/// <summary>
/// Branches the request pipeline based on the result of the given predicate.
/// </summary>
/// <param name="app"></param>
/// <param name="predicate">Invoked with the request environment to determine if the branch should be taken</param>
/// <param name="configuration">Configures a branch to take</param>
/// <returns></returns>
public static IMiddlewareBuilder <TContext> MapWhen <TContext>(this IMiddlewareBuilder <TContext> app, Predicate <TContext> predicate, Action <IMiddlewareBuilder <TContext> > configuration)
where TContext : ContextBase
{
if (app == null)
{
throw new ArgumentNullException(nameof(app));
}
if (predicate == null)
{
throw new ArgumentNullException(nameof(predicate));
}
if (configuration == null)
{
throw new ArgumentNullException(nameof(configuration));
}
// create branch
var branchBuilder = app.New();
configuration(branchBuilder);
var branch = branchBuilder.Build();
// put middleware in pipeline
var options = new MapWhenOptions <TContext>
{
Predicate = predicate,
Branch = branch,
};
return(app.Use(next => new MapWhenMiddleware <TContext>(next, options).Invoke));
}
/// <summary>
/// Creates a new instance of <see cref="MapWhenMiddleware"/>.
/// </summary>
/// <param name="next">The delegate representing the next middleware in the request pipeline.</param>
/// <param name="options">The middleware options.</param>
public MapWhenMiddleware(MiddlewareDelegate <TContext> next, MapWhenOptions <TContext> options)
{
_next = next ?? throw new ArgumentNullException(nameof(next));
_options = options ?? throw new ArgumentNullException(nameof(options));
}
