new: new -script allows to run JS code to instrument session

session/script_builtin_runtime.go

@@ -0,0 +1,67 @@
+package session
+
+import (
+	"github.com/bettercap/bettercap/js"
+	"github.com/evilsocket/islazy/log"
+	"github.com/robertkrimen/otto"
+)
+
+func jsRunFunc(call otto.FunctionCall) otto.Value {
+	argv := call.ArgumentList
+	argc := len(argv)
+	if argc != 1 {
+		return js.ReportError("run accepts one string argument")
+	} else if argv[0].IsString() == false {
+		return js.ReportError("run accepts one string argument")
+	}
+
+	for _, cmd := range ParseCommands(argv[0].String()) {
+		if err := I.Run(cmd); err != nil {
+			return js.ReportError("error running '%s': %v", cmd, err)
+		}
+	}
+
+	return js.NullValue
+}
+
+func jsOnEventFunc(call otto.FunctionCall) otto.Value {
+	argv := call.ArgumentList
+	argc := len(argv)
+	cb := otto.NullValue()
+	filterExpr := ""
+
+	// just one argument, a function to receive all events
+	if argc == 1 {
+		if argv[0].IsFunction() == false {
+			return js.ReportError("the single argument must be a function")
+		}
+		cb = argv[0]
+	} else {
+		if argc != 2 {
+			return js.ReportError("expected two arguments (event_name, callback), got %d", argc)
+		} else if argv[0].IsString() == false {
+			return js.ReportError("first argument must be a string")
+		} else if argv[1].IsFunction() == false {
+			return js.ReportError("second argument must be a function")
+		}
+
+		filterExpr = argv[0].String()
+		cb = argv[1]
+	}
+
+	// start a go routine for this event listener
+	go func(expr string, cb otto.Value) {
+		listener := I.Events.Listen()
+		defer I.Events.Unlisten(listener)
+
+		for event := range listener {
+			if expr == "" || event.Tag == expr {
+				if _, err := cb.Call(otto.NullValue(), event); err != nil {
+					I.Events.Log(log.ERROR, "error dispatching event %s: %v", event.Tag, err)
+				}
+			}
+		}
+	}(filterExpr, cb)
+
+	return js.NullValue
+}