IMethodInterceptor

IMethodInterceptor Interface¶

Intercepts method invocations on a service. Implement this interface to create reusable cross-cutting concerns like logging, caching, or timing.

public interface IMethodInterceptor

Example¶

public class LoggingInterceptor : IMethodInterceptor
{
    private readonly ILogger _logger;

    public LoggingInterceptor(ILogger logger) => _logger = logger;

    public async ValueTask<object?> InterceptAsync(IMethodInvocation invocation)
    {
        _logger.LogInformation("Calling {Method}", invocation.Method.Name);
        var sw = Stopwatch.StartNew();
        try
        {
            var result = await invocation.ProceedAsync();
            _logger.LogInformation("{Method} completed in {Elapsed}ms", 
                invocation.Method.Name, sw.ElapsedMilliseconds);
            return result;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "{Method} failed", invocation.Method.Name);
            throw;
        }
    }
}

Remarks¶

Unlike decorators (which require implementing every method of an interface), interceptors handle any method invocation with a single implementation. Apply interceptors to services using InterceptAttribute<TInterceptor>.

Interceptors are resolved from the DI container and can have their own dependencies. They are automatically excluded from Needlr's auto-registration because they are internal infrastructure resolved by generated proxy classes, not by user code.

Methods¶