1 files changed, 67 insertions, 0 deletions
diff --git a/paste/wareweb/notify.py b/paste/wareweb/notify.py
new file mode 100644
index 0000000..c4ced66
--- /dev/null
+++ b/paste/wareweb/notify.py
@@ -0,0 +1,67 @@
+import event
+
+__all__ = ['Notify']
+
+class Notify(object):
+
+    """
+    This allows you to queue messages to be displayed to the user on
+    the next page the user reads.  This allows you to give messages in
+    response to POST requests, then redirect to a another page and
+    display that message (e.g, 'event added').
+    
+    Usage::
+
+        class SitePage(Servlet):
+            message = Notify()
+
+        class MyPage(SitePage):
+            def setup(self):
+                if something_done:
+                    self.message.write('All good!')
+                    self.redirect(...)
+            def respond(self):
+                write header...
+                if self.message:
+                    self.write('<div class="message">%s</div>\n'
+                               % self.message.html)
+    """
+
+    def __addtoclass__(self, attr, cls):
+        cls.listeners.append(self.servlet_event)
+        self.name = attr
+
+    def servlet_event(self, name, servlet, *args, **kw):
+        if name == 'start_awake':
+            setattr(servlet, self.name, Message(servlet))
+        elif name == 'end_sleep':
+            if getattr(servlet, '_notify_written', False):
+                if 'notify.messages' in servlet.session:
+                    del servlet.session['notify.messages']
+        return event.Continue
+        
+class Message(object):
+
+    def __init__(self, servlet):
+        self.servlet = servlet
+
+    def write(self, message):
+        session = self.servlet.session
+        messages = session.get('notify.messages') or []
+        messages.append(message)
+        session['notify.messages'] = messages
+
+    def __nonzero__(self):
+        return bool(self.servlet.session.get('notify.messages'))
+
+    def html__get(self):
+        messages = self.servlet.session.get('notify.messages') or []
+        self.servlet._notify_written = True
+        return self.peek
+    html = property(html__get)
+    
+    def peek__get(self):
+        messages = self.servlet.session.get('notify.messages') or []
+        return '<br>'.join(messages)
+    peek = property(peek__get)
+