cli: Print out available tus extensions

cmd/tusd/cli/serve.go

@@ -54,7 +54,7 @@ func Serve() {
 		SetupHookMetrics()
 	}
 
-	stdout.Printf(Composer.Capabilities())
+	stdout.Printf("Supported tus extensions: %s\n", handler.SupportedExtensions())
 
 	// Do not display the greeting if the tusd handler will be mounted at the root
 	// path. Else this would cause a "multiple registrations for /" panic.

pkg/handler/unrouted_handler.go

@@ -155,6 +155,13 @@ func NewUnroutedHandler(config Config) (*UnroutedHandler, error) {
 	return handler, nil
 }
 
+// SupportedExtensions returns a comma-separated list of the supported tus extensions.
+// The availability of an extension usually depends on whether the provided data store
+// implements some additional interfaces.
+func (handler *UnroutedHandler) SupportedExtensions() string {
+	return handler.extensions
+}
+
 // Middleware checks various aspects of the request and ensures that it
 // conforms with the spec. Also handles method overriding for clients which
 // cannot make PATCH AND DELETE requests. If you are using the tusd handlers