具有重试计数和重试延迟的文件上传-C＃中的最佳方法

Question

I have a case there i want upload files with Retry count and Retry delay

Currently i am doing upload like

Status UploadWithRetry(string sourceFile, string destinationFolder, int retryCount, int retryIntervalSeconds)
    {

        Status uploadStatus = new FileTransferStatus { FilePath = sourceFile };

        var fileName = Path.GetFileName(sourceFile);

        using (var fileStream = new FileStream(sourceFile, FileMode.Open))
        {

                _client.UploadFile(fileStream, destinationFilePath, null);
                 Status.Success = true;
                return uploadStatus;
            }
        }

    }

How can i modify it to include logic for Retry count and retry delay. Can anyone help on this.

Answer 1

I would refactor your code this way:

Status UploadWithRetry(string sourceFile, string destinationFolder, int maxRetryCount, int retryIntervalSeconds)
{      

    var fileName = Path.GetFileName(sourceFile);
    var uploadAttempts = 0;
    var success = false;
    var status = new FileTransferStatus { FilePath = sourceFile };
    while(uploadAttempts < maxRetryCount && !success){
        status = UploadFile(sourceFile);
        uploadAttempts++;
        success = status.Success;
    }
    if(uploadAttempts >= maxRetryCount){
        //throw new Exception(); //I would advise against this
        status.Message = "Max retry attempts reached."; //display this message to the frontend
    }
    return status;
}

Status UploadFile(string sourceFile){
    using (var fileStream = new FileStream(sourceFile, FileMode.Open))
    {
            Status uploadStatus = new FileTransferStatus { FilePath = sourceFile };
            try{

                _client.UploadFile(fileStream, destinationFilePath, null);
                Status.Success = true;
            }
            catch(Exception ex){
                Status.Success = false;
            }
            return uploadStatus;
        }
    }
}

For your delay you could use thread.sleep but or use some kind of timer. I hope this helps you on your way. EDIT: I like a mix of my answer with Donald Jansen's answer!

Answer 2

You could use recurrsion and to delay the next try use Task.Delay(..).Wait() Something like the following

Status UploadWithRetry(string sourceFile, string destinationFolder, int retryCount, int retryIntervalSeconds)
{

    Status uploadStatus = new FileTransferStatus { FilePath = sourceFile };

    var fileName = Path.GetFileName(sourceFile);

    var status = default(Status);
    using (var fileStream = new FileStream(sourceFile, FileMode.Open))
    {

            _client.UploadFile(fileStream, destinationFilePath, null);
             Status.Success = true;

            status = uploadStatus;
        }
    }
    if (retryCount == 0)
        return status;
    Task.Delay(TimeSpan.FromSeconds(retryIntervalSeconds)).Wait();
    return UploadWithRetry(sourceFile, destinationFolder, retryCount - 1, retryIntervalSeconds);
}

Edit: I would mix sanders answer with mine, I didn't include the try..catch..finaly in mine which he did

Edit2: If you take the UploadFile from sander and use the following it should work great

    Status UploadWithRetry(string sourceFile, string destinationFolder, int retryCount, int retryIntervalSeconds)
    {
        var status = UploadFile(sourceFile);

        if (status.Success)
            return status;

        if (retryCount == 0) //OR THROW EXCEPTION HERE
            return status;
        Task.Delay(TimeSpan.FromSeconds(retryIntervalSeconds)).Wait();
        return UploadWithRetry(sourceFile, destinationFolder, retryCount - 1, retryIntervalSeconds);
    }