Cloud.File.Storage.Manager.AmazonS3 3.0.0

Cloud File Storage Manager

Provides complete implementation to handle easily cloud file storage operations like get informations about files, reading, downloadURL generation, file update, file move and delete. Primarily for Amazon S3 right now.

Built on the AWS SDK for .NET v4 (AWSSDK.S3 4.x). Checksums are computed and validated only where S3 requires them, so S3 compatible servers keep working. The SDK's own AWS_ENDPOINT_URL_S3 environment variable points the client at another endpoint (for example LocalStack); presigned download URLs then use that endpoint's scheme.

Configuration

Let's add a section to the appsettings.json

"AmazonS3torageSettings": {
    "IsAnonymus": false,
    "AccessKey": "",
    "SecretKey": "",
    "BucketName": "",
    "BucketRegion": ""
}

In the application, configure this settings part

services.AddSingleton<ICloudFileStorageManager, AmazonS3FileStorageManager>(services => new AmazonS3FileStorageManager(new AmazonS3FileStorageManagerOptions()
{
    IsAnonymus = config.GetSection("AmazonS3torageSettings").GetValue<bool>("IsAnonymus"),
    AccessKey = config.GetSection("AmazonS3torageSettings").GetValue<string>("AccessKey"),
    SecretKey = config.GetSection("AmazonS3torageSettings").GetValue<string>("SecretKey"),
    BucketName = config.GetSection("AmazonS3torageSettings").GetValue<string>("BucketName"),
    BucketRegion = config.GetSection("AmazonS3torageSettings").GetValue<string>("BucketRegion")
}));  

Behaviour

• Directory listings return one level: the files directly in the folder plus its sub-folders (from the S3 common prefixes). Folder marker keys ending with / are not listed as files.
• File info is resolved with a single ListObjectsV2 request for the exact key, so only s3:ListBucket is needed; s3:GetObject and s3:ListBucketVersions are not required for it.
• Deleting a folder removes every key under its prefix in pages of up to 1000 keys. If S3 reports any failed key, an IOException is thrown naming the first failure.
• Delete returns true when something was deleted and false when nothing existed under the path.
• Moving copies the object with a single CopyObject request and then deletes the original; S3 limits this to objects of at most 5 GB.
• Use ReadFileVersionAsync(versionId, pathSegments) to read a specific object version with root-relative path segments; a null or empty version id reads the current version. The older ReadFileAsync(versionId, absolutePathSegments) overload is obsolete and only accepts paths under the configured root. On a variable typed as AmazonS3FileStorageManager, a call like ReadFileAsync("dir", "file.txt") binds to that overload with "dir" as the version id; use the ICloudFileStorageManager interface or ReadFileVersionAsync for plain reads.
• Request presigned download URLs for at most 7 days, the S3 limit for signature version 4. The validity is not capped by the library: for a longer validity the AWS SDK falls back to a legacy signature version 2 URL, which buckets and regions without signature version 2 support reject.
• Path segments . and .. are rejected.
• The configured root directory itself cannot be deleted, moved or overwritten.