将本地领域转换为同步领域：“customSchema”无法访问答案

【问题标题】：Converting local Realms to synced Realms: 'customSchema' is inaccessible将本地领域转换为同步领域：“customSchema”无法访问
【发布时间】：2017-09-18 09:28:55
【问题描述】：

我在文档中阅读了有关 Converting Local Realms to Synced Realms 部分的信息，并找到了用于 Objective-C 的 nice recipe，但我无法在完全用 Swift 实现的应用上实现它。

var syncConfig = Realm.Configuration()
syncConfig.syncConfiguration = SyncConfiguration(user: user, realmURL: server.appendingPathComponent("/~/app1"))
syncConfig.customSchema = localRealm.schema
~~~~~~~~~~~~~~~~~~~~~~~
^ 'customSchema' is inaccessible due to 'private' protection level

我什至添加了import Realm.Private，但没有解决问题。

我应该明确地使用 Objective-C 来进行这个操作吗？

【问题讨论】：

标签： swift realm realm-mobile-platform

【解决方案1】：

没有公开的customSchema 属性，您可以随时参考文档（了解什么是供公众使用的最佳方法）：

https://realm.io/docs/objc/2.10.1/api/Classes/RLMRealmConfiguration.html

【讨论】：

感谢您的回答。那么为什么配方要使用它呢？

【解决方案2】：

没有更好的选择，我决定在我的 Swift 项目中使用 Objective-C。所以，我添加了一个SWIFT_OBJC_BRIDGING_HEADER（当你添加一个Objective-C文件时，Xcode会自动这样做）并创建了一个RealmConverter对象：

RealmConverter.h

#import <Foundation/Foundation.h>

@import Realm;

NS_ASSUME_NONNULL_BEGIN

@interface RealmConverter : NSObject

- (void)convertLocalToSyncRealm:(NSURL *)server local:(NSURL *)local username:(NSString *)username password:(NSString *)password completion:(void (^)(NSError * _Nullable))completion;

@end

NS_ASSUME_NONNULL_END

RealmConverter.m

#import "RealmConverter.h"

@import Realm.Dynamic;
@import Realm.Private;

@implementation RealmConverter

- (void)convertLocalToSyncRealm:(NSURL *)server local:(NSURL *)local username:(NSString *)username password:(NSString *)password completion:(void (^)(NSError * _Nullable))completion {
    RLMRealmConfiguration *configuration = [[RLMRealmConfiguration alloc] init];
    configuration.fileURL = local;
    configuration.dynamic = true;
    configuration.readOnly = YES;

    RLMRealm *localRealm = [RLMRealm realmWithConfiguration:configuration error:nil];

    RLMSyncCredentials *credentials = [RLMSyncCredentials credentialsWithUsername:username password:password register:YES];
    [RLMSyncUser logInWithCredentials:credentials authServerURL:server onCompletion:^(RLMSyncUser *syncUser, NSError *error) {
        if (error) {
            completion(error);
            return;
        }

        dispatch_async(dispatch_get_main_queue(), ^{
            RLMRealmConfiguration *syncConfig = [[RLMRealmConfiguration alloc] init];
            syncConfig.syncConfiguration = [[RLMSyncConfiguration alloc] initWithUser:syncUser realmURL:[NSURL URLWithString:[NSString stringWithFormat:@"realm://%@:%@/~/<redacted>", server.host, server.port]]];
            syncConfig.customSchema = [localRealm.schema copy];

            RLMRealm *syncRealm = [RLMRealm realmWithConfiguration:syncConfig error:nil];
            syncRealm.schema = syncConfig.customSchema;

            NSError *error = nil;
            [syncRealm transactionWithBlock:^{
                NSArray *objectSchema = syncConfig.customSchema.objectSchema;
                for (RLMObjectSchema *schema in objectSchema) {
                    RLMResults *allObjects = [localRealm allObjects:schema.className];
                    for (RLMObject *object in allObjects) {
                        RLMCreateObjectInRealmWithValue(syncRealm, schema.className, object, true);
                    }
                }
                completion(nil);
            } error:&error];

            if (error) {
                completion(error);
            }
        });
    }];
}

@end

然后将 #import "RealmConverter.h" 添加到您的桥接头中，然后在您的 Swift 代码中使用它，例如：

RealmConverter().convertLocal(toSyncRealm: URL(string: "http://localhost:9080")!, local: Realm.Configuration.defaultConfiguration.fileURL!, username: "user@example.com", password: "12345678") { error in
    print("Done:", error ?? "nil")
}

【讨论】：

【解决方案3】：

在这里找到了 Swift 函数的一个端口：https://github.com/realm/realm-cocoa/issues/538

import Realm
import Realm.Dynamic
import RealmSwift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let sourceFilePath = Bundle.main.url(forResource: "fieldFlow", withExtension: "realm")
    let configuration = RLMRealmConfiguration()
    configuration.fileURL = sourceFilePath
    configuration.dynamic = true
    configuration.readOnly = true

    let localRealm = try! RLMRealm(configuration: configuration)

    let creds = SyncCredentials.usernamePassword(username: "admin@realm.io", password: "password")
    SyncUser.logIn(with: creds, server: URL(string: "http://localhost:9080")!) { (syncUser, error) in
        DispatchQueue.main.async {
            if let syncUser = syncUser {
                self.copyToSyncRealmWithRealm(realm: localRealm, user: syncUser)
            }
        }
    }
}

func copyToSyncRealmWithRealm(realm: RLMRealm, user: RLMSyncUser) {
    let syncConfig = RLMRealmConfiguration()
    syncConfig.syncConfiguration = RLMSyncConfiguration(user: user, realmURL: URL(string: "realm://localhost:9080/~/fieldRow")!)
    syncConfig.customSchema = realm.schema

    let syncRealm = try! RLMRealm(configuration: syncConfig)
    syncRealm.schema = syncConfig.customSchema!
    try! syncRealm.transaction {
        let objectSchema = syncConfig.customSchema!.objectSchema
        for schema in objectSchema {
            let allObjects = realm.allObjects(schema.className)
            for i in 0..<allObjects.count {
                let object = allObjects[i]
                RLMCreateObjectInRealmWithValue(syncRealm, schema.className, object, true)
            }
        }
    }
}

【讨论】：