[Grok-dev] what is grok.View.flash()?

[Martijn Faassen]

Hey,

Douglas Cerna already mentions how it can be used. I'll just dump a bit 
of the code I've used:

from zope import component
from z3c.flashmessage.interfaces import IMessageReceiver

class Feedback(grok.View):
     grok.context(Interface)
     grok.require('zope.Public')

     def now(self):
         return render_now()

     def messages(self):
         receiver = component.getUtility(IMessageReceiver)
         return [m.message for m in receiver.receive(u'message')]

     def errors(self):
         receiver = component.getUtility(IMessageReceiver)
         return [m.message for m in receiver.receive(u'error')]

with a feedback.pt

<tal:block tal:define="now view/now;">
     <ul id="messages"
         tal:define="messages python:view.messages()"
         tal:condition="messages">
         <li tal:repeat="message messages">
         <span tal:replace="now"></span>: <span 
tal:replace="message"></span>
         </li>
     </ul>

     <ul id="errors"
         tal:define="messages python:view.errors()"
         tal:condition="messages">
         <li tal:repeat="message messages">
         <span tal:replace="now"></span>: <span 
tal:replace="message"></span>
         </li>
     </ul>
</tal:block>

You can then use <tal:block replace="structure context/@@feedback" /> at 
the top of your page. You can also use this in an ajaxy way (by loading 
@@feedback again), by doing an innerHTML replacement of a special area 
of your page each time you do something that could cause a feedback update.

I think it would be worthwhile if some of this were more 
"out-of-the-boxy", as Brandon's right that all this is not very obvious.

See also the z3c.flashmessage documentation.

Regards,

Martijn