Add websocket example

code/websocket-example.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"path/filepath"
+	"time"
+
+	"github.com/conformal/btcrpcclient"
+	"github.com/conformal/btcutil"
+	"github.com/conformal/btcwire"
+)
+
+// This example demonstrates a connection to the bitcoin network
+// by using websockets via btcd, use of notifications and an rpc
+// call to getblockcount.
+//
+// Install and run btcd:
+// 		$ go get github.com/conformal/btcd/...
+//		$ btcd -u rpcuser -P rpcpass
+//
+// Install btcrpcclient:
+// 		$ go get github.com/conformal/btcrpcclient
+//
+// Run this example:
+// 		$ go run websocket-example.go
+//
+func main() {
+	// Only override the handlers for notifications you care about.
+	// Also note most of these handlers will only be called if you register
+	// for notifications. See the documentation of the btcrpcclient
+	// NotificationHandlers type for more details about each handler.
+	ntfnHandlers := btcrpcclient.NotificationHandlers{
+		OnBlockConnected: func(hash *btcwire.ShaHash, height int32) {
+			log.Printf("Block connected: %v (%d)", hash, height)
+		},
+		OnBlockDisconnected: func(hash *btcwire.ShaHash, height int32) {
+			log.Printf("Block disconnected: %v (%d)", hash, height)
+		},
+	}
+
+	// Connect to local btcd RPC server using websockets.
+	btcdHomeDir := btcutil.AppDataDir("btcd", false)
+	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
+	if err != nil {
+		log.Fatal(err)
+	}
+	connCfg := &btcrpcclient.ConnConfig{
+		Host:         "localhost:8334",
+		Endpoint:     "ws",
+		User:         "rpcuser",
+		Pass:         "rpcpass",
+		Certificates: certs,
+	}
+	client, err := btcrpcclient.New(connCfg, &ntfnHandlers)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Register for block connect and disconnect notifications.
+	if err := client.NotifyBlocks(); err != nil {
+		log.Fatal(err)
+	}
+	log.Println("NotifyBlocks: Registration Complete")
+
+	// Get the current block count.
+	blockCount, err := client.GetBlockCount()
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("Block count: %d", blockCount)
+
+	// For this example gracefully shutdown the client after 10 seconds.
+	// Ordinarily when to shutdown the client is highly application
+	// specific.
+	log.Println("Client shutdown in 10 seconds...")
+	time.AfterFunc(time.Second*10, func() {
+		log.Println("Client shutting down...")
+		client.Shutdown()
+		log.Println("Client shutdown complete.")
+	})
+
+	// Wait until the client either shuts down gracefully (or the user
+	// terminates the process with Ctrl+C).
+	client.WaitForShutdown()
+}