/// <summary>
/// Returns a LegacyPDQIDRedirectionMap created from the specified datafile. If avaialble, a cached
/// copy of the map is returned; otherwise, the data file is parsed and a new map created.
/// </summary>
/// <param name="datafile">Location of a data file creating comma-separated pairs of
/// cdrids and nciids for use as redirection targets.</param>
/// <param name="context">The current HTTP Context object.</param>
/// <returns>A (possibly empty) RedirectionMap.</returns>
public static LegacyPDQIDRedirectionMap GetMap(String datafile, HttpContext context)
{
log.Trace("Enter GetMap().");
LegacyPDQIDRedirectionMap map;
Cache cache = context.Cache;
Object lockObj = new Object();
try
{
log.DebugFormat("Load cache for '{0}'.", datafile);
map = (LegacyPDQIDRedirectionMap)cache[datafile];
if (map == null)
{
lock (lockObj)
{
// Check whether the cache was loaded while we waited for the lock.
map = (LegacyPDQIDRedirectionMap)cache[datafile];
if (map == null)
{
// There was no cached redirection map. Load it from the file system.
log.DebugFormat("Cache miss. Loading redirection map from '{0}'.", datafile);
CacheItemRemovedCallback onRemove = new CacheItemRemovedCallback(RemovedItemCallback);
CacheDependency fileDependency = new CacheDependency(datafile);
map = LoadMapFromFile(datafile);
cache.Add(datafile, map, fileDependency, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.AboveNormal, onRemove);
}
else
{
log.Debug("Cached redirection map found on second chance retrieval.");
}
}
}
else
{
// A cached redirection map was found. Return it.
log.Debug("Loading cached redirection map.");
}
}
catch (Exception ex)
{
log.Error("Error while getting the redirection map.", ex);
// Instead of letting the request die,
// swallow the exception and return an empty map.
map = new LegacyPDQIDRedirectionMap();
}
return(map);
}
/// <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 LegacyPDQIDRedirectionMap LoadMapFromFile(String datafile, char[] separators = null)
{
log.Trace("Enter LoadMapFromFile().");
//If no separators are specified, then default to commas.
separators = separators ?? new char[1] {
','
};
LegacyPDQIDRedirectionMap map = new LegacyPDQIDRedirectionMap();
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>
/// Handles redirections for old /clinicaltrials/search/view?id=cdrid
/// </summary>
/// <param name="?"></param>
private void RedirectForOldCDRIDViewURLs(HttpContext context)
{
//If the url is not what we are looking for, bail
if (!context.Request.Url.AbsolutePath.Equals("/about-cancer/treatment/clinical-trials/search/view", StringComparison.InvariantCultureIgnoreCase))
{
return;
}
//If there is no map, then bail
if (String.IsNullOrWhiteSpace(PDQNCIIDMapFilePath))
{
//TODO: Log warning?
return;
}
int cdrID = Strings.ToInt(context.Request.Params["cdrid"]);
//Invalid ID format, so bail
if (cdrID < 1)
{
return;
}
string mapFullPath = HttpContext.Current.Server.MapPath(PDQNCIIDMapFilePath);
LegacyPDQIDRedirectionMap map = LegacyPDQIDRedirectionMap.GetMap(mapFullPath, context);
//Map entry does not exist, bail
if (!map.Contains(cdrID.ToString()))
{
return;
}
string nciID = map[cdrID.ToString()];
//This is not a valid trial
if (!IsValidTrial(nciID))
{
return;
}
string redirectPath = string.Format("{0}?id={1}&r=1", this.SearchResultsPrettyUrl, nciID);
// Add redirect query parameter for analytics
redirectPath += "&redirect=true";
//Finally redirect.
NCI.Web.CDE.Application.PermanentRedirector.DoPermanentRedirect(context.Response, redirectPath, "NCTID Redirect");
}
