In this tutorial I am going to show you How to use Google finance Currency Converter and convert currencies very easily in PHP. It takes an amount and 2 currencies from and to and then send it to Google finance using HTTP request and get the amount value converted in given currency, we have used curl to send request. In final stage we parse response and show results.

Index.php Contains PHP code to show drop-down lists for conversion with a text box.

<?php
include "convert.php";
$from 		= isset($_POST['from']) ? $_POST['from'] : '';
$to 		= isset($_POST['to']) ? $_POST['to'] : '';
$amount 	= isset($_POST['amount']) ? $_POST['amount'] : '';
$content = "";
if($_POST){
    if(!is_numeric($amount)){
	$content .= "<br><span style='background-color:red;padding:5px;color:#fff;'>Invalid amount.</span>";
    }
    elseif($from == $to){
	$content .= "<br><span style='background-color:red;padding:5px;color:#fff;'>Please select distinct currencies.</span>";
    }
    else{
	$rawData = currencyConvert($from,$to,$amount);
	$regex 	= '#\<span class=bld\>(.+?)\<\/span\>#s';
	preg_match($regex, $rawData, $converted);
	$result = $converted[0];
	if($result == ""){
	    $content .= "<br><span style='background-color:red;padding:5px;color:#fff;'>Exchange Rate not available.</span>";
	}
	else{
	    $content .= "<br><span style='background-color:lime;padding:5px;'>".$amount." ".$from." = ".$result."</span>";
	}
    }    
}
$listFrom = '
<select name="to">
<option  value="AED">United Arab Emirates Dirham (AED)</option>
<option  value="EUR">Euro (€)</option>
<option  value="GBP">British Pound Sterling (£)</option>
<option  value="INR">Indian Rupee (Rs.)</option>
<option  value="PKR">Pakistani Rupee (PKR)</option>
<option  value="SGD">Singapore Dollar (SGD)</option>
<option  value="USD">US Dollar ($)</option>
</select>
';

$listTo = '
<select name="to">
<option  value="AED">United Arab Emirates Dirham (AED)</option>
<option  value="EUR">Euro (€)</option>
<option  value="GBP">British Pound Sterling (£)</option>
<option  value="INR">Indian Rupee (Rs.)</option>
<option  value="PKR">Pakistani Rupee (PKR)</option>
<option  value="SGD">Singapore Dollar (SGD)</option>
<option  value="USD">US Dollar ($)</option>
</select>
';
$listFrom  = str_replace("\"$from\"","\"$from\" selected",$listFrom); // Make dropdown selected
$listTo    = str_replace("\"$to\"","\"$to\" selected",$listTo); // Make dropdown selected

$content .='<form action="" method="post" name="f">
<input name="amount" maxlength="12" size="5" autocomplete="off" value="'.$amount.'"><br />
<div>
'.$listFrom.'
</div>
<div style="padding: 6px 8px">to</div>
<div>
'.$listTo.'
</div>
<input type=submit value="Convert">
</form>';
?>

In drop-down we have added few values you can get complete drop-down by downloading script. Included convert.php file contains a function which send HTTP request and return response back. convert.php Contains a function which send HTTP request and return response back.

<?php
function currencyConvert($from,$to,$amount){

    $url = "http://www.google.com/finance/converter?a=$amount&from=$from&to=$to"; 

    $request = curl_init(); 
    $timeOut = 0; 
    curl_setopt ($request, CURLOPT_URL, $url); 
    curl_setopt ($request, CURLOPT_RETURNTRANSFER, 1); 

    curl_setopt ($request, CURLOPT_USERAGENT,"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)"); 
    curl_setopt ($request, CURLOPT_CONNECTTIMEOUT, $timeOut); 
    $response = curl_exec($request); 
    curl_close($request); 

    return $response;
} 
?>

This function accept 3 parameters and send request to Google finance using HTTP and it will return complete code.

I hope this simple tutorial help you and please don’t forget to give us your feedback.