double-opt-in / core / credit_link.php

credit_link.php in Double Opt-In for Contact Form 7 – Secure, GDPR-Compliant Email Verification 5.5.0, at core/credit_link.php

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1	<?php
2	/**
3	* The optional "Double Opt-In by Forge12" credit on the confirmation page.
4	*
5	* Off by default, and it has to stay that way. WordPress.org's plugin guidelines
6	* are explicit: "All 'Powered By' or credit displays and links included in the
7	* plugin code must be optional and default to not show on users' front-facing
8	* websites", and the choice has to be made through "clearly stated and
9	* understandable choices, not buried in the terms of use or documentation". A
10	* pre-enabled credit is grounds for removal from the directory, so the default
11	* below is not a preference — it is the condition for being listed at all.
12	*
13	* Kept in its own file rather than woven into the confirmation path: the feature
14	* is one setting, one URL and one line of markup, and holding it together makes
15	* it as easy to remove as it was to add. It attaches through the same public
16	* filter a third party would use.
17	*/
18
19	namespace forge12\contactform7\CF7DoubleOptIn;
20
21	if ( ! defined( 'ABSPATH' ) ) {
22	exit;
23	}
24
25	/**
26	* Setting key inside `f12-doi-settings`.
27	*/
28	const CREDIT_SETTING_KEY = 'credit_link';
29
30	/**
31	* Whether the site owner has asked for the credit to be shown.
32	*
33	* Absent means off. Only an explicit 1 turns it on — the reverse of the
34	* plugin's other defaults, deliberately.
35	*/
36	function is_credit_enabled(): bool {
37	$settings = get_option( 'f12-doi-settings', array() );
38
39	if ( ! is_array( $settings ) \|\| ! isset( $settings[ CREDIT_SETTING_KEY ] ) ) {
40	return false;
41	}
42
43	return (int) $settings[ CREDIT_SETTING_KEY ] === 1;
44	}
45
46	/**
47	* Where the credit points.
48	*/
49	function get_credit_url(): string {
50	/**
51	* Filter the destination of the credit link specifically.
52	*
53	* Kept alongside the general f12_doi_product_url filter, which has already
54	* run by this point: someone overriding where the credit on their
55	* confirmation page points should not have to special-case every other link
56	* to the product site as well.
57	*
58	* @param string $url The full URL including its query arguments.
59	*
60	* @since 5.2.0
61	*/
62	return (string) apply_filters( 'f12_doi_credit_url', get_product_url( 'confirmation-credit' ) );
63	}
64
65	/**
66	* The credit markup, or an empty string when it is switched off.
67	*
68	* `rel="nofollow"` on purpose. The point of the link is that a curious site
69	* owner can follow it, not that it passes ranking signals from sites whose
70	* owners agreed to a small thank-you — claiming the latter would make every
71	* installation look like a paid link scheme, which is precisely how search
72	* engines describe links distributed through plugins.
73	*
74	* @param bool $force Render even when the setting is off. Only for the preview
75	* in the admin notice: someone deciding whether to switch
76	* this on is really asking "will it make my page look
77	* cluttered", and the honest answer is to show them the
78	* exact thing rather than describe it.
79	*
80	* @return string
81	*/
82	function get_credit_markup( bool $force = false ): string {
83	if ( ! $force && ! is_credit_enabled() ) {
84	return '';
85	}
86
87	$markup = sprintf(
88	'<p class="f12-doi-credit"><a href="%s" target="_blank" rel="nofollow noopener">%s</a></p>',
89	esc_url( get_credit_url() ),
90	esc_html__( 'Double Opt-In by Forge12', 'double-opt-in' )
91	);
92
93	/**
94	* Filter the credit markup.
95	*
96	* @param string $markup The rendered credit, or '' when switched off.
97	* @param bool $force Whether rendering was forced for a preview.
98	*
99	* @since 5.2.0
100	*/
101	return (string) apply_filters( 'f12_doi_credit_markup', $markup, $force );
102	}
103
104	/**
105	* Attach the credit to the confirmation page.
106	*
107	* Typed as mixed rather than string on purpose: this hangs on a public filter,
108	* so another plugin earlier in the chain can hand over anything at all. Passing
109	* that through untouched is better than breaking someone's page over a credit.
110	*
111	* @param mixed $html Whatever the confirmation output point has collected.
112	*
113	* @return mixed
114	*/
115	function append_credit( $html ) {
116	if ( ! is_string( $html ) ) {
117	return $html;
118	}
119
120	$credit = get_credit_markup();
121
122	return $credit === '' ? $html : $html . $credit;
123	}
124
125	add_filter( 'f12_doi_confirmation_output', __NAMESPACE__ . '\append_credit', 20 );
126