ILIAS  release_6 Revision v6.24-5-g0c8bfefb3b8
EstimatedReadingTime.php
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1<?php declare(strict_types=1);
2/* Copyright (c) 1998-2019 ILIAS open source, Extended GPL, see docs/LICENSE */
3
4namespace ILIAS\Refinery\String;
5
6use ILIAS\Refinery\DeriveApplyToFromTransform;
7use ILIAS\Refinery\DeriveInvokeFromTransform;
8use ILIAS\Refinery\Transformation;
9
10class EstimatedReadingTime implements Transformation
11{
12 use DeriveApplyToFromTransform;
13 use DeriveInvokeFromTransform;
14
16 private $wordsPerMinute = 275;
17
19 private $firstImageReadingTimeInSeconds = 12;
20
22 private $withImages = false;
23
28 public function __construct(bool $withImages)
29 {
30 $this->withImages = $withImages;
31 }
32
36 public function transform($from)
37 {
38 if (!is_string($from)) {
39 throw new \InvalidArgumentException(__METHOD__ . " the argument is not a string.");
40 }
41
42 return $this->calculate($from);
43 }
44
49 private function calculate(string $text) : int
50 {
51 $text = mb_convert_encoding(
52 '<!DOCTYPE html><html><head><meta charset="utf-8"/></head><body>' . $text . '</body></html>',
53 'HTML-ENTITIES',
54 'UTF-8'
55 );
56
57 $document = new \DOMDocument();
58 if (!@$document->loadHTML($text)) {
59 throw new \InvalidArgumentException(__METHOD__ . " the argument is not a XHTML string.");
60 }
61
62 $numberOfWords = 0;
63
64 $xpath = new \DOMXPath($document);
65 $textNodes = $xpath->query('//text()');
66 if ($textNodes->length > 0) {
67 foreach ($textNodes as $textNode) {
69 if ($textNode instanceof \DOMCdataSection) {
70 continue;
71 }
72
73 $wordsInContent = array_filter(preg_split('/\s+/', $textNode->textContent));
74
75 $wordsInContent = array_filter($wordsInContent, function (string $word) {
76 return preg_replace('/^\pP$/', '', $word) !== '';
77 });
78
79 $numberOfWords += count($wordsInContent);
80 }
81 }
82
83 if ($this->withImages) {
84 $imageNodes = $document->getElementsByTagName('img');
85 $numberOfWords += $this->calculateWordsForImages($imageNodes->length);
86 }
87
88 $readingTime = ceil($numberOfWords / $this->wordsPerMinute);
89
90 return (int) $readingTime;
91 }
92
98 private function calculateWordsForImages(int $numberOfImages) : float
99 {
100 $time = 0.0;
101
102 for ($i = 1; $i <= $numberOfImages; $i++) {
103 if ($i >= 10) {
104 $time += 3 * ((int) $this->wordsPerMinute / 60);
105 } else {
106 $time += (12 - ($i - 1)) * ((int) $this->wordsPerMinute / 60);
107 }
108 }
109
110 return $time;
111 }
112}
php
An exception for terminatinating execution or to throw for unit testing.
ILIAS\Refinery\String\EstimatedReadingTime\transform
transform($from)
Perform the transformation.Please use this for transformations. It's more performant than calling inv...
Definition: EstimatedReadingTime.php:36
ILIAS\Refinery\String\EstimatedReadingTime\__construct
__construct(bool $withImages)
ReadingTime constructor.
Definition: EstimatedReadingTime.php:28
ILIAS\Refinery\Transformation
A transformation is a function from one datatype to another.
Definition: Transformation.php:18
$i
$i
Definition: metadata.php:24