1 files changed, 64 insertions, 0 deletions
diff --git a/eth/downloader/api.go b/eth/downloader/api.go
new file mode 100644
index 000000000..9deff22a1
--- /dev/null
+++ b/eth/downloader/api.go
@@ -0,0 +1,64 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package downloader
+
+import (
+	rpc "github.com/ethereum/go-ethereum/rpc/v2"
+)
+
+// PublicDownloaderAPI provides an API which gives informatoin about the current synchronisation status.
+// It offers only methods that operates on data that can be available to anyone without security risks.
+type PublicDownloaderAPI struct {
+	d *Downloader
+}
+
+// NewPublicDownloaderAPI create a new PublicDownloaderAPI.
+func NewPublicDownloaderAPI(d *Downloader) *PublicDownloaderAPI {
+	return &PublicDownloaderAPI{d}
+}
+
+// Progress gives progress indications when the node is synchronising with the Ethereum network.
+type Progress struct {
+	Origin  uint64 `json:"startingBlock"`
+	Current uint64 `json:"currentBlock"`
+	Height  uint64 `json:"highestBlock"`
+}
+
+// SyncingResult provides information about the current synchronisation status for this node.
+type SyncingResult struct {
+	Syncing bool     `json:"syncing"`
+	Status  Progress `json:"status"`
+}
+
+// Syncing provides information when this nodes starts synchronising with the Ethereumn network and when it's finished.
+func (s *PublicDownloaderAPI) Syncing() (rpc.Subscription, error) {
+	sub := s.d.mux.Subscribe(StartEvent{}, DoneEvent{}, FailedEvent{})
+
+	output := func(event interface{}) interface{} {
+		switch event.(type) {
+		case StartEvent:
+			result := &SyncingResult{Syncing: true}
+			result.Status.Origin, result.Status.Current, result.Status.Height = s.d.Progress()
+			return result
+		case DoneEvent, FailedEvent:
+			return false
+		}
+		return nil
+	}
+
+	return rpc.NewSubscriptionWithOutputFormat(sub, output), nil
+}