[Checkins] SVN: grok/branches/luciano-tutorial/doc/ completed explanation of the "delete" part of CRUD

Fri Jul 13 17:15:54 EDT 2007

Log message for revision 77887:
  completed explanation of the "delete" part of CRUD 
  

Changed:
  U   grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app.py
  U   grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app_templates/index.pt
  A   grok/branches/luciano-tutorial/doc/groktut/crud2/
  U   grok/branches/luciano-tutorial/doc/tutorial.txt

-=-
Modified: grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app.py
===================================================================

--- grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app.py	2007-07-13 20:51:34 UTC (rev 77886)
+++ grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app.py	2007-07-13 21:15:54 UTC (rev 77887)
@@ -1,5 +1,4 @@
 import grok
-from zope import interface, schema
 
 class Pebbles(grok.Application, grok.Container):
 
@@ -25,12 +24,7 @@
             self.context.eatMammoth(name)
         self.redirect(self.url('index'))
 
-class IMammoth(interface.Interface):
-    name = schema.TextLine(title=u"Name", required=True)
-    weight = schema.Int(title=u'Weight', min=0)
-
 class Mammoth(grok.Model):
-    #implements(IMammoth)
     def __init__(self, name, weight):
         self.name = name
         self.weight = weight
@@ -38,8 +32,4 @@
 class MammothDetails(grok.View):
     grok.context(Mammoth)
     grok.name('index')
-    
-class Edit(grok.EditForm):
-    grok.context(Mammoth)
-    pass
 

Modified: grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app_templates/index.pt
===================================================================
--- grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app_templates/index.pt	2007-07-13 20:51:34 UTC (rev 77886)
+++ grok/branches/luciano-tutorial/doc/groktut/crud/src/pebbles/app_templates/index.pt	2007-07-13 21:15:54 UTC (rev 77887)
@@ -3,8 +3,10 @@
 </head>
 <body>
   <h2>Mammoths</h2>
-  
-  <form tal:attributes="action python:view.url('eat')" method="POST">
+
+  <em tal:condition="not:context/keys">(no mammoths)</em>   
+  <form tal:condition="context/keys" 
+      tal:attributes="action python:view.url('eat')" method="POST">
   <ul>
     <li tal:repeat="key context/keys">
        <input type="checkbox" name="names:list" tal:attributes="value key">

Copied: grok/branches/luciano-tutorial/doc/groktut/crud2 (from rev 77881, grok/branches/luciano-tutorial/doc/groktut/crud)

Modified: grok/branches/luciano-tutorial/doc/tutorial.txt
===================================================================
--- grok/branches/luciano-tutorial/doc/tutorial.txt	2007-07-13 20:51:34 UTC (rev 77886)
+++ grok/branches/luciano-tutorial/doc/tutorial.txt	2007-07-13 21:15:54 UTC (rev 77887)
@@ -1196,9 +1196,6 @@
   if you need to store large quantities of items. 
 
 
-
-
-
 Containers 
 ----------
 
@@ -1329,6 +1326,53 @@
 modifications, you would be on your way to building your own content
 management system with Grok.
 
+CRUD
+----
 
+Many web apps do CRUD (Create, Retrieve, Update, Delete). Our ``Pebbles`` apps already allows the creation of and retrieval of ``Mammoth`` instances, so we are already half way there. The rest is easy as well.
 
+First let's implement the delete operation. Here is the new ``index.pt`` template::  
 
+.. include:: groktut/containers/src/pebbles/app_templates/index.pt
+  :literal:
+
+Here we have transformed the listing into a form, with one checkbox for 
+each mammoth. If there are no mammoths, we use ``tal:condition`` statements
+to omit the form and display the text "(no mammoths)".
+
+The form ``action`` attribute is generated by the ``view.url('eat')`` call.
+In this case, the ``url`` method will produce the URL of the view named ``eat`` in the same context, that is, the ``Pebble`` app.
+
+The ``name`` attribute for all checkboxes is the same. The ``:list`` suffix
+tells Grok that the values should be transformed into a list. This simplifies
+the coding of the method that will handle the action, because it will always
+receive a list in the ``name`` argument, even if only one checkbox is
+selected.
+
+.. sidebar:: Request data marshalling
+
+  One of the many services provided by the Zope is the automatic conversion of
+  form fields to Python types, including collection types. The `Zope 2.6
+  manual`__ describes the field name suffixes available, of which ``:list`` 
+  is just one example.
+
+  __ http://www.zope.org/Documentation/Books/ZopeBook/2_6Edition/ScriptingZope.stx/#2-77
+
+Now let's see the changes in ``app.py``::
+
+.. include:: groktut/crud/src/pebbles/app.py
+  :literal:
+
+First we implemented the ``eatMammoth`` method in the ``Pebbles`` application.
+Again, we can handle the container like a regular Python dictionary, so there
+is no special API call: we just delete the item.
+
+The delete form submits to the ``Eat`` view. Here we implement the ``render```
+method instead of the ``update`` as before, because the ``Eat`` view has no
+template. The ``render`` method just iterates over the received names and 
+calls the ``context.eatMammoth`` method for each of them, and then redirects
+to the index.
+
+
+
+ action of that form view that handles the  is the target of the ``index.pt`` form action. 

