ios - 正确检查 NSDictionary 结构

Question

我必须与复杂的 API 和复杂的 JSON 响应进行交互。我使用的是 AFNetworking，JSON 响应会自动转换为 NSDictionary。

我不确定 JSON 结构将始终如我所期望的那样，因此我开始编写大量防御代码。

if (response &&
    [response isKindOfClass:[NSDictionary class]] &&
    [[response valueForKey:@"result"] isKinfOfClass:[NSString class]]....

我想知道是否可以编写一些将空 JSON 响应作为"template"并检查响应是否与模板“匹配”的代码。有人已经处理过这种问题了吗？

Answer 1

为了从 JASON 响应中将值插入到核心数据中，我一直在使用这个可以用作函数的类别

@implementation NSManagedObject (safeSetValuesKeysWithDictionary)

- (void)safeSetValuesForKeysWithDictionary:(NSDictionary *)keyedValues
{
    NSDictionary *attributes = [[self entity] attributesByName];
    for (NSString *attribute in attributes) {
        id value = [keyedValues objectForKey:attribute];
        if (value == nil) {
            // Don't attempt to set nil, or you'll overwite values in self that aren't present in keyedValues
            continue;
        }
        NSAttributeType attributeType = [[attributes objectForKey:attribute] attributeType];
        if ((attributeType == NSStringAttributeType) && ([value isKindOfClass:[NSNumber class]])) {
            value = [value stringValue];
        } else if (((attributeType == NSInteger16AttributeType) || (attributeType == NSInteger32AttributeType) || (attributeType == NSInteger64AttributeType) || (attributeType == NSBooleanAttributeType)) && ([value isKindOfClass:[NSString class]])) {
            value = [NSNumber numberWithInteger:[value  integerValue]];
        } else if ((attributeType == NSFloatAttributeType) && ([value isKindOfClass:[NSString class]])) {
            value = [NSNumber numberWithDouble:[value doubleValue]];
        } else if ((attributeType == NSDateAttributeType) && ([value isKindOfClass:[NSString class]])) {
            NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
            [dateFormat setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"];
            value = [dateFormat dateFromString:[[value componentsSeparatedByString: @"."] objectAtIndex:0]];
        } else if ((attributeType == NSDoubleAttributeType) && ([value isKindOfClass:[NSString class]])) {
            value = [NSNumber numberWithDouble:[value doubleValue]];
        }

        [self setValue:value forKey:attribute];
    }
}

@end