There's a difference between property and datastore type.
On Oct 30, 4:30 pm, luismgz <[EMAIL PROTECTED]> wrote:
> There are other options too, such as pickling a dictionary into a blob
> property, or saving its string representation into a StringProperty
> and then use eval() to get it back "alive".
> However, all these have issues and I guess that performance-wise they
> are suboptimal...
>
> On Oct 30, 1:16 pm, Anthony <[EMAIL PROTECTED]> wrote:
>
> > I don't know if this will help but I've built a custom property for
> > dealing with basic dict items. It's based on StringListProperty, so
> > you still have some indexing for searching on keys, or "key:value"
> > pairs.
>
> > The code has not been tested much yet...
>
> > class DictListProperty(db.StringListProperty):
> > def __init__(self, *args, **kwds):
> > #cache reads so we only process list once
> > self._cache = None
> > super(DictListProperty, self).__init__(*args, **kwds)
>
> > def get_value_for_datastore(self, model_instance):
> > value = super(DictListProperty,
> > self).get_value_for_datastore(model_instance)
> > if value is None:
> > return None
> > else:
> > #convert dict to list of key:value
> > l=[]
> > for k, v in value.items():
> > #expand any lists out (for tag lists etc)
> > if isinstance(v,list):
> > l.append(k)#add empty key with no
> > value so we know this is a list
> > for i in v:
> > l.append(k+":"+str(i))
> > else:
> > l.append(k+":"+str(v))
> > return self.data_type(l)
>
> > def validate(self, value):
> > return value
>
> > def make_value_from_datastore(self, value):
> > if self._cache is None:
> > if value is None:
> > return None
> > elif isinstance(value, list):
> > self._cache = {}
> > #split list of key:values back into dict
> > for v in value:
> > s=v.split(":",1)
> > if len(s)==1 and
> > self._cache.has_key(s[0]): #special case for
> > single item list
> > self._cache[s[0]] =
> > list(self._cache[s[0]])
> > elif len(s)==1: #special case for
> > empty list
> > self._cache[s[0]] = []
> > elif self._cache.has_key(s[0]):
> > #add to list
> > self._cache[s[0]] =
> > list(self._cache[s[0]])
> >
> > self._cache[s[0]].append(s[1])
> > else:
> > self._cache[s[0]]=s[1]
> > return self._cache
> > else:
> > return None
> > else:
> > return self._cache
>
> > #Tests..
>
> > class TestModel(db.Model):
> > d = DictListProperty()
>
> > #Main Test
> > t = TestModel()
> > t.d = {"a":1,"b":"2test","c":"3:test'here'withsemicolon
> > +junk&in,string"} #basic key:value structure, non-strings saved as
> > string
> > t.d["list"]=[0,1,2,3] #lists are also supported, expanded and stored
> > as d,d:0,d:1,d:2 etc. so can be indexed.
> > t.d["empty"]=[] #empty list will return as empty list, stored as just
> > "key"
> > t.put()
>
> > t = TestModel.get(p.key())
> > #t = Test.all().filter("d = ","b:2test").get() #for equality you need
> > to combine full "key:value" as string
> > #t = Test.all().filter("d = ","list:2").get() #lists are expanded for
> > indexing
> > #t = Test.all().filter("d >= ","c:").get() #inequalities can be user
> > to to test for just keys.
> > self.response.out.write(t.d) #returns a dict
> > self.response.out.write(t.d["list"]) #lists are re-combined
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