/// <summary>
/// Performs a targeting evaluation using the provided <see cref="TargetingContext"/> to determine if a feature should be enabled.
/// </summary>
/// <param name="context">The feature evaluation context.</param>
/// <param name="targetingContext">The targeting context to use during targeting evaluation.</param>
/// <exception cref="ArgumentNullException">Thrown if either <paramref name="context"/> or <paramref name="targetingContext"/> is null.</exception>
/// <returns>True if the feature is enabled, false otherwise.</returns>
public Task <bool> EvaluateAsync(FeatureFilterEvaluationContext context, ITargetingContext targetingContext)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (targetingContext == null)
{
throw new ArgumentNullException(nameof(targetingContext));
}
TargetingFilterSettings settings = context.Parameters.Get <TargetingFilterSettings>() ?? new TargetingFilterSettings();
if (!TryValidateSettings(settings, out string paramName, out string message))
{
throw new ArgumentException(message, paramName);
}
//
// Check if the user is being targeted directly
if (targetingContext.UserId != null &&
settings.Audience.Users != null &&
settings.Audience.Users.Any(user => targetingContext.UserId.Equals(user, ComparisonType)))
{
return(Task.FromResult(true));
}
//
// Check if the user is in a group that is being targeted
if (targetingContext.Groups != null &&
settings.Audience.Groups != null)
{
foreach (string group in targetingContext.Groups)
{
GroupRollout groupRollout = settings.Audience.Groups.FirstOrDefault(g => g.Name.Equals(group, ComparisonType));
if (groupRollout != null)
{
string audienceContextId = $"{targetingContext.UserId}\n{context.FeatureName}\n{group}";
if (IsTargeted(audienceContextId, groupRollout.RolloutPercentage))
{
return(Task.FromResult(true));
}
}
}
}
//
// Check if the user is being targeted by a default rollout percentage
string defaultContextId = $"{targetingContext.UserId}\n{context.FeatureName}";
return(Task.FromResult(IsTargeted(defaultContextId, settings.Audience.DefaultRolloutPercentage)));
}
/// <summary>
/// Performs validation of targeting settings.
/// </summary>
/// <param name="settings">The settings to validate.</param>
/// <param name="paramName">The name of the invalid setting, if any.</param>
/// <param name="reason">The reason that the setting is invalid.</param>
/// <returns>True if the provided settings are valid. False if the provided settings are invalid.</returns>
private bool TryValidateSettings(TargetingFilterSettings settings, out string paramName, out string reason)
{
const string OutOfRange = "The value is out of the accepted range.";
const string RequiredParameter = "Value cannot be null.";
paramName = null;
reason = null;
if (settings.Audience == null)
{
paramName = nameof(settings.Audience);
reason = RequiredParameter;
return(false);
}
if (settings.Audience.DefaultRolloutPercentage < 0 || settings.Audience.DefaultRolloutPercentage > 100)
{
paramName = $"{settings.Audience}.{settings.Audience.DefaultRolloutPercentage}";
reason = OutOfRange;
return(false);
}
if (settings.Audience.Groups != null)
{
int index = 0;
foreach (GroupRollout groupRollout in settings.Audience.Groups)
{
index++;
if (groupRollout.RolloutPercentage < 0 || groupRollout.RolloutPercentage > 100)
{
//
// Audience.Groups[1].RolloutPercentage
paramName = $"{settings.Audience}.{settings.Audience.Groups}[{index}].{groupRollout.RolloutPercentage}";
reason = OutOfRange;
return(false);
}
}
}
return(true);
}
