rss-bridge/bridges/FeedReducerBridge.php
2023-07-31 20:43:18 +02:00

65 lines
2.1 KiB
PHP

<?php
class FeedReducerBridge extends FeedExpander
{
const MAINTAINER = 'mdemoss';
const NAME = 'Feed Reducer';
const URI = 'http://github.com/RSS-Bridge/rss-bridge/';
const DESCRIPTION = 'Choose a percentage of a feed you want to see.';
const PARAMETERS = [ [
'url' => [
'name' => 'Feed URI',
'exampleValue' => 'https://lorem-rss.herokuapp.com/feed?length=42',
'required' => true
],
'percentage' => [
'name' => 'percentage',
'type' => 'number',
'exampleValue' => 50,
'required' => true
]
]];
const CACHE_TIMEOUT = 3600;
public function collectData()
{
$url = $this->getInput('url');
if (preg_match('#^http(s?)://#i', $url)) {
$this->collectExpandableDatas($url);
} else {
throw new Exception('URI must begin with http(s)://');
}
}
public function getItems()
{
$filteredItems = [];
$intPercentage = (int)preg_replace('/[^0-9]/', '', $this->getInput('percentage'));
foreach ($this->items as $item) {
// The URL is included in the hash:
// - so you can change the output by adding a local-part to the URL
// - so items with the same URI in different feeds won't be correlated
// $pseudoRandomInteger will be a 16 bit unsigned int mod 100.
// This won't be uniformly distributed 1-100, but should be close enough.
$data = $item['uri'] . '::' . $this->getInput('url');
$hash = hash('sha256', $data, true);
// S = unsigned 16-bit int
$pseudoRandomInteger = unpack('S', $hash)[1] % 100;
if ($pseudoRandomInteger < $intPercentage) {
$filteredItems[] = $item;
}
}
return $filteredItems;
}
public function getName()
{
$trimmedPercentage = preg_replace('/[^0-9]/', '', $this->getInput('percentage') ?? '');
return parent::getName() . ' [' . $trimmedPercentage . '%]';
}
}