/// <summary>
/// Gets or creates a TailInfo object that contains information about tailing
/// the specified file.
/// </summary>
/// <param name="context">HttpContext object</param>
/// <param name="fileName">The name of the file to tail.</param>
/// <param name="lines">The number of lines to return on the initial request.</param>
/// <returns>A TailInfo object that is saved on the session.</returns>
private TailInfo GetTailInfo(HttpContext context, string fileName, int lines)
{
TailInfo ti = null;
// Is there already tail information on the session?
Hashtable ht = context.Session["TailInfo"] as Hashtable;
if (ht == null)
{
context.Session["TailInfo"] = ht = new Hashtable();
}
// See if there is information for this file in the hashtable.
if (ht.ContainsKey(fileName))
{
ti = ht[fileName] as TailInfo;
}
else
{
ht[fileName] = ti = new TailInfo(lines, -1);
}
return(ti);
}
public void TailInfo_Test()
{
var tailinfo = new TailInfo(1000000);
tailinfo.LastTail.ToShortDateString().Should().Be(DateTime.Now.ToShortDateString());
}
/// <summary>
/// Enables processing of HTTP Web requests by a custom HttpHandler
/// that implements the IHttpHandler interface.
/// </summary>
/// <param name="context">An HttpContext object that provides
/// references to the intrinsic server objects (for example,
/// Request, Response, Session, and Server) used to service HTTP requests.</param>
public void ProcessRequest(HttpContext context)
{
// Setup the response.
HttpRequest request = context.Request;
HttpResponse response = context.Response;
try
{
// Only respond to GET method.
if (String.Compare(request.HttpMethod, "GET", true) == 0)
{
// The file name of the url is the file that is to be downloaded.
string fileName = Path.GetFileName(request.Url.LocalPath);
iFolderAdmin web = context.Session["Connection"] as iFolderAdmin;
if (web == null)
{
context.Response.Redirect("Login.aspx");
}
// Get the size of the file.
long fileSize = GetFileSize(web, fileName);
// New requests will contain the number of lines to send back.
int lines = GetLineCount(request);
// Get information about tailing the specified file.
TailInfo ti = GetTailInfo(context, fileName, lines);
// Get the line data.
int length;
ArrayList lineData = GetTailData(web, fileName, fileSize, ti, out length);
// Setup the response.
response.Clear();
response.BufferOutput = false;
response.Cache.SetCacheability(HttpCacheability.NoCache);
response.ContentType = "text/plain";
response.AddHeader("Content-Length", length.ToString());
foreach (byte[] line in lineData)
{
response.OutputStream.Write(line, 0, line.Length);
}
response.Close();
}
else
{
log.Debug(context, "Error: Invalid http method - {0}", request.HttpMethod);
response.StatusCode = ( int )HttpStatusCode.BadRequest;
response.Close();
}
}
catch (Exception ex)
{
log.Debug(context, "Error: {0}", ex.Message);
log.Debug(context, "Stack trace: {0}", ex.StackTrace);
response.StatusCode = ( int )HttpStatusCode.InternalServerError;
response.Close();
}
}
/// <summary>
/// Gets the specified tail data.
/// </summary>
/// <param name="web">iFolderAdmin object</param>
/// <param name="fileName">The name of the file to tail.</param>
/// <param name="fileLength">The current length of the file.</param>
/// <param name="ti">The tail information saved on the session.</param>
/// <param name="length">Receives the total length of the data in the ArrayList.</param>
/// <returns>An array of byte arrays containing file data.</returns>
private ArrayList GetTailData(iFolderAdmin web, string fileName, long fileLength, TailInfo ti, out int length)
{
ArrayList tailLines = new ArrayList(ti.Lines);
length = 0;
// Build the path to the log handler.
UriBuilder uri = new UriBuilder(web.Url);
uri.Path = String.Format("/simias10/admindata/{0}", fileName);
// Is this a first request?
if (ti.Offset == -1)
{
// Have to guess how much data to request.
byte[] buffer = new byte[ti.Lines * 256];
// Read one buffer size from the end of the file.
long readLength = (fileLength > buffer.Length) ? buffer.Length : fileLength;
// Calculate the offset to read from.
ti.Offset = fileLength - readLength;
// Add the query string part.
uri.Query = String.Format("offset={0}&length={1}", ti.Offset, readLength);
// Build the web request to get the data.
HttpWebRequest webRequest = WebRequest.Create(uri.Uri) as HttpWebRequest;
webRequest.Method = "GET";
webRequest.PreAuthenticate = true;
webRequest.Credentials = web.Credentials;
webRequest.CookieContainer = web.CookieContainer;
HttpWebResponse webResponse = webRequest.GetResponse() as HttpWebResponse;
try
{
Stream sr = webResponse.GetResponseStream();
int bytesRead = sr.Read(buffer, 0, ( int )readLength);
if (bytesRead > 0)
{
// Get the specified number of lines until the data is all read.
for (int lines = 0, eob = bytesRead - 1;
(lines < ti.Lines) && (eob >= 0);
++lines)
{
byte[] line = GetLineData(buffer, eob, true);
if (line.Length > 0)
{
tailLines.Add(line);
eob -= line.Length;
length += line.Length;
}
else
{
// No lines exist in the buffer. Return no data.
eob = -1;
}
}
// If any data was returned, update the offset.
if (tailLines.Count > 0)
{
ti.Offset += bytesRead;
tailLines.Reverse();
}
}
}
finally
{
webResponse.Close();
}
}
else
{
// See if there is data to read.
long readLength = fileLength - ti.Offset;
if (readLength > 0)
{
// Make sure the read request is not too large.
if (readLength > BufferSize)
{
readLength = BufferSize;
}
// Read to the end of the file.
byte[] buffer = new byte[readLength];
// Add the query string part.
uri.Query = String.Format("offset={0}&length={1}", ti.Offset, readLength);
// Build the web request to get the data.
HttpWebRequest webRequest = WebRequest.Create(uri.Uri) as HttpWebRequest;
webRequest.Method = "GET";
webRequest.PreAuthenticate = true;
webRequest.Credentials = web.Credentials;
webRequest.CookieContainer = web.CookieContainer;
HttpWebResponse webResponse = webRequest.GetResponse() as HttpWebResponse;
try
{
Stream sr = webResponse.GetResponseStream();
int bytesRead = sr.Read(buffer, 0, ( int )readLength);
if (bytesRead > 0)
{
// Get the specified number of lines until the data is all read.
for (int eob = bytesRead - 1; eob >= 0;)
{
byte[] line = GetLineData(buffer, eob, false);
if (line.Length > 0)
{
tailLines.Add(line);
eob -= line.Length;
length += line.Length;
}
else
{
// No lines exist in the buffer. Return no data.
eob = -1;
}
}
// If any data was returned, update the offset.
if (tailLines.Count > 0)
{
ti.Offset += length;
tailLines.Reverse();
}
}
}
finally
{
webResponse.Close();
}
}
}
return(tailLines);
}
