php – 在wocoommerce中过滤货币并将其从usd转换为inr for ccave

我在wordpress网站上使用ccavenue支付网关.
插件网址为 https://wordpress.org/plugins/ccavenue-payment-gateway-woocommerce/
但我有一个问题,我的基础货币是inr和ccavenue只接受inr付款,所以当用户将货币切换到usd然后ccavenue将40美元作为inr40.
我想在转换到ccavenue页面之前转换货币.
相同的代码片段是.

public function generate_ccavenue_form($order_id){

        global $woocommerce;
        $order = new WC_Order($order_id);
        $redirect_url = ($this -> redirect_page_id=="" || $this -> redirect_page_id==0)?get_site_url() . "/":get_permalink($this -> redirect_page_id);
      //For wooCoomerce 2.0

        $redirect_url = add_query_arg( 'wc-api',get_class( $this ),$redirect_url );
        $order_id = $order_id.'_'.date("ymds");
        $checksum = $this -> getCheckSum($this -> merchant_id,$order->order_total,$order_id,$redirect_url,$this -> working_key);


        $ccavenue_args = array(
            'Merchant_Id' => $this -> merchant_id,'Amount' => $order->order_total,'Order_Id' => $order_id,'Redirect_Url' => $redirect_url,'Checksum' => $checksum,'currency_code' => get_woocommerce_currency(),'billing_cust_name' => $order -> billing_first_name .' '. $order -> billing_last_name,'billing_cust_address' => $order -> billing_address_1,'billing_cust_country' => $order -> billing_country,'billing_cust_state' => $order -> billing_state,'billing_cust_city' => $order -> billing_city,'billing_zip' => $order -> shipping_postcode,'billing_cust_tel' => $order -> billing_phone,'billing_cust_email' => $order -> billing_email,'delivery_cust_name' => $order -> shipping_first_name .' '. $order -> shipping_last_name,'delivery_cust_address' => $order -> shipping_address_1,'delivery_cust_country' => $order -> shipping_country,'delivery_cust_state' => $order -> shipping_state,'delivery_cust_tel' => $order -> shipping_phone,'delivery_cust_notes' => '','Merchant_Param' => '','billing_zip_code' => $order -> billing_postcode,'delivery_cust_city' => $order -> shipping_city,'delivery_zip_code' => $order -> shipping_postcode
            );

        $ccavenue_args_array = array();
        foreach($ccavenue_args as $key => $value){
            $ccavenue_args_array[] = "<input type='hidden' name='$key' value='$value'/>";
        }

我想我必须在function.php中为此添加一个过滤器钩子.
但我无法为此制作和添加过滤器.

<?php
$from_currency    = 'USD';
$to_currency    = 'INR';
$amount            = 1;
$results = converCurrency($from_currency,$to_currency,$amount);
$regularExpression     = '#&;span class=bld&;(.+?)&;/span&;#s';
preg_match($regularExpression,$results,$finalData);
echo $finalData[0];

function converCurrency($from,$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;
} 
?>