feat: improve extension engine (#298)

1. support onError event
2. add built-in MessageError

pkg/download/downloader.go

@@ -225,7 +225,10 @@ func (d *Downloader) Resolve(req *base.Request) (rr *ResolveResult, err error) {
 		return
 	}
 
-	res := d.triggerOnResolve(req)
+	res, err := d.triggerOnResolve(req)
+	if err != nil {
+		return
+	}
 	if res != nil && len(res.Files) > 0 {
 		rr = &ResolveResult{
 			Res: res,
@@ -525,9 +528,6 @@ func (d *Downloader) emit(eventKey EventKey, task *Task, errs ...error) {
 			Task: task,
 			Err:  err,
 		})
-		if eventKey == EventKeyError {
-			d.emit(EventKeyFinally, task, err)
-		}
 	}
 }
 
@@ -572,27 +572,36 @@ func (d *Downloader) getProtocolConfig(name string, v any) bool {
 func (d *Downloader) watch(task *Task) {
 	err := task.fetcher.Wait()
 	if err != nil {
-		task.updateStatus(base.DownloadStatusError)
-		d.storage.Put(bucketTask, task.ID, task.clone())
+		d.doOnError(task, err)
+		return
+	}
+	task.Progress.Used = task.timer.Used()
+	if task.Meta.Res.Size == 0 {
+		task.Meta.Res.Size = task.fetcher.Progress().TotalDownloaded()
+	}
+	used := task.Progress.Used / int64(time.Second)
+	if used == 0 {
+		used = 1
+	}
+	totalSize := task.Meta.Res.Size
+	task.Progress.Speed = totalSize / used
+	task.Progress.Downloaded = totalSize
+	task.updateStatus(base.DownloadStatusDone)
+	d.storage.Put(bucketTask, task.ID, task.clone())
+	d.emit(EventKeyDone, task)
+	d.emit(EventKeyFinally, task, err)
+	d.notifyRunning()
+}
+
+func (d *Downloader) doOnError(task *Task, err error) {
+	d.Logger.Warn().Err(err).Msgf("task download failed, task id: %s", task.ID)
+	task.updateStatus(base.DownloadStatusError)
+	d.triggerOnError(task, err)
+	if task.Status == base.DownloadStatusError {
 		d.emit(EventKeyError, task, err)
-	} else {
-		task.Progress.Used = task.timer.Used()
-		if task.Meta.Res.Size == 0 {
-			task.Meta.Res.Size = task.fetcher.Progress().TotalDownloaded()
-		}
-		used := task.Progress.Used / int64(time.Second)
-		if used == 0 {
-			used = 1
-		}
-		totalSize := task.Meta.Res.Size
-		task.Progress.Speed = totalSize / used
-		task.Progress.Downloaded = totalSize
-		task.updateStatus(base.DownloadStatusDone)
-		d.storage.Put(bucketTask, task.ID, task.clone())
-		d.emit(EventKeyDone, task)
 		d.emit(EventKeyFinally, task, err)
+		d.notifyRunning()
 	}
-	d.notifyRunning()
 }
 
 func (d *Downloader) restoreFetcher(task *Task) error {
@@ -697,26 +706,18 @@ func (d *Downloader) doStart(task *Task) (err error) {
 		}
 	}
 
-	cloneTask := task.clone()
 	isCreate := task.Status == base.DownloadStatusReady
-	task.updateStatus(base.DownloadStatusRunning)
 
 	doStart := func() error {
 		task.lock.Lock()
 		defer task.lock.Unlock()
 
-		req := d.triggerOnStart(cloneTask)
-		if req != nil {
-			task.Meta.Req = req
-			task.fetcher.Meta().Req = req
-		}
+		d.triggerOnStart(task)
+		task.updateStatus(base.DownloadStatusRunning)
 
 		if task.Meta.Res == nil {
 			err := task.fetcher.Resolve(task.Meta.Req)
 			if err != nil {
-				task.updateStatus(base.DownloadStatusError)
-				d.storage.Put(bucketTask, task.ID, task.clone())
-				d.emit(EventKeyError, task, err)
 				return err
 			}
 			task.Meta.Res = task.fetcher.Meta().Res
@@ -762,7 +763,7 @@ func (d *Downloader) doStart(task *Task) (err error) {
 	go func() {
 		err := doStart()
 		if err != nil {
-			d.Logger.Error().Stack().Err(err).Msgf("start task failed, task id: %s", task.ID)
+			d.doOnError(task, err)
 		}
 	}()
 

pkg/download/engine/engine.go

@@ -3,6 +3,7 @@ package engine
 import (
 	_ "embed"
 	"errors"
+	gojaerror "github.com/GopeedLab/gopeed/pkg/download/engine/inject/error"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/file"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/formdata"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/vm"
@@ -125,6 +126,9 @@ func NewEngine(cfg *Config) *Engine {
 		runtime.SetFieldNameMapper(goja.TagFieldNameMapper("json", true))
 		vm.Enable(runtime)
 		gojaurl.Enable(runtime)
+		if err := gojaerror.Enable(runtime); err != nil {
+			return
+		}
 		if err := file.Enable(runtime); err != nil {
 			return
 		}
@@ -167,7 +171,11 @@ func resolveResult(value goja.Value) (any, error) {
 		case goja.PromiseStateFulfilled:
 			return p.Result().Export(), nil
 		case goja.PromiseStateRejected:
-			return nil, errors.New(p.Result().String())
+			if err, ok := p.Result().Export().(error); ok {
+				return nil, err
+			} else {
+				return nil, errors.New(p.Result().String())
+			}
 		}
 	}
 	return export, nil

pkg/download/engine/engine_test.go

@@ -7,7 +7,9 @@ import (
 	"errors"
 	"fmt"
 	"github.com/GopeedLab/gopeed/internal/test"
+	gojaerror "github.com/GopeedLab/gopeed/pkg/download/engine/inject/error"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/file"
+	gojautil "github.com/GopeedLab/gopeed/pkg/download/engine/util"
 	"github.com/GopeedLab/gopeed/pkg/util"
 	"github.com/dop251/goja"
 	"io"
@@ -20,13 +22,24 @@ import (
 )
 
 func TestPolyfill(t *testing.T) {
+	doTestPolyfill(t, "MessageError")
 	doTestPolyfill(t, "XMLHttpRequest")
 	doTestPolyfill(t, "Blob")
 	doTestPolyfill(t, "FormData")
 	doTestPolyfill(t, "fetch")
 	doTestPolyfill(t, "__gopeed_create_vm")
 }
 
+func TestError(t *testing.T) {
+	engine := NewEngine(nil)
+	_, err := engine.RunString(`
+      throw new MessageError('test');
+	`)
+	if me, ok := gojautil.AssertError[*gojaerror.MessageError](err); !ok {
+		t.Fatalf("expect MessageError, but got %v", me)
+	}
+}
+
 func TestFetch(t *testing.T) {
 	server := startServer()
 	defer server.Close()

pkg/download/engine/inject/error/module.go

@@ -0,0 +1,29 @@
+package error
+
+import (
+	"github.com/dop251/goja"
+)
+
+type MessageError struct {
+	Message string `json:"message"`
+}
+
+func (e *MessageError) Error() string {
+	return e.Message
+}
+
+func Enable(runtime *goja.Runtime) error {
+	messageError := runtime.ToValue(func(call goja.ConstructorCall) *goja.Object {
+		var message string
+		if len(call.Arguments) > 0 {
+			message = call.Arguments[0].String()
+		}
+		instance := &MessageError{
+			Message: message,
+		}
+		instanceValue := runtime.ToValue(instance).(*goja.Object)
+		instanceValue.SetPrototype(call.This.Prototype())
+		return instanceValue
+	})
+	return runtime.Set("MessageError", messageError)
+}

pkg/download/engine/inject/xhr/module.go

@@ -2,9 +2,9 @@ package xhr
 
 import (
 	"bytes"
-	"github.com/GopeedLab/gopeed/pkg/download/engine/inject"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/file"
 	"github.com/GopeedLab/gopeed/pkg/download/engine/inject/formdata"
+	"github.com/GopeedLab/gopeed/pkg/download/engine/util"
 	"github.com/dop251/goja"
 	"io"
 	"mime/multipart"
@@ -316,7 +316,7 @@ func (xhr *XMLHttpRequest) parseData(data goja.Value) any {
 func Enable(runtime *goja.Runtime, proxyUrl *url.URL) error {
 	progressEvent := runtime.ToValue(func(call goja.ConstructorCall) *goja.Object {
 		if len(call.Arguments) < 1 {
-			inject.ThrowTypeError(runtime, "Failed to construct 'ProgressEvent': 1 argument required, but only 0 present.")
+			util.ThrowTypeError(runtime, "Failed to construct 'ProgressEvent': 1 argument required, but only 0 present.")
 		}
 		instance := &ProgressEvent{
 			Type: call.Argument(0).String(),

pkg/download/engine/util/util.go

@@ -0,0 +1,24 @@
+package util
+
+import (
+	"github.com/dop251/goja"
+)
+
+func ThrowTypeError(vm *goja.Runtime, msg string) {
+	panic(vm.NewTypeError(msg))
+}
+
+func AssertError[T error](err error) (t T, r bool) {
+	if err == nil {
+		return
+	}
+	if e, ok := err.(T); ok {
+		return e, true
+	}
+	if e, ok := err.(*goja.Exception); ok {
+		if ee, okk := e.Value().Export().(T); okk {
+			return ee, true
+		}
+	}
+	return
+}