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Reactive Relational Database Connectivity Driver Implementation for Postgresql
/*
* Copyright 2017-2020 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.r2dbc.postgresql.client;
import io.r2dbc.postgresql.authentication.AuthenticationHandler;
import io.r2dbc.postgresql.message.backend.AuthenticationMessage;
import io.r2dbc.postgresql.message.backend.AuthenticationOk;
import io.r2dbc.postgresql.message.backend.BackendMessage;
import io.r2dbc.postgresql.message.frontend.FrontendMessage;
import io.r2dbc.postgresql.message.frontend.StartupMessage;
import io.r2dbc.postgresql.util.Assert;
import reactor.core.publisher.EmitterProcessor;
import reactor.core.publisher.Flux;
import reactor.core.publisher.FluxSink;
import reactor.util.annotation.Nullable;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
/**
* A utility class that encapsulates the Start-up message flow.
*/
public final class StartupMessageFlow {
private StartupMessageFlow() {
}
/**
* Execute the Start-up message flow.
*
* @param applicationName the name of the application connecting to the server
* @param authenticationHandlerProvider the {@link Function} used to provide an {@link AuthenticationHandler} to use for authentication
* @param client the {@link Client} to exchange messages with
* @param database the database to connect to
* @param username the username to authenticate with
* @param options the connection options
* @return the messages received after authentication is complete, in response to this exchange
* @throws IllegalArgumentException if {@code applicationName}, {@code authenticationHandler}, {@code client}, or {@code username} is {@code null}
*/
public static Flux exchange(String applicationName, Function authenticationHandlerProvider, Client client,
@Nullable String database, String username, @Nullable Map options) {
Assert.requireNonNull(applicationName, "applicationName must not be null");
Assert.requireNonNull(authenticationHandlerProvider, "authenticationHandlerProvider must not be null");
Assert.requireNonNull(client, "client must not be null");
Assert.requireNonNull(username, "username must not be null");
EmitterProcessor requestProcessor = EmitterProcessor.create();
FluxSink requests = requestProcessor.sink();
AtomicReference authenticationHandler = new AtomicReference<>(null);
return client.exchange(requestProcessor.startWith(new StartupMessage(applicationName, database, username, options)))
.handle((message, sink) -> {
if (message instanceof AuthenticationOk) {
requests.complete();
} else if (message instanceof AuthenticationMessage) {
try {
AuthenticationMessage authenticationMessage = (AuthenticationMessage) message;
if (authenticationHandler.get() == null) {
authenticationHandler.compareAndSet(null, authenticationHandlerProvider.apply(authenticationMessage));
}
FrontendMessage response = authenticationHandler.get().handle(authenticationMessage);
if (response != null) {
requests.next(response);
}
} catch (Exception e) {
requests.error(e);
sink.error(e);
}
} else {
sink.next(message);
}
});
}
}