jellyfin/MediaBrowser.Common/Net/Handlers/BaseHandler.cs
LukePulverenti Luke Pulverenti luke pulverenti 6ab63eaf95 Made BaseHandler.ProcessRequest virtual
2012-08-10 23:06:25 -04:00

381 lines
12 KiB
C#

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using MediaBrowser.Common.Logging;
namespace MediaBrowser.Common.Net.Handlers
{
public abstract class BaseHandler
{
private Stream CompressedStream { get; set; }
public virtual bool? UseChunkedEncoding
{
get
{
return null;
}
}
private bool _TotalContentLengthDiscovered = false;
private long? _TotalContentLength = null;
public long? TotalContentLength
{
get
{
if (!_TotalContentLengthDiscovered)
{
_TotalContentLength = GetTotalContentLength();
}
return _TotalContentLength;
}
}
/// <summary>
/// Returns true or false indicating if the handler writes to the stream asynchronously.
/// If so the subclass will be responsible for disposing the stream when complete.
/// </summary>
protected virtual bool IsAsyncHandler
{
get
{
return false;
}
}
protected virtual bool SupportsByteRangeRequests
{
get
{
return false;
}
}
/// <summary>
/// The original HttpListenerContext
/// </summary>
protected HttpListenerContext HttpListenerContext { get; set; }
/// <summary>
/// The original QueryString
/// </summary>
protected NameValueCollection QueryString
{
get
{
return HttpListenerContext.Request.QueryString;
}
}
protected List<KeyValuePair<long, long?>> _RequestedRanges = null;
protected IEnumerable<KeyValuePair<long, long?>> RequestedRanges
{
get
{
if (_RequestedRanges == null)
{
_RequestedRanges = new List<KeyValuePair<long, long?>>();
if (IsRangeRequest)
{
// Example: bytes=0-,32-63
string[] ranges = HttpListenerContext.Request.Headers["Range"].Split('=')[1].Split(',');
foreach (string range in ranges)
{
string[] vals = range.Split('-');
long start = 0;
long? end = null;
if (!string.IsNullOrEmpty(vals[0]))
{
start = long.Parse(vals[0]);
}
if (!string.IsNullOrEmpty(vals[1]))
{
end = long.Parse(vals[1]);
}
_RequestedRanges.Add(new KeyValuePair<long, long?>(start, end));
}
}
}
return _RequestedRanges;
}
}
protected bool IsRangeRequest
{
get
{
return HttpListenerContext.Request.Headers.AllKeys.Contains("Range");
}
}
/// <summary>
/// Gets the MIME type to include in the response headers
/// </summary>
public abstract string ContentType { get; }
/// <summary>
/// Gets the status code to include in the response headers
/// </summary>
protected int StatusCode { get; set; }
/// <summary>
/// Gets the cache duration to include in the response headers
/// </summary>
public virtual TimeSpan CacheDuration
{
get
{
return TimeSpan.FromTicks(0);
}
}
private bool _LastDateModifiedDiscovered = false;
private DateTime? _LastDateModified = null;
/// <summary>
/// Gets the last date modified of the content being returned, if this can be determined.
/// This will be used to invalidate the cache, so it's not needed if CacheDuration is 0.
/// </summary>
public DateTime? LastDateModified
{
get
{
if (!_LastDateModifiedDiscovered)
{
_LastDateModified = GetLastDateModified();
}
return _LastDateModified;
}
}
public virtual bool CompressResponse
{
get
{
return true;
}
}
private bool ClientSupportsCompression
{
get
{
string enc = HttpListenerContext.Request.Headers["Accept-Encoding"] ?? string.Empty;
return enc.IndexOf("deflate", StringComparison.OrdinalIgnoreCase) != -1 || enc.IndexOf("gzip", StringComparison.OrdinalIgnoreCase) != -1;
}
}
private string CompressionMethod
{
get
{
string enc = HttpListenerContext.Request.Headers["Accept-Encoding"] ?? string.Empty;
if (enc.IndexOf("deflate", StringComparison.OrdinalIgnoreCase) != -1)
{
return "deflate";
}
if (enc.IndexOf("gzip", StringComparison.OrdinalIgnoreCase) != -1)
{
return "gzip";
}
return null;
}
}
public virtual void ProcessRequest(HttpListenerContext ctx)
{
HttpListenerContext = ctx;
Logger.LogInfo("Http Server received request at: " + ctx.Request.Url.ToString());
Logger.LogInfo("Http Headers: " + string.Join(",", ctx.Request.Headers.AllKeys.Select(k => k + "=" + ctx.Request.Headers[k])));
ctx.Response.AddHeader("Access-Control-Allow-Origin", "*");
ctx.Response.KeepAlive = true;
if (SupportsByteRangeRequests && IsRangeRequest)
{
ctx.Response.Headers["Accept-Ranges"] = "bytes";
}
// Set the initial status code
// When serving a range request, we need to return status code 206 to indicate a partial response body
StatusCode = SupportsByteRangeRequests && IsRangeRequest ? 206 : 200;
ctx.Response.ContentType = ContentType;
TimeSpan cacheDuration = CacheDuration;
if (ctx.Request.Headers.AllKeys.Contains("If-Modified-Since"))
{
DateTime ifModifiedSince;
if (DateTime.TryParse(ctx.Request.Headers["If-Modified-Since"].Replace(" GMT", string.Empty), out ifModifiedSince))
{
// If the cache hasn't expired yet just return a 304
if (IsCacheValid(ifModifiedSince, cacheDuration, LastDateModified))
{
StatusCode = 304;
}
}
}
if (StatusCode == 200 || StatusCode == 206)
{
ProcessUncachedResponse(ctx, cacheDuration);
}
else
{
ctx.Response.StatusCode = StatusCode;
ctx.Response.SendChunked = false;
DisposeResponseStream();
}
}
private void ProcessUncachedResponse(HttpListenerContext ctx, TimeSpan cacheDuration)
{
long? totalContentLength = TotalContentLength;
// By default, use chunked encoding if we don't know the content length
bool useChunkedEncoding = UseChunkedEncoding == null ? (totalContentLength == null) : UseChunkedEncoding.Value;
// Don't force this to true. HttpListener will default it to true if supported by the client.
if (!useChunkedEncoding)
{
ctx.Response.SendChunked = false;
}
// Set the content length, if we know it
if (totalContentLength.HasValue)
{
ctx.Response.ContentLength64 = totalContentLength.Value;
}
// Add the compression header
if (CompressResponse && ClientSupportsCompression)
{
ctx.Response.AddHeader("Content-Encoding", CompressionMethod);
}
// Add caching headers
if (cacheDuration.Ticks > 0)
{
CacheResponse(ctx.Response, cacheDuration, LastDateModified);
}
PrepareUncachedResponse(ctx, cacheDuration);
// Set the status code
ctx.Response.StatusCode = StatusCode;
if (StatusCode == 200 || StatusCode == 206)
{
// Finally, write the response data
Stream outputStream = ctx.Response.OutputStream;
if (CompressResponse && ClientSupportsCompression)
{
if (CompressionMethod.Equals("deflate", StringComparison.OrdinalIgnoreCase))
{
CompressedStream = new DeflateStream(outputStream, CompressionLevel.Fastest, false);
}
else
{
CompressedStream = new GZipStream(outputStream, CompressionLevel.Fastest, false);
}
outputStream = CompressedStream;
}
WriteResponseToOutputStream(outputStream);
if (!IsAsyncHandler)
{
DisposeResponseStream();
}
}
else
{
ctx.Response.SendChunked = false;
DisposeResponseStream();
}
}
protected virtual void PrepareUncachedResponse(HttpListenerContext ctx, TimeSpan cacheDuration)
{
}
private void CacheResponse(HttpListenerResponse response, TimeSpan duration, DateTime? dateModified)
{
DateTime lastModified = dateModified ?? DateTime.Now;
response.Headers[HttpResponseHeader.CacheControl] = "public, max-age=" + Convert.ToInt32(duration.TotalSeconds);
response.Headers[HttpResponseHeader.Expires] = DateTime.Now.Add(duration).ToString("r");
response.Headers[HttpResponseHeader.LastModified] = lastModified.ToString("r");
}
protected abstract void WriteResponseToOutputStream(Stream stream);
protected void DisposeResponseStream()
{
if (CompressedStream != null)
{
CompressedStream.Dispose();
}
HttpListenerContext.Response.OutputStream.Dispose();
}
private bool IsCacheValid(DateTime ifModifiedSince, TimeSpan cacheDuration, DateTime? dateModified)
{
if (dateModified.HasValue)
{
DateTime lastModified = NormalizeDateForComparison(dateModified.Value);
ifModifiedSince = NormalizeDateForComparison(ifModifiedSince);
return lastModified <= ifModifiedSince;
}
DateTime cacheExpirationDate = ifModifiedSince.Add(cacheDuration);
if (DateTime.Now < cacheExpirationDate)
{
return true;
}
return false;
}
/// <summary>
/// When the browser sends the IfModifiedDate, it's precision is limited to seconds, so this will account for that
/// </summary>
private DateTime NormalizeDateForComparison(DateTime date)
{
return new DateTime(date.Year, date.Month, date.Day, date.Hour, date.Minute, date.Second);
}
protected virtual long? GetTotalContentLength()
{
return null;
}
protected virtual DateTime? GetLastDateModified()
{
return null;
}
}
}