RKManagedObjectImporter crashes while importing when source attribute starts from symbol '@'

[larryonoff]

RestKit version is (0.20.0pre6).

The following error received: *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFDictionary 0x825cc20> valueForUndefinedKey:]: this class is not key value coding-compliant for the key project.'

Crash happens at the class RKMappingOperation in method applyAttributeMappings, code : id value = (attributeMapping.sourceKeyPath == nil) ? self.sourceObject : [self.sourceObject valueForKeyPath:attributeMapping.sourceKeyPath];

There are piece of my code:
[assignmentMapping addAttributeMappingsFromDictionary:@{@"@project": @"projectId"}];

Source attribute is '@project', which starts from the symbol '@'.

Possible solution is described there http://stackoverflow.com/questions/13294696/error-getting-valueforkey-in-an-nsdictionary-for-key-containing-character.

[blakewatters]

This is a known limitation and a consequence of RestKit's reliance on Cocoa's key-value coding system for property access. The '@' prefix is reserved for denominating key-value collection operators.

You are going to need to change that JSON format to effectively work with RestKit. Using objectForKey: is a non-starter because it means that you can no longer use key-paths for access to nested properties (i.e. @"user.address.city").

[larryonoff]

Thank you.

[unlucio]

Hello,
I'm pretty much having the same issue but i cannot change the JSON returned by the API :(
Is there any workaround on this?

If I manually call the service and query the JSON object I get (ie:

 [AFJSONRequestOperation JSONRequestOperationWithRequest:request
            success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) { ...

)

I can get those keys with no problems:

[JSON objectForKey:@"@type"]

Since restKit is using AFN as well, I'm not getting why those keys are un-usable :(

thx for help

[unlucio]

I think I kind of came up with a work around in this patch:
#1384

Now restkit is working for me with the @keys :)

[larryonoff]

Maybe the solution will be to introduce some kind of flag or special prefix symbol or escaping. I really like the idea of collection operators support.

[unlucio]

It still supports those.
The work around simply looks if it can find the dam key with valueForKey or it tries with objectForKey, that's all. No flags needed, too much to know about. Things should work automagically as long as they can :)

[larryonoff]

Thanks. Then I'm looking forward to the new RestKit release with the improvement.