将文件上传到S3存储桶：等待fileTransferUtility.UploadAsyncfilePath，_bucket

问题描述

我正在尝试将文件上传到S3存储桶，但是在上存在null引用异常 await fileTransferUtility.UploadAsync(filePath,_bucket)

public class FileUploadService : IFileUploadService
{
    private readonly string _bucket;

    public FileUploadService()
    {
        _bucket = ConfigurationManager.AppSettings["S3Bucket"];
    }

    public async Task UploadFile(string filePath,CognitoAWSCredentials cred)
    {
        IAmazonS3 client = new AmazonS3Client(cred);
        TransferUtility fileTransferUtility = new TransferUtility(client);
        await fileTransferUtility.UploadAsync(filePath,_bucket);
    }
}

这是异常的堆栈跟踪的相关部分：

在 Amazon.S3.Util.BucketRegionDetector.GetUsEast1ClientFromCredentials（ImmutableCredentials 凭据） Amazon.S3.Util.BucketRegionDetector.GetHeadBucketPreSignedUrl（String bucketName，ImmutableCredentials凭据）位于 Amazon.S3.Util.BucketRegionDetector.d__13.MoveNext（） 在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（Task 任务） System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务 任务） Amazon.S3.Util.BucketRegionDetector.d__12.MoveNext（） ...

不确定我是怎么做的，因为我是AWS新手。我通过以下方式检索CognitoAWSCredentials：

string clientId = ConfigurationManager.AppSettings["CLIENT_ID"];
string poolId = ConfigurationManager.AppSettings["USERPOOL_ID"];
RegionEndpoint region = RegionEndpoint.EnumerableAllRegions.First(q => q.SystemName == "us-east-1");
provider = new AmazonCognitoIdentityProviderClient(new AnonymousAWSCredentials(),region);    

CognitoUserPool userPool = new CognitoUserPool(poolId,clientId,provider);
CognitoUser user = new CognitoUser(username,userPool,provider);

AuthFlowResponse context = await user.StartWithSrpAuthAsync(new InitiateSrpAuthRequest()
{
    Password = password
});

CognitoAWSCredentials cred = user.GetCognitoAWSCredentials(poolId,region);

解决方法

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