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Added support for listening to notifications #52

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Added support for listening to notifications #52

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9 changes: 9 additions & 0 deletions src/main/java/io/r2dbc/postgresql/PostgresqlConnection.java
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Expand Up @@ -21,15 +21,18 @@
import io.r2dbc.postgresql.client.SimpleQueryMessageFlow;
import io.r2dbc.postgresql.client.TransactionStatus;
import io.r2dbc.postgresql.codec.Codecs;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.util.Assert;
import io.r2dbc.spi.Connection;
import io.r2dbc.spi.IsolationLevel;
import org.reactivestreams.Publisher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.Disposable;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.util.function.Consumer;
import java.util.function.Function;

import static io.r2dbc.postgresql.client.TransactionStatus.IDLE;
Expand Down Expand Up @@ -165,6 +168,12 @@ public Mono<Void> rollbackTransactionToSavepoint(String name) {
});
}

public Disposable addNotificationListener(Consumer<NotificationResponse> consumer) {
Assert.requireNonNull(consumer, "consumer must not be null");

return this.client.addNotificationListener(consumer);
}

@Override
public Mono<Void> setTransactionIsolationLevel(IsolationLevel isolationLevel) {
Assert.requireNonNull(isolationLevel, "isolationLevel must not be null");
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11 changes: 11 additions & 0 deletions src/main/java/io/r2dbc/postgresql/client/Client.java
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Expand Up @@ -18,13 +18,16 @@

import io.netty.buffer.ByteBufAllocator;
import io.r2dbc.postgresql.message.backend.BackendMessage;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.message.backend.ReadyForQuery;
import io.r2dbc.postgresql.message.frontend.FrontendMessage;
import org.reactivestreams.Publisher;
import reactor.core.Disposable;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.util.Optional;
import java.util.function.Consumer;

/**
* An abstraction that wraps the networking part of exchanging methods.
Expand Down Expand Up @@ -75,4 +78,12 @@ public interface Client {
*/
TransactionStatus getTransactionStatus();

/**
* Add a consumer of notification messages.
*
* @param consumer the consumer of notification messages
* @return a new {@link Disposable} that can be used to cancel the underlying subscription.
* @throws IllegalArgumentException if {@code consumer} is {@code null}
*/
Disposable addNotificationListener(Consumer<NotificationResponse> consumer);
}
14 changes: 14 additions & 0 deletions src/main/java/io/r2dbc/postgresql/client/ReactorNettyClient.java
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Expand Up @@ -25,13 +25,15 @@
import io.r2dbc.postgresql.message.backend.ErrorResponse;
import io.r2dbc.postgresql.message.backend.Field;
import io.r2dbc.postgresql.message.backend.NoticeResponse;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.message.backend.ReadyForQuery;
import io.r2dbc.postgresql.message.frontend.FrontendMessage;
import io.r2dbc.postgresql.message.frontend.Terminate;
import io.r2dbc.postgresql.util.Assert;
import org.reactivestreams.Publisher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.Disposable;
import reactor.core.publisher.EmitterProcessor;
import reactor.core.publisher.Flux;
import reactor.core.publisher.FluxSink;
Expand All @@ -50,6 +52,7 @@
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Collectors;

Expand Down Expand Up @@ -104,6 +107,11 @@ public final class ReactorNettyClient implements Client {
sink.next(message);
});

private final EmitterProcessor<NotificationResponse> notificationProcessor = EmitterProcessor.create(false);

private final BiConsumer<BackendMessage, SynchronousSink<BackendMessage>> handleNotificationResponse = handleBackendMessage(NotificationResponse.class,
(message, sink) -> this.notificationProcessor.onNext(message));

/**
* Creates a new frame processor connected to a given TCP connection.
*
Expand All @@ -124,6 +132,7 @@ private ReactorNettyClient(Connection connection) {
.concatMap(decoder::decode)
.doOnNext(message -> this.logger.debug("Response: {}", message))
.handle(this.handleNoticeResponse)
.handle(this.handleNotificationResponse)
.handle(this.handleErrorResponse)
.handle(this.handleBackendKeyData)
.handle(this.handleReadyForQuery)
Expand Down Expand Up @@ -258,6 +267,11 @@ public TransactionStatus getTransactionStatus() {
return this.transactionStatus.get();
}

@Override
public Disposable addNotificationListener(Consumer<NotificationResponse> consumer) {
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Isn't it better to expose Flux<NotificationResponse> here?

return this.notificationProcessor.subscribe(consumer);
}

@SuppressWarnings("unchecked")
private static <T extends BackendMessage> BiConsumer<BackendMessage, SynchronousSink<BackendMessage>> handleBackendMessage(Class<T> type, BiConsumer<T, SynchronousSink<BackendMessage>> consumer) {
return (message, sink) -> {
Expand Down
56 changes: 56 additions & 0 deletions src/test/java/io/r2dbc/postgresql/client/ReactorNettyClientTest.java
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Expand Up @@ -19,14 +19,19 @@
import io.r2dbc.postgresql.authentication.PasswordAuthenticationHandler;
import io.r2dbc.postgresql.message.backend.CommandComplete;
import io.r2dbc.postgresql.message.backend.DataRow;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.message.backend.RowDescription;
import io.r2dbc.postgresql.message.frontend.Query;
import io.r2dbc.postgresql.util.PostgresqlServerExtension;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.RegisterExtension;
import reactor.core.Disposable;
import reactor.core.publisher.FluxProcessor;
import reactor.core.publisher.Mono;
import reactor.core.publisher.MonoProcessor;
import reactor.core.publisher.UnicastProcessor;
import reactor.test.StepVerifier;

import java.util.Arrays;
Expand Down Expand Up @@ -142,4 +147,55 @@ void parallelExchange() {
.verifyComplete();
}

@Test
void handleNotify() {
UnicastProcessor<NotificationResponse> response = UnicastProcessor.create();
this.client.addNotificationListener(response::onNext);

this.client
.exchange(Mono.just(new Query("LISTEN events")))
.blockLast();

SERVER.getJdbcOperations().execute("NOTIFY events, 'test'");

StepVerifier.create(response)
.assertNext(message -> assertThat(message.getPayload()).isEqualTo("test"))
.thenCancel()
.verify();
}

@Test
void handleTrigger() {
SERVER.getJdbcOperations().execute(
"CREATE OR REPLACE FUNCTION notify_event() RETURNS TRIGGER AS $$\n" +
" DECLARE\n" +
" payload JSON;\n" +
" BEGIN\n" +
" payload = row_to_json(NEW);\n" +
" PERFORM pg_notify('events', payload::text);\n" +
" RETURN NULL;\n" +
" END;\n" +
"$$ LANGUAGE plpgsql;");

SERVER.getJdbcOperations().execute(
"CREATE TRIGGER notify_test_event\n" +
"AFTER INSERT OR UPDATE OR DELETE ON test\n" +
" FOR EACH ROW EXECUTE PROCEDURE notify_event();");

UnicastProcessor<NotificationResponse> response = UnicastProcessor.create();
this.client.addNotificationListener(response::onNext);

this.client
.exchange(Mono.just(new Query("LISTEN events")))
.blockLast();

SERVER.getJdbcOperations().execute("INSERT INTO test VALUES (100)");
SERVER.getJdbcOperations().execute("INSERT INTO test VALUES (1000)");

StepVerifier.create(response)
.assertNext(message -> assertThat(message.getPayload()).isEqualTo("{\"value\":100}"))
.assertNext(message -> assertThat(message.getPayload()).isEqualTo("{\"value\":1000}"))
.thenCancel()
.verify();
}
}
10 changes: 10 additions & 0 deletions src/test/java/io/r2dbc/postgresql/client/TestClient.java
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Expand Up @@ -18,10 +18,12 @@

import io.netty.buffer.ByteBufAllocator;
import io.r2dbc.postgresql.message.backend.BackendMessage;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.message.frontend.FrontendMessage;
import io.r2dbc.postgresql.util.Assert;
import io.r2dbc.postgresql.util.TestByteBufAllocator;
import org.reactivestreams.Publisher;
import reactor.core.Disposable;
import reactor.core.publisher.EmitterProcessor;
import reactor.core.publisher.Flux;
import reactor.core.publisher.FluxSink;
Expand All @@ -31,6 +33,7 @@
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Function;

import static io.r2dbc.postgresql.client.TransactionStatus.IDLE;
Expand All @@ -53,6 +56,8 @@ public final class TestClient implements Client {

private final TransactionStatus transactionStatus;

private final EmitterProcessor<NotificationResponse> notificationProcessor = EmitterProcessor.create(false);

private TestClient(boolean expectClose, @Nullable Integer processId, @Nullable Integer secretKey, Flux<Window> windows, TransactionStatus transactionStatus) {
this.expectClose = expectClose;
this.processId = processId;
Expand Down Expand Up @@ -120,6 +125,11 @@ public TransactionStatus getTransactionStatus() {
return this.transactionStatus;
}

@Override
public Disposable addNotificationListener(Consumer<NotificationResponse> consumer) {
return this.notificationProcessor.subscribe(consumer);
}

public static final class Builder {

private final List<Window.Builder<?>> windows = new ArrayList<>();
Expand Down