Question

I’m attempting to build a currency converter function in PHP.

I have all my rates cached in a JSON file. (https://raw.github.com/currencybot/open-exchange-rates/master/latest.json)

My script takes GET values from the URL like so:

.com?amnt=10&from=USD&to=GBP

I’ve accessed the rates from those values like so:

    $string = file_get_contents("cache/latest.json");
    $jsonRates = json_decode($string, true);

    foreach ($jsonRates as $rates => $rate) {
        $fromRate = $rate[$from];
        $toRate = $rate[$to];
    }   

Now I’m stuck. I have everything I need, I just have no idea what to do with it. How do I convert the $amnt variable from USD to GBP in this particular scenario.

Thanks!

Answer 1

You’re looking for something like this, but this only works FROM USD.

    $string = file_get_contents("cache/latest.json");
    $jsonRates = json_decode($string, true);

    foreach ($jsonRates["rates"] as $currency => $rate) {
        if($currency==$_GET["to"]) {
            echo $_GET["amnt"] * $rate;
            break;
        }
    }

Try this to do all conversions:

echo number_format(($_GET["amnt"]/$jsonRates["rates"][$_GET["from"]])*$jsonRates["rates"][$_GET["to"]],3);