php loops foreach file-get-contents file-put-contents

Is there a better way cycle through these PHP codes, maybe with foreach loop?

I use file_get_contents to grab a remote pricing (updated daily), use substr to keep only the portions I want (stripping out the currency symbols and other data from the output and only keeping the numbers) and use file_put_contents to store it into a cache directory which I refer to later.

This is what I have now:-

<?php

$cacheDirectory = $_SERVER['DOCUMENT_ROOT'] . '/cache/';

// Small Plan - US
$cachefile_SM_US = $cacheDirectory . 'SM_US.cache';

if(file_exists($cachefile_SM_US)) {
    if(time() - filemtime($cachefile_SM_US) > 1600) {
        // too old , re-fetch
        $cache_SM_US = file_get_contents('https://remotedomain.com/?get=price&product=10&currency=1');
        $substr_SM_US = substr($cache_SM_US,17,2);
        file_put_contents($cachefile_SM_US, $substr_SM_US);
        } else {
            // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_SM_US = file_get_contents('https://remotedomain.com/?get=price&product=10&currency=1');
    $substr_SM_US = substr($cache_SM_US,17,2);
    file_put_contents($cachefile_SM_US, $substr_SM_US);
}

// Large Plan - US
$cachefile_LG_US = $cacheDirectory . 'LG_US.cache';

if(file_exists($cachefile_LG_US)) {
    if(time() - filemtime($cachefile_LG_US) > 1600) {
        // too old , re-fetch
        $cache_LG_US = file_get_contents('https://remotedomain.com/?get=price&product=20&currency=1');
        $substr_LG_US = substr($cache_LG_US,17,2);
        file_put_contents($cachefile_LG_US, $substr_LG_US);
    } else {
        // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_LG_US = file_get_contents('https://remotedomain.com/?get=price&product=20&currency=1');
    $substr_LG_US = substr($cache_LG_US,17,2);
    file_put_contents($cachefile_LG_US, $substr_LG_US);
}

// Small Plan - EU
$cachefile_SM_EU = $cacheDirectory . 'SM_EU.cache';

if(file_exists($cachefile_SM_EU)) {
    if(time() - filemtime($cachefile_SM_EU) > 1600) {
        // too old , re-fetch
        $cache_SM_EU = file_get_contents('https://remotedomain.com/?get=price&product=10&currency=2');
        $substr_SM_EU = substr($cache_SM_EU,17,2);
        file_put_contents($cachefile_SM_EU, $substr_SM_EU);
        } else {
            // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_SM_EU = file_get_contents('https://remotedomain.com/?get=price&product=10&currency=2');
    $substr_SM_EU = substr($cache_SM_EU,17,2);
    file_put_contents($cachefile_SM_EU, $substr_SM_EU);
}

// Large Plan - EU
$cachefile_LG_EU = $cacheDirectory . 'LG_EU.cache';

if(file_exists($cachefile_LG_EU)) {
    if(time() - filemtime($cachefile_LG_EU) > 1600) {
        // too old , re-fetch
        $cache_LG_EU = file_get_contents('https://remotedomain.com/?get=price&product=20&currency=2');
        $substr_LG_EU = substr($cache_LG_EU,17,2);
        file_put_contents($cachefile_LG_EU, $substr_LG_EU);
    } else {
        // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_LG_EU = file_get_contents('https://remotedomain.com/?get=price&product=20&currency=2');
    $substr_LG_EU = substr($cache_LG_EU,17,2);
    file_put_contents($cachefile_LG_EU, $substr_LG_EU);
}

?>

This manual way works when there are only two products (10 and 20) and two currencies (1 and 2) as I only need to do it 4 times to get all the pricing I need.

However, I am going to significantly expand the number of products to at least 12 products and 9 currencies so it is not realistic to do them manually.

I believe this can be done more efficiently with PHP foreach loop but I tried a few days and didn't manage to get it to work, maybe because of my weaker understanding of the concept.

I managed to split it up into this:-

<?php

$cacheDirectory = $_SERVER['DOCUMENT_ROOT'] . '/cache/';

$url = 'https://remotedomain.com/?get=price';
$productA = 10;
$productB = 20;
$USD = 1;
$EUR = 2;

// Small Plan - US
$cachefile_SM_US = $cacheDirectory . 'SM_US.cache';

if(file_exists($cachefile_SM_US)) {
    if(time() - filemtime($cachefile_SM_US) > 1600) {
        // too old , re-fetch
        $cache_SM_US = file_get_contents($url . '&product=' . $productA . '&currency=' . $USD);
        $substr_SM_US = substr($cache_SM_US,17,2);
        file_put_contents($cachefile_SM_US, $substr_SM_US);
        } else {
            // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_SM_US = file_get_contents($url . '&product=' . $productA . '&currency=' . $USD);
    $substr_SM_US = substr($cache_SM_US,17,2);
    file_put_contents($cachefile_SM_US, $substr_SM_US);
}

// Large Plan - US
$cachefile_LG_US = $cacheDirectory . 'LG_US.cache';

if(file_exists($cachefile_LG_US)) {
    if(time() - filemtime($cachefile_LG_US) > 1600) {
        // too old , re-fetch
        $cache_LG_US = file_get_contents($url . '&product=' . $productB . '&currency=' . $USD);
        $substr_LG_US = substr($cache_LG_US,17,2);
        file_put_contents($cachefile_LG_US, $substr_LG_US);
    } else {
        // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_LG_US = file_get_contents($url . '&product=' . $productB . '&currency=' . $USD);
    $substr_LG_US = substr($cache_LG_US,17,2);
    file_put_contents($cachefile_LG_US, $substr_LG_US);
}

// Small Plan - EU
$cachefile_SM_EU = $cacheDirectory . 'SM_EU.cache';

if(file_exists($cachefile_SM_EU)) {
    if(time() - filemtime($cachefile_SM_EU) > 1600) {
        // too old , re-fetch
        $cache_SM_EU = file_get_contents($url . '&product=' . $productA . '&currency=' . $EUR);
        $substr_SM_EU = substr($cache_SM_EU,17,2);
        file_put_contents($cachefile_SM_EU, $substr_SM_EU);
        } else {
            // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_SM_EU = file_get_contents($url . '&product=' . $productA . '&currency=' . $EUR);
    $substr_SM_EU = substr($cache_SM_EU,17,2);
    file_put_contents($cachefile_SM_EU, $substr_SM_EU);
}

// Large Plan - EU
$cachefile_LG_EU = $cacheDirectory . 'LG_EU.cache';

if(file_exists($cachefile_LG_EU)) {
    if(time() - filemtime($cachefile_LG_EU) > 1600) {
        // too old , re-fetch
        $cache_LG_EU = file_get_contents($url . '&product=' . $productB . '&currency=' . $EUR);
        $substr_LG_EU = substr($cache_LG_EU,17,2);
        file_put_contents($cachefile_LG_EU, $substr_LG_EU);
    } else {
        // cache is still fresh
    }
} else {
    // no cache, create one
    $cache_LG_EU = file_get_contents($url . '&product=' . $productB . '&currency=' . $EUR);
    $substr_LG_EU = substr($cache_LG_EU,17,2);
    file_put_contents($cachefile_LG_EU, $substr_LG_EU);
}

?>

The challenge I have now is how to turn this into a foreach loop which will cycle through each product and each currencies.

Appreciate pointers in the right direction.

Thank you!

Solution

Absolutely. Take a look at this example :)

<?php declare(strict_types=1);

interface CacheNormalizer
{
    public function normalize(string $text): string;
}

interface PlanDomainToCache
{
    public function buildUrl(Plan $plan): string;
}

final class CachedRemoteSiteManager
{
    /** @var int Time To Live Cache */
    private $timeToLive;

    /** @var CacheNormalizer */
    private $cacheNormalizer;

    /** @var PlanDomainToCache */
    private $planDomainToCache;

    public function __construct(
        int $timeToLive,
        CacheNormalizer $cacheNormalizer,
        PlanDomainToCache $planDomainToCache
    ) {
        $this->timeToLive = $timeToLive;
        $this->cacheNormalizer = $cacheNormalizer;
        $this->planDomainToCache = $planDomainToCache;
    }

    public function updateIfNecessary(Plan $plan): void
    {
        if ($this->shouldCreateOrUpdateCache($plan)) {
            $this->createOrUpdateCache($plan);
        }
    }

    private function shouldCreateOrUpdateCache(Plan $plan): bool
    {
        return !file_exists($plan->cacheDirectory())
            || time() - filemtime($plan->cacheDirectory()) > $this->timeToLive;
    }

    private function createOrUpdateCache(Plan $plan): void
    {
        $urlToCache = $this->planDomainToCache->buildUrl($plan);
        $textToCache = file_get_contents($urlToCache);

        file_put_contents(
            $plan->cacheDirectory(),
            $this->cacheNormalizer->normalize($textToCache)
        );
    }
}

final class Plan
{
    /** @var string */
    private $cacheDirectory;

    /** @var int */
    private $product;

    /** @var int */
    private $currency;

    public function __construct(string $cacheDir, int $product, int $currency)
    {
        $this->cacheDirectory = $cacheDir;
        $this->product = $product;
        $this->currency = $currency;
    }

    public function cacheDirectory(): string
    {
        return $this->cacheDirectory;
    }

    public function product(): int
    {
        return $this->product;
    }

    public function currency(): int
    {
        return $this->currency;
    }
}

// Usage example:

$cacheDirectory = $_SERVER['DOCUMENT_ROOT'] . '/cache/';
$productA = 10;
$productB = 20;
$USD = 1;
$EUR = 2;

/** @var Plan[] */
$plansToCache = [
    new Plan($cacheDirectory . 'SM_US.cache', $productA, $USD),
    new Plan($cacheDirectory . 'LG_US.cache', $productB, $USD),
    new Plan($cacheDirectory . 'SM_EU.cache', $productA, $EUR),
    new Plan($cacheDirectory . 'LG_EU.cache', $productB, $EUR),
];

$cacheManager = new CachedRemoteSiteManager(
    $cacheTtl = 1600,
    new class implements CacheNormalizer {
        public function normalize(string $text): string
        {
            return substr($text, 17, 2);
        }
    },
    new class implements PlanDomainToCache {
        public function buildUrl(Plan $plan): string
        {
            return sprintf(
                'https://remotedomain.com/?get=price&product=%d&currency=%d',
                $plan->product(),
                $plan->currency()
            );
        }
    }
);

foreach ($plansToCache as $plan) {
    $cacheManager->updateIfNecessary($plan);
}

As you can see at the bottom, in the "usage example", I extracted all details (almost all of them) so we can easily define:

how we want to normalize the cached data (using the CacheNormalizer)
how we want to build the URL that we want to cache (using PlanDomainToCache).

UPDATED:

If you want to see how could you extract/decouple every detail from the ending code, inverting the dependencies upwards even for the "Persistence" layer: https://gist.github.com/Chemaclass/01d3f42685ff69f6897192202a32014d