using System;

using System.Collections.Generic;

using System.IO;

using System.Threading;

using System.Threading.Tasks;

using ServiceStack.Web;

namespace ServiceStack

{

public class CompressedFileResult

: IStreamWriterAsync, IHasOptions

{

public const int Adler32ChecksumLength = 4;

public const string DefaultContentType = MimeTypes.Xml;

public string FilePath { get; private set; }

public Dictionary<string, string> Headers { get; private set; }

public IDictionary<string, string> Options => this.Headers;

public CompressedFileResult(string filePath)

: this(filePath, CompressionTypes.Deflate)

{ }

public CompressedFileResult(string filePath, string compressionType)

: this(filePath, compressionType, DefaultContentType)

{ }

public CompressedFileResult(string filePath, string compressionType, string contentMimeType)

{

if (!CompressionTypes.IsValid(compressionType))

throw new ArgumentException(@"Must be either 'deflate' or 'gzip'", compressionType);

this.FilePath = filePath;

this.Headers = new Dictionary<string, string> {

{ HttpHeaders.ContentType, contentMimeType },

{ HttpHeaders.ContentEncoding, compressionType },

};

}

public async Task WriteToAsync(Stream responseStream, CancellationToken token = new CancellationToken())

{

using (var fs = new FileStream(this.FilePath, FileMode.Open, FileAccess.Read))

{

fs.Position = Adler32ChecksumLength;

await fs.CopyToAsync(responseStream, token);

await responseStream.FlushAsync(token);

}

}

}

}