internal string GetChildActionUniqueId(ActionExecutingContext filterContext)
{
StringBuilder 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
DescriptorUtil.AppendUniqueId(uniqueIdBuilder, 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
BuildUniqueIdFromActionParameters(uniqueIdBuilder, filterContext);
// 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 dramtically different keys).
using (SHA256Cng sha = new SHA256Cng())
{
return(Convert.ToBase64String(sha.ComputeHash(Encoding.UTF8.GetBytes(uniqueIdBuilder.ToString()))));
}
}
private string CreateUniqueId()
{
var builder = new StringBuilder(base.UniqueId);
DescriptorUtil.AppendUniqueId(builder, MethodInfo);
return(builder.ToString());
}
internal void BuildUniqueIdFromActionParameters(
StringBuilder builder,
ActionExecutingContext filterContext
)
{
if (String.Equals(VaryByParam, "none", StringComparison.OrdinalIgnoreCase))
{
// nothing to do
return;
}
if (String.Equals(VaryByParam, "*", StringComparison.Ordinal))
{
// use all available key/value pairs. Keys need to be sorted so we end up with a stable identifier.
IEnumerable <KeyValuePair <string, object> > orderedParameters =
filterContext.ActionParameters.OrderBy(
k => k.Key,
StringComparer.OrdinalIgnoreCase
);
foreach (KeyValuePair <string, object> item in orderedParameters)
{
DescriptorUtil.AppendUniqueId(builder, item.Key.ToUpperInvariant());
DescriptorUtil.AppendUniqueId(builder, item.Value);
}
return;
}
LazyInitializer.EnsureInitialized(ref _tokenizedVaryByParams, _splitVaryByParamThunk);
// By default, filterContext.ActionParameter is a case insensitive (StringComparer.OrdinalIgnoreCase)
// dictionary. If the user has replaced it with a dictionary that uses a different comparer, we'll
// wrap it in a Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)
// This allows us to lookup values for action parameters when the VaryByParam token key differs in case.
Dictionary <string, object> keyValues = GetCaseInsensitiveActionParametersDictionary(
filterContext.ActionParameters
);
for (int i = 0; i < _tokenizedVaryByParams.Length; i++)
{
string key = _tokenizedVaryByParams[i];
DescriptorUtil.AppendUniqueId(builder, key);
object value;
keyValues.TryGetValue(key, out value);
DescriptorUtil.AppendUniqueId(builder, value);
}
}
