AWS S3中的物理文件访问

Question

I would like to move some local application into the Amazon cloud which internally works on the FileInfo to process some files.

I know about the bucket concept as well as the file adaption using S3FileInfo which is pointing to the stored files within the buckets.

But since the application is using FileInfo I was wondering if there is any chance I can somehow create a FileInfo instance pointing to a file within buckets?

Answer 1

FileInfo class cannot be used to work with S3 objects directly. A couple of things you can do:

1. Map the S3 folder to a drive on the machine

You can use a tool like TntDrive . Then you can access files you'd normally do, something like:

FileInfo file = new FileInfo(@"Z:\Path\myfile.doc");

2. You can create an abstraction layer while accessing files. I recently worked on something like that in a project. What I did was access the objects through a common interface. You can have a look at the code snippet below.

This way file system dependency is encapsulated inside TextFilePersistanceProvider class only and the remaining application can work with any source.

public interface IGamePersistanceProvider
{
    void Save(Game game);
}

public class TextFilePersistanceProvider : IGamePersistanceProvider
{
    private IConfigurationProvider _configurationProvider;
    public TextFilePersistanceProvider(IConfigurationProvider configurationProvider)
    {
        _configurationProvider = configurationProvider;
    }

    public void Save(Game game)
    {
        if (game == null) { throw new ArgumentException("Unexpected parameter"); }

        var filePath = _configurationProvider.GetValue<string>("LatestGamePath");

        var gameAsJson = JsonConvert.SerializeObject(game, Formatting.None, new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Auto });

        File.WriteAllText(filePath, gameAsJson);
    }
}

public class S3PersistanceProvider : IGamePersistanceProvider
{
    private IConfigurationProvider _configurationProvider;
    public S3PersistanceProvider(IConfigurationProvider configurationProvider)
    {
        _configurationProvider = configurationProvider;
    }

    public void Save(Game game)
    {
        if (game == null) { throw new ArgumentException("Unexpected parameter"); }

        var gameAsJson = JsonConvert.SerializeObject(game, Formatting.None, new JsonSerializerSettings
        {
            TypeNameHandling = TypeNameHandling.Auto,
        });

        string accessKey = _configurationProvider.GetValue<dynamic>("S3Credentials").AccessKey.ToString();
        string secretKey = _configurationProvider.GetValue<dynamic>("S3Credentials").SecretKey.ToString();
        string bucketName = _configurationProvider.GetValue<dynamic>("S3Credentials").BucketName.ToString();
        string key = game.Name;

        using (var s3Client = new AmazonS3Client(new BasicAWSCredentials(accessKey, secretKey), RegionEndpoint.EUWest1))
        {
            var transferUtil = new TransferUtility(s3Client);
            var memStream = new MemoryStream(Encoding.UTF8.GetBytes(gameAsJson));
            transferUtil.Upload(memStream, bucketName, key);
        }
    }
}

I hope this helps a bit.