Question

I have the following Django and Flex code:

Django

class Author(models.Model):   name = models.CharField(max_length=30)  class Book(models.Model):   title = models.CharField(max_length=30)   author = models.ForeignKeyField(Author) 

Flex

package com.myproject.models.vo {     [Bindable]     [RemoteClass(alias='myproject.models.Book')]      public class BookVO     {         public var id:int;         public var title:String;         public var author: AuthorVO;     } } 

As you can see in this example, Author is a foreign key in my Book model. Now I’d like to acccess the author’s name when I call my BookVO in Flex. As such, I’d expect code like the following to work, but ‘author_name’ results in a null:

var book = new BookVO(); var author_name = book.author.name; 

I realize I could call an AuthorVO directly, but the crux of this question is how can you retrieve foreign-keyed values using Flex when your VOs are bound to a remote object? I’m currently using PyAMF to bridge the gap between Flex and Django, but I’m not sure that’s relevant.

Answer 1

Ok, Here’s an example…

Model:

class Logger(models.Model):     lname = models.CharField(max_length=80)      def __unicode__(self):         return self.lname     # #  class DataSource(models.Model):     dsname = models.CharField(max_length=80)     def __unicode__(self):         return self.dsname     # #  class LoggedEvent(models.Model):     # who's data is this?     who = models.ForeignKey(Logger)     # what source?     source = models.ForeignKey(DataSource)     # the day (and, for some events also the time)     when = models.DateTimeField()     # the textual description of the event, often the raw data     what = models.CharField(max_length=200)     # from -1.0 to 1.0 this is the relative     # importance of the event     weight = models.FloatField()      def __unicode__(self):         return u'%2.2f %s:%s - %s' % (self.weight, self.source, self.who, self.what)     # # 

Here’s my amfgateway.py

def fetch_events(request, source):     events = LoggedEvent.objects.select_related().all()     return events #  services = {     'recall.fetch_events': fetch_events, }  gateway = DjangoGateway(services) 

and here’s my Actionscript for the receiving side of the AMF call:

protected function onRetrievedEvents(result: Object): void {      for each(var evt: Object in result) {         var who: Object = evt._who_cache.lname;  ... 

The evt._who_cache.lname is populated with the select_related() and missing when the select related is missing. If I get rid of the select_related() call, then I see the error:

TypeError: Error #1010: A term is undefined and has no properties. 

You must be trying a different technique with your RemoteClass… so the select_related might not be the problem at all… (otherwise my first answer wouldn’t have gotten negged.) The rest is up to you.