internal string GetChildActionUniqueId(ActionExecutingContext filterContext)
{
var uniqueIdBuilder = new StringBuilder();
// Start with a prefix, presuming that we share the cache with other users
uniqueIdBuilder.Append(CacheKeyPrefix);
// Unique ID of the action description
uniqueIdBuilder.Append(filterContext.ActionDescriptor.UniqueId);
// Unique ID from the VaryByCustom settings, if any
uniqueIdBuilder.Append(MyDescriptorUtil.CreateUniqueId(VaryByCustom));
if (!String.IsNullOrEmpty(VaryByCustom))
{
string varyByCustomResult = filterContext.HttpContext.ApplicationInstance.GetVaryByCustomString(HttpContext.Current, VaryByCustom);
uniqueIdBuilder.Append(varyByCustomResult);
}
// Unique ID from the VaryByParam settings, if any
uniqueIdBuilder.Append(GetUniqueIdFromActionParameters(filterContext, SplitVaryByParam(VaryByParam)));
// The key is typically too long to be useful, so we use a cryptographic hash
// as the actual key (better randomization and key distribution, so small vary
// values will generate dramatically different keys).
using (SHA256 sha = SHA256.Create())
{
return(Convert.ToBase64String(sha.ComputeHash(Encoding.UTF8.GetBytes(uniqueIdBuilder.ToString()))));
}
}
private static string GetUniqueIdFromActionParameters(ActionExecutingContext filterContext, IEnumerable <string> keys)
{
// Generate a unique ID of normalized key names + key values
var keyValues = new Dictionary <string, object>(filterContext.ActionParameters, StringComparer.OrdinalIgnoreCase);
keys = (keys ?? keyValues.Keys).Select(key => key.ToUpperInvariant())
.OrderBy(key => key, StringComparer.Ordinal);
return(MyDescriptorUtil.CreateUniqueId(keys.Concat(keys.Select(key => keyValues.ContainsKey(key) ? keyValues[key] : null))));
}