php使用Canal监听msyql的过程详解

Sure, here is a detailed explanation of how to use Canal in PHP to listen for changes in a MySQL database:

1. Install Canal

Download the latest version of Canal from the Apache website: https://downloads.apache.org/

Extract the downloaded archive to a directory on your server.

2. Configure Canal

Create a configuration file for Canal in the conf directory of the extracted archive. The configuration file should specify the following:

• The MySQL server connection details:
  • Hostname
  • Port
  • Username
  • Password
• The destination for the parsed Canal events:
  • Type (e.g., file, Kafka)
  • Location (e.g., filename, Kafka topic)
• Other optional settings (e.g., filter rules, event format)

3. Start Canal Server

Start the Canal server using the following command:

bin/canal.sh server -D conf/canal.properties

4. Write a PHP script to connect to Canal

Create a PHP script that will connect to the Canal server and receive event notifications. The script will need to use the Canal PHP client library, which can be installed using Composer:

composer require canal/canal-php

Here is an example of how to connect to Canal and receive event notifications:

<?php

require __DIR__ . '/vendor/autoload.php';

use Canal\Client\CanalConnectorFactory;
use Canal\Client\CanalClient;
use Canal\Protocol\Message;

$client = CanalConnectorFactory::createClient(CanalClient::TYPE_SOCKET_CLUE);
$client->connect("127.0.0.1", 11111);
$client->checkValid();

$subscribeFilter = "example_db.*\\..*";
$client->subscribe("1000", "example_group", $subscribeFilter);

while (true) {
    $message = $client->get(10);
    if ($entries = $message->getEntries()) {
        foreach ($entries as $entry) {
            echo "Event type: " . $entry->getHeader()->getEventType() . "\n";
            echo "Entry: " . json_encode($entry->getData(), JSON_PRETTY_PRINT) . "\n";
        }
    }
}

$client->disConnect();

This script will subscribe to all tables in the example_db database and print the event type and data for each event it receives.

5. Test Canal

Make some changes to the data in the MySQL database that you are monitoring. The Canal server should parse the changes and send them to the PHP script, which will print them to the console.

Additional notes:

• You can use the CanalAdminClient class to manage Canal instances, such as starting and stopping them.
• You can use the CanalConnector class to connect to Canal in a more flexible way.
• You can configure Canal to filter events based on various criteria, such as database, table, or event type.
• You can use Canal to consume events in a variety of ways, such as writing them to files, sending them to a queue, or processing them directly in your application.