chore: add aria2 rpc package

pkg/aria2/rpc/notification.go

@@ -0,0 +1,44 @@
+package rpc
+
+import (
+	log "github.com/sirupsen/logrus"
+)
+
+type Event struct {
+	Gid string `json:"gid"` // GID of the download
+}
+
+// The RPC server might send notifications to the client.
+// Notifications is unidirectional, therefore the client which receives the notification must not respond to it.
+// The method signature of a notification is much like a normal method request but lacks the id key
+
+type websocketResponse struct {
+	clientResponse
+	Method string  `json:"method"`
+	Params []Event `json:"params"`
+}
+
+// Notifier handles rpc notification from aria2 server
+type Notifier interface {
+	// OnDownloadStart will be sent when a download is started.
+	OnDownloadStart([]Event)
+	// OnDownloadPause will be sent when a download is paused.
+	OnDownloadPause([]Event)
+	// OnDownloadStop will be sent when a download is stopped by the user.
+	OnDownloadStop([]Event)
+	// OnDownloadComplete will be sent when a download is complete. For BitTorrent downloads, this notification is sent when the download is complete and seeding is over.
+	OnDownloadComplete([]Event)
+	// OnDownloadError will be sent when a download is stopped due to an error.
+	OnDownloadError([]Event)
+	// OnBtDownloadComplete will be sent when a torrent download is complete but seeding is still going on.
+	OnBtDownloadComplete([]Event)
+}
+
+type DummyNotifier struct{}
+
+func (DummyNotifier) OnDownloadStart(events []Event)      { log.Printf("%s started.", events) }
+func (DummyNotifier) OnDownloadPause(events []Event)      { log.Printf("%s paused.", events) }
+func (DummyNotifier) OnDownloadStop(events []Event)       { log.Printf("%s stopped.", events) }
+func (DummyNotifier) OnDownloadComplete(events []Event)   { log.Printf("%s completed.", events) }
+func (DummyNotifier) OnDownloadError(events []Event)      { log.Printf("%s error.", events) }
+func (DummyNotifier) OnBtDownloadComplete(events []Event) { log.Printf("bt %s completed.", events) }