Fix ping pong configuration and update docs

Signed-off-by: Lorenzo <[email protected]>

Author: lorenzodonini

README.md

@@ -486,18 +486,27 @@ own logging system.
 
 ### Websocket ping-pong
 
-The websocket package currently supports client-initiated pings only.
+The websocket package supports configuring ping pong for both endpoints.
 
-If your setup requires the server to be the initiator of a ping-pong (e.g. for web-based charge points),
-you may disable ping-pong entirely and just rely on the heartbeat mechanism:
+By default, the client sends a ping every 54 seconds and waits for a pong for 60 seconds, before timing out.
+The values can be configured as follows:
+```go
+cfg := ws.NewClientTimeoutConfig()
+cfg.PingPeriod = 10 * time.Second
+cfg.PongWait = 20 * time.Second
+websocketClient.SetTimeoutConfig(cfg)
+```
 
+By default, the server does not send out any pings and waits for a ping from the client for 60 seconds, before timing out.
+To configure the server to send out pings, the `PingPeriod` and `PongWait` must be set to a value greater than 0:
 ```go
 cfg := ws.NewServerTimeoutConfig()
-cfg.PingWait = 0 // this instructs the server to wait forever
+cfg.PingPeriod = 10 * time.Second
+cfg.PongWait = 20 * time.Second
 websocketServer.SetTimeoutConfig(cfg)
 ```
 
-> A server-initiated ping may be supported in a future release.
+To disable sending ping messages, set the `PingPeriod` value to `0`.
 
 ## OCPP 2.0.1 Usage
 

ws/client.go

@@ -341,7 +341,6 @@ func (c *client) Start(urlStr string) error {
 		ws,
 		resp.TLS,
 		NewDefaultWebSocketConfig(
-			true,
 			c.timeoutConfig.WriteWait,
 			0,
 			c.timeoutConfig.PingPeriod,

ws/server.go

@@ -418,11 +418,10 @@ out:
 		conn,
 		r.TLS,
 		NewDefaultWebSocketConfig(
-			false,
 			s.timeoutConfig.WriteWait,
 			s.timeoutConfig.PingWait,
-			0,
-			0),
+			s.timeoutConfig.PingPeriod,
+			s.timeoutConfig.PongWait),
 		s.handleMessage,
 		s.handleDisconnect,
 		func(_ Channel, err error) {

ws/websocket.go

@@ -61,10 +61,10 @@ func SetLogger(logger logging.Logger) {
 // To set a custom configuration, refer to the server's SetTimeoutConfig method.
 // If no configuration is passed, a default configuration is generated via the NewServerTimeoutConfig function.
 type ServerTimeoutConfig struct {
-	WriteWait   time.Duration // The timeout for network write operations. After a timeout, the connection is closed.
-	PingWait    time.Duration // The timeout for waiting for a ping from the client. After a timeout, the connection is closed.
-	PingEnabled bool          // Whether the server should send ping messages to each client.
-	PingPeriod  time.Duration // The interval for sending ping messages to a client. This is only relevant if PingEnabled is true.
+	WriteWait  time.Duration // The timeout for network write operations. After a timeout, the connection is closed.
+	PingWait   time.Duration // The timeout for waiting for a ping from the client. After a timeout, the connection is closed.
+	PingPeriod time.Duration // The interval for sending ping messages to a client. If set to 0, no pings are sent.
+	PongWait   time.Duration // The timeout for waiting for a pong from the server. After a timeout, the connection is closed. Needs to be set, if server is configured to send ping messages.
 }
 
 // NewServerTimeoutConfig creates a default timeout configuration for a websocket endpoint.
@@ -73,10 +73,10 @@ type ServerTimeoutConfig struct {
 // You may change fields arbitrarily and pass the struct to a SetTimeoutConfig method.
 func NewServerTimeoutConfig() ServerTimeoutConfig {
 	return ServerTimeoutConfig{
-		WriteWait:   defaultWriteWait,
-		PingWait:    defaultPingWait,
-		PingEnabled: false,
-		PingPeriod:  defaultPingPeriod,
+		WriteWait:  defaultWriteWait,
+		PingWait:   defaultPingWait,
+		PingPeriod: 0,
+		PongWait:   0,
 	}
 }
 
@@ -88,8 +88,8 @@ func NewServerTimeoutConfig() ServerTimeoutConfig {
 type ClientTimeoutConfig struct {
 	WriteWait               time.Duration // The timeout for network write operations. After a timeout, the connection is closed.
 	HandshakeTimeout        time.Duration // The timeout for the initial handshake to complete.
-	PongWait                time.Duration // The timeout for waiting for a pong from the server. After a timeout, the connection is closed.
-	PingPeriod              time.Duration
+	PongWait                time.Duration // The timeout for waiting for a pong from the server. After a timeout, the connection is closed. Needs to be set, if client is configured to send ping messages.
+	PingPeriod              time.Duration // The interval for sending ping messages to a server. If set to 0, no pings are sent.
 	RetryBackOffRepeatTimes int
 	RetryBackOffRandomRange int
 	RetryBackOffWaitMinimum time.Duration
@@ -191,13 +191,12 @@ type PingConfig struct {
 //
 // No custom configuration functions are run. Overrides need to be applied externally.
 func NewDefaultWebSocketConfig(
-	sendPing bool,
 	writeWait time.Duration,
 	readWait time.Duration,
 	pingPeriod time.Duration,
 	pongWait time.Duration) WebSocketConfig {
 	var pingCfg *PingConfig
-	if sendPing {
+	if pingPeriod > 0 {
 		pingCfg = &PingConfig{
 			PingPeriod: pingPeriod,
 			PongWait:   pongWait,