rss-bridge/bridges/GoogleScholarBridge.php

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<?php
class GoogleScholarBridge extends BridgeAbstract
{
const NAME = 'Google Scholar v2';
const URI = 'https://scholar.google.com/';
const DESCRIPTION = 'Search for publications or follow authors on Google Scholar.';
const MAINTAINER = 'nicholasmccarthy';
const CACHE_TIMEOUT = 86400; // 24h
const PARAMETERS = [
'user' => [
'userId' => [
'name' => 'User ID',
'exampleValue' => 'qc6CJjYAAAAJ',
'required' => true
]
],
'query' => [
'q' => [
'name' => 'Search Query',
'title' => 'Search Query',
'required' => true,
'exampleValue' => 'machine learning'
],
'cites' => [
'name' => 'Cites',
'required' => false,
'default' => '',
'exampleValue' => '1275980731835430123',
'title' => 'Parameter defines unique ID for an article to trigger Cited By searches. Usage of cites
will bring up a list of citing documents in Google Scholar. Example value: cites=1275980731835430123.
Usage of cites and q parameters triggers search within citing articles.'
],
'language' => [
'name' => 'Language',
'required' => false,
'default' => '',
'exampleValue' => 'en',
'title' => 'Parameter defines the language to use for the Google Scholar search. '
],
'minCitations' => [
'name' => 'Minimum Citations',
'required' => false,
'type' => 'number',
'default' => '0',
'title' => 'Parameter defines the minimum number of citations in order for the results to be included.'
],
'sinceYear' => [
'name' => 'Since Year',
'required' => false,
'type' => 'number',
'default' => '0',
'title' => 'Parameter defines the year from which you want the results to be included.'
],
'untilYear' => [
'name' => 'Until Year',
'required' => false,
'type' => 'number',
'default' => '0',
'title' => 'Parameter defines the year until which you want the results to be included.'
],
'sortBy' => [
'name' => 'Sort By Date',
'type' => 'checkbox',
'default' => false,
'title' => 'Parameter defines articles added in the last year, sorted by date. Alternatively sorts
by relevance. This overrides Since-Until Year values.',
],
'includePatents' => [
'name' => 'Include Patents',
'type' => 'checkbox',
'default' => false,
'title' => 'Include Patents',
],
'includeCitations' => [
'name' => 'Include Citations',
'type' => 'checkbox',
'default' => true,
'title' => 'Parameter defines whether you would like to include citations or not.',
],
'reviewArticles' => [
'name' => 'Only Review Articles',
'type' => 'checkbox',
'default' => false,
'title' => 'Parameter defines whether you would like to show only review articles or not (these
articles consist of topic reviews, or discuss the works or authors you have searched for).',
],
'numResults' => [
'name' => 'Number of Results (max 20)',
'required' => false,
'type' => 'number',
'default' => 10,
'exampleValue' => 10,
'title' => 'Number of results to return'
]
],
];
public function getIcon()
{
return 'https://scholar.google.com/favicon.ico';
}
public function collectData()
{
switch ($this->queriedContext) {
case 'user':
$userId = $this->getInput('userId');
$uri = self::URI . '/citations?hl=en&view_op=list_works&sortby=pubdate&user=' . $userId;
$html = getSimpleHTMLDOM($uri) or returnServerError('Could not fetch Google Scholar data.');
$publications = $html->find('tr[class="gsc_a_tr"]');
foreach ($publications as $publication) {
$articleUrl = self::URI . htmlspecialchars_decode($publication->find('a[class="gsc_a_at"]', 0)->href);
$articleTitle = $publication->find('a[class="gsc_a_at"]', 0)->plaintext;
# fetch the article itself to extract rest of content
$contentArticle = getSimpleHTMLDOMCached($articleUrl);
$articleEntries = $contentArticle->find('div[class="gs_scl"]');
$articleDate = '';
$articleAbstract = '';
$articleAuthor = '';
$content = '';
foreach ($articleEntries as $entry) {
$field = $entry->find('div[class="gsc_oci_field"]', 0)->plaintext;
$value = $entry->find('div[class="gsc_oci_value"]', 0)->plaintext;
if ($field == 'Publication date') {
$articleDate = $value;
} elseif ($field == 'Description') {
$articleAbstract = $value;
} elseif ($field == 'Authors') {
$articleAuthor = $value;
} elseif ($field == 'Scholar articles' || $field == 'Total citations') {
continue;
} else {
$content = $content . $field . ': ' . $value . '<br><br>';
}
}
$content = $content . $articleAbstract;
$item = [];
$item['title'] = $articleTitle;
$item['uri'] = $articleUrl;
$item['timestamp'] = strtotime($articleDate);
$item['author'] = $articleAuthor;
$item['content'] = $content;
$this->items[] = $item;
if (count($this->items) >= 10) {
break;
}
}
break;
case 'query':
$query = urlencode($this->getInput('q'));
$cites = $this->getInput('cites');
$language = $this->getInput('language');
$sinceYear = $this->getInput('sinceYear');
$untilYear = $this->getInput('untilYear');
$minCitations = (int)$this->getInput('minCitations');
$includeCitations = $this->getInput('includeCitations');
$includePatents = $this->getInput('includePatents');
$reviewArticles = $this->getInput('reviewArticles');
$sortBy = $this->getInput('sortBy');
$numResults = $this->getInput('numResults');
# Build URI
$uri = self::URI . 'scholar?q=' . $query;
$uri .= $sinceYear != 0 ? '&as_ylo=' . $sinceYear : '';
$uri .= $untilYear != 0 ? '&as_yhi=' . $untilYear : '';
$uri .= $language != '' ? '&hl=' . $language : '';
$uri .= $includePatents ? '&as_vis=7' : '&as_vis=0';
$uri .= $includeCitations ? '&as_vis=0' : ($includePatents ? '&as_vis=1' : '');
$uri .= $reviewArticles ? '&as_rr=1' : '';
$uri .= $sortBy ? '&scisbd=1' : '';
$uri .= $numResults ? '&num=' . $numResults : '';
$html = getSimpleHTMLDOM($uri) or returnServerError('Could not fetch Google Scholar data.');
$publications = $html->find('div[class="gs_r gs_or gs_scl"]');
foreach ($publications as $publication) {
$articleTitleElement = $publication->find('h3[class="gs_rt"]', 0);
$articleUrl = $articleTitleElement->find('a', 0)->href;
$articleTitle = $articleTitleElement->plaintext;
$articleDateElement = $publication->find('div[class="gs_a"]', 0);
$articleDate = $articleDateElement ? $articleDateElement->plaintext : '';
$articleAbstractElement = $publication->find('div[class="gs_rs"]', 0);
$articleAbstract = $articleAbstractElement ? $articleAbstractElement->plaintext : '';
$articleAuthorElement = $publication->find('div[class="gs_a"]', 0);
$articleAuthor = $articleAuthorElement ? $articleAuthorElement->plaintext : '';
$bottomRowElement = $publication->find('div[class="gs_fl"]', 0);
$item = [
'title' => $articleTitle,
'uri' => $articleUrl,
'timestamp' => strtotime($articleDate),
'author' => $articleAuthor,
'content' => $articleAbstract
];
switch ($this->queriedContext) {
case 'user':
$this->items[] = $item;
break;
case 'query':
$citedBy = 0;
if ($bottomRowElement) {
$anchorTags = $bottomRowElement->find('a');
foreach ($anchorTags as $anchorTag) {
if (strpos($anchorTag->plaintext, 'Cited') !== false) {
$parts = explode('Cited by ', $anchorTag->plaintext);
if (isset($parts[1])) {
$citedBy = (int)$parts[1];
}
break;
}
}
}
if ($citedBy >= $minCitations) {
$this->items[] = $item;
}
break;
}
}
break;
}
}
}