ios - 从 Response(RestKit) 加载对象时出错

Question

我为其余的 Response 创建了一个映射，并将其命名为 Data。在通过 RKObjectManager 进行其余调用后，它不会加载对象。而是执行 RKObjetLoader 的 didFailWithError 方法。我的实现类继承自 RKObjectLoaderDelegate。

@implementation RKObjectLoaderExamples

    -(void)loadData{
        RKObjectMapping* mapping = [RKObjectMapping mappingForClass:[Data class]];
        RKObjectManager* manager = [RKObjectManager objectManagerWithBaseURL:@"http://localhost:8080/activiti-rest/service"];  
        [manager loadObjectsAtResourcePath:@"/process-definitions?start=0&size=10&sort=id&order=asc&username=kermit&password=kermit" objectMapping:mapping delegate:self]  ;
        NSLog(@"Loaded Data");
    }

    // RKObjectLoaderDelegate methods  

    - (void)objectLoader:(RKObjectLoader*)objectLoader didLoadObjects:(NSArray*)objects {  
        NSLog(@"objectLoaded");
        Data* data = [objects objectAtIndex:0];  
        NSLog(@"Loaded Key: %@, Name: %@", data.key, data.name);  
    }  


    - (void)objectLoader:(RKObjectLoader*)objectLoader didFailWithError:(NSError*)error {  
        NSLog(@"Encountered an error: %@", error);  
    }
@end  

我得到的错误信息如下

2011-11-16 14:36:38.971 Views[16753:fb03] W restkit.network:RKResponse.m:182 Received an authentication challenge without any credentials to satisfy the request.
2011-11-16 14:36:38.974 Views[16753:fb03] W restkit.network:RKObjectLoader.m:242 Unable to find parser for MIME Type 'text/html'
2011-11-16 14:36:38.975 Views[16753:fb03] W restkit.network:RKObjectLoader.m:259 Encountered unexpected response with status code: 401 (MIME Type: text/html)
2011-11-16 14:36:38.976 Views[16753:fb03] Encountered an error: Error Domain=org.restkit.RestKit.ErrorDomain Code=4 "The operation couldn’t be completed. (org.restkit.RestKit.ErrorDomain error 4.)"

请帮忙!

更正后我将函数更改为

-(void)loadData{

    [RKClient setSharedClient:[[RKClient alloc] initWithBaseURL:@"http://localhost:8080/activiti-rest/service"]];
    RKObjectMapping* mapping = [RKObjectMapping mappingForClass:[Data class]];
    RKObjectManager* manager = [RKObjectManager objectManagerWithBaseURL:@"http://localhost:8080/activiti-rest/service"];  
     [manager setClient:[RKClient sharedClient]];
    [[RKClient sharedClient] setUsername:@"kermit"];
    [[RKClient sharedClient] setPassword:@"kermit"];
    [manager loadObjectsAtResourcePath:@"/process-definitions?start=0&size=10&sort=id&order=asc" objectMapping:mapping delegate:self]  ;
    NSLog(@"Loaded Data");

}

是否正确？因为现在对象似乎已加载，但我得到的索引 0 超出了空数组的范围。我做错了吗？

Answer 1

您的 API 返回 HTTP 错误 401 未授权。您的后端是否需要 HTTP 身份验证？如果是这样，请向 RKClient 提供正确的凭据:

[[RKClient sharedClient] setUsername:myUsername];
[[RKClient sharedClient] setPassword:myPassword];

编辑:

我相信您在设置 RestKit 时遇到了一些基本问题。考虑以下示例。

//in your appdelegate
RKObjectManager* manager = [RKObjectManager objectManagerWithBaseURL:@"http://localhost:8080/activiti-rest/service"]; 
[[RKClient sharedClient] setUsername:@"kermit"];
[RKClient sharedClient] setPassword:@"kermit"];

// don't forget to create your mapping here
RKObjectMapping *dataMapping = [RKObjectMapping mappingForClass:[Data class]];
[dataMapping mapKeyPath:@"myKeyPath" toAttribute:@"myAttr"];
[[manager mappingProvider] addObjectMapping: dataMapping];

那么，你就可以做到这一点。

 -(void)loadData{
    // fetch your mapping
    [RKObjectMapping *mapping = [[RKObjectManager sharedManager].mappingProvider objectMappingForClass:[Data class]]; 
    //request data
    [[RKObjectManager sharedManager] loadObjectsAtResourcePath:@"/process-definitions?start=0&size=10&sort=id&order=asc" objectMapping:mapping delegate:self];
}

首先，您需要进行设置(RKClient、映射和 RKObjectManager)- 您只需一次。它们是单例，所以设置被保留。我发现执行此操作的最佳位置是 AppDelegate - 随意尝试，但请务必在执行任何请求之前进行设置。

当您要执行任何请求时，只需使用您的 [[RKObjectManager sharedManager] 单例来加载实际对象。

此外，我建议您阅读一些文档，例如。 Object Mapping guide