Appengine cloud endpoint messages and iOS Core Data

问题

I have an endpoint message from Google Cloud Endpoint that I would like to persist in iOS Core Data. The endpoint message look like this

.h

#if GTL_BUILT_AS_FRAMEWORK
  #import "GTL/GTLObject.h"
#else
  #import "GTLObject.h"
#endif

@class GTLFarmercloudendpointChicken;
@class GTLFarmercloudendpointPig;
@class GTLFarmercloudendpointCow;

// ----------------------------------------------------------------------------
//
//   GTLFarmercloudendpointFarmer
//

@interface GTLFarmercloudendpointFarmer : GTLObject
@property (retain) NSArray *chickens;  // of GTLFarmercloudendpointChicken
@property (retain) NSArray *pigs;  // of GTLFarmercloudendpointPig
@property (retain) NSArray *cows;  // of GTLFarmercloudendpointCow
@property (copy) NSString *biography;
@property (retain) NSNumber *userid;  // longLongValue
@property (copy) NSString *username;
@end

.m

/* This file was generated by the ServiceGenerator.
 * The ServiceGenerator is Copyright (c) 2014 Google Inc.
 */

//
//  GTLFarmercloudendpointFarmer.m
//

// ----------------------------------------------------------------------------
// NOTE: This file is generated from Google APIs Discovery Service.
// Service:
//   Farmercloudendpoint/1
// Description:
//   Farmer API
// Classes:
//   GTLFarmercloudendpointFarmer (0 custom class methods, 6 custom properties)

#import "GTLFarmercloudendpointFarmer.h"

#import "GTLFarmercloudendpointChicken.h”
#import "GTLFarmercloudendpointCow.h”
#import "GTLFarmercloudendpointPig.h”

// ----------------------------------------------------------------------------
//
//   GTLFarmercloudendpointFarmer
//

@implementation GTLFarmercloudendpointFarmer
@dynamic chickens, pigs, cows, biography, userid, username;

+ (NSDictionary *)arrayPropertyToClassMap {
  NSDictionary *map =
    [NSDictionary dictionaryWithObjectsAndKeys:
      [GTLFarmercloudendpointChicken class], @“chickens”,
      [GTLFarmercloudendpointPig class], @“pigs”,
      [GTLFarmercloudendpointCow class], @“cows”,
      nil];
  return map;
}

@end

So that well meaning people do not misunderstand the question: these are messages not App-Engine datastore entities. This means: on the server, after I query the datastore (or a sql db, or whatever, really), I create java POJOs (my server is in Java) and these POJOs are sent to the client using Google Cloud Endpoint. So please avoid discussions of Core Data VS datastore as I saw in a similar question here.

On another note: observe that the message classes that Google Cloud Endpoint generate do not extend NSManagedObject. So a linking converter is missing so that I could persist my endpoint message in Core Data. Other than meticulously creating a linking for each message myself, any ideas how to accomplish this? For example imagine that class GTLFarmercloudendpointCow may itself contain an NSArray of Eggs. Manually creating a linker becomes daunting very quickly.

A similar problem exists in fact if I try to save the endpoint message as a file: in that case I need a NSCoder coder/encoder for each nested class in the message else I cannot use NSKeyedArchiver.

来源：https://stackoverflow.com/questions/25817671/appengine-cloud-endpoint-messages-and-ios-core-data

标签

ios

google-app-engine

core-data

xcode5

google-cloud-endpoints