Add example for conditional option

error_writer.go

@@ -40,7 +40,7 @@ type ErrorWriter struct {
 // NewErrorWriter constructs an ErrorWriter. To properly recognize supported
 // RPC Content-Types in net/http middleware, you must pass the same
 // HandlerOptions to NewErrorWriter and any wrapped Connect handlers.
-// Conditional options are ignored.
+// Options supplied via [WithConditionalHandlerOptions] are ignored.
 func NewErrorWriter(opts ...HandlerOption) *ErrorWriter {
 	config := newHandlerConfig("", StreamTypeUnary, opts)
 	writer := &ErrorWriter{

interceptor_example_test.go

@@ -95,3 +95,14 @@ func ExampleWithInterceptors() {
 	// inner interceptor: after call
 	// outer interceptor: after call
 }
+
+func ExampleWithConditionalHandlerOptions() {
+	connect.WithConditionalHandlerOptions(func(spec connect.Spec) []connect.HandlerOption {
+		var options []connect.HandlerOption
+		if spec.Procedure == pingv1connect.PingServicePingProcedure {
+			options = append(options, connect.WithReadMaxBytes(1024))
+		}
+		return options
+	})
+	// Output:
+}

option.go

@@ -166,34 +166,12 @@ func WithRequireConnectProtocolHeader() HandlerOption {
 	return &requireConnectProtocolHeaderOption{}
 }
 
-// WithConditionalHandlerOptions is a function that returns a HandlerOption.
+// WithConditionalHandlerOptions accepts a function that returns a HandlerOption.
 // It's used to conditionally apply HandlerOption to a Handler based on the Spec.
-// For example, to apply a HandlerOption only to a specific procedure:
-//
-//	connect.WithConditionalHandlerOptions(func(spec connect.Spec) (options []connect.HandlerOption) {
-//		if spec.Procedure == pingv1connect.PingServicePingProcedure {
-//			options = append(options, connect.WithReadMaxBytes(1024))
-//		}
-//		return options
-//	})
 func WithConditionalHandlerOptions(conditional func(spec Spec) []HandlerOption) HandlerOption {
 	return &conditionalHandlerOptions{conditional: conditional}
 }
 
-type conditionalHandlerOptions struct {
-	conditional func(spec Spec) []HandlerOption
-}
-
-func (o *conditionalHandlerOptions) applyToHandler(config *handlerConfig) {
-	spec := config.newSpec()
-	if spec.Procedure == "" {
-		return // ignore empty specs
-	}
-	for _, option := range o.conditional(spec) {
-		option.applyToHandler(config)
-	}
-}
-
 // Option implements both [ClientOption] and [HandlerOption], so it can be
 // applied both client-side and server-side.
 type Option interface {
@@ -585,3 +563,17 @@ func withProtoJSONCodecs() HandlerOption {
 		WithCodec(&protoJSONCodec{codecNameJSONCharsetUTF8}),
 	)
 }
+
+type conditionalHandlerOptions struct {
+	conditional func(spec Spec) []HandlerOption
+}
+
+func (o *conditionalHandlerOptions) applyToHandler(config *handlerConfig) {
+	spec := config.newSpec()
+	if spec.Procedure == "" {
+		return // ignore empty specs
+	}
+	for _, option := range o.conditional(spec) {
+		option.applyToHandler(config)
+	}
+}