Method

ServerSentEvents::send

Send one event.

Description#

public ServerSentEvents::send(
    string $data,
    ?string $event = null,
    ?string $id = null,
    ?int $retry = null
): void

$data may hold any line endings: each line becomes a data: field, which the browser joins with "\n" again. Line breaks (and NUL in $id) are removed from $event and $id, so they cannot inject a field.

Parameters#

$data string: The event's data
$event ?string = null: The event's name: the browser's addEventListener($event, ...), message when null
$id ?string = null: Sets the browser's last event id, which it sends back as Last-Event-ID when it reconnects
$retry ?int = null: Milliseconds the browser waits before it reconnects

Errors / Exceptions#

Exception	When
`IOException`	When the client is gone

Examples#

Example 1Event names, ids and retry

use Swerve\ClientRequest;
use Swerve\RequestHandler;
use Swerve\ServerSentEvents;

$app = new RequestHandler(function (ClientRequest $request) {
    $events = new ServerSentEvents($request);
    $events->send('plain message');                                  // EventSource's onmessage
    $events->send("two\nlines", event: 'note');                      // addEventListener('note', ...)
    $events->send('{"price":101.5}', event: 'tick', id: '42', retry: 5000);
});

if (debug_backtrace()) {
    return $app;   // swerve loads this file: it is the application's swerve.php
}

// Run directly: serve the application with swerve, and send it requests
require __DIR__ . '/../serve.php';
serve(__FILE__, ["GET /events HTTP/1.1\r\nHost: example\r\n\r\n"]);

Output

HTTP/1.1 200 OK
content-type: text/event-stream
cache-control: no-cache
x-accel-buffering: no
Server: Swerve
Transfer-Encoding: chunked
Connection: close

15
data: plain message


23
event: note
data: two
data: lines


36
event: tick
id: 42
retry: 5000
data: {"price":101.5}


0

Example 2

$sse->send(json_encode($order), event: 'order', id: (string) $order->id);