add node version endpoint (#505)

Co-authored-by: Lazy Nina <>

routes/exchange.go

@@ -31,6 +31,8 @@ var (
 	IsBlacklisted = []byte{1}
 )
 
+const NodeVersion = "3.4.4"
+
 const (
 	// RoutePathAPIBase ...
 	RoutePathAPIBase = "/api/v1"
@@ -46,6 +48,8 @@ const (
 	RoutePathAPINodeInfo = "/api/v1/node-info"
 	// RoutePathAPIBlock ...
 	RoutePathAPIBlock = "/api/v1/block"
+	// RoutePathAPINodeVersion ...
+	RoutePathAPINodeVersion = "/api/v1/node-version"
 )
 
 // APIRoutes returns the routes for the public-facing API.
@@ -100,6 +104,13 @@ func (fes *APIServer) APIRoutes() []Route {
 			fes.APIBlock,
 			PublicAccess,
 		},
+		{
+			"APINodeVersion",
+			[]string{"GET"},
+			RoutePathAPINodeVersion,
+			fes.APINodeVersion,
+			PublicAccess,
+		},
 	}
 
 	return APIRoutes
@@ -1373,6 +1384,21 @@ func (fes *APIServer) APIBlock(ww http.ResponseWriter, rr *http.Request) {
 	}
 }
 
+type APINodeVersionResponse struct {
+	Version string
+}
+
+// APINodeVersion returns the version of the node.
+func (fes *APIServer) APINodeVersion(ww http.ResponseWriter, rr *http.Request) {
+	if err := json.NewEncoder(ww).Encode(&APINodeVersionResponse{
+		Version: NodeVersion,
+	}); err != nil {
+		APIAddError(ww, fmt.Sprintf("APINodeVersion: Problem encoding response "+
+			"as JSON: %v", err))
+		return
+	}
+}
+
 // TODO: This is a somewhat redundant version of processTransaction It exists
 // because the API needed to cut out the derivation of the public key from the
 // user object, among other things.