PostgresqlConnectionFactory.java

/*
 * Copyright 2017-2019 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;

import io.r2dbc.postgresql.authentication.AuthenticationHandler;
import io.r2dbc.postgresql.authentication.PasswordAuthenticationHandler;
import io.r2dbc.postgresql.authentication.SASLAuthenticationHandler;
import io.r2dbc.postgresql.client.Client;
import io.r2dbc.postgresql.client.ReactorNettyClient;
import io.r2dbc.postgresql.client.StartupMessageFlow;
import io.r2dbc.postgresql.codec.DefaultCodecs;
import io.r2dbc.postgresql.message.backend.AuthenticationMessage;
import io.r2dbc.postgresql.util.Assert;
import io.r2dbc.spi.ConnectionFactory;
import reactor.core.publisher.Mono;

/**
 * An implementation of {@link ConnectionFactory} for creating connections to a PostgreSQL database.
 */
public final class PostgresqlConnectionFactory implements ConnectionFactory {

    private final Mono<? extends Client> clientFactory;

    private final PostgresqlConnectionConfiguration configuration;

    /**
     * Creates a new connection factory.
     *
     * @param configuration the configuration to use connections
     * @throws IllegalArgumentException if {@code configuration} is {@code null}
     */
    public PostgresqlConnectionFactory(PostgresqlConnectionConfiguration configuration) {
        this(Mono.defer(() -> {
            Assert.requireNonNull(configuration, "configuration must not be null");

            return ReactorNettyClient.connect(configuration.getHost(), configuration.getPort(), configuration.getConnectTimeout()).cast(Client.class);
        }), configuration);
    }

    PostgresqlConnectionFactory(Mono<? extends Client> clientFactory, PostgresqlConnectionConfiguration configuration) {
        this.clientFactory = Assert.requireNonNull(clientFactory, "clientFactory must not be null");
        this.configuration = Assert.requireNonNull(configuration, "configuration must not be null");
    }

    @Override
    public Mono<PostgresqlConnection> create() {
        return this.clientFactory
            .delayUntil(client ->
                StartupMessageFlow
                    .exchange(this.configuration.getApplicationName(), this::getAuthenticationHandler, client, this.configuration.getDatabase(), this.configuration.getUsername())
                    .handle(PostgresqlServerErrorException::handleErrorResponse))
            .map(client -> new PostgresqlConnection(client, new DefaultCodecs(client.getByteBufAllocator()), DefaultPortalNameSupplier.INSTANCE, new IndefiniteStatementCache(client)))
            .delayUntil(this::setSchema);
    }

    @Override
    public PostgresqlConnectionFactoryMetadata getMetadata() {
        return PostgresqlConnectionFactoryMetadata.INSTANCE;
    }

    @Override
    public String toString() {
        return "PostgresqlConnectionFactory{" +
            "clientFactory=" + this.clientFactory +
            ", configuration=" + this.configuration +
            '}';
    }

    private AuthenticationHandler getAuthenticationHandler(AuthenticationMessage message) {
        if (PasswordAuthenticationHandler.supports(message)) {
            return new PasswordAuthenticationHandler(this.configuration.getPassword(), this.configuration.getUsername());
        } else if (SASLAuthenticationHandler.supports(message)) {
            return new SASLAuthenticationHandler(this.configuration.getPassword(), this.configuration.getUsername());
        } else {
            throw new IllegalStateException(String.format("Unable to provide AuthenticationHandler capable of handling %s", message));
        }
    }

    private Mono<Void> setSchema(PostgresqlConnection connection) {
        if (this.configuration.getSchema() == null) {
            return Mono.empty();
        }

        return connection.createStatement(String.format("SET SCHEMA '%s'", this.configuration.getSchema()))
            .execute()
            .then();
    }

}