Rss-Bridge/bridges/AmazonPriceTrackerBridge.php

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4.6 KiB
PHP
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<?php
class AmazonPriceTrackerBridge extends BridgeAbstract {
const MAINTAINER = 'captn3m0';
const NAME = 'Amazon Price Tracker';
const URI = 'https://www.amazon.com/';
const CACHE_TIMEOUT = 3600; // 1h
const DESCRIPTION = 'Tracks price for a single product on Amazon';
const PARAMETERS = array(
array(
'asin' => array(
'name' => 'ASIN',
'required' => true,
'exampleValue' => 'B071GB1VMQ',
// https://stackoverflow.com/a/12827734
'pattern' => 'B[\dA-Z]{9}|\d{9}(X|\d)',
),
'tld' => array(
'name' => 'Country',
'type' => 'list',
'values' => array(
'Australia' => 'com.au',
'Brazil' => 'com.br',
'Canada' => 'ca',
'China' => 'cn',
'France' => 'fr',
'Germany' => 'de',
'India' => 'in',
'Italy' => 'it',
'Japan' => 'co.jp',
'Mexico' => 'com.mx',
'Netherlands' => 'nl',
'Spain' => 'es',
'Sweden' => 'se',
'United Kingdom' => 'co.uk',
'United States' => 'com',
),
'defaultValue' => 'com',
),
));
protected $title;
/**
* Generates domain name given a amazon TLD
*/
private function getDomainName() {
return 'https://www.amazon.' . $this->getInput('tld');
}
/**
* Generates URI for a Amazon product page
*/
public function getURI() {
if (!is_null($this->getInput('asin'))) {
return $this->getDomainName() . '/dp/' . $this->getInput('asin') . '/';
}
return parent::getURI();
}
/**
* Scrapes the product title from the html page
* returns the default title if scraping fails
*/
private function getTitle($html) {
$titleTag = $html->find('#productTitle', 0);
if (!$titleTag) {
return $this->getDefaultTitle();
} else {
return trim(html_entity_decode($titleTag->innertext, ENT_QUOTES));
}
}
/**
* Title used by the feed if none could be found
*/
private function getDefaultTitle() {
return 'Amazon.' . $this->getInput('tld') . ': ' . $this->getInput('asin');
}
/**
* Returns name for the feed
* Uses title (already scraped) if it has one
*/
public function getName() {
if (isset($this->title)) {
return $this->title;
} else {
return parent::getName();
}
}
private function parseDynamicImage($attribute) {
$json = json_decode(html_entity_decode($attribute), true);
if ($json and count($json) > 0) {
return array_keys($json)[0];
}
}
/**
* Returns a generated image tag for the product
*/
private function getImage($html) {
$imageSrc = $html->find('#main-image-container img', 0);
if ($imageSrc) {
$hiresImage = $imageSrc->getAttribute('data-old-hires');
$dynamicImageAttribute = $imageSrc->getAttribute('data-a-dynamic-image');
$image = $hiresImage ?: $this->parseDynamicImage($dynamicImageAttribute);
}
$image = $image ?: 'https://placekitten.com/200/300';
return <<<EOT
<img width="300" style="max-width:300;max-height:300" src="$image" alt="{$this->title}" />
EOT;
}
/**
* Return \simple_html_dom object
* for the entire html of the product page
*/
private function getHtml() {
$uri = $this->getURI();
return getSimpleHTMLDOM($uri) ?: returnServerError('Could not request Amazon.');
}
private function scrapePriceFromMetrics($html) {
$asinData = $html->find('#cerberus-data-metrics', 0);
// <div id="cerberus-data-metrics" style="display: none;"
// data-asin="B00WTHJ5SU" data-asin-price="14.99" data-asin-shipping="0"
// data-asin-currency-code="USD" data-substitute-count="-1" ... />
if ($asinData) {
return array(
'price' => $asinData->getAttribute('data-asin-price'),
'currency' => $asinData->getAttribute('data-asin-currency-code'),
'shipping' => $asinData->getAttribute('data-asin-shipping')
);
}
return false;
}
private function scrapePriceGeneric($html) {
$priceDiv = $html->find('span.offer-price', 0) ?: $html->find('.a-color-price', 0);
preg_match('/^\s*([A-Z]{3}|£|\$)\s?([\d.,]+)\s*$/', $priceDiv->plaintext, $matches);
if (count($matches) === 3) {
return array(
'price' => $matches[2],
'currency' => $matches[1],
'shipping' => '0'
);
}
return false;
}
/**
* Scrape method for Amazon product page
* @return [type] [description]
*/
public function collectData() {
$html = $this->getHtml();
$this->title = $this->getTitle($html);
$imageTag = $this->getImage($html);
$data = $this->scrapePriceFromMetrics($html) ?: $this->scrapePriceGeneric($html);
$item = array(
'title' => $this->title,
'uri' => $this->getURI(),
'content' => "$imageTag<br/>Price: {$data['price']} {$data['currency']}",
);
if ($data['shipping'] !== '0') {
$item['content'] .= "<br>Shipping: {$data['shipping']} {$data['currency']}</br>";
}
$this->items[] = $item;
}
}