/// <summary>
/// Check If-Unmodified-Since header
/// </summary>
/// <param name="objRequest"></param>
/// <param name="objDownload"></param>
/// <returns></returns>
private static bool CheckIfUnmodifiedSince(HttpRequest objRequest, DownloadFile objFile)
{
string sSinceDate;
DateTime dtSinceDate;
bool bReturn;
// Retrieve If-Unmodified-Since Header
sSinceDate = DownloadHandler.RetrieveHeader(objRequest, HTTP_HEADER_IF_UNMODIFIED_SINCE, String.Empty);
if (String.IsNullOrEmpty(sSinceDate))
{
sSinceDate = DownloadHandler.RetrieveHeader(objRequest, HTTP_HEADER_UNLESS_MODIFIED_SINCE, String.Empty);
}
if (String.IsNullOrEmpty(sSinceDate))
{
bReturn = true;
}
else
{
bool bTry = DateTime.TryParse(sSinceDate, out dtSinceDate); //dtSinceDate is a local date without millisecs
DateTime dtSinceDateUTC = dtSinceDate.ToUniversalTime();
DateTime dtLastWriteTimeUTC = new DateTime(
objFile.LastWriteTimeUTC.Year,
objFile.LastWriteTimeUTC.Month,
objFile.LastWriteTimeUTC.Day,
objFile.LastWriteTimeUTC.Hour,
objFile.LastWriteTimeUTC.Minute,
objFile.LastWriteTimeUTC.Second,
DateTimeKind.Utc);
if (bTry)
{
bReturn = (dtLastWriteTimeUTC <= dtSinceDateUTC); // True if the file was not modified
}
else
{
bReturn = false;
}
}
return(bReturn);
}
/// <summary>
/// Check If-None-Match header
/// </summary>
/// <param name="objRequest"></param>
/// <param name="objResponse"></param>
/// <param name="objDownload"></param>
/// <returns></returns>
private static bool CheckIfNoneMatch(HttpRequest objRequest, HttpResponse objResponse, DownloadFile objFile) //Careful ByVal
{
string sRequestHeaderIfNoneMatch;
string[] arrEntityIDs;
bool bReturn = true;
string sReturn = "";
// Get Request If-None-Match Header value
sRequestHeaderIfNoneMatch = DownloadHandler.RetrieveHeader(objRequest, HTTP_HEADER_IF_NONE_MATCH, String.Empty);
if (String.IsNullOrEmpty(sRequestHeaderIfNoneMatch))
{
bReturn = true; // Perform request normally
}
else if (sRequestHeaderIfNoneMatch.Equals("*"))
{
objResponse.StatusCode = 412; // logically invalid request
bReturn = false;
}
else
{
arrEntityIDs = sRequestHeaderIfNoneMatch.Replace("bytes=", "").Split(",".ToCharArray());
// EntIDs were sent - Look for a match to the current one
for (int iLoop = arrEntityIDs.GetLowerBound(0); iLoop <= arrEntityIDs.GetUpperBound(0); iLoop++)
{
if (arrEntityIDs[iLoop].Trim().Equals(objFile.EntityTag))
{
sReturn = arrEntityIDs[iLoop];
// One of the requested entities matches the current file's tag,
objResponse.AppendHeader(HTTP_HEADER_ENTITY_TAG, sReturn);
objResponse.StatusCode = 304; // Not Modified
bReturn = true;
}
}
}
return(bReturn);
}
/// <summary>
/// Check If-Modified-Since header
/// </summary>
/// <param name="objRequest"></param>
/// <param name="objDownload"></param>
/// <returns></returns>
private static bool CheckIfModifiedSince(HttpRequest objRequest, DownloadFile objFile) //Careful ByVal
{
string sSinceDate;
DateTime dtSinceDate;
bool bReturn;
// Retrieve If-Modified-Since Header
sSinceDate = DownloadHandler.RetrieveHeader(objRequest, HTTP_HEADER_IF_MODIFIED_SINCE, String.Empty);
if (String.IsNullOrEmpty(sSinceDate))
{
bReturn = true; // if (no date was sent - assume we need to re-download the whole file
}
else
{
bool bTry = DateTime.TryParse(sSinceDate, out dtSinceDate); //dtSinceDate is a local date without millisecs
DateTime dtSinceDateUTC = dtSinceDate.ToUniversalTime();
DateTime dtLastWriteTimeUTC = new DateTime(
objFile.LastWriteTimeUTC.Year,
objFile.LastWriteTimeUTC.Month,
objFile.LastWriteTimeUTC.Day,
objFile.LastWriteTimeUTC.Hour,
objFile.LastWriteTimeUTC.Minute,
objFile.LastWriteTimeUTC.Second,
DateTimeKind.Utc);
if (bTry)
{
bReturn = (dtLastWriteTimeUTC > dtSinceDateUTC); // True if the file was actually modified
}
else
{
bReturn = false;
}
}
return(bReturn);
}
public void ProcessRequest(HttpContext context)
{
if (context == null)
{
throw new ArgumentNullException("context"); //Very theoretical
}
HttpRequest objRequest = context.Request;
System.Diagnostics.Debug.Assert(objRequest != null);
HttpResponse objResponse = context.Response;
System.Diagnostics.Debug.Assert(objResponse != null);
//TODO: Maybe we can calculate a timeout in propertion of content length
context.Server.ScriptTimeout = 24 * 60 * 60; //1 day
string sUserName = context.User.Identity.Name;
DownloadFile objDownload = null; // Custom File information object...
Stream objDownloadStream;
long[] arliRequestedRangesBegin = new long[0]; // Start of Chunk
long[] arliRequestedRangesEnd = new long[0]; // End of Chunk
int iResponseContentLength = 0;
int iBytesToRead;
int iLengthOfReadChunk;
bool bWasDownloadInterrupted = false; //Was download Interupted
bool bIsChunkRequest = false;
bool bMultipart = false;
byte[] arrBuffer = new byte[BUFFER_SIZE];
//Get to the file that was requested.
//ONLY FILE TYPES WITH EXTENSIONS MAPPED IN WEB.CONFIG WILL CALL THIS CODE
try
{
Guid gFileGuid = new Guid(System.IO.Path.GetFileNameWithoutExtension(objRequest.FilePath));
objDownload = new DownloadFile(gFileGuid, sUserName);
}
catch
{
//ArgumentNullException, FormatException, OverflowException, DataLayerException, BusinessLayerException
}
//Clear the response
objResponse.Clear();
//Added by JLC after the following article
//http://support.softartisans.com/kbview.aspx?ID=766
objResponse.Buffer = false;
string strMethod = objRequest.HttpMethod;
//We could support more request types
if (!strMethod.Equals(HTTP_METHOD_GET) && !strMethod.Equals(HTTP_METHOD_HEAD))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionRequestTypeNotImplemented, strMethod);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorRequestTypeNotImplemented,
null);
//objResponse.StatusCode = 501; //HTTP Request Type Not implemented
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(501, sErrorMessage);
}
else if ((objDownload == null) || (!objDownload.Exists))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionCannotRetrieveDownload, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorCannotRetrieveDownload,
new HttpException(404, sErrorMessage));
//objResponse.StatusCode = 404; //File Not found
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(404, sErrorMessage);
}
else if (objDownload.IsExpired)
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionDownloadExpired, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorDownloadExpired,
new HttpException(410, sErrorMessage));
//objResponse.StatusCode = 410; //File no more available. Probably expired.
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(410, sErrorMessage);
}
else if (!objDownload.CanDownload)
{
if (context.User.Identity.IsAuthenticated)
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionUnauthorizedDownload, sUserName, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorUnauthorizedDownload,
new HttpException(403, sErrorMessage));
//objResponse.StatusCode = 403; //Forbidden
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(403, sErrorMessage);
}
else
{
string sErrorMessage = Resources.ExceptionAuthenticationRequired;
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorAuthenticationRequired,
new HttpException(401, sErrorMessage));
//objResponse.StatusCode = 401; //Authentication required
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(401, sErrorMessage);
}
}
else if (objDownload.Length > Int32.MaxValue)
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionResponseTooLarge, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorResponseTooLarge,
new HttpException(413, sErrorMessage));
//objResponse.StatusCode = 413; //Request for too many bytes
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(413, sErrorMessage);
}
else if (!DownloadHandler.ParseRequestHeaderRange(objRequest, objDownload.Length, ref arliRequestedRangesBegin, ref arliRequestedRangesEnd, ref bIsChunkRequest))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionInvalidRanges, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorInvalidRanges,
new HttpException(400, sErrorMessage));
//objResponse.StatusCode = 400; //Bad request
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(400, sErrorMessage);
}
else if (!DownloadHandler.CheckIfModifiedSince(objRequest, objDownload))
{
//Not an error - just tells the browser to download from its cache
objResponse.StatusCode = 304; //Not modified
}
else if (!DownloadHandler.CheckIfUnmodifiedSince(objRequest, objDownload))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionPreconditionFailed, objRequest.FilePath, "If-Unmodified-Since");
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorPreconditionFailed,
new HttpException(412, sErrorMessage));
//objResponse.StatusCode = 412; //modified pre-condition failed
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(412, sErrorMessage);
}
else if (!DownloadHandler.CheckIfMatch(objRequest, objDownload))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionPreconditionFailed, objRequest.FilePath, "If-Match");
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorPreconditionFailed,
new HttpException(412, sErrorMessage));
//objResponse.StatusCode = 412; //Entitiy Precondition failed
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(412, sErrorMessage);
}
else if (!DownloadHandler.CheckIfNoneMatch(objRequest, objResponse, objDownload))
{
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionPreconditionFailed, objRequest.FilePath, "If-None-Match");
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorPreconditionFailed,
new HttpException(412, sErrorMessage));
System.Diagnostics.Trace.WriteLine("Nothing to download");
//objResponse.StatusCode = 412; //Entitiy Precondition failed
//Same issue as with upload module: we raise an exception to be redirected to Application_Error and Custom Errors
//and display a nice custom error message
throw new HttpException(412, sErrorMessage);
}
else
{
//Everything is good so far.
if (bIsChunkRequest && DownloadHandler.CheckIfRange(objRequest, objDownload)) // Valid Chunk Request
{
bMultipart = (bool)(arliRequestedRangesBegin.GetUpperBound(0) > 0);
// Loop through chunks to calculate the total length
for (int iLoop = arliRequestedRangesBegin.GetLowerBound(0); iLoop <= arliRequestedRangesBegin.GetUpperBound(0); iLoop++)
{
iResponseContentLength += Convert.ToInt32(arliRequestedRangesEnd[iLoop] - arliRequestedRangesBegin[iLoop]) + 1;
if (bMultipart)
{
// Calc length of the headers
iResponseContentLength += MULTIPART_BOUNDARY.Length;
iResponseContentLength += objDownload.ContentType.Length;
iResponseContentLength += arliRequestedRangesBegin[iLoop].ToString(CultureInfo.InvariantCulture).Length;
iResponseContentLength += arliRequestedRangesEnd[iLoop].ToString(CultureInfo.InvariantCulture).Length;
iResponseContentLength += objDownload.Length.ToString(CultureInfo.InvariantCulture).Length;
iResponseContentLength += 49; // add length needed for multipart header
}
}
if (bMultipart)
{
// Calc length of last intermediate header
iResponseContentLength += MULTIPART_BOUNDARY.Length;
iResponseContentLength += 8; // length of dash and line break
}
else
{
objResponse.AppendHeader(HTTP_HEADER_CONTENT_RANGE, "bytes "
+ arliRequestedRangesBegin[0].ToString(CultureInfo.InvariantCulture) + "-"
+ arliRequestedRangesEnd[0].ToString(CultureInfo.InvariantCulture) + "/"
+ objDownload.Length.ToString(CultureInfo.InvariantCulture));
}
objResponse.StatusCode = 206; // Partial Response
}
else
{
//Not a Chunck request or Entity doesn't match
//Start a new download of the entire file
iResponseContentLength = Convert.ToInt32(objDownload.Length);
objResponse.StatusCode = 200; //Status OK
}
string sEncodedFileName = HttpUtility.UrlPathEncode(objDownload.FileName); //This is for Unicode file names like chinese file names
objResponse.AppendHeader(HTTP_HEADER_CONTENT_DISPOSITION, HTTP_HEADER_CONTENT_DISPOSITION_ATTACHMENT + sEncodedFileName);
objResponse.AppendHeader(HTTP_HEADER_CONTENT_LENGTH, iResponseContentLength.ToString(CultureInfo.InvariantCulture));
objResponse.AppendHeader(HTTP_HEADER_LAST_MODIFIED, objDownload.LastWriteTimeUTC.ToString("r", CultureInfo.InvariantCulture));
objResponse.AppendHeader(HTTP_HEADER_ACCEPT_RANGES, HTTP_HEADER_ACCEPT_RANGES_BYTES);
objResponse.AppendHeader(HTTP_HEADER_ENTITY_TAG, "\"" + objDownload.EntityTag + "\""); // Entity Tag muss be Quote Enclosed
if (bMultipart)
{
// File real MIME type gets pushed into the response object later
objResponse.ContentType = MULTIPART_CONTENTTYPE;
}
else
{
objResponse.ContentType = objDownload.ContentType;
}
if (objRequest.HttpMethod.Equals(HTTP_METHOD_HEAD))
{
// Only the HEAD was requested
}
else
{
objResponse.Flush();
// We're Downloading !!
objDownload.State = DownloadFile.DownloadState.DownloadInProgress;
objDownloadStream = objDownload.DownloadStream;
// Process all the requested chunks.
for (int iLoop = arliRequestedRangesBegin.GetLowerBound(0); iLoop <= arliRequestedRangesBegin.GetUpperBound(0); iLoop++)
{
//TODO: Problem is CanSeek is not supported
objDownloadStream.Seek(arliRequestedRangesBegin[iLoop], System.IO.SeekOrigin.Begin);
iBytesToRead = Convert.ToInt32(arliRequestedRangesEnd[iLoop] - arliRequestedRangesBegin[iLoop]) + 1;
if (bMultipart)
{
// Send Headers
objResponse.Output.WriteLine("--" + MULTIPART_BOUNDARY); // Indicate the part boundry
objResponse.Output.WriteLine(HTTP_HEADER_CONTENT_TYPE + ": " + objDownload.ContentType);
objResponse.Output.WriteLine(HTTP_HEADER_CONTENT_RANGE + ": bytes "
+ arliRequestedRangesBegin[iLoop].ToString(CultureInfo.InvariantCulture) + "-"
+ arliRequestedRangesEnd[iLoop].ToString(CultureInfo.InvariantCulture) + "/"
+ objDownload.Length.ToString(CultureInfo.InvariantCulture));
objResponse.Output.WriteLine();
}
// Send the Data.
while (iBytesToRead > 0)
{
if (objResponse.IsClientConnected)
{
iLengthOfReadChunk = objDownloadStream.Read(arrBuffer, 0, Math.Min(arrBuffer.Length, iBytesToRead));
objResponse.OutputStream.Write(arrBuffer, 0, iLengthOfReadChunk);
objResponse.Flush();
Array.Resize <byte>(ref arrBuffer, BUFFER_SIZE);
iBytesToRead -= iLengthOfReadChunk;
}
else
{
// DOWNLOAD INTERRUPTED
iBytesToRead = -1;
bWasDownloadInterrupted = true;
}
}
if (bMultipart)
{
objResponse.Output.WriteLine(); // Mark the end of the part
}
if (bWasDownloadInterrupted)
{
break;
}
}
// Download finished or cancelled...
if (bWasDownloadInterrupted)
{
//Download broken...
objDownload.State = DownloadFile.DownloadState.DownloadBroken;
string sErrorMessage = String.Format(Resources.Culture, Resources.ExceptionRequestAbort, objRequest.FilePath);
HealthMonitoringManager.LogErrorEvent(
sErrorMessage,
objDownload,
DownloadRequestErrorEvent.RuntimeErrorRequestAbort,
new System.Net.WebException(sErrorMessage, System.Net.WebExceptionStatus.ConnectionClosed));
}
else
{
if (bMultipart)
{
objResponse.Output.WriteLine("--" + MULTIPART_BOUNDARY + "--");
objResponse.Output.WriteLine();
}
// Download Complete
objDownload.State = DownloadFile.DownloadState.DownloadFinished;
HealthMonitoringManager.LogSucessEvent(
Resources.MessageDownloadCompleted,
objDownload,
DownloadRequestSuccessEvent.RuntimeDownloadSuccessCompleted);
}
objDownloadStream.Close();
}
}
objResponse.End();
}
/// <summary>
///
/// </summary>
/// <param name="objRequest"></param>
/// <param name="lBegin"></param>
/// <param name="lEnd"></param>
/// <param name="lMax"></param>
/// <param name="bRangeRequest"></param>
/// <returns></returns>
private static bool ParseRequestHeaderRange(HttpRequest objRequest, long lMax, ref long[] lBegin, ref long[] lEnd, ref bool bRangeRequest) //Some ByVal some ByRef
{
bool bValidRangesRet;
string sSource;
//int iLoop;
string[] arrRanges;
// Retrieve Range Header from Request
sSource = DownloadHandler.RetrieveHeader(objRequest, HTTP_HEADER_RANGE, String.Empty);
if (String.IsNullOrEmpty(sSource)) // No Range was requested
{
Array.Resize <long>(ref lBegin, 1);
Array.Resize <long>(ref lEnd, 1);
lBegin[0] = 0;
lEnd[0] = lMax - 1;
bValidRangesRet = true;
bRangeRequest = false;
}
else
{
bValidRangesRet = true;
bRangeRequest = true;
// Remove "bytes=" string, and split the rest
arrRanges = sSource.Replace("bytes=", "").Split(",".ToCharArray());
Array.Resize <long>(ref lBegin, arrRanges.GetUpperBound(0) + 1);
Array.Resize <long>(ref lEnd, arrRanges.GetUpperBound(0) + 1);
// Check each Range request
for (int iLoop = arrRanges.GetLowerBound(0); iLoop <= arrRanges.GetUpperBound(0); iLoop++)
{
// arrRange(0) is the begin value - arrRange(1) is the end value.
string[] arrRange = arrRanges[iLoop].Split("-".ToCharArray());
if (String.IsNullOrEmpty(arrRange[1])) // No end was specified
{
lEnd[iLoop] = lMax - 1;
}
else
{
lEnd[iLoop] = long.Parse(arrRange[1], CultureInfo.InvariantCulture);
}
if (String.IsNullOrEmpty(arrRange[0]))
{
// Calculate the beginning and end.
lBegin[iLoop] = lMax - 1 - lEnd[iLoop];
lEnd[iLoop] = lMax - 1;
}
else
{
lBegin[iLoop] = long.Parse(arrRange[0], CultureInfo.InvariantCulture);
}
// Begin and end must not exceed the total file size
if ((lBegin[iLoop] > (lMax - 1)) || (lEnd[iLoop] > (lMax - 1)))
{
bValidRangesRet = false;
}
// Begin and end cannot be < 0
if ((lBegin[iLoop] < 0) || (lEnd[iLoop] < 0))
{
bValidRangesRet = false;
}
// End must be larger or equal to begin value
if (lEnd[iLoop] < lBegin[iLoop])
{
bValidRangesRet = false;
}
}
}
return(bValidRangesRet);
}
