page_actions.go

package engine

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/go-rod/rod"
	"github.com/go-rod/rod/lib/input"
	"github.com/go-rod/rod/lib/proto"
	"github.com/go-rod/rod/lib/utils"
	"github.com/kitabisa/go-ci"
	"github.com/pkg/errors"
	"github.com/projectdiscovery/gologger"
	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/contextargs"
	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/expressions"
	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/protocolstate"
	contextutil "github.com/projectdiscovery/utils/context"
	"github.com/projectdiscovery/utils/errkit"
	fileutil "github.com/projectdiscovery/utils/file"
	folderutil "github.com/projectdiscovery/utils/folder"
	stringsutil "github.com/projectdiscovery/utils/strings"
	urlutil "github.com/projectdiscovery/utils/url"
	"github.com/segmentio/ksuid"
)

var (
	errinvalidArguments = errkit.New("invalid arguments provided")
	ErrLFAccessDenied   = errkit.New("Use -allow-local-file-access flag to enable local file access")
	// ErrActionExecDealine is the error returned when alloted time for action execution exceeds
	ErrActionExecDealine = errkit.New("headless action execution deadline exceeded").SetKind(errkit.ErrKindDeadline).Build()
)

const (
	errCouldNotGetElement  = "could not get element"
	errCouldNotScroll      = "could not scroll into view"
	errElementDidNotAppear = "Element did not appear in the given amount of time"
)

// ExecuteActions executes a list of actions on a page.
func (p *Page) ExecuteActions(input *contextargs.Context, actions []*Action) (outData ActionData, err error) {
	outData = make(ActionData)

	// waitFuncs are function that needs to be executed after navigation
	// typically used for waitEvent
	waitFuncs := make([]func() error, 0)

	// avoid any future panics caused due to go-rod library
	// TODO(dwisiswant0): remove this once we get the RCA.
	defer func() {
		if ci.IsCI() {
			return
		}

		if r := recover(); r != nil {
			err = errkit.Newf("panic on headless action: %v", r)
		}
	}()

	for _, act := range actions {
		switch act.ActionType.ActionType {
		case ActionNavigate:
			err = p.NavigateURL(act, outData)
			if err == nil {
				// if navigation successful trigger all waitFuncs (if any)
				for _, waitFunc := range waitFuncs {
					if waitFunc != nil {
						if err := waitFunc(); err != nil {
							return nil, errkit.Wrap(err, "error occurred while executing waitFunc")
						}
					}
				}

				p.lastActionNavigate = act
			}
		case ActionScript:
			err = p.RunScript(act, outData)
		case ActionClick:
			err = p.ClickElement(act, outData)
		case ActionRightClick:
			err = p.RightClickElement(act, outData)
		case ActionTextInput:
			err = p.InputElement(act, outData)
		case ActionScreenshot:
			err = p.Screenshot(act, outData)
		case ActionTimeInput:
			err = p.TimeInputElement(act, outData)
		case ActionSelectInput:
			err = p.SelectInputElement(act, outData)
		case ActionWaitDOM:
			event := proto.PageLifecycleEventNameDOMContentLoaded
			err = p.WaitPageLifecycleEvent(act, outData, event)
		case ActionWaitFCP:
			event := proto.PageLifecycleEventNameFirstContentfulPaint
			err = p.WaitPageLifecycleEvent(act, outData, event)
		case ActionWaitFMP:
			event := proto.PageLifecycleEventNameFirstMeaningfulPaint
			err = p.WaitPageLifecycleEvent(act, outData, event)
		case ActionWaitIdle:
			event := proto.PageLifecycleEventNameNetworkIdle
			err = p.WaitPageLifecycleEvent(act, outData, event)
		case ActionWaitLoad:
			event := proto.PageLifecycleEventNameLoad
			err = p.WaitPageLifecycleEvent(act, outData, event)
		case ActionWaitStable:
			err = p.WaitStable(act, outData)
		// NOTE(dwisiswant0): Mapping `ActionWaitLoad` to `Page.WaitStable`,
		// just in case waiting for the `proto.PageLifecycleEventNameLoad` event
		// doesn't meet expectations.
		// case ActionWaitLoad, ActionWaitStable:
		// 	err = p.WaitStable(act, outData)
		case ActionGetResource:
			err = p.GetResource(act, outData)
		case ActionExtract:
			err = p.ExtractElement(act, outData)
		case ActionWaitEvent:
			var waitFunc func() error
			waitFunc, err = p.WaitEvent(act, outData)
			if waitFunc != nil {
				waitFuncs = append(waitFuncs, waitFunc)
			}
		case ActionWaitDialog:
			err = p.HandleDialog(act, outData)
		case ActionFilesInput:
			if p.options.Options.AllowLocalFileAccess {
				err = p.FilesInput(act, outData)
			} else {
				err = ErrLFAccessDenied
			}
		case ActionAddHeader:
			err = p.ActionAddHeader(act, outData)
		case ActionSetHeader:
			err = p.ActionSetHeader(act, outData)
		case ActionDeleteHeader:
			err = p.ActionDeleteHeader(act, outData)
		case ActionSetBody:
			err = p.ActionSetBody(act, outData)
		case ActionSetMethod:
			err = p.ActionSetMethod(act, outData)
		case ActionKeyboard:
			err = p.KeyboardAction(act, outData)
		case ActionDebug:
			err = p.DebugAction(act, outData)
		case ActionSleep:
			err = p.SleepAction(act, outData)
		case ActionWaitVisible:
			err = p.WaitVisible(act, outData)
		default:
			continue
		}
		if err != nil {
			return nil, errors.Wrap(err, "error occurred executing action")
		}
	}
	return outData, nil
}

type rule struct {
	*sync.Once
	Action ActionType
	Part   string
	Args   map[string]string
}

// WaitVisible waits until an element appears.
func (p *Page) WaitVisible(act *Action, out ActionData) error {
	timeout, err := getTimeout(p, act)
	if err != nil {
		return errors.Wrap(err, "Wrong timeout given")
	}

	pollTime, err := getTimeParameter(p, act, "pollTime", 100, time.Millisecond)
	if err != nil {
		return errors.Wrap(err, "Wrong polling time given")
	}

	element, _ := p.Sleeper(pollTime, timeout).
		Timeout(timeout).
		pageElementBy(act.Data)

	if element != nil {
		if err := element.WaitVisible(); err != nil {
			return errors.Wrap(err, errElementDidNotAppear)
		}
	} else {
		return errors.New(errElementDidNotAppear)
	}

	return nil
}

func (p *Page) Sleeper(pollTimeout, timeout time.Duration) *Page {
	page := *p
	page.page = page.Page().Sleeper(func() utils.Sleeper {
		return createBackOffSleeper(pollTimeout, timeout)
	})
	return &page
}

func (p *Page) Timeout(timeout time.Duration) *Page {
	page := *p
	page.page = page.Page().Timeout(timeout)
	return &page
}

func createBackOffSleeper(pollTimeout, timeout time.Duration) utils.Sleeper {
	backoffSleeper := utils.BackoffSleeper(pollTimeout, timeout, func(duration time.Duration) time.Duration {
		return duration
	})

	return func(ctx context.Context) error {
		if ctx.Err() != nil {
			return ctx.Err()
		}

		return backoffSleeper(ctx)
	}
}

func getNavigationFunc(p *Page, act *Action, event proto.PageLifecycleEventName) (func(), error) {
	dur, err := getTimeout(p, act)
	if err != nil {
		return nil, errors.Wrap(err, "Wrong timeout given")
	}

	fn := p.page.Timeout(dur).WaitNavigation(event)

	return fn, nil
}

func getTimeout(p *Page, act *Action) (time.Duration, error) {
	return getTimeParameter(p, act, "timeout", 5, time.Second)
}

// getTimeParameter returns a time parameter from an action. It first tries to
// get the parameter as an integer, then as a time.Duration, and finally falls
// back to the default value (multiplied by the unit).
func getTimeParameter(p *Page, act *Action, argName string, defaultValue, unit time.Duration) (time.Duration, error) {
	argValue, err := p.getActionArg(act, argName)
	if err != nil {
		return time.Duration(0), err
	}

	convertedValue, err := strconv.Atoi(argValue)
	if err == nil {
		return time.Duration(convertedValue) * unit, nil
	}

	// fallback to time.ParseDuration
	parsedTimeValue, err := time.ParseDuration(argValue)
	if err == nil {
		return parsedTimeValue, nil
	}

	return defaultValue * unit, nil
}

// ActionAddHeader executes a AddHeader action.
func (p *Page) ActionAddHeader(act *Action, out ActionData) error {
	args := make(map[string]string)

	part, err := p.getActionArg(act, "part")
	if err != nil {
		return err
	}

	args["key"], err = p.getActionArg(act, "key")
	if err != nil {
		return err
	}

	args["value"], err = p.getActionArg(act, "value")
	if err != nil {
		return err
	}

	p.rules = append(p.rules, rule{
		Action: ActionAddHeader,
		Part:   part,
		Args:   args,
	})

	return nil
}

// ActionSetHeader executes a SetHeader action.
func (p *Page) ActionSetHeader(act *Action, out ActionData) error {
	args := make(map[string]string)

	part, err := p.getActionArg(act, "part")
	if err != nil {
		return err
	}

	args["key"], err = p.getActionArg(act, "key")
	if err != nil {
		return err
	}

	args["value"], err = p.getActionArg(act, "value")
	if err != nil {
		return err
	}

	p.rules = append(p.rules, rule{
		Action: ActionSetHeader,
		Part:   part,
		Args:   args,
	})

	return nil
}

// ActionDeleteHeader executes a DeleteHeader action.
func (p *Page) ActionDeleteHeader(act *Action, out ActionData) error {
	args := make(map[string]string)

	part, err := p.getActionArg(act, "part")
	if err != nil {
		return err
	}

	args["key"], err = p.getActionArg(act, "key")
	if err != nil {
		return err
	}

	p.rules = append(p.rules, rule{
		Action: ActionDeleteHeader,
		Part:   part,
		Args:   args,
	})

	return nil
}

// ActionSetBody executes a SetBody action.
func (p *Page) ActionSetBody(act *Action, out ActionData) error {
	args := make(map[string]string)

	part, err := p.getActionArg(act, "part")
	if err != nil {
		return err
	}

	args["body"], err = p.getActionArg(act, "body")
	if err != nil {
		return err
	}

	p.rules = append(p.rules, rule{
		Action: ActionSetBody,
		Part:   part,
		Args:   args,
	})

	return nil
}

// ActionSetMethod executes an SetMethod action.
func (p *Page) ActionSetMethod(act *Action, out ActionData) error {
	args := make(map[string]string)

	part, err := p.getActionArg(act, "part")
	if err != nil {
		return err
	}

	args["method"], err = p.getActionArg(act, "method")
	if err != nil {
		return err
	}

	p.rules = append(p.rules, rule{
		Action: ActionSetMethod,
		Part:   part,
		Args:   args,
		Once:   &sync.Once{},
	})

	return nil
}

// NavigateURL executes an ActionLoadURL actions loading a URL for the page.
func (p *Page) NavigateURL(action *Action, out ActionData) error {
	url, err := p.getActionArg(action, "url")
	if err != nil {
		return err
	}

	if url == "" {
		return errinvalidArguments
	}

	parsedURL, err := urlutil.ParseURL(url, true)
	if err != nil {
		return errkit.Newf("failed to parse url %v while creating http request", url)
	}

	// ===== parameter automerge =====
	// while merging parameters first preference is given to target params
	finalparams := parsedURL.Params.Clone()
	finalparams.Merge(p.inputURL.Params.Encode())
	parsedURL.Params = finalparams

	if err := p.page.Navigate(parsedURL.String()); err != nil {
		return errkit.Wrapf(err, "could not navigate to url %s", parsedURL.String())
	}

	p.updateLastNavigatedURL()

	return nil
}

// RunScript runs a script on the loaded page
func (p *Page) RunScript(act *Action, out ActionData) error {
	code, err := p.getActionArg(act, "code")
	if err != nil {
		return err
	}

	if code == "" {
		return errinvalidArguments
	}

	hook, err := p.getActionArg(act, "hook")
	if err != nil {
		return err
	}

	if hook == "true" {
		if _, err := p.page.EvalOnNewDocument(code); err != nil {
			return err
		}
	}

	data, err := p.page.Eval(code)
	if err != nil {
		return err
	}

	if data != nil && act.Name != "" {
		out[act.Name] = data.Value.String()
	}

	return nil
}

// ClickElement executes click actions for an element.
func (p *Page) ClickElement(act *Action, out ActionData) error {
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}
	if err = element.Click(proto.InputMouseButtonLeft, 1); err != nil {
		return errors.Wrap(err, "could not click element")
	}
	return nil
}

// KeyboardAction executes a keyboard action on the page.
func (p *Page) KeyboardAction(act *Action, out ActionData) error {
	keys, err := p.getActionArg(act, "keys")
	if err != nil {
		return err
	}

	return p.page.Keyboard.Type([]input.Key(keys)...)
}

// RightClickElement executes right click actions for an element.
func (p *Page) RightClickElement(act *Action, out ActionData) error {
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}
	if err = element.Click(proto.InputMouseButtonRight, 1); err != nil {
		return errors.Wrap(err, "could not right click element")
	}
	return nil
}

// Screenshot executes screenshot action on a page
func (p *Page) Screenshot(act *Action, out ActionData) error {
	to, err := p.getActionArg(act, "to")
	if err != nil {
		return err
	}

	if to == "" {
		to = ksuid.New().String()
		if act.Name != "" {
			out[act.Name] = to
		}
	}

	var data []byte

	fullpage, err := p.getActionArg(act, "fullpage")
	if err != nil {
		return err
	}

	if fullpage == "true" {
		data, err = p.page.Screenshot(true, &proto.PageCaptureScreenshot{})
	} else {
		data, err = p.page.Screenshot(false, &proto.PageCaptureScreenshot{})
	}
	if err != nil {
		return errors.Wrap(err, "could not take screenshot")
	}

	to, err = fileutil.CleanPath(to)
	if err != nil {
		return errkit.Newf("could not clean output screenshot path %s", to)
	}

	// allow if targetPath is child of current working directory
	if !protocolstate.IsLfaAllowed(p.options.Options) {
		cwd, err := os.Getwd()
		if err != nil {
			return errkit.Wrap(err, "could not get current working directory")
		}

		if !strings.HasPrefix(to, cwd) {
			// writing outside of cwd requires -lfa flag
			return ErrLFAccessDenied
		}
	}

	mkdir, err := p.getActionArg(act, "mkdir")
	if err != nil {
		return err
	}

	// edgecase create directory if mkdir=true and path contains directory
	if mkdir == "true" && stringsutil.ContainsAny(to, folderutil.UnixPathSeparator, folderutil.WindowsPathSeparator) {
		// creates new directory if needed based on path `to`
		// TODO: replace all permission bits with fileutil constants (https://github.com/projectdiscovery/utils/issues/113)
		if err := os.MkdirAll(filepath.Dir(to), 0700); err != nil {
			return errkit.Wrap(err, "failed to create directory while writing screenshot")
		}
	}

	// actual file path to write
	filePath := to
	if !strings.HasSuffix(filePath, ".png") {
		filePath += ".png"
	}

	if fileutil.FileExists(filePath) {
		// return custom error as overwriting files is not supported
		return errkit.Newf("failed to write screenshot, file %v already exists", filePath)
	}
	err = os.WriteFile(filePath, data, 0540)
	if err != nil {
		return errors.Wrap(err, "could not write screenshot")
	}
	gologger.Info().Msgf("Screenshot successfully saved at %v\n", filePath)
	return nil
}

// InputElement executes input element actions for an element.
func (p *Page) InputElement(act *Action, out ActionData) error {
	value, err := p.getActionArg(act, "value")
	if err != nil {
		return err
	}
	if value == "" {
		return errinvalidArguments
	}
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}
	if err = element.Input(value); err != nil {
		return errors.Wrap(err, "could not input element")
	}
	return nil
}

// TimeInputElement executes time input on an element
func (p *Page) TimeInputElement(act *Action, out ActionData) error {
	value, err := p.getActionArg(act, "value")
	if err != nil {
		return err
	}
	if value == "" {
		return errinvalidArguments
	}
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}
	t, err := time.Parse(time.RFC3339, value)
	if err != nil {
		return errors.Wrap(err, "could not parse time")
	}
	if err := element.InputTime(t); err != nil {
		return errors.Wrap(err, "could not input element")
	}
	return nil
}

// SelectInputElement executes select input statement action on a element
func (p *Page) SelectInputElement(act *Action, out ActionData) error {
	value, err := p.getActionArg(act, "value")
	if err != nil {
		return err
	}
	if value == "" {
		return errinvalidArguments
	}
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}

	var selectedBool bool

	selected, err := p.getActionArg(act, "selected")
	if err != nil {
		return err
	}

	if selected == "true" {
		selectedBool = true
	}

	selector, err := p.getActionArg(act, "selector")
	if err != nil {
		return err
	}

	if err := element.Select([]string{value}, selectedBool, selectorBy(selector)); err != nil {
		return errors.Wrap(err, "could not select input")
	}

	return nil
}

// WaitPageLifecycleEvent waits for specified page lifecycle event name
func (p *Page) WaitPageLifecycleEvent(act *Action, out ActionData, event proto.PageLifecycleEventName) error {
	fn, err := getNavigationFunc(p, act, event)
	if err != nil {
		return err
	}

	fn()

	// log the navigated request (even if it is a redirect)
	p.updateLastNavigatedURL()

	return nil
}

// WaitStable waits until the page is stable
func (p *Page) WaitStable(act *Action, out ActionData) error {
	dur := time.Second // default stable page duration: 1s

	timeout, err := getTimeout(p, act)
	if err != nil {
		return errors.Wrap(err, "Wrong timeout given")
	}

	argDur := act.Data["duration"]
	if argDur != "" {
		dur, err = time.ParseDuration(argDur)
		if err != nil {
			dur = time.Second
		}
	}

	if err := p.page.Timeout(timeout).WaitStable(dur); err != nil {
		return err
	}

	// log the navigated request (even if it is a redirect)
	p.updateLastNavigatedURL()

	return nil
}

// GetResource gets a resource from an element from page.
func (p *Page) GetResource(act *Action, out ActionData) error {
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}
	resource, err := element.Resource()
	if err != nil {
		return errors.Wrap(err, "could not get src for element")
	}
	if act.Name != "" {
		out[act.Name] = string(resource)
	}
	return nil
}

// FilesInput acts with a file input element on page
func (p *Page) FilesInput(act *Action, out ActionData) error {
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}

	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}

	value, err := p.getActionArg(act, "value")
	if err != nil {
		return err
	}
	filesPaths := strings.Split(value, ",")

	if err := element.SetFiles(filesPaths); err != nil {
		return errors.Wrap(err, "could not set files")
	}

	return nil
}

// ExtractElement extracts from an element on the page.
func (p *Page) ExtractElement(act *Action, out ActionData) error {
	element, err := p.pageElementBy(act.Data)
	if err != nil {
		return errors.Wrap(err, errCouldNotGetElement)
	}

	if err = element.ScrollIntoView(); err != nil {
		return errors.Wrap(err, errCouldNotScroll)
	}

	target, err := p.getActionArg(act, "target")
	if err != nil {
		return err
	}

	switch target {
	case "attribute":
		attribute, err := p.getActionArg(act, "attribute")
		if err != nil {
			return err
		}

		if attribute == "" {
			return errors.New("attribute can't be empty")
		}

		attrValue, err := element.Attribute(attribute)
		if err != nil {
			return errors.Wrap(err, "could not get attribute")
		}

		if act.Name != "" {
			out[act.Name] = *attrValue
		}
	default:
		text, err := element.Text()
		if err != nil {
			return errors.Wrap(err, "could not get element text node")
		}

		if act.Name != "" {
			out[act.Name] = text
		}
	}
	return nil
}

// WaitEvent waits for an event to happen on the page.
func (p *Page) WaitEvent(act *Action, out ActionData) (func() error, error) {
	event, err := p.getActionArg(act, "event")
	if err != nil {
		return nil, err
	}

	if event == "" {
		return nil, errors.New("event not recognized")
	}

	var waitEvent proto.Event

	gotType := proto.GetType(event)
	if gotType == nil {
		return nil, errkit.Newf("event %q does not exist", event)
	}

	tmp, ok := reflect.New(gotType).Interface().(proto.Event)
	if !ok {
		return nil, errkit.Newf("event %q is not a page event", event)
	}

	waitEvent = tmp

	// allow user to specify max-duration for wait-event
	maxDuration, err := getTimeParameter(p, act, "max-duration", 5, time.Second)
	if err != nil {
		return nil, err
	}

	// Just wait the event to happen
	waitFunc := func() (err error) {
		// execute actual wait event
		ctx, cancel := context.WithTimeoutCause(context.Background(), maxDuration, ErrActionExecDealine)
		defer cancel()

		err = contextutil.ExecFunc(ctx, p.page.WaitEvent(waitEvent))

		return
	}

	return waitFunc, nil
}

// HandleDialog handles JavaScript dialog (alert, confirm, prompt, or onbeforeunload).
func (p *Page) HandleDialog(act *Action, out ActionData) error {
	maxDuration, err := getTimeParameter(p, act, "max-duration", 10, time.Second)
	if err != nil {
		return err
	}

	ctx, cancel := context.WithTimeout(context.Background(), maxDuration)
	defer cancel()

	wait, handle := p.page.HandleDialog()
	fn := func() (*proto.PageJavascriptDialogOpening, error) {
		dialog := wait()
		err := handle(&proto.PageHandleJavaScriptDialog{
			Accept:     true,
			PromptText: "",
		})

		return dialog, err
	}

	dialog, err := contextutil.ExecFuncWithTwoReturns(ctx, fn)
	if err == nil && act.Name != "" {
		out[act.Name] = true
		out[act.Name+"_type"] = string(dialog.Type)
		out[act.Name+"_message"] = dialog.Message
	}

	return nil
}

// pageElementBy returns a page element from a variety of inputs.
//
// Supported values for by: r -> selector & regex, x -> xpath, js -> eval js,
// search => query, default ("") => selector.
func (p *Page) pageElementBy(data map[string]string) (*rod.Element, error) {
	by, ok := data["by"]
	if !ok {
		by = ""
	}
	page := p.page

	switch by {
	case "r", "regex":
		return page.ElementR(data["selector"], data["regex"])
	case "x", "xpath":
		return page.ElementX(data["xpath"])
	case "js":
		return page.ElementByJS(&rod.EvalOptions{JS: data["js"]})
	case "search":
		elms, err := page.Search(data["query"])
		if err != nil {
			return nil, err
		}

		if elms.First != nil {
			return elms.First, nil
		}
		return nil, errors.New("no such element")
	default:
		return page.Element(data["selector"])
	}
}

// DebugAction enables debug action on a page.
func (p *Page) DebugAction(act *Action, out ActionData) error {
	p.instance.browser.engine.SlowMotion(5 * time.Second)
	p.instance.browser.engine.Trace(true)
	return nil
}

// SleepAction sleeps on the page for a specified duration
func (p *Page) SleepAction(act *Action, out ActionData) error {
	duration, err := getTimeParameter(p, act, "duration", 5, time.Second)
	if err != nil {
		return err
	}

	time.Sleep(duration)

	return nil
}

// selectorBy returns a selector from a representation.
func selectorBy(selector string) rod.SelectorType {
	switch selector {
	case "r":
		return rod.SelectorTypeRegex
	case "css":
		return rod.SelectorTypeCSSSector
	case "regex":
		return rod.SelectorTypeRegex
	default:
		return rod.SelectorTypeText
	}
}

func (p *Page) getActionArg(action *Action, arg string) (string, error) {
	var err error

	argValue := action.GetArg(arg)

	if p.instance.interactsh != nil {
		var interactshURLs []string
		argValue, interactshURLs = p.instance.interactsh.Replace(argValue, p.InteractshURLs)
		p.addInteractshURL(interactshURLs...)
	}

	exprs := getExpressions(argValue, p.variables)

	err = expressions.ContainsUnresolvedVariables(exprs...)
	if err != nil {
		return "", errkit.Wrapf(err, "argument %q, value: %q", arg, argValue)
	}

	argValue, err = expressions.Evaluate(argValue, p.variables)
	if err != nil {
		return "", fmt.Errorf("could not get value for argument %q: %s", arg, err)
	}

	return argValue, nil
}