How to get connection join/left event in ktor - kotlin

I want to implement the record of adding client connections in ktor's websocket, but I can't find the corresponding document. Is there a way to achieve this?
like this
install(websockets)
...
routing {
onOpen(session){
...
}
}

Related

Koin custom lifetime of service

I am trying to setup/extend Koin so that it respects the lifetime of a Ktor request.
I would like to inject a new service instance per request and share it throughout, but destroy it at request end.
Has anyone already tried this? Is it possible to extend Koin to handle this scenario or should I just build something on my own?
Ideally I'm looking to create something like this:
single<CoolService> { CoolServiceImpl() }
factory<CoolerService> { CoolerServiceImpl() }
request<CoolestService> { CoolestServiceImpl() } // THIS

Wiremock proxying to different Url like Apache ProxyPass

I am trying to achieve something very simple:
Proxy a request to
mock.com/foo?paramA=valueA&paramB=valueB
to
backend.com/bar?paramA=valueA&paramB=valueB
And I would like to do this with a json config.
The problem is that proxyBaseUrl always takes the FULL Url from the input and appends it, so
{
"request": {
"method": "GET",
"urlPattern": "/foo/.*"
},
"response": {
"proxyBaseUrl": "http://backend.com/bar"
}
}
I get a request to
http://backend.com/bar/foo?paramA=valueA&paramB=valueB
which is obviously not what I need.
I need some way to grab part of the request url with a capture group, e.g.
"urlPattern": "/foo/(.*)"
and then a way to insert the captured group - and only that - into the target url path.
How can this be done, with a JSON config?
I have checked the wiremock documentation and browsed a dozen discussions but it's still not clear to me.
These two postings had the same question and did not receive any answers:
https://groups.google.com/g/wiremock-user/c/UPO2vw4Jmhw/m/Rx0e8FtZBQAJ
https://groups.google.com/g/wiremock-user/c/EVw1qK7k8Fo/m/5iYg1SQEBAAJ
So I am wondering if this is at all possible in wiremock? (in Apache it's a 2-liner)
As far as I know, proxying isn't configurable in this way. Looking at the documentation, WireMock will only proxy the same request via the proxyBaseUrl.
Unfortunately, it looks like your best bet is going to be to write a custom response transformer that does this redirect for you. I don't think the request/response objects given in the transformer class will handle redirection on their own, so you will probably need to set up your own client to forward the requests.
Psuedo code like:
class MyCustomTransformer extends ResponseTransformer {
public String getName() {
return "MyCustomTransformer";
}
#Override
public Response transform(Request request, Response response, FileSource files, Parameters parameters) {
Pattern pattern = Pattern.compile("/regex/url/to/match/");
Matcher matcher = pattern.matcher(request.getUrl());
if (matcher.matches()) {
// Code to modify request and send via your own client
// For the example, you've saved the returned response as `responseBody`
return Response.Builder.like(response).but().body(responseBody.toJSONString()).build();
} else {
return response
}
}
}

Different JSON (de)serialization configs on different endpoints using Spring WebFlux

My micro service needs to communicate with 2 different services over HTTP. 1 has an API contract with snake_case JSON, while the other uses camelCase. How can I configure WebFlux to deserialize and serialize JSON with a certain Jackson ObjectMapper on a set of functional endpoints, while use another one on different endpoints?
The WebFlux documentation shows how to wire in another ObjectMapper, but this applies to all the endpoints of my API. So right now either all my JSON in snake_case or in camelCase. Cant find any resource to solve this issue, but it must be doable right?
Update: to make it clear I want to configure the web server which receives the requests from other services, not the webclient for sending http requests myself. I know how to do the latter.
you can use the #JsonNaming annotation on the classes you want to serialize/deserialize and specify what type of naming strategy you want.
jackson-advanced-annotations
Okay, so this is not the cleaned up solution, I will use this solution from our library, but the basic gist of my work around looks like this:
#Controller
public class Handler {
private ObjectMapper mapper;
public Handler(#Qualifier("snakeCaseWrapper") ObjectMapper mapper) {
this.mapper = mapper;
}
Mono<ServerResponse> returnUser(final ServerRequest request) {
//REQUEST DESERIALIZATION
var messageReader = new DecoderHttpMessageReader<>(new Jackson2JsonDecoder(mapper));
var configuredRequest = ServerRequest.create(request.exchange(), List.of(messageReader));
//RESPONSE SERIALIZATION
return configuredRequest.bodyToMono(UserDto.class)
.map(userDto -> {
try {
return mapper.writeValueAsString(userDto);
} catch (JsonProcessingException e) {
e.printStackTrace();
//properly handle the error here
return "";
}
})
.flatMap(json -> ServerResponse.ok()
.contentType(MediaType.APPLICATION_JSON)
.body(BodyInserters.fromObject(json))
);
}
}
This is the only way I could find to programatically choose which kind of ObjectMapper I want to use for a specific endpoint/handler method for request deserialization. For response serialization, the trick was to first use the ObjectMapper to serialize the response body to a String, and put that String into the response with BodyInserters.fromObject(json) .
It works, so I'm happy with it.

Quarkus AMQP send message to queue after request business logic

Once I receive a HTTP Get/Post I have to persist and object and then send a message to a queue where other services are listening to start doing other complex work
My current issue is that I can't just call a method with an #Outgoing("channel") annotation, I tried that and just keeps on executing the method without calling
Is there a way to call a method to send a JSON payload to a queue using the Quarkus framework?
PS: Im also trying to use rabbitMQ and switched back to ActiveMQ
Ive followed the Quarkus tuturial on reactive messaging and tried to register something on in implemented resource, but no luck
#Path("/part")
class PartService : PanacheRepository<PartDao>, Logging {
#GET
#Produces(MediaType.APPLICATION_JSON)
#Transactional
fun fetchParts(): List<PartDao> {
val partDao = PartDao(label = "Test", status = PartStatus.INBANK, creatorId = "ghost-007")
partDao.persist()
if (partDao.isPersistent) {
// Send a message to a queue -> PoC
send(partDao)
}
return findAll().list()
}
#Outgoing("part-persisted")
#Transactional
fun send(partDao: PartDao): CompletionStage<AmqpMessage<*>> {
val future = CompletableFuture<AmqpMessage<*>>()
val message = "hello from sender"
// Debug proposes
println("Sending (data): $message")
logger.debug(partDao.toString())
future.complete(AmqpMessage(message))
return future
}
}
Expected:
Register message "hello from sender" in queue after doing:
curl http://localhost/part
Actual results:
send method just keeps on executing
If I understand correctly, you want to call a method that would put something into a stream.
To my knowledge, you have to use an Emitter to do it, see e.g. https://github.com/michalszynkiewicz/devoxxpl-demo/blob/master/search/src/main/java/com/example/search/SearchEndpoint.java#L23
See https://smallrye.io/smallrye-reactive-messaging/#_stream documentation.

Apache Http Client Put Request Error

I'm trying to upload a file using the Apache Http Client's PUT method. The code is as below;
def putFile(resource: String, file: File): (Int, String) = {
val httpClient = new DefaultHttpClient(connManager)
httpClient.getCredentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(un, pw))
val url = address + "/" + resource
val put = new HttpPut(url)
put.setEntity(new FileEntity(file, "application/xml"))
executeHttp(httpClient, put) match {
case Success(answer) => (answer.getStatusLine.getStatusCode, "Successfully uploaded file")
case Failure(e) => {
e.printStackTrace()
(-1, e.getMessage)
}
}
}
When I tried running the method, I get to see the following error:
org.apache.http.NoHttpResponseException: The target server failed to respond
at org.apache.http.impl.conn.DefaultResponseParser.parseHead(DefaultResponseParser.java:101)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:252)
at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:281)
at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:247)
at org.apache.http.impl.conn.AbstractClientConnAdapter.receiveResponseHeader(AbstractClientConnAdapter.java:219)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:298)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:633)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:454)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
I do not know what has gone wrong? I'm able to do GET requests, but PUT seems not to work! Any clues as to where I should look for?
Look on the server. If GET Works, but PUT does not, then you have to figure out the receiving end.
Also, you may want to write a simple HTML File that has a form with PUT Method in it to rule out your Java Part.
As a sidenode: Its technically possible that something in between stops the request from going through or the response reaching you. Best setup a dummy HTTP Server to do the testing against.
Maybe its also a timeout issue, so the server takes to long to process your PUT.
The connection you are trying to use is a stale connection and therefore the request is failing.
But why are you only seeing an error for the PUT request and you are not seeing it for the GET request?
If you check the DefaultHttpRequestRetryHandler class you will see that by default HttpClient attempts to automatically recover from I/O exceptions. The default auto-recovery mechanism is limited to just a few exceptions that are known to be safe.
HttpClient will make no attempt to recover from any logical or HTTP protocol errors (those derived from HttpException class).
HttpClient will automatically retry those methods that are assumed to be idempotent. Your GET request, but not your PUT request!!
HttpClient will automatically retry those methods that fail with a transport exception while the HTTP request is still being transmitted to the target server (i.e. the request has not been fully transmitted to the server).
This is why you don't notice any error with your GET request, because the retry mechanism handles it.
You should define a CustomHttpRequestRetryHandler extending the DefaultHttpRequestRetryHandler. Something like this:
public class CustomHttpRequestRetryHandler extends DefaultHttpRequestRetryHandler {
#Override
public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
if(exception instanceof NoHttpResponseException) {
return true;
}
return super.retryRequest(exception, executionCount, context);
}
}
Then just assign your CustomHttpRequestRetryHandler
final HttpClientBuilder httpClientBuilder = HttpClients.custom();
httpClientBuilder.setRetryHandler(new CustomHttpRequestRetryHandler());
And that's it, now your PUT request is handled by your new RetryHandler (like the GET was by the default one)