title: How do you use RestKit resource path mappings with query strings?
body: <p>I'm trying to use the object loader to fetch objects from an API with that needs to pass in a type as a query parameter (e.g. <a href="http://example.com/api/households/:householdId/checklist_items?kind=todo" rel="nofollow">http://example.com/api/households/:householdId/checklist_items?kind=todo</a>) but no matter which way I try registering the resource path it doesn't seem to want to locate my mapping.</p>
  
  <p>I'm setting up a mapping like this:</p>
  
  <pre><code>RKObjectMapping* mapping = [RKObjectMapping mappingForClass:[RMChecklistItem class]];
  [mapping mapKeyPath:@"id" toAttribute:@"checklistItemId"];
  [mapping mapKeyPath:@"kind" toAttribute:@"kind"];
  [mapping mapKeyPath:@"title" toAttribute:@"title"];
  [mapping mapKeyPath:@"completed" toAttribute:@"completed"];
  [mapping mapKeyPath:@"abilities" toAttribute:@"abilities"];
  [mapping mapKeyPath:@"comments" toRelationship:@"comments" 
          withMapping:[provider objectMappingForClass:[RMComment class]]];
  </code></pre>
  
  <p>And registering it with the object mapping provider using the base path and a version with the query string:</p>
  
  <pre><code>[provider addObjectMapping:mapping];
  [provider setObjectMapping:mapping forResourcePathPattern:@"/api/households/:householdId/checklist_items"];
  [provider setObjectMapping:mapping forResourcePathPattern:@"/api/households/:householdId/checklist_items?kind=:kind"];
  </code></pre>
  
  <p>But when I try to use it:</p>
  
  <pre><code>NSDictionary *params [NSDictionary dictionaryWithObject:@"todo" forKey:@"kind"];
  NSString *path = [NSString stringWithFormat:@"/api/households/%i/checklist_items", householdId.intValue];
  [[RKObjectManager sharedManager] loadObjectsAtResourcePath:[path stringByAppendingQueryParameters:params] usingBlock:^(RKObjectLoader *loader) {
      loader.onDidLoadObjects = ^(NSArray *objects) {
          NSLog(@"%@", objects);
      };
      loader.onDidFailWithError = ^(NSError *error) {
          NSLog(@"%@", error);
      };
      loader.onDidFailLoadWithError = ^(NSError *error) {
          NSLog(@"%@", error);
      };
  }];
  </code></pre>
  
  <p>It goes badly:</p>
  
  <pre><code>2012-07-20 12:13:18.533 roommates[22399:13d03] D restkit.object_mapping:RKObjectMapper.m:336 Performing object mapping sourceObject: (
          {
          abilities =         {
              destroy = 1;
          };
          comments =         (
          );
          completed = 0;
          id = 44;
          kind = todo;
          title = "and do the dishes";
      },
          {
          abilities =         {
              destroy = 1;
          };
          comments =         (
                          {
                  body = "your!";
                  "created_at" = "2012-07-18T22:20:08-05:00";
                  "creator_id" = 16;
                  id = 70;
              }
          );
          completed = 0;
          id = 43;
          kind = todo;
          title = "pick you shit up";
      },
          {
          abilities =         {
              destroy = 1;
          };
          comments =         (
                          {
                  body = "did it";
                  "created_at" = "2012-07-18T22:19:56-05:00";
                  "creator_id" = 16;
                  id = 69;
              }
          );
          completed = 0;
          id = 40;
          kind = todo;
          title = "Pay Rent";
      }
  )
   and targetObject: (null)
  2012-07-20 12:13:18.539 roommates[22399:13d03] T restkit.object_mapping:RKObjectMapper.m:293 Examining keyPath 'users' for mappable content...
  2012-07-20 12:13:18.539 roommates[22399:13d03] D restkit.object_mapping:RKObjectMapper.m:120 Found a collection containing only NSNull values, considering the collection unmappable...
  2012-07-20 12:27:47.702 roommates[22399:13d03] D restkit.object_mapping:RKObjectMapper.m:303 Found unmappable value at keyPath: users
  2012-07-20 12:27:47.705 roommates[22399:13d03] D restkit.object_mapping:RKObjectMapper.m:367 The following operations are in the queue: (
  )
  2012-07-20 12:27:51.065 roommates[22399:13d03] W restkit.object_mapping:RKObjectMapper.m:87 Adding mapping error: Could not find an object mapping for keyPath: ''
  2012-07-20 12:27:51.066 roommates[22399:13d03] E restkit.network:RKObjectLoader.m:234 Encountered errors during mapping: Could not find an object mapping for keyPath: ''
  </code></pre>