Re: [Zope] How to make a ZPT-based form that calls itself?

J Cameron Cooper Wed, 11 May 2005 13:26:51 -0700

Ken Winter wrote:

Hi Zopers -
I'm trying to make a ZPT-based HTML form that:
1. Displays the records in a MySQL 'Person' table;
2. Offers a field for updating this table (in my simple test example, it
accepts the Id of a Person to delete);
3. When you push its 'Submit' button, updates the database; and then
4. Automatically redisplays itself, showing the updated 'Person' records.
After a lot of help from the folks on various Zope lists, I've made it
through steps 1-3, but I'm stuck on step 4 and I can't find an example or
tutorial telling me how to do it.
The relevant code snippets are:
The ZPT's body...
<table width="100%" height="100%" border="0" cellpadding="6" cellspacing="0"> <tr> <td width="1084" height="531" align="left" valign="top"><font color="#000000" face="Verdana, Arial, Helvetica, sans-serif"> <h1> People (deletion test)</h1> <table tal:repeat="row here/dbobs/read_all_people" width="100%" border="0" cellspacing="0" cellpadding="0"><font face="Verdana, Arial, Helvetica, sans-serif"> <tr> <td width="44%" tal:content="string:${row/person_id} - ${row/first_name} ${row/middle_names} ${row/last_name}">Filler</td> <td width="56%"> </td> </tr> </table> <p></p> <form action="dbobs/delete_person_py" method="post" name="delete_form"> <p>Id of Person To Delete: <input type="text" name="person_id:int" /> </p> <p> <input name="do_delete" type="submit" id="do_delete" value="Delete this Person" /> </p> </form> <p>The "Ids" are the numbers in front of each person's name.</p> <p><a href="deltest.htm">Refresh This Page</a></p> <p tal:replace="python:here.dbobs.test1('MyParamValue')">Junk</p> </font></td> </tr> </table>
...The one-line Python script "delete_person_py" that the form's action
attribute calls...
container.delete_person(person_id=context.REQUEST.get('person_id'))
...The Z SQL method delete_person(person_id) that the Python script calls...
delete from person where <dtml-sqltest person_id op=eq type=int>
...And a URL to the test page in its current incarnation...
http://dhat.vega.zettai.net/clients/ridhwan/dhr3/deltest.htm
What's wrong with this page is that you have to hit the "Refresh This Page"
link to get it to do what I want it to do automatically.
I suspect that what I'm missing is some basic HTML knowledge.  But whatever
it is, I'd appreciate your help in suggesting the missing piece.

You submit to a script, going that url, and the script is responsible for providing the output of the page.

Since you write no output, you see no action in your browser. Some browsers may display a blank page, which probably would have been more helpful to you.

You want your script to do something. It might print out some text to form HTML, but that's nasty. It usually will either (a) call some other object, like a page template, to provide output, or (b) do a redirect.

Case A:
  return context.some_page()

Case B:
  context.REQUEST.RESPONSE.redirect('some_page')

In your case, since this is a destructive method, you probably want do a redirect, back to your listing.

A more advanced and flexible technique is to use FormController. With that, you specify by configuration if you want redirect or traverse and where to go based on the results of the script (success, failure, some other state.)

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Re: [Zope] How to make a ZPT-based form that calls itself?

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