using System;

using System.IO;

using System.Net;

using ServiceStack.Text;

using ServiceStack.Web;

namespace ServiceStack

{

public static class HttpResultExtensions

{

/// <summary>

/// Shortcut to get the ResponseDTO whether it's bare or inside a IHttpResult

/// </summary>

/// <param name="response"></param>

/// <returns></returns>

public static object GetDto(this object response)

{

if (response == null) return null;

var httpResult = response as IHttpResult;

return httpResult != null ? httpResult.Response : response;

}

/// <summary>

/// Alias of AsDto

/// </summary>

public static object GetResponseDto(this object response)

{

return GetDto(response);

}

/// <summary>

/// Shortcut to get the ResponseDTO whether it's bare or inside a IHttpResult

/// </summary>

/// <param name="response"></param>

/// <returns>TResponse if found; otherwise null</returns>

public static TResponse GetDto<TResponse>(this object response) where TResponse : class

{

if (response == null) return default(TResponse);

var httpResult = response as IHttpResult;

return (httpResult != null ? httpResult.Response : response) as TResponse;

}

/// <summary>

/// Alias of AsDto

/// </summary>

public static TResponse GetResponseDto<TResponse>(this object response) where TResponse : class

{

return GetDto<TResponse>(response);

}

public static object CreateErrorResponse(this IHttpError httpError)

{

if (httpError == null) return null;

var errorDto = httpError.GetDto();

if (errorDto != null) return errorDto;

return new ErrorResponse {

ResponseStatus = new ResponseStatus {

ErrorCode = httpError.ErrorCode,

Message = httpError.Message,

StackTrace = httpError.StackTrace,

}

};

}

/// <summary>

/// Whether the response is an IHttpError or Exception

/// </summary>

public static bool IsErrorResponse(this object response)

{

return response != null && (response is IHttpError || response is Exception);

}

/// <summary>

/// rangeHeader should be of the format "bytes=0-" or "bytes=0-12345" or "bytes=123-456"

/// </summary>

public static void ExtractHttpRanges(this string rangeHeader, long contentLength, out long rangeStart, out long rangeEnd)

{

var rangeParts = rangeHeader.SplitOnFirst("=")[1].SplitOnFirst("-");

rangeStart = Int64.Parse(rangeParts[0]);

rangeEnd = rangeParts.Length == 2 && !String.IsNullOrEmpty(rangeParts[1])

? Int32.Parse(rangeParts[1]) //the client requested a chunk

: contentLength - 1;

}

/// <summary>

/// Adds 206 PartialContent Status, Content-Range and Content-Length headers

/// </summary>

public static void AddHttpRangeResponseHeaders(this IResponse response, long rangeStart, long rangeEnd, long contentLength)

{

response.AddHeader(HttpHeaders.ContentRange, "bytes {0}-{1}/{2}".Fmt(rangeStart, rangeEnd, contentLength));

response.StatusCode = (int)HttpStatusCode.PartialContent;

response.SetContentLength(rangeEnd - rangeStart + 1);

}

/// <summary>

/// Writes partial range as specified by start-end, from fromStream to toStream.

/// </summary>

public static void WritePartialTo(this Stream fromStream, Stream toStream, long start, long end)

{

if (!fromStream.CanSeek)

throw new InvalidOperationException(

"Sending Range Responses requires a seekable stream eg. FileStream or MemoryStream");

long totalBytesToSend = end - start + 1;

const int bufferSize = 0x1000;

var buffer = new byte[bufferSize];

long bytesRemaining = totalBytesToSend;

fromStream.Seek(start, SeekOrigin.Begin);

while (bytesRemaining > 0)

{

var count = bytesRemaining <= buffer.Length

? fromStream.Read(buffer, 0, (int)Math.Min(bytesRemaining, int.MaxValue))

: fromStream.Read(buffer, 0, buffer.Length);

try

{

//Log.DebugFormat("Writing {0} to response",System.Text.Encoding.UTF8.GetString(buffer));

toStream.Write(buffer, 0, count);

toStream.Flush();

bytesRemaining -= count;

}

catch (Exception httpException)

{

/* in Asp.Net we can call HttpResponseBase.IsClientConnected

* to see if the client broke off the connection

* and avoid trying to flush the response stream.

* I'm not quite I can do the same here without some invasive changes,

* so instead I'll swallow the exception that IIS throws in this situation.*/

if (httpException.Message == "An error occurred while communicating with the remote host. The error code is 0x80070057.")

return;

throw;

}

}

}

}

}