first draft of network crawler

rpc/core_client/ws_client.go

@@ -0,0 +1,47 @@
+package core_client
+
+import (
+	"github.com/gorilla/websocket"
+	"github.com/tendermint/tendermint/rpc"
+	"net/http"
+)
+
+// A websocket client subscribes and unsubscribes to events
+type WSClient struct {
+	host string
+	conn *websocket.Conn
+}
+
+// create a new connection
+func NewWSClient(addr string) *WSClient {
+	return &WSClient{
+		host: addr,
+	}
+}
+
+func (wsc *WSClient) Dial() error {
+	dialer := websocket.DefaultDialer
+	rHeader := http.Header{}
+	conn, _, err := dialer.Dial(wsc.host, rHeader)
+	if err != nil {
+		return err
+	}
+	wsc.conn = conn
+	return nil
+}
+
+// subscribe to an event
+func (wsc *WSClient) Subscribe(eventid string) error {
+	return wsc.conn.WriteJSON(rpc.WSRequest{
+		Type:  "subscribe",
+		Event: eventid,
+	})
+}
+
+// unsubscribe from an event
+func (wsc *WSClient) Unsubscribe(eventid string) error {
+	return wsc.conn.WriteJSON(rpc.WSRequest{
+		Type:  "unsubscribe",
+		Event: eventid,
+	})
+}