I tried to search in api docs as well as examples, but there weren't any example demonstrating how to send pings and receive pings. The only example was of how to connect to websocket and to send a text here.
I also saw chat sample here of server side and i carefully followed that as well (i.e. set ping interval in server side configuration of WebSocket installation).
I start listening both side for pongs but none of the side was receiving any ping messages.
And there is no option to configure the client side for pings as you can see here.
I'm so much confused about how to send pings.
This is my server side:
embeddedServer(
CIO,
80
) {
install(io.ktor.websocket.WebSockets) {
pingPeriod = Duration.ofSeconds(20)
}
routing {
webSocket("/ws") {
for (frame in incoming) {
when (frame) {
is Frame.Pong -> {
println("ping's response recieved")
}
is Frame.Ping -> {
// just temporary block
println("ping recieved")
}
is Frame.Text -> {
println(frame.readText())
}
}
}
}
}
}.apply { start() }
This is my client side:
val client = HttpClient(CIO) {
install(WebSockets)
}
client.ws(
method = HttpMethod.Get,
host = "127.0.0.1",
port = 80,
path = "/ws"
) {
send(Frame.Text("Hello World!"))
for (frame in incoming) {
when (frame) {
is Frame.Pong -> {
println("ping's response received")
}
is Frame.Ping -> {
// just temporary block
println("ping recieved from server")
}
is Frame.Text -> {
println(frame.readText())
}
}
}
}
Result:
Hello World!
i.e websocket is connected, text are able to transferred, but unfortunately can't use ping/pong feature.
I also found some functions for this here pinger and ponger but now it says its part of api and gets automatically start with initiation of WebsocketSession and i also tried to put pinger in client side but that didn't send ping to server whatsoever.
Result of above code is simply Hello world gets printed in server console as sent from client side but no ping received messages.
I was having trouble getting OkHttp to use ping/pong so I filed this issue https://github.com/ktorio/ktor/issues/1803 and one of the developers replied "well the only thing I can recommend you is to try CIO out. Is does support manual Ping/Pong processing using RawWebSockets."
Haven't tried it myself but you should check out https://github.com/ktorio/ktor/blob/master/ktor-features/ktor-websockets/jvm/test/io/ktor/tests/websocket/RawWebSocketTest.kt
Related
I am new to ktor and trying to create api in it.As I have downloaded project from ktor.io and opened it inside IntelliJ idea community edition then run button is showing disabled and when I am running it on right clicking on application.kt file and clicking on run application option.Its showing:
ktor.application - Responding at http://0.0.0.0:8080
When I am going to this link on webpage it is showing:
The web page at http://0.0.0.0:8080/ might be temporarily down or it may have moved permanently to a new web address.
Even if I have get route defined below is my code:
Application.kt
fun main() {
embeddedServer(Netty, port = 8080, host = "0.0.0.0") {
configureRouting()
}.start(wait = true)
}
Routing.kt
fun Application.configureRouting() {
// Starting point for a Ktor app:
routing {
get("/") {
call.respondText("Hello World!")
}
}
}
Someone let me know What is an issue and how can I resolve it.
I have a ratchet server, that I try to access via Websocket. It is similar to the tutorial: logging when there is a new client or when it receives a message. The Ratchet server reports having successfully established a connection while the Kotlin client does not (the connection event in Kotlin is never fired). I am using the socket-io-java module v.2.0.1. The client shows a timeout after the specified timeout time, gets detached at the server and attaches again after a short while, just as it seems to think, the connection did not properly connect (because of a missing connection response?).
The successful connection confirmation gets reported to the client, if the client is a Websocket-Client in the JS-console of Chrome, but not to my Kotlin app. Even an Android emulator running on the same computer doesn´t get a response (So I think the problem is not wi-fi related).
The connection works fine with JS, completing the full handshake, but with an Android app it only reaches the server, but never the client again.
That´s my server code:
<?php
namespace agroSMS\Websockets;
use Ratchet\ConnectionInterface;
use Ratchet\MessageComponentInterface;
class SocketConnection implements MessageComponentInterface
{
protected \SplObjectStorage $clients;
public function __construct() {
$this->clients = new \SplObjectStorage;
}
function onOpen(ConnectionInterface $conn)
{
$this->clients->attach($conn);
error_log("New client attached");
}
function onClose(ConnectionInterface $conn)
{
$this->clients->detach($conn);
error_log("Client detached");
}
function onError(ConnectionInterface $conn, \Exception $e)
{
echo "An error has occurred: {$e->getMessage()}\n";
$conn->close();
}
function onMessage(ConnectionInterface $from, $msg)
{
error_log("Received message: $msg");
// TODO: Implement onMessage() method.
}
}
And the script that I run in the terminal:
<?php
use Ratchet\Server\IoServer;
use agroSMS\Websockets\SocketConnection;
use Ratchet\WebSocket\WsServer;
use Ratchet\Http\HttpServer;
require dirname(__DIR__) . '/vendor/autoload.php';
$server = IoServer::factory(
new HttpServer(
new WsServer(
new SocketConnection()
)
)
);
$server->run();
What I run in the browser for tests (returns "Connection established" in Chrome, but for some reason not in the Browser "Brave"):
var conn = new WebSocket('ws://<my-ip>:80');
conn.onopen = function(e) {
console.log("Connection established!");
};
conn.onmessage = function(e) {
console.log(e.data);
};
What my Kotlin-code looks like:
try {
val uri = URI.create("ws://<my-ip>:80")
val options = IO.Options.builder()
.setTimeout(60000)
.setTransports(arrayOf(WebSocket.NAME))
.build()
socket = IO.socket(uri, options)
socket.connect()
.on(Socket.EVENT_CONNECT) {
Log.d(TAG, "[INFO] Connection established")
socket.send(jsonObject)
}
.once(Socket.EVENT_CONNECT_ERROR) {
val itString = gson.toJson(it)
Log.d(TAG, itString)
}
}catch(e : Exception) {
Log.e(TAG, e.toString())
}
After a minute the Kotlin code logs a "timeout"-error, detaches from the server, and attaches again.
When I stop the script on the server, it then gives an error: "connection reset, websocket error" (which makes sense, but why doesn´t he get the connection in the first time?)
I also tried to "just" change the protocol to "wss" in the url, in case it might be the problem, even though my server doesn´t even work with SSL, but this just gave me another error:
[{"cause":{"bytesTransferred":0,"detailMessage":"Read timed out","stackTrace":[],"suppressedExceptions":[]},"detailMessage":"websocket error","stackTrace":[],"suppressedExceptions":[]}]
And the connection isn´t even established at the server. So this try has been more like a down-grade.
I went to the github page of socket.io-java-client to find a solution to my problem there and it turned out, the whole problem was, that I misunderstood a very important concept:
That socket.io uses Websockets doesn´t mean it is compatible with Websockets.
So speaking in clear words:
If you use socket.io at client side, you also need to use it at the server side and vice versa. Since socket.io sends a lot of meta data with its packets, a pure Websocket-server will accept their connection establishment, but his acknowledgement coming back will not be accepted by the socket.io client.
You have to go for either full socket.io or full pure Websockets.
I tried to connect to a websocket server with SSL. But always failed on connection(...).
I am new to cpprestsdk, I can't find doc on how to set SSL information to websocket_client.
websocket_client_config config;
config.set_server_name("wss://host:port/v3/api");
websocket_client client(config);
auto fileStream = std::make_sharedconcurrency::streams::ostream();
pplx::task requestTask = fstream::open_ostream(U("results2.html"))
.then([&](ostream outFile)
{
*fileStream = outFile;
// Create http_client to send the request.
uri wsuri(U("wss://host:port/v3/api"));
client.connect(wsuri).wait();
websocket_outgoing_message msg;
msg.set_utf8_message(obj.serialize());
client.send(msg).wait();
printf("send success: %s\n", obj.serialize().c_str());
return client.receive().get();
})
it throws "Error exception:set_fail_handler: 8: TLS handshake failed".
Documentation for cpprestsdk can be found here
C++ REST SDK WebSocket client. Although this doesn't show all the necessary information related to cpprestsdk it will help you.
And also you can get an SSL test example here. I show a simple websocket client implemented using SSL or wss:// scheme
websocket_client client;
std::string body_str("hello");
try
{
client.connect(U("wss://echo.websocket.org/")).wait();
auto receive_task = client.receive().then([body_str](websocket_incoming_message ret_msg) {
VERIFY_ARE_EQUAL(ret_msg.length(), body_str.length());
auto ret_str = ret_msg.extract_string().get();
VERIFY_ARE_EQUAL(body_str.compare(ret_str), 0);
VERIFY_ARE_EQUAL(ret_msg.message_type(), websocket_message_type::text_message);
});
websocket_outgoing_message msg;
msg.set_utf8_message(body_str);
client.send(msg).wait();
receive_task.wait();
client.close().wait();
}
catch (const websocket_exception& e)
{
if (is_timeout(e.what()))
{
// Since this test depends on an outside server sometimes it sporadically can fail due to timeouts
// especially on our build machines.
return;
}
throw;
}
And further examples here to guide you get it successfully is found here
https://github.com/microsoft/cpprestsdk/wiki/Web-Socket
How can I know on the server side when a client connected or disconnected from server?
Does ZeroC Ice provides some callback functions for those events?
Minimal demo:
Server side
try(com.zeroc.Ice.Communicator communicator = com.zeroc.Ice.Util.initialize(args))
{
com.zeroc.Ice.ObjectAdapter adapter =
communicator.createObjectAdapterWithEndpoints("Hello", "default -h localhost -p 10000");
adapter.add(new HelloI(), com.zeroc.Ice.Util.stringToIdentity("hello"));
adapter.activate();
communicator.waitForShutdown();
}
Client side
try(com.zeroc.Ice.Communicator communicator = com.zeroc.Ice.Util.initialize(args))
{
HelloPrx hello = HelloPrx.checkedCast(communicator.stringToProxy("hello:default -h localhost -p 10000"));
hello.sayHello();
}
From the Server side you can check current.con member and register a close callback if it's a connection that hasn't been seen before see setCloseCallback
current is com.zeroc.Ice.Current parameter passed to all servant methods, for example in sayHello implementation you can do
#Override
public void sayHello(int delay, com.zeroc.Ice.Current current)
{
// Check if current.con is a new connection, you will
// need to keep track of that in your code.
// Install a close callback for the connection.
current.con.setCloseCallback(con ->
{
// Close callback
});
}
Here is my paho client code
// Create a client instance
client = new Paho.MQTT.Client('127.0.0.1', 1883, "clientId");
// set callback handlers
client.onConnectionLost = onConnectionLost;
client.onMessageArrived = onMessageArrived;
// connect the client
client.connect({onSuccess:onConnect});
// called when the client connects
function onConnect() {
// Once a connection has been made, make a subscription and send a message.
console.log("onConnect");
client.subscribe("/World");
message = new Paho.MQTT.Message("Hello");
message.destinationName = "/World";
client.send(message);
}
// called when the client loses its connection
function onConnectionLost(responseObject) {
if (responseObject.errorCode !== 0) {
console.log("onConnectionLost:"+responseObject.errorMessage);
}
}
// called when a message arrives
function onMessageArrived(message) {
console.log("onMessageArrived:"+message.payloadString);
}
On Rabbitmq server everything is default seetings. When i run this code i get WebSocket connection to 'ws://127.0.0.1:1883/mqtt' failed: Connection closed before receiving a handshake response
What i am missing ?
From my personal experience with Paho MQTT JavaScript library and RabbitMQ broker on windows, here is a list of things that you need to do to be able to use MQTT from JS from within a browser:
Install rabbitmq_web_mqtt plugin (you may find latest binary here, copy it to "c:\Program Files\RabbitMQ Server\rabbitmq_server-3.6.2\plugins\", and enable from command line using "rabbitmq-plugins enable rabbitmq_web_mqtt".
Of course, MQTT plugin also needs to be enabled on broker
For me, client was not working with version 3.6.1 of RabbitMQ, while it works fine with version 3.6.2 (Windows)
Port to be used for connections is 15675, NOT 1883!
Make sure to specify all 4 parameters when making instance of Paho.MQTT.Client. In case when you omit one, you get websocket connection error which may be quite misleading.
Finally, here is a code snippet which I tested and works perfectly (just makes connection):
client = new Paho.MQTT.Client("localhost", 15675, "/ws", "client-1");
//set callback handlers
client.onConnectionLost = onConnectionLost;
client.onMessageArrived = onMessageArrived;
//connect the client
client.connect({
onSuccess : onConnect
});
//called when the client connects
function onConnect() {
console.log("Connected");
}
//called when the client loses its connection
function onConnectionLost(responseObject) {
if (responseObject.errorCode !== 0) {
console.log("onConnectionLost:" + responseObject.errorMessage);
}
}
//called when a message arrives
function onMessageArrived(message) {
console.log("onMessageArrived:" + message.payloadString);
}
It's not clear in the question but I assume you are running the code above in a web browser.
This will be making a MQTT connection over Websockets (as shown in the error). This is different from a native MQTT over TCP connection.
The default pure MQTT port if 1883, Websocket support is likely to be on a different port.
You will need to configure RabbitMQ to accept MQTT over Websockets as well as pure MQTT, this pull request for RabbitMQ seams to talk about adding this capability. It mentions that this capability was only added in version 3.6.x and that the documentaion is still outstanding (as of 9th Feb 2016)