Question

I was just trying to parse a JSON-Object which includes a 2-dimensional array.

Example:

{
  "2dimarray": [
                 [{"key": "val"}, {"key": "val"}],
                 [{"key": "val"}, {"key": "val"}]
               ]
}

Assuming the contents of 2dimarray[x][y] are only of one type, I added the mapping:

[objectMapping mapKeyPath:@"2dimarray" toRelationship:@"2dimarray" withMapping: myMappingForIncludedObjects];

In the log RestKit tells me:

W restkit.object_mapping:RKObjectMappingOperation.m:438 WARNING: Detected a relationship mapping for a collection containing another collection. This is probably not what you want. Consider using a KVC collection operator (such as @unionOfArrays) to flatten your mappable collection.

But actually it is what I want. Basicly I assumed that the object mapper would fill my Objective-C property NSArray* 2dimarray with NSArray*s that include objects that are mapped with myMappingForIncludedObjects. Instead, each array is mapped (which fails, of course) with myMappingForIncludedObjects.

What am I doing wrong? Or better: What do I need to do to archive the behavior I expected?

Answer 1

I believe that the issue you cite is Blake explaining the problem, not a solution. I don’t think RestKit is set up to handle the mapping that you describe (an array of arrays of objects). You can walk through an example of what he describes in the issue as well as looking at his commit, and you’ll see that the introduced logic was aimed at detecting the problem and logging it for debugging purposes.