RKManagedObjectStore subclass that is configuration-aware

RDManagedObjectStore.h

//
//  RDManagedObjectStore.h
//  Capri
//
//  Created by Sixten Otto on 4/17/12.
//  Copyright (c) 2012 Results Direct. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#import <RestKit/CoreData.h>

@interface RDManagedObjectStore : RKManagedObjectStore

+ (RDManagedObjectStore*)objectStoreWithStoreFilename:(NSString *)storeFilename inDirectory:(NSString *)directory usingSeedDatabaseName:(NSString *)nilOrNameOfSeedDatabaseInMainBundle managedObjectModel:(NSManagedObjectModel*)nilOrManagedObjectModel configuration:(NSString *)nilOrModelConfiguration;

- (NSError *)addPersistentStoreForConfiguration:(NSString *)configuration withFilename:(NSString *)storeFilename inDirectory:(NSString *)directory;

@end

RDManagedObjectStore.m

//
//  RDManagedObjectStore.m
//  Capri
//
//  Created by Sixten Otto on 4/17/12.
//  Copyright (c) 2012 Results Direct. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#import "RDManagedObjectStore.h"

#import <RestKit/RKDirectory.h>
#import <RestKit/RKSearchWordObserver.h>


@interface RKManagedObjectStore (Private)

- (void)createPersistentStoreCoordinator;
- (void)createStoreIfNecessaryUsingSeedDatabase:(NSString*)seedDatabase;

@end


@interface RDManagedObjectStore ()

@property (nonatomic, strong, readwrite) NSString *storeFilename;
@property (nonatomic, strong, readwrite) NSString *pathToStoreFile;
@property (nonatomic, strong, readwrite) NSManagedObjectModel *managedObjectModel;
@property (nonatomic, strong, readwrite) NSPersistentStoreCoordinator *persistentStoreCoordinator;
@property (nonatomic, strong, readwrite) NSManagedObjectContext *primaryManagedObjectContext;

@property (copy, nonatomic) NSString *configuration;

- (id)initWithStoreFilename:(NSString *)storeFilename inDirectory:(NSString *)nilOrDirectoryPath usingSeedDatabaseName:(NSString *)nilOrNameOfSeedDatabaseInMainBundle managedObjectModel:(NSManagedObjectModel*)nilOrManagedObjectModel configuration:(NSString *)nilOrModelConfiguration;

- (NSError *)addPersistentStoreForConfiguration:(NSString *)configuration URL:(NSURL *)storeURL;

@end


@implementation RDManagedObjectStore

@synthesize storeFilename = rd_storeFilename;
@synthesize pathToStoreFile = rd_pathToStoreFile;
@synthesize managedObjectModel = rd_managedObjectModel;
@synthesize persistentStoreCoordinator = rd_persistentStoreCoordinator;
@synthesize primaryManagedObjectContext = rd_primaryManagedObjectContext;

@synthesize configuration = rd_configuration;

+ (RDManagedObjectStore*)objectStoreWithStoreFilename:(NSString *)storeFilename inDirectory:(NSString *)directory usingSeedDatabaseName:(NSString *)nilOrNameOfSeedDatabaseInMainBundle managedObjectModel:(NSManagedObjectModel*)nilOrManagedObjectModel configuration:(NSString *)nilOrModelConfiguration
{
  return [[self alloc] initWithStoreFilename:storeFilename inDirectory:directory usingSeedDatabaseName:nilOrNameOfSeedDatabaseInMainBundle managedObjectModel:nilOrManagedObjectModel configuration:nilOrModelConfiguration];
}

- (id)initWithStoreFilename:(NSString *)storeFilename inDirectory:(NSString *)nilOrDirectoryPath usingSeedDatabaseName:(NSString *)nilOrNameOfSeedDatabaseInMainBundle managedObjectModel:(NSManagedObjectModel*)nilOrManagedObjectModel configuration:(NSString *)nilOrModelConfiguration {
  self = [self init];
  if (self) {
    self.storeFilename = storeFilename;
    self.configuration = nilOrModelConfiguration;
    
    if( nilOrDirectoryPath == nil ) {
      nilOrDirectoryPath = [RKDirectory applicationDataDirectory];
      [RKDirectory ensureDirectoryExistsAtPath:nilOrDirectoryPath error:nil];
    }
    else {
      BOOL isDir;
      NSAssert1([[NSFileManager defaultManager] fileExistsAtPath:nilOrDirectoryPath isDirectory:&isDir] && isDir == YES, @"Specified storage directory exists", nilOrDirectoryPath);
    }
    self.pathToStoreFile = [nilOrDirectoryPath stringByAppendingPathComponent:storeFilename];
    
    if (nilOrManagedObjectModel == nil) {
      nilOrManagedObjectModel = [NSManagedObjectModel mergedModelFromBundles:[NSBundle allBundles]];
    }
    NSMutableArray *allManagedObjectModels = [NSMutableArray arrayWithObject:nilOrManagedObjectModel];
    self.managedObjectModel = [NSManagedObjectModel modelByMergingModels:allManagedObjectModels];
    
    if (nilOrNameOfSeedDatabaseInMainBundle) {
      [self createStoreIfNecessaryUsingSeedDatabase:nilOrNameOfSeedDatabaseInMainBundle];
    }
    
    [self createPersistentStoreCoordinator];
    self.primaryManagedObjectContext = [self newManagedObjectContext];
    
    self.cacheStrategy = [RKInMemoryManagedObjectCache new];
    
    // Ensure there is a search word observer
    [RKSearchWordObserver sharedObserver];
    
    // Hydrate the defaultObjectStore
    if (! [[self class] defaultObjectStore] ) {
      [[self class] setDefaultObjectStore:self];
    }
  }
  
  return self;
}


- (NSError *)addPersistentStoreForConfiguration:(NSString *)configuration URL:(NSURL *)storeURL
{
  NSPersistentStore* store = nil;
  NSError *error = nil;
  
  /* There seems to be trouble with combining configurations and migration. So
   * do this in two steps: first, attach the store with NO configuration,
   * but WITH migration options; then remove it and reattach WITH configuration,
   * but NOT migration options.
   *
   * http://blog.atwam.com/blog/2012/05/11/multiple-persistent-stores-and-seed-data-with-core-data/
   * http://stackoverflow.com/questions/1774359/core-data-migration-error-message-model-does-not-contain-configuration-xyz
   * 
   */
  
  // migration pass
  NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                           [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                           [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption,
                           nil];
  
  store = [self.persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error];
  if( nil == store ) {
    return error;
  }
  
  // remove store
  if( ![self.persistentStoreCoordinator removePersistentStore:store error:&error] ) {
    return error;
  }
  
  // reattach store
  store = [self.persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:configuration URL:storeURL options:nil error:&error];
  if( nil == store ) {
    return error;
  }
  
  return nil;
}

- (NSError *)addPersistentStoreForConfiguration:(NSString *)configuration withFilename:(NSString *)storeFilename inDirectory:(NSString *)directory
{
  NSURL* storeURL = [[NSURL fileURLWithPath:directory] URLByAppendingPathComponent:storeFilename];
  return [self addPersistentStoreForConfiguration:configuration URL:storeURL];
}

- (void)createPersistentStoreCoordinator {
  NSURL *storeUrl = [NSURL fileURLWithPath:self.pathToStoreFile];
  
  self.persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];
  
  NSError* error = [self addPersistentStoreForConfiguration:self.configuration URL:storeUrl];
  
  if( error ) {
    if (self.delegate != nil && [self.delegate respondsToSelector:@selector(managedObjectStore:didFailToCreatePersistentStoreCoordinatorWithError:)]) {
      [self.delegate managedObjectStore:self didFailToCreatePersistentStoreCoordinatorWithError:error];
    }
    else {
      NSAssert(NO, @"Managed object store failed to create persistent store coordinator: %@", error);
    }
  }
}

- (NSManagedObjectContext *)newManagedObjectContext
{
  NSManagedObjectContext *managedObjectContext = nil;
  if( [NSThread isMainThread] ) {
    managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
  }
  else {
    managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSConfinementConcurrencyType];
  }
  [managedObjectContext setPersistentStoreCoordinator:self.persistentStoreCoordinator];
  [managedObjectContext setUndoManager:nil];
  [managedObjectContext setMergePolicy:NSMergeByPropertyStoreTrumpMergePolicy];
  managedObjectContext.managedObjectStore = self;
  
  return managedObjectContext;
}

@end

usage.m

    // set up object store
    RDManagedObjectStore* store = [RDManagedObjectStore
                                   objectStoreWithStoreFilename:@"Server.sqlite"
                                   inDirectory:appSupportPath
                                   usingSeedDatabaseName:[self serverSeedDatabaseName]
                                   managedObjectModel:managedObjectModel
                                   configuration:@"Server"];
    store.delegate = self;
    
    // don't back up the server-sourced content
    [self setDontBackupOnURL:[[store.persistentStoreCoordinator.persistentStores lastObject] URL]];
    
    // separate storage for user-generated content
    [store addPersistentStoreForConfiguration:@"UserGenerated" withFilename:@"UserGenerated.sqlite" inDirectory:appSupportPath];