Changes between Version 5 and Version 6 of CustomFormFields

Timestamp:

Mar 15, 2006, 9:07:55 AM (20 years ago)

Author:

Lllama

Comment:

Update explaining why custom manipulators are a better option

CustomFormFields

@@ -8 +8 @@
 
 {{{
-
+#!python
 class Port(meta.model):
     number = meta.IntegerField()
@@ -47 +47 @@
 
 {{{
+#!python
 class FormPortField(formfields.TextField):
 
@@ -117 +118 @@
 
 Wow.  What a mess.  We end up validating the data three times over.  What a pain.  But it works.
+
+=== Update 15.03.2006 ===
+
+After much searching and fiddling and wondering I've decided that I went about this all wrong.  Custom form fields are not the answer to my problem, manipulators are.  This is the code I'm now using:
+
+{{{
+#!python
+class ApplicationAddManipulator(applications.AddManipulator):
+
+    def __init__(self):
+        applications.AddManipulator.__init__(self)
+        newfields = []
+        for field in self.fields:
+            if field.field_name == 'ports':
+                field = formfields.TextField(field_name='ports', length=30, maxlength=200, validator_list=[self.isValidPortList])
+            newfields.append(field)
+        self.fields = newfields
+
+    def isValidPortList(self, field_data, all_data):
+        for port in field_data.split(','):
+            if port.lower().strip() != 'icmp':
+                try:
+                    no, proto = port.split(':')
+                except ValueError:
+                    raise validators.ValidationError, _("Ports should be specified in the form 'number:protocol'.  E.g. '80:tcp'")
+                try:
+                    if int(no) < 1 or int(no) > 65355:
+                        raise validators.ValidationError, _("Port number must be between 1 and 65355")
+                except ValueError:
+                    raise validators.ValidationError, _("Port number must be between 1 and 65355")
+                if proto.lower().strip() not in ['tcp', 'udp']:
+                    raise validators.ValidationError, _("Protocol must be either 'TCP' or 'UDP'")
+
+    def save(self, new_data):
+        portIds = []
+        if new_data['ports'] and new_data['ports'].strip().lower():
+            for port in new_data['ports'].split(','):
+                if port.strip().lower() == 'icmp':
+                    portIds.append(ports.get_object(protocol__exact='icmp').id)
+                else:
+                    no, proto = port.strip().lower().split(':')
+                    portIds.append(ports.get_object(protocol__exact=proto, number__exact=int(no)).id)
+            new_data['ports'] = portIds
+        return applications.AddManipulator.save(self, new_data)
+}}}
+
+Here's what the code actually does.  The new custom manipulator subclasses the standard AddManipulator for the Application model.  When a new instance is created (i.e. the __init__ method is called) then the AddManipulator's fields are copied and the 'ports' multiple-select box replaced with a standard text field.  The field has a custom validator attached to it and the save method is overridden to convert the user's input into a valid list of ports.
+
+Why is this better?  Validation is only done where appropriate - in the 'isValidPortList' function and nowhere else.
+
+Are there still issues?  Yep.  I still don't like the calling of 'do_html2python' when data could be invalid.  This really doesn't appear to make sense to me.  A lot of the manipulator code will change when Magic Removal hits trunk.  To what extent this will correct my concerns remains to be seen.