content-control / classes / Base / Stream.php

Stream.php in Content Control – The Ultimate Content Restriction Plugin! Restrict Content, Create Conditional Blocks & More 2.6.4, at classes/Base/Stream.php

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1	<?php
2	/**
3	* Plugin controller.
4	*
5	* @copyright (c) 2021, Code Atlantic LLC.
6	*
7	* @package ContentControl
8	*/
9
10	namespace ContentControl\Base;
11
12	defined( 'ABSPATH' ) \|\| exit;
13
14	/**
15	* HTTP Stream class.
16	*/
17	class Stream {
18
19	/**
20	* Stream name.
21	*
22	* @var string
23	*/
24	protected $stream_name;
25
26	/**
27	* Version.
28	*
29	* @var string
30	*/
31	const VERSION = '1.0.0';
32
33	/**
34	* Stream constructor.
35	*
36	* @param string $stream_name Stream name.
37	*/
38	public function __construct( $stream_name = 'stream' ) {
39	$this->stream_name = $stream_name;
40	}
41
42	/**
43	* Start SSE stream.
44	*
45	* @return void
46	*/
47	public function start() {
48	if ( headers_sent() ) {
49	// Do not start the stream if headers have already been sent.
50	return;
51	}
52
53	// Disable default disconnect checks.
54	ignore_user_abort( true );
55
56	// phpcs:disable WordPress.PHP.IniSet.Risky, WordPress.PHP.NoSilencedErrors.Discouraged
57	@ini_set( 'zlib.output_compression', '0' );
58	@ini_set( 'implicit_flush', '1' );
59	@ini_set( 'log_limit', '8096' );
60
61	@ob_end_clean();
62	set_time_limit( 0 );
63	// phpcs:enable WordPress.PHP.IniSet.Risky, WordPress.PHP.NoSilencedErrors.Discouraged
64
65	$this->send_headers();
66	}
67
68	/**
69	* Send SSE headers.
70	*
71	* @return void
72	*/
73	public function send_headers() {
74	header( 'Content-Type: text/event-stream' );
75	header( 'Stream-Name: ' . $this->stream_name );
76	header( 'Cache-Control: no-cache' );
77	header( 'Connection: keep-alive' );
78	// Nginx: unbuffered responses suitable for Comet and HTTP streaming applications.
79	header( 'X-Accel-Buffering: no' );
80	$this->flush_buffers();
81	}
82
83	/**
84	* Flush buffers.
85	*
86	* Uses a micro delay to prevent the stream from flushing too quickly.
87	*
88	* @return void
89	*/
90	protected function flush_buffers() {
91	// This is for the buffer achieve the minimum size in order to flush data.
92
93	// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
94	echo str_repeat( ' ', 1024 * 8 ) . PHP_EOL;
95
96	flush(); // Unless both are called. Some browsers will still cache.
97
98	// Neccessary to prevent the stream from flushing too quickly.
99	usleep( 1000 );
100	}
101
102	/**
103	* Send general message/data to the client.
104	*
105	* @param mixed $data Data to send.
106	*
107	* @return void
108	*/
109	public function send_data( $data ) {
110	$data = is_string( $data ) ? $data : \wp_json_encode( $data );
111
112	// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
113	echo "data: {$data}" . PHP_EOL;
114	echo PHP_EOL;
115
116	$this->flush_buffers();
117	}
118
119	/**
120	* Send an event to the client.
121	*
122	* @param string $event Event name.
123	* @param mixed $data Data to send.
124	*
125	* @return void
126	*/
127	public function send_event( $event, $data = '' ) {
128	$data = is_string( $data ) ? $data : \wp_json_encode( $data );
129
130	// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
131	echo "event: {$event}" . PHP_EOL;
132	// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
133	echo "data: {$data}" . PHP_EOL;
134	echo PHP_EOL;
135
136	$this->flush_buffers();
137	}
138
139	/**
140	* Send an error to the client.
141	*
142	* @param array{message:string}\|string $error Error message.
143	*
144	* @return void
145	*/
146	public function send_error( $error ) {
147	$this->send_event( 'error', $error );
148	}
149
150	/**
151	* Check if the connection should abort.
152	*
153	* @return bool
154	*/
155	public function should_abort() {
156	return (bool) connection_aborted();
157	}
158	}
159