using ServiceStack.Web;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Net;
using System.Threading;
using System.Threading.Tasks;
namespace MediaBrowser.Server.Implementations.HttpServer
{
public class RangeRequestWriter : IStreamWriter, IHttpResult
{
///
/// Gets or sets the source stream.
///
/// The source stream.
private Stream SourceStream { get; set; }
private string RangeHeader { get; set; }
private bool IsHeadRequest { get; set; }
private long RangeStart { get; set; }
private long RangeEnd { get; set; }
private long RangeLength { get; set; }
private long TotalContentLength { get; set; }
public bool Throttle { get; set; }
public long ThrottleLimit { get; set; }
public long MinThrottlePosition;
///
/// The _options
///
private readonly Dictionary _options = new Dictionary();
///
/// The us culture
///
private static readonly CultureInfo UsCulture = new CultureInfo("en-US");
///
/// Additional HTTP Headers
///
/// The headers.
public Dictionary Headers
{
get { return _options; }
}
///
/// Gets the options.
///
/// The options.
public IDictionary Options
{
get { return Headers; }
}
///
/// Initializes a new instance of the class.
///
/// The range header.
/// The source.
/// Type of the content.
/// if set to true [is head request].
public RangeRequestWriter(string rangeHeader, Stream source, string contentType, bool isHeadRequest)
{
if (string.IsNullOrEmpty(contentType))
{
throw new ArgumentNullException("contentType");
}
RangeHeader = rangeHeader;
SourceStream = source;
IsHeadRequest = isHeadRequest;
ContentType = contentType;
Options["Content-Type"] = contentType;
Options["Accept-Ranges"] = "bytes";
StatusCode = HttpStatusCode.PartialContent;
SetRangeValues();
}
///
/// Sets the range values.
///
private void SetRangeValues()
{
var requestedRange = RequestedRanges[0];
TotalContentLength = SourceStream.Length;
// If the requested range is "0-", we can optimize by just doing a stream copy
if (!requestedRange.Value.HasValue)
{
RangeEnd = TotalContentLength - 1;
}
else
{
RangeEnd = requestedRange.Value.Value;
}
RangeStart = requestedRange.Key;
RangeLength = 1 + RangeEnd - RangeStart;
// Content-Length is the length of what we're serving, not the original content
Options["Content-Length"] = RangeLength.ToString(UsCulture);
Options["Content-Range"] = string.Format("bytes {0}-{1}/{2}", RangeStart, RangeEnd, TotalContentLength);
if (RangeStart > 0)
{
SourceStream.Position = RangeStart;
}
}
///
/// The _requested ranges
///
private List> _requestedRanges;
///
/// Gets the requested ranges.
///
/// The requested ranges.
protected List> RequestedRanges
{
get
{
if (_requestedRanges == null)
{
_requestedRanges = new List>();
// Example: bytes=0-,32-63
var ranges = RangeHeader.Split('=')[1].Split(',');
foreach (var range in ranges)
{
var vals = range.Split('-');
long start = 0;
long? end = null;
if (!string.IsNullOrEmpty(vals[0]))
{
start = long.Parse(vals[0], UsCulture);
}
if (!string.IsNullOrEmpty(vals[1]))
{
end = long.Parse(vals[1], UsCulture);
}
_requestedRanges.Add(new KeyValuePair(start, end));
}
}
return _requestedRanges;
}
}
///
/// Writes to.
///
/// The response stream.
public void WriteTo(Stream responseStream)
{
if (Throttle)
{
responseStream = new ThrottledStream(responseStream, ThrottleLimit)
{
MinThrottlePosition = MinThrottlePosition
};
}
var task = WriteToAsync(responseStream);
Task.WaitAll(task);
}
///
/// Writes to async.
///
/// The response stream.
/// Task.
private async Task WriteToAsync(Stream responseStream)
{
// Headers only
if (IsHeadRequest)
{
return;
}
using (var source = SourceStream)
{
// If the requested range is "0-", we can optimize by just doing a stream copy
if (RangeEnd >= TotalContentLength - 1)
{
await source.CopyToAsync(responseStream).ConfigureAwait(false);
}
else
{
await CopyToAsyncInternal(source, responseStream, Convert.ToInt32(RangeLength), CancellationToken.None).ConfigureAwait(false);
}
}
}
private async Task CopyToAsyncInternal(Stream source, Stream destination, int copyLength, CancellationToken cancellationToken)
{
const int bufferSize = 81920;
var array = new byte[bufferSize];
int count;
while ((count = await source.ReadAsync(array, 0, array.Length, cancellationToken).ConfigureAwait(false)) != 0)
{
var bytesToCopy = Math.Min(count, copyLength);
await destination.WriteAsync(array, 0, bytesToCopy, cancellationToken).ConfigureAwait(false);
copyLength -= bytesToCopy;
if (copyLength <= 0)
{
break;
}
}
}
public string ContentType { get; set; }
public IRequest RequestContext { get; set; }
public object Response { get; set; }
public IContentTypeWriter ResponseFilter { get; set; }
public int Status { get; set; }
public HttpStatusCode StatusCode
{
get { return (HttpStatusCode)Status; }
set { Status = (int)value; }
}
public string StatusDescription { get; set; }
public int PaddingLength { get; set; }
}
}