feat(extension): expose request mutation methods on task.meta.req (#1538)

pkg/download/extension_task_request.go

@@ -0,0 +1,140 @@
+package download
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/GopeedLab/gopeed/pkg/base"
+	btProtocol "github.com/GopeedLab/gopeed/pkg/protocol/bt"
+	httpProtocol "github.com/GopeedLab/gopeed/pkg/protocol/http"
+	"github.com/GopeedLab/gopeed/pkg/util"
+	"github.com/dop251/goja"
+)
+
+// ExtensionTaskRequest exposes request operations without exposing the backing task.
+// It always reads the current request so a retained handle sees subsequent updates.
+type ExtensionTaskRequest struct {
+	*base.Request
+	task *Task
+}
+
+// SetUrl replaces the task request URL.
+func (r *ExtensionTaskRequest) SetUrl(url string) { r.task.Meta.Req.URL = url }
+
+// SetLabels replaces all labels on the request.
+func (r *ExtensionTaskRequest) SetLabels(labels map[string]string) {
+	r.Labels = labels
+}
+
+// PutLabel sets a label on the request.
+func (r *ExtensionTaskRequest) PutLabel(key, value string) {
+	if r.Labels == nil {
+		r.Labels = make(map[string]string)
+	}
+	r.Labels[key] = value
+}
+
+// DelLabel deletes a label from the request.
+func (r *ExtensionTaskRequest) DelLabel(key string) {
+	delete(r.Labels, key)
+}
+
+// mutateTaskExtra converts into an independent protocol value before mutation.
+// Other protocols are a no-op. Failed conversion or mutation must not change the live request.
+func mutateTaskExtra[E any](task *Task, protocol string, mutate func(*E) error) error {
+	if task.Protocol != protocol {
+		return nil
+	}
+	if task.Meta == nil || task.Meta.Req == nil {
+		return fmt.Errorf("task request is missing")
+	}
+	var extra E
+	if err := util.MapToStruct(task.Meta.Req.Extra, &extra); err != nil {
+		return err
+	}
+	if err := mutate(&extra); err != nil {
+		return err
+	}
+	task.Meta.Req.Extra = &extra
+	return nil
+}
+
+func (t *ExtensionTaskRequest) SetMethod(method string) error {
+	return mutateTaskExtra(t.task, "http", func(extra *httpProtocol.ReqExtra) error { extra.Method = method; return nil })
+}
+
+func (t *ExtensionTaskRequest) SetBody(body string) error {
+	return mutateTaskExtra(t.task, "http", func(extra *httpProtocol.ReqExtra) error { extra.Body = body; return nil })
+}
+
+// decodeHeaders omits undefined properties and rejects non-string values.
+func decodeHeaders(value *goja.Object) (map[string]string, error) {
+	if value == nil {
+		return nil, fmt.Errorf("headers must be an object")
+	}
+	data, err := value.MarshalJSON()
+	if err != nil {
+		return nil, err
+	}
+	var input map[string]*string
+	if err := json.Unmarshal(data, &input); err != nil {
+		return nil, err
+	}
+	if input == nil {
+		return nil, fmt.Errorf("headers must be an object")
+	}
+	headers := make(map[string]string, len(input))
+	seen := make(map[string]bool, len(input))
+	for name, value := range input {
+		if value == nil {
+			return nil, fmt.Errorf("header %q must be a string", name)
+		}
+		lower := strings.ToLower(name)
+		if seen[lower] {
+			return nil, fmt.Errorf("duplicate header name %q", name)
+		}
+		seen[lower] = true
+		headers[http.CanonicalHeaderKey(name)] = *value
+	}
+	return headers, nil
+}
+
+func (t *ExtensionTaskRequest) SetHeaders(headers *goja.Object) error {
+	return mutateTaskExtra(t.task, "http", func(extra *httpProtocol.ReqExtra) error {
+		values, err := decodeHeaders(headers)
+		if err != nil {
+			return err
+		}
+		extra.Header = values
+		return nil
+	})
+}
+
+func (t *ExtensionTaskRequest) PutHeader(name, value string) error {
+	return mutateTaskExtra(t.task, "http", func(extra *httpProtocol.ReqExtra) error {
+		if extra.Header == nil {
+			extra.Header = make(map[string]string)
+		}
+		deleteHeader(extra.Header, name)
+		extra.Header[http.CanonicalHeaderKey(name)] = value
+		return nil
+	})
+}
+
+func (t *ExtensionTaskRequest) DelHeader(name string) error {
+	return mutateTaskExtra(t.task, "http", func(extra *httpProtocol.ReqExtra) error { deleteHeader(extra.Header, name); return nil })
+}
+
+func deleteHeader(headers map[string]string, name string) {
+	for key := range headers {
+		if strings.EqualFold(key, name) {
+			delete(headers, key)
+		}
+	}
+}
+
+func (t *ExtensionTaskRequest) SetTrackers(trackers []string) error {
+	return mutateTaskExtra(t.task, "bt", func(extra *btProtocol.ReqExtra) error { extra.Trackers = append([]string{}, trackers...); return nil })
+}