如何在没有 Amazon Cognito 的情况下使用 AWS S3？

我正在使用 Node.js REST API 来验证我的用户。一旦他们通过身份验证，我就允许他们发布带有文字的照片。我的计划是将照片的文本和 URL 存储在数据库中。这样，当他们访问帖子提要时，我的应用程序将查询数据库以获取文本和 URL，然后使用所有 URL 直接从 S3 获取图像。这是正确的方法吗？如果是的话，为什么我不能在不使用 cognito 的情况下这样做。我正在努力削减成本，但似乎 cognito 毫无用处，因为我已经使用 API 添加了身份验证。

这是我迄今为止的代码。

    let S3BucketName = "*******"

    // configure authentication with Cognito
    let CognitoPoolID = "*************"
    let Region = AWSRegionType.USEast1
    let credentialsProvider = AWSCognitoCredentialsProvider(regionType:Region,
                                                            identityPoolId:CognitoPoolID)
    let configuration = AWSServiceConfiguration(region:Region, credentialsProvider:credentialsProvider)
    AWSServiceManager.defaultServiceManager().defaultServiceConfiguration = configuration

    let ext = "png"
    let imageURL = NSBundle.mainBundle().URLForResource("iimage", withExtension: ext)!

    let uploadRequest = AWSS3TransferManagerUploadRequest()
    uploadRequest.body = imageURL
    uploadRequest.key = NSProcessInfo.processInfo().globallyUniqueString + "." + ext
    uploadRequest.bucket = S3BucketName
    uploadRequest.contentType = "image/" + ext

    let transferManager = AWSS3TransferManager.defaultS3TransferManager()
    transferManager.upload(uploadRequest).continueWithBlock { (task) -> AnyObject! in
        if let error = task.error {
            print("Upload failed (\(error))")
        }
        if let exception = task.exception {
            print("Upload failed (\(exception))")
        }
        if task.result != nil {
            let s3URL = NSURL(string: "http://s3.amazonaws.com/\(S3BucketName)/\(uploadRequest.key!)")!
            print("Uploaded to:\n\(s3URL)")
        }
        else {
            print("Unexpected empty result.")
        }
        return nil
    }

对于没有认知的情况，请使用它

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    AWSStaticCredentialsProvider *credentialsProvider = [[AWSStaticCredentialsProvider alloc] initWithAccessKey:AWS_ACCESS_KEY secretKey:AWS_SECRET_KEY];

    AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionAPSoutheast1
                                                                     credentialsProvider:credentialsProvider];

    AWSServiceManager.defaultServiceManager.defaultServiceConfiguration = configuration;
}

并用于上传图像使用

AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];

AWSS3TransferManagerUploadRequest *uploadRequest = [AWSS3TransferManagerUploadRequest new];
uploadRequest.bucket = AWS_S3_BUCKET_NAME;
uploadRequest.key = @"cards/image.png";
uploadRequest.contentType = @"image/png";
uploadRequest.body = imageURL;

[[transferManager upload:uploadRequest] continueWithExecutor:[AWSExecutor mainThreadExecutor]
                                                   withBlock:^id(AWSTask *task) {
                                                       if (task.error) {
                                                           if ([task.error.domain isEqualToString:AWSS3TransferManagerErrorDomain]) {
                                                               switch (task.error.code)
                                                               {
                                                                   case AWSS3TransferManagerErrorCancelled:
                                                                   case AWSS3TransferManagerErrorPaused:
                                                                       break;

                                                                   default:
                                                                       NSLog(@"Error: %@", task.error);
                                                                       break;
                                                               }
                                                           }
                                                           else
                                                           {
                                                               // Unknown error.
                                                               NSLog(@"Error: %@", task.error);
                                                           }
                                                       }

                                                       if (task.result)
                                                       {
                                                           AWSS3TransferManagerUploadOutput *uploadOutput = task.result;
                                                            NSLog(@"success: %@", uploadOutput);
                                                       }
                                                       return nil;
                                                   }];