double-opt-in / src / Service / DoiMailHeaders.php

DoiMailHeaders.php in Double Opt-In for Contact Form 7 – Secure, GDPR-Compliant Email Verification 5.8.0, at src/Service/DoiMailHeaders.php

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1	<?php
2	/**
3	* Lets extensions add headers to the mails of the double opt-in itself.
4	*
5	* @package Forge12\DoubleOptIn\Service
6	* @since 5.8.0
7	*/
8
9	declare( strict_types=1 );
10
11	namespace Forge12\DoubleOptIn\Service;
12
13	use Forge12\DoubleOptIn\Events\Lifecycle\OptInCreatedEvent;
14	use Forge12\DoubleOptIn\EventSystem\EventDispatcherInterface;
15
16	if ( ! defined( 'ABSPATH' ) ) {
17	exit;
18	}
19
20	/**
21	* The confirmation mail leaves through five integrations and two resend
22	* paths, each building its own headers. Instead of a hook in each of
23	* them, this recognises the mail on its way through wp_mail() — the way
24	* OptInMailTracker recognises its failure — and runs its headers through
25	* `f12_doi_mail_headers`. addon-opt-out adds List-Unsubscribe there.
26	*
27	* A mail is expected after an opt-in is created (`confirmation`) or when
28	* a sender announces one (`resend`, `reminder`). The first wp_mail() to
29	* that recipient is it; the expectation then ends, as it does when the
30	* integration reports the confirmation mail as sent. Other mails of the
31	* request — notifications, a second form — pass untouched.
32	*
33	* @api Core API 4.6.0
34	*/
35	class DoiMailHeaders {
36
37	public const FILTER = 'f12_doi_mail_headers';
38
39	public const KIND_CONFIRMATION = 'confirmation';
40	public const KIND_RESEND = 'resend';
41	public const KIND_REMINDER = 'reminder';
42
43	/** @var int */
44	private $optInId = 0;
45
46	/** @var string */
47	private $recipient = '';
48
49	/** @var string */
50	private $kind = '';
51
52	public function register( EventDispatcherInterface $dispatcher ): void {
53	$dispatcher->addListener(
54	OptInCreatedEvent::class,
55	function ( OptInCreatedEvent $event ): void {
56	$this->expect( $event->getOptInId(), $event->getEmail(), self::KIND_CONFIRMATION );
57	}
58	);
59	add_filter( 'wp_mail', array( $this, 'filterMail' ), 20 );
60	add_action( 'f12_cf7_doubleoptin_sent', array( $this, 'forget' ), 100, 0 );
61	}
62
63	/**
64	* Announce that the next mail to $recipient is a double opt-in mail.
65	*/
66	public function expect( int $optInId, string $recipient, string $kind ): void {
67	$this->optInId = $optInId;
68	$this->recipient = OptInMailTracker::normalise( $recipient );
69	$this->kind = $kind;
70	}
71
72	public function forget(): void {
73	$this->optInId = 0;
74	$this->recipient = '';
75	$this->kind = '';
76	}
77
78	/**
79	* @param mixed $atts wp_mail() arguments.
80	*
81	* @return mixed
82	*/
83	public function filterMail( $atts ) {
84	if ( $this->optInId <= 0 \|\| ! is_array( $atts ) ) {
85	return $atts;
86	}
87
88	$to = $atts['to'] ?? array();
89	$to = is_array( $to ) ? $to : explode( ',', (string) $to );
90	if ( ! in_array( $this->recipient, array_map( array( OptInMailTracker::class, 'normalise' ), $to ), true ) ) {
91	return $atts;
92	}
93
94	$optInId = $this->optInId;
95	$kind = $this->kind;
96	$this->forget();
97
98	// Nobody listening: the mail leaves exactly as built.
99	if ( ! has_filter( self::FILTER ) ) {
100	return $atts;
101	}
102
103	$headers = self::lines( $atts['headers'] ?? array() );
104
105	/**
106	* Headers of a double opt-in mail (confirmation, resend, reminder).
107	*
108	* Return header lines (`Name: value`). Line breaks inside a line
109	* are removed.
110	*
111	* @since 5.8.0
112	*
113	* @param string[] $headers Header lines as they stand.
114	* @param int $optInId The opt-in the mail belongs to.
115	* @param string $kind confirmation, resend or reminder.
116	*/
117	$filtered = apply_filters( 'f12_doi_mail_headers', $headers, $optInId, $kind );
118
119	$atts['headers'] = is_array( $filtered ) ? self::lines( $filtered ) : $headers;
120
121	return $atts;
122	}
123
124	/**
125	* wp_mail() takes headers as a newline-separated string or an array.
126	*
127	* @param mixed $headers
128	*
129	* @return string[]
130	*/
131	private static function lines( $headers ): array {
132	if ( ! is_array( $headers ) ) {
133	$headers = explode( "\n", str_replace( "\r\n", "\n", (string) $headers ) );
134	}
135
136	$lines = array();
137	foreach ( $headers as $line ) {
138	if ( ! is_scalar( $line ) ) {
139	continue;
140	}
141	$line = trim( str_replace( array( "\r", "\n" ), ' ', (string) $line ) );
142	if ( $line !== '' && strpos( $line, ':' ) !== false ) {
143	$lines[] = $line;
144	}
145	}
146
147	return $lines;
148	}
149	}
150