[Twisted-web] [Nevow] changing the attributes of a node

Tue Jul 25 06:58:58 CDT 2006

Manlio Perillo ha scritto:
> Hi.
> 
> I need to set/unset an attribute (checked) on a <input type="checkbox">
> element (in a xml template).
> 
> I'm using IQ.onePattern, but the problem is that the node is "removed"
> from the "stan context".
> 
> Now I'm doing this from my render function:
> 

Sorry, the example was wrong.
Here is my template:

<!DOCTYPE html
  PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:n="http://nevow.com/ns/nevow/0.1"
      lang="en" xml:lang="en">
  <head>
    <title>Test</title>
  </head>
  <body>
    <form action="update" method="post">
      <table>
        <caption />
        <thead />
        <tbody n:render="sequence" n:data="list">
          <tr n:pattern="item" n:render="item">
            <td><n:slot name="x" /></td>
            <td>
              <input n:pattern="checked" type="checkbox">
                <n:attr name="name"><n:slot name="x" /></n:attr>
              </input>
            </td>
          </tr>
        </tbody>
      </table>

      <p>
        <input class="button" type="submit" value="update" />
        <input class="button" type="reset" value="reset" />
      </p>
    </form>
  </body>
</html>

And my code:

from nevow import rend, loaders, inevow, static, url, tags

class Page(rend.Page):
    docFactory = loaders.xmlfile("node.xhtml")

    def data_list(self, ctx, data):
        return [1, 2, 3]

    def render_item(self, ctx, data):
        ctx.fillSlots("x", data)

        checked = ctx.tag.onePattern("checked")
        if data > 1 :
             checked.attributes["checked"] = "true"

        ctx.tag.children[-1] = checked
        return ctx.tag

from twisted.cred import portal, checkers, credentials
from twisted.application import service, strports

from nevow import appserver

application = service.Application("test")
site = appserver.NevowSite(Page())

addr = "tcp:80:interface=127.0.0.1"
strports.service(addr, site).setServiceParent(application)

The code now works, but this is an hack (because I have to know where to
put the node).
Is there a better solution?

Thanks and regards  Manlio Perillo