/// <summary>
/// Private helper method to encapsulate the logic for loading and parsing the datafile.
/// </summary>
/// <param name="datafile">Location of a data file creating comma-separated pairs of
/// old URLs and new URLs for use as redirection targets.</param>
/// <returns></returns>
private static RedirectionMap LoadMapFromFile(String datafile)
{
log.Trace("Enter LoadMapFromFile().");
SimpleRedirectorConfigurationSection config = SimpleRedirectorConfigurationSection.Get();
char[] separators = new char[1];
separators[0] = config.DataSource.Separator;
RedirectionMap map = new RedirectionMap();
try
{
if (!File.Exists(datafile))
{
log.ErrorFormat("Datafile '{0}' not found.", datafile);
throw new FileNotFoundException(datafile);
}
}
catch (Exception ex)
{
log.ErrorFormat("Error while loading urls from {0}.", ex, datafile);
// Swallow the exception. The worst case is we return an empty dictionary
// and nothing gets redirected.
}
String[] listOfUrlPairs = File.ReadAllLines(datafile);
foreach (String urlPair in listOfUrlPairs)
{
String[] urls = urlPair.Trim().Split(separators);
if (urls.Length >= 2)
{
try
{
map.Add(urls[0], urls[1]);
}
catch (Exception ex)
{
log.ErrorFormat("Duplicate URL found in RedirectMap: {0}", ex, urls[0]);
}
}
if (urls.Length != 2)
{
// We can recover from this problem. No exception needed.
log.WarnFormat("Expected only two urls, found {0} in '{1}'.", urls.Length, urlPair);
}
}
return(map);
}
/// <summary>
/// Private helper to find the redirection URL mapped to a given input URL.
/// </summary>
/// <param name="url">The URL to examine for a replacement</param>
/// <param name="context"></param>
/// <returns></returns>
private String GetRedirectUrl(String url, HttpContext context)
{
String redirect = null;
string urlWithSlash;
if (url.LastIndexOf("/") == url.Length - 1)
{
urlWithSlash = url;
url = url.Substring(0, url.Length - 1);
}
else
{
urlWithSlash = url + "/";
}
SimpleRedirectorConfigurationSection config = SimpleRedirectorConfigurationSection.Get();
String datafile = HttpContext.Current.Server.MapPath(config.DataSource.DataFile);
RedirectionMap urlMap = RedirectionMap.GetMap(datafile, context);
if (urlMap.Contains(url))
{
if (urlMap.ContainsMultiple(url))
{
log.DebugFormat("Url: '{0}' has multiple instances in redirect map.", url);
}
redirect = urlMap[url];
log.DebugFormat("Url '{0}' found; redirects to '{1}'.", url, redirect);
}
else if (urlMap.Contains(urlWithSlash))
{
if (urlMap.ContainsMultiple(urlWithSlash))
{
log.DebugFormat("Url: '{0}' has multiple instances in redirect map.", urlWithSlash);
}
redirect = urlMap[urlWithSlash];
log.DebugFormat("Url '{0}' found; redirects to '{1}'.", urlWithSlash, redirect);
}
else
{
log.DebugFormat("No match found for url '{0}.", url);
}
return(redirect);
}