How to load multiple unrelated objects with RestKit?

Question

I need to load mulitple objects that don't have relationships but located on the same remote API using RestKit into CoreData (in other words download remote objects to use them locally in iOS)

So I've setup my Client and objectManager:

client = [RKClient clientWithBaseURL:[NSURL URLWithString:baseUrl]]; 
[client setUsername:@"someUsername"];
[client setPassword:@"somePassword"];

objectManager = [RKObjectManager managerWithBaseURLString:baseUrl];
[objectManager setClient:client];

Then I setup some mappings for one Object#1:

RKManagedObjectMapping* companyMapping = [RKManagedObjectMapping mappingForEntityWithName:@"Company" inManagedObjectStore:objectManager.objectStore];
companyMapping.primaryKeyAttribute = @"backendID";
[companyMapping mapKeyPath:@"id" toAttribute:@"backendID"];
[companyMapping mapKeyPath:@"company_name" toAttribute:@"companyName"];

Then I setup some mappings for Object #2:

RKManagedObjectMapping* eventMapping = [RKManagedObjectMapping mappingForEntityWithName:@"Event" inManagedObjectStore:objectManager.objectStore];
eventMapping.primaryKeyAttribute = @"backendID";
[eventMapping mapKeyPath:@"id" toAttribute:@"backendID"];
[eventMapping mapKeyPath:@"description" toAttribute:@"eventDescription"];

After that I set objectMapping to mappingProvider:

 [objectManager.mappingProvider setObjectMapping:companyMapping forResourcePathPattern:remoteObjectPath];
 [objectManager.mappingProvider setObjectMapping:eventMapping forResourcePathPattern:remoteObjectPath];

And lastly I call "loadObjects..." for both of these objects one after another:

[objectManager loadObjectsAtResourcePath:remoteCompaniesObjectPath delegate:self];
[objectManager loadObjectsAtResourcePath:remoteEventsObjectPath delegate:self];

What happens after this that data from both Companies and Events is somehow loaded into the Events table, so table data is completely unusable. If I run only loadObjectsAtResourcePath:remoteCompaniesObjectPath then everything works as expected remote Company object downloads into it's own table in the CoreData.

While it does make sense why it's happening (data For Companies starting to load and gets new mapping, so it loads to the wrong table) the QUESTION is: How to call loadObjectsAtResourcePath:remoteObjectPath methods to load multiple unrelated objects so they would properly loaded into their respective tables in the CoreData???

AdiTheExplorer AdiTheExplorer · Accepted Answer · 2012-06-21T06:12:46

Well I think there is nothing There for restkit to distinguish between two object types company and events.

There are two ways of going about this. Both are straightforward, upto you what to choose:

You provide a rootkeypath to restkit for both company and events. And then you modify your api to include a rootkeypath in the json. Something like below..

["company":{ "Backendid":1 "company name":"abc" } {"events":{ {Backendid":1 "description":"party" }]

In this case restkit will know which is an event and what is a company and will automatically map to the right table.. Checkout rkgithub example for more tips.
You set your online api to have 2 different urls for both. So then the different URL will be make sure restkit doesn't get tables mixed up.

Also something to ask here, does your events column have a company name column as well? Because I would have thought restkit will give you an error as from your mapping there doesn't seem to be a column named company name in an events table. Are you trying to do some sort of to-many relationship here? Where company has-many events type of thing.

How to load multiple unrelated objects with RestKit?

2 Answers