download handler

gistfile1.cs

using System;
using System.IO;
using System.Web;
using System.Web.UI;
using System.Xml.XPath;

namespace MyLovely.Web.App

{
    /// <summary>
    /// Reads a media node's id from the querystring and writes it to the response.
    /// </summary>
    public partial class DownloadHandler : UserControl
    {
        private string _queryStringKey = "mediaID";

        /// <summary>
        /// The querystring parameter to read
        /// </summary>
        public string QueryStringKey
        {
            get { return _queryStringKey; }
            set
            {
                if (!String.IsNullOrEmpty(value))
                {
                    _queryStringKey = value;
                }
            }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            string strMediaID = Request.QueryString[QueryStringKey];
            int mediaID;
            if(Int32.TryParse(strMediaID, out mediaID))
            {
                WriteMediaFileToResponse(mediaID);
            }
        }

        public void WriteMediaFileToResponse(int mediaID)
        {
            XPathNavigator navigator = umbraco.library.GetMedia(mediaID, false).Current;
            if (navigator != null)
            {
                var filePathNode = navigator.SelectSingleNode("//umbracoFile");
                var fileNameNode = navigator.SelectSingleNode("//@nodeName");
                if (filePathNode != null && fileNameNode != null)
                {
                    string mediaFilePath = filePathNode.InnerXml;
                    string mediaFileName = HttpUtility.UrlPathEncode(fileNameNode.InnerXml);
                    string fileExtension = Path.GetExtension(mediaFilePath);
                    string attachment = String.Format("attachment; filename=\"{0}{1}\"", mediaFileName, fileExtension);
                    
                    Response.Clear();
                    Response.ClearHeaders();
                    Response.ClearContent();
                    Response.AddHeader("content-disposition", attachment);
                    Response.AddHeader("content-type", GetMimeType(fileExtension));
                    Response.WriteFile(mediaFilePath);
                }
            }
        }

        private static string GetMimeType(string ext)
        {
            if (String.IsNullOrEmpty(ext)) return "application/unknown";
            
            string mimeType;
            switch (ext.ToLower())
            {
                case ".doc":
                    mimeType = "application/msword";
                    break;
                case ".docx":
                    mimeType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
                    break;
                case ".eps":
                    mimeType = "application/postscript";
                    break;
                case ".exe":
                    mimeType = "application/octet-stream";
                    break;
                case ".flv":
                    mimeType = "video/x-flv";
                    break;
                case ".gif":
                    mimeType = "image/gif";
                    break;
                case ".jpeg":
                case ".jpg":
                    mimeType = "image/jpeg";
                    break;
                case ".mp3":
                    mimeType = "audio/mpeg";
                    break;
                case ".pdf":
                    mimeType = "application/pdf";
                    break;
                case ".png":
                    mimeType = "image/png";
                    break;
                case ".ppt":
                    mimeType = "application/vnd.ms-powerpoint";
                    break;
                case ".pptx":
                    mimeType = "application/vnd.openxmlformats-officedocument.presentationml.presentation";
                    break;
                case ".tif":
                case ".tiff":
                    mimeType = "image/tiff";
                    break;
                case ".txt":
                    mimeType = "text/plain";
                    break;
                case ".xls":
                    mimeType = "application/vnd.ms-excel";
                    break;
                case ".xlsx":
                    mimeType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                    break;
                default:
                    mimeType = "application/unknown";
                    break;
            }
            return mimeType;
        }
    }
}