td>
+                    <select name="os0">
+                    %(options)s
+                    </select></table>
+                    <input type="hidden" name="option_index" value="0">
+                    %(hiddens)s
+                """ % {'options': '\n'.join(options),
+                       'hiddens': '\n'.join(hiddens),
+                       'name': 'Amount'}
+
+        return mark_safe(output)