plausible-analytics / src / Client / lib / HeaderSelector.php

HeaderSelector.php in Plausible Analytics trunk, at src/Client/lib/HeaderSelector.php

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1	<?php
2	/**
3	* HeaderSelector
4	* PHP version 7.4
5	*
6	* @category Class
7	* @package Plausible\Analytics\WP\Client
8	* @author OpenAPI Generator team
9	* @link https://openapi-generator.tech
10	*/
11
12	/**
13	* Plausible Plugins API
14	*
15	* No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
16	*
17	* The version of the OpenAPI document: 1.0-rc
18	* Generated by: https://openapi-generator.tech
19	* OpenAPI Generator version: 7.0.1
20	*/
21
22	/**
23	* NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
24	* https://openapi-generator.tech
25	* Do not edit the class manually.
26	*/
27
28	namespace Plausible\Analytics\WP\Client;
29
30	/**
31	* HeaderSelector Class Doc Comment
32	*
33	* @category Class
34	* @package Plausible\Analytics\WP\Client
35	* @author OpenAPI Generator team
36	* @link https://openapi-generator.tech
37	*/
38	class HeaderSelector {
39	/**
40	* @param string[] $accept
41	* @param string $contentType
42	* @param bool $isMultipart
43	*
44	* @return string[]
45	*/
46	public function selectHeaders( array $accept, string $contentType, bool $isMultipart ): array {
47	$headers = [];
48
49	$accept = $this->selectAcceptHeader( $accept );
50	if ( $accept !== null ) {
51	$headers['Accept'] = $accept;
52	}
53
54	if ( ! $isMultipart ) {
55	if ( $contentType === '' ) {
56	$contentType = 'application/json';
57	}
58
59	$headers['Content-Type'] = $contentType;
60	}
61
62	return $headers;
63	}
64
65	/**
66	* Return the header 'Accept' based on an array of Accept provided.
67	*
68	* @param string[] $accept Array of header
69	*
70	* @return null\|string Accept (e.g. application/json)
71	*/
72	private function selectAcceptHeader( array $accept ): ?string {
73	# filter out empty entries
74	$accept = array_filter( $accept );
75
76	if ( count( $accept ) === 0 ) {
77	return null;
78	}
79
80	# If there's only one Accept header, just use it
81	if ( count( $accept ) === 1 ) {
82	return reset( $accept );
83	}
84
85	# If none of the available Accept headers is of type "json", then just use all them
86	$headersWithJson = preg_grep( '~(?i)^(application/json\|[^;/ \t]+/[^;/ \t]+[+]json)[ \t](;.)?$~', $accept );
87	if ( count( $headersWithJson ) === 0 ) {
88	return implode( ',', $accept );
89	}
90
91	# If we got here, then we need add quality values (weight), as described in IETF RFC 9110, Items 12.4.2/12.5.1,
92	# to give the highest priority to json-like headers - recalculating the existing ones, if needed
93	return $this->getAcceptHeaderWithAdjustedWeight( $accept, $headersWithJson );
94	}
95
96	/**
97	* Create an Accept header string from the given "Accept" headers array, recalculating all weights
98	*
99	* @param string[] $accept Array of Accept Headers
100	* @param string[] $headersWithJson Array of Accept Headers of type "json"
101	*
102	* @return string "Accept" Header (e.g. "application/json, text/html; q=0.9")
103	*/
104	private function getAcceptHeaderWithAdjustedWeight( array $accept, array $headersWithJson ): string {
105	$processedHeaders = [
106	'withApplicationJson' => [],
107	'withJson' => [],
108	'withoutJson' => [],
109	];
110
111	foreach ( $accept as $header ) {
112
113	$headerData = $this->getHeaderAndWeight( $header );
114
115	if ( stripos( $headerData['header'], 'application/json' ) === 0 ) {
116	$processedHeaders['withApplicationJson'][] = $headerData;
117	} elseif ( in_array( $header, $headersWithJson, true ) ) {
118	$processedHeaders['withJson'][] = $headerData;
119	} else {
120	$processedHeaders['withoutJson'][] = $headerData;
121	}
122	}
123
124	$acceptHeaders = [];
125	$currentWeight = 1000;
126
127	$hasMoreThan28Headers = count( $accept) > 28;
128
129	foreach ( $processedHeaders as $headers ) {
130	if ( count( $headers ) > 0 ) {
131	$acceptHeaders[] = $this->adjustWeight( $headers, $currentWeight, $hasMoreThan28Headers );
132	}
133	}
134
135	$acceptHeaders = array_merge( ...$acceptHeaders );
136
137	return implode( ',', $acceptHeaders );
138	}
139
140	/**
141	* Given an Accept header, returns an associative array splitting the header and its weight
142	*
143	* @param string $header "Accept" Header
144	*
145	* @return array with the header and its weight
146	*/
147	private function getHeaderAndWeight( string $header ): array {
148	# matches headers with weight, splitting the header and the weight in $outputArray
149	if ( preg_match( '/(.);\sq=(1(?:\.0+)?\|0\.\d+)$/', $header, $outputArray ) === 1 ) {
150	$headerData = [
151	'header' => $outputArray[1],
152	'weight' => (int) ( $outputArray[2] * 1000 ),
153	];
154	} else {
155	$headerData = [
156	'header' => trim( $header ),
157	'weight' => 1000,
158	];
159	}
160
161	return $headerData;
162	}
163
164	/**
165	* @param array[] $headers
166	* @param float $currentWeight
167	* @param bool $hasMoreThan28Headers
168	*
169	* @return string[] array of adjusted "Accept" headers
170	*/
171	private function adjustWeight( array $headers, float &$currentWeight, bool $hasMoreThan28Headers ): array {
172	usort( $headers, function ( array $a, array $b ) {
173	return $b['weight'] - $a['weight'];
174	} );
175
176	$acceptHeaders = [];
177	foreach ( $headers as $index => $header ) {
178	if ( $index > 0 && $headers[ $index - 1 ]['weight'] > $header['weight'] ) {
179	$currentWeight = $this->getNextWeight( $currentWeight, $hasMoreThan28Headers );
180	}
181
182	$weight = $currentWeight;
183
184	$acceptHeaders[] = $this->buildAcceptHeader( $header['header'], $weight );
185	}
186
187	$currentWeight = $this->getNextWeight( $currentWeight, $hasMoreThan28Headers );
188
189	return $acceptHeaders;
190	}
191
192	/**
193	* @param string $header
194	* @param int $weight
195	*
196	* @return string
197	*/
198	private function buildAcceptHeader( string $header, int $weight ): string {
199	if ( $weight === 1000 ) {
200	return $header;
201	}
202
203	return trim( $header, '; ' ) . ';q=' . rtrim( sprintf( '%0.3f', $weight / 1000 ), '0' );
204	}
205
206	/**
207	* Calculate the next weight, based on the current one.
208	*
209	* If there are less than 28 "Accept" headers, the weights will be decreased by 1 on its highest significant digit, using the
210	* following formula:
211	*
212	* next weight = current weight - 10 ^ (floor(log(current weight - 1)))
213	*
214	* ( current weight minus ( 10 raised to the power of ( floor of (log to the base 10 of ( current weight minus 1 ) ) ) ) )
215	*
216	* Starting from 1000, this generates the following series:
217	*
218	* 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
219	*
220	* The resulting quality codes are closer to the average "normal" usage of them (like "q=0.9", "q=0.8" and so on), but it only works
221	* if there is a maximum of 28 "Accept" headers. If we have more than that (which is extremely unlikely), then we fall back to a 1-by-1
222	* decrement rule, which will result in quality codes like "q=0.999", "q=0.998" etc.
223	*
224	* @param int $currentWeight varying from 1 to 1000 (will be divided by 1000 to build the quality value)
225	* @param bool $hasMoreThan28Headers
226	*
227	* @return int
228	*/
229	public function getNextWeight( int $currentWeight, bool $hasMoreThan28Headers ): int {
230	if ( $currentWeight <= 1 ) {
231	return 1;
232	}
233
234	if ( $hasMoreThan28Headers ) {
235	return $currentWeight - 1;
236	}
237
238	return $currentWeight - 10 ** floor( log10($currentWeight - 1) );
239	}
240	}
241