我有一个自定义插件，以前编码到functions.php并且工作正常。我提取了代码，我正在创建一个独立的插件。当我这样做时，网站的后端很好，插件可以完成应该做的事情，但是前端显示500错误。
<?php
function add_bulk_coupons() {
$prod = new MM_Product();
$selectedProds = array();
$id = 0;
if(isset($p->id))
{
$id = $p->id;
}
$coupon = new MM_Coupon($id);
$prods = $coupon->getProducts();
if(!$coupon->isValid())
{
$coupon->setStartDate(Date("m/d/Y"));
}
$editable = "";
if(MM_Coupon::isBeingUsed($coupon->getId()))
{
$editable = "disabled='disabled'";
}
$products = MM_HtmlUtils::createCheckboxGroup(MM_Product::getAll(), "mm_products", $prods);
/*
//testing coupon restr
$x = 30;
while($x <= 1029):
global $wpdb;
$sql = "INSERT INTO mm_coupon_restrictions (coupon_id, product_id) VALUES ('".$x."','1')";
$wpdb->query( $wpdb->prepare( $sql ) );
$x++;
endwhile;
*/
if(isset($_POST) && !empty($_POST)):
global $wpdb;
$coupon_variables = '';
foreach($_POST as $key=>$value):
if($key == 'number_of_coupons' || $key == 'mm_products' || $key == 'coupon_name' || $key == 'coupon_code') continue;
if($value == '') $value = NULL;
if($key == 'end_date' || $key == 'start_date'):
$value = date("Y-m-d H:i:s", strtotime($value));
endif;
if($coupon_variables==''):
$coupon_variables .= "'".$value."'";
else:
$coupon_variables .= ','."'".$value."'";
endif;
endforeach;
$x = 1;
while($x <= $_POST['number_of_coupons']):
$coupon_name = $_POST['coupon_name'].$x;
$rand = rand(10000000, 90000000);
$coupon_code = $_POST['coupon_code'].$rand;
$sql = "INSERT INTO mm_coupons (coupon_name, coupon_code, coupon_type, coupon_value, coupon_value_currency, description, quantity, start_date, end_date, recurring_billing_setting, is_gift, gift_user_id, gift_order_item_id, date_modified, date_added) VALUES ('".$coupon_name."','".$coupon_code."',".$coupon_variables.")";
$wpdb->query( $wpdb->prepare( $sql ) );
$sql = "SELECT id FROM mm_coupons ORDER BY id DESC LIMIT 1";
$theid = $wpdb->get_results( $sql );
//print_r( $theid );
$x++;
endwhile;
echo '<div class="success" style="color: #000;background-color: #ebf8a4;border-color: #a2d246;margin: 1em 0 1em;border: 1px solid;background-repeat: no-repeat;background-position: 10px 50%;padding: 10px 10px 10px 10px;-moz-border-radius: 5px;-webkit-border-radius: 5px;border-radius: 5px;-moz-box-shadow: 0 1px 1px #fff inset;-webkit-box-shadow: 0 1px 1px #fff inset;box-shadow: 0 1px 1px #fff inset;">Successfully Created '.$_POST['number_of_coupons'].' Coupons. <a href="https://www.hurlbutvisuals.com/blog/wp-admin/admin.php?page=product_settings&module=coupons">View Them Now</a></div>';
endif;
?>
<form action="" method="post">
<div id="mm-coupons-container">
<br />
<h3>Create your coupons</h3>
<table cellspacing="10">
<tr>
<td width="140">Name Prefix*</td>
<td><input type='hidden' id='id' value='<?php echo $coupon->getId(); ?>' />
<input id="mm_coupon_name" name="coupon_name" type="text" value='<?php echo $coupon->getCouponName(); ?>' style='width:300px;' />
</td>
</tr>
<tr>
<td width="140">Coupon Code Prefix*</td>
<td>
<input id="mm_coupon_code" name="coupon_code" <?php echo $editable; ?> type="text" value='<?php echo strtoupper($coupon->getCouponCode()); ?>' />
</td>
</tr>
<tr>
<td width="140">Discount*</td>
<td>
<select id="mm_coupon_type" name="coupon_type" <?php echo $editable; ?> onchange="mmjs.typeChangeHandler();">
<option value='<?php echo MM_Coupon::$TYPE_PERCENTAGE; ?>' <?php echo (($coupon->getCouponType() == MM_Coupon::$TYPE_PERCENTAGE)?"selected":""); ?>>% Off</option>
<option value='<?php echo MM_Coupon::$TYPE_DOLLAR; ?>' <?php echo (($coupon->getCouponType() == MM_Coupon::$TYPE_DOLLAR)?"selected":""); ?>>$ Off</option>
<option value='<?php echo MM_Coupon::$TYPE_FREE; ?>' <?php echo (($coupon->getCouponType() == MM_Coupon::$TYPE_FREE)?"selected":""); ?>>Free</option>
</select>
<input id="mm_coupon_value" name="coupon_value" <?php echo $editable; ?> type="text" value='<?php echo $coupon->getCouponValue(); ?>' style="width:85px;" />
<input type="hidden" name="coupon_value_currency" value='' />
<input type="hidden" name="description" value='' />
</td>
</tr>
<tr>
<td>Number of coupons to create</td>
<td>
<input id="mm_quantity" name="quantity" type="hidden" style='width: 80px;' value='1' />
<input id="mm_quantity" name="number_of_coupons" type="text" style='width: 80px;' value='<?php echo $coupon->getQuantity(); ?>' />
</td>
</tr>
<tr>
<td valign="top" width="140">Restrictions</td>
<td>
<table>
<tr>
<td width="140">Start Date</td>
<td>
<?php echo MM_Utils::getCalendarIcon(); ?>
<input id="mm_start_date" name="start_date" type="text" value='<?php echo $coupon->getStartDate(); ?>' style="width:110px;" />
</td>
</tr>
<tr>
<td>End Date</td>
<td>
<?php echo MM_Utils::getCalendarIcon(); ?>
<input id="mm_end_date" name="end_date" type="text" value='<?php echo $coupon->getEndDate(); ?>' style="width:110px;" />
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td colspan="2">
<div style="width: 98%; margin-top: 8px;" class="mm-divider"></div>
</td>
</tr>
<tr>
<td width="140" style="vertical-align:top;">Subscription Options</td>
<td>
<div id="mm_subscription_options_section">
<p style="margin:0px 0px 5px 0px;"><input id="mm_recurring_setting_first" <?php echo $editable; ?> name="recurring_billing_setting" type="radio" value='first' <?php echo (($coupon->getRecurringBillingSetting()=="first")?"checked":""); ?> /> Apply discount to the first charge only</p>
<p style="margin:10px 0px 0px 0px;"><input id="mm_recurring_setting_all" <?php echo $editable; ?> name="recurring_billing_setting" type="radio" value='all' <?php echo (($coupon->getRecurringBillingSetting()=="all")?"checked":""); ?> /> Apply discount to all charges</p>
</div>
<input type="hidden" name="is_gift" value='0' />
<input type="hidden" name="gift_user_id" value='0' />
<input type="hidden" name="gift_order_item_id" value='0' />
<input type="hidden" name="date_modified" value='<?php echo date("Y-m-d H:i:s"); ?>' />
<input type="hidden" name="date_added" value='<?php echo date("Y-m-d H:i:s"); ?>' />
</td>
</tr>
<tr>
<td colspan="2">
<div style="width: 98%; margin-top: 8px;" class="mm-divider"></div>
</td>
</tr>
<tr valign='top'>
<td valign='top'>Valid Products</td>
<td valign='top'>
<div style="overflow: auto; height: 165px; width: 250px; border: 1px solid #ccc;">
<?php echo $products; ?>
</div>
</td>
</tr>
</table>
</div>
<script type='text/javascript'>
jQuery(document).ready(function(){
jQuery("#mm_start_date").datepicker();
jQuery("#mm_end_date").datepicker();
});
</script>
<div class="mm-dialog-footer-container">
<div class="mm-dialog-button-container">
<button class="mm-ui-button blue">Save Coupon</button>
</div>
</div>
</form>
<?php
}