httphandler.cs

Sharp Map 用于制作GIS系统S harp Map 用于制作GIS系统S harp Map 用于制作GIS系统

// Copyright 2005, 2006 - Morten Nielsen (www.iter.dk)
//
// This file is part of SharpMap.
// SharpMap is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// SharpMap is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with SharpMap; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Collections.Generic;
using System.Text;

namespace SharpMap.Web
{
	/// <summary>
	/// HttpHandler class for web applications
	/// </summary>
	public class HttpHandler : System.Web.IHttpHandler
	{
		#region IHttpHandler Members

		/// <summary>
		/// Enable Http pooling
		/// </summary>
		public bool IsReusable
		{
			get { return true; }
		}

		/// <summary>
		/// Returns the requested image in an http imagestream
		/// </summary>
		/// <param name="context">HttpContext</param>
		public void ProcessRequest(System.Web.HttpContext context)
		{
			string imgID = context.Request.QueryString["ID"];
			if (context.Cache[imgID] == null)
			{
				context.Response.Clear();
				context.Response.Write("Invalid Image requested");
				return;
			}
			if (context.Cache[imgID].GetType() == typeof(System.Drawing.Bitmap))
			{
				context.Response.ContentType = "image/png";
				System.Drawing.Bitmap b = (System.Drawing.Bitmap)context.Cache[imgID];
				// send the image to the viewer
				System.IO.MemoryStream MS = new System.IO.MemoryStream();
				b.Save(MS, System.Drawing.Imaging.ImageFormat.Png);
				// tidy up  
				b.Dispose();

				byte[] buffer = MS.ToArray();
				context.Response.OutputStream.Write(buffer, 0, buffer.Length);
			}
			else if (context.Cache[imgID].GetType() == typeof(byte[]))
			{
				context.Response.ContentType = "image/png";
				byte[] buffer = (byte[])context.Cache[imgID];
				context.Response.OutputStream.Write(buffer, 0, buffer.Length);
				return;
			}
			context.Response.End();
		}		
		

		#endregion
	}
}