1. 购物车(shopping cart)

   2. [货运方式(delivery method)]

   3. 支付方式(payment method)

   4. 订单确认(confirmation)

   5. [第三方网站支付]

   6. 订单处理(checkout process)——这一步比较重要，因为会在这里将购物车中的信息写入订单

   7. 下单成功(checkout success)

   这样的流程在正常情况下是没有任何问题的。但是，从第5步到第6部的过程中，用户可能以为付款成功就直接关闭掉网页了，或者由于网络原因造成不能正常跳转到checkout_process页面，这样造成的后果是很严重的，因为订单不能被正常的创建。

   基于上述的分析， 我们希望稍微地改变一下流程，即在支付之前订单已经创建好了，这样就算在支付时不能从第三方支付网站跳转回来，我们也不会存在用户付款成功却在后台没有订单的情况了。经过修改后的蓝图基本是下面这样的：

   1. 在checkour_confirmation页面确认订单后，都会直接proccess，并且进入checkour_success页面,可以在这里进入付款页面。如下图所示：

   2. 如果当时客户没能付款，也可进入自己的后台对历史订单进行付款。如下图所示：

   下面我们就来看看如何一步一步来实现上述的功能。

  1. 首先我们需要对现有的支付模块进行一个改造。需要对支付方式的class增加一个字段paynow_action_url，用来表示进行支付的页面url，另外还需要增加一个函数，paynow_button($order_id)，来获取支付表单的参数隐藏域代码。
要增加paynow_action_url字段，请在类payment的构造函数中最后加上下面的代码：
复制代码 代码如下:
if ( (zen_not_null($module)) && (in_array($module.".php", $this->modules)) && (isset($GLOBALS[$module]->paynow_action_url)) ) {
$this->paynow_action_url = $GLOBALS[$module]->paynow_action_url;
}

要增加paynow_button($order_id)函数，请在payment类的最后一个函数之后加上如下的代码：
复制代码 代码如下:
function paynow_button($order_id){
if (is_array($this->modules)) {
if (is_object($GLOBALS[$this->selected_module])) {
return $GLOBALS[$this->selected_module]->paynow_button($order_id);
}
}
}

2. 以paypal支付方式为例子，说明如何具体实现。为了不破坏paypal原有的代码，我们将paypal.php文件拷贝一个副本出来，并命名为paypalsimple.php，并对里面的代码做适当的修改。代码如下所示，可以看到，这里去掉了对form_action_url的指定，并给定了paynow_action_url，因为我们希望用户点击“确认订单”后直接进入checkout_process，所以如果不指定form_action_url，那么确认订单的表单就会直接提交到checkout_process页面了，而paynow_action_url就是以前的form_action_url的值。paynow_button函数的实现也很简单，这里只是将原先的process_button()函数的内容剪切过来而已，只不过我们没有使用全局的$order变量，而是使用$order = new order($order_id),来重新构造的一个对象，这样做是为在历史订单中显示pay now按钮做准备的。
paypalsimple.php
复制代码 代码如下:
<?php
/**
* @package paypalsimple payment module
* @copyright Copyright 2003-2006 Zen Cart Development Team
* @copyright Portions Copyright 2003 osCommerce
* @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
* @version $Id: paypalsimple.php 4960 2009-12-29 11:46:46Z gary $
*/
// ensure dependencies are loaded
include_once((IS_ADMIN_FLAG === true ? DIR_FS_CATALOG_MODULES : DIR_WS_MODULES) . "payment/paypal/paypal_functions.php");
class paypalsimple {
var $code, $title, $description, $enabled;
// class constructor
function paypalsimple() {
global $order;
$this->code = "paypalsimple";
$this->title = MODULE_PAYMENT_PAYPAL_SIMPLE_TEXT_TITLE;
if(IS_ADMIN_FLAG === true){
$this->title = MODULE_PAYMENT_PAYPAL_SIMPLE_TEXT_ADMIN_TITLE;
}
$this->description = MODULE_PAYMENT_PAYPAL_SIMPLE_TEXT_DESCRIPTION;
$this->sort_order = MODULE_PAYMENT_PAYPAL_SIMPLE_SORT_ORDER;
$this->enabled = ((MODULE_PAYMENT_PAYPAL_SIMPLE_STATUS == "True") ? true : false);
if ((int)MODULE_PAYMENT_PAYPAL_SIMPLE_ORDER_STATUS_ID > 0) {
$this->order_status = MODULE_PAYMENT_PAYPAL_SIMPLE_ORDER_STATUS_ID;
}
$this->paynow_action_url = "https://" . MODULE_PAYMENT_PAYPAL_SIMPLE_HANDLER;
if (is_object($order)) $this->update_status();
}
// class methods
function update_status() {
global $order, $db;
if ( ($this->enabled == true) && ((int)MODULE_PAYMENT_PAYPAL_SIMPLE_ZONE > 0) ) {
$check_flag = false;
$check = $db->Execute("select zone_id from " . TABLE_ZONES_TO_GEO_ZONES . " where geo_zone_id = "" . MODULE_PAYMENT_PAYPAL_SIMPLE_ZONE . "" and zone_country_id = "" . $order->billing["country"]["id"] . "" order by zone_id");
while (!$check->EOF) {
if ($check->fields["zone_id"] < 1) {
$check_flag = true;
break;
} elseif ($check->fields["zone_id"] == $order->billing["zone_id"]) {
$check_flag = true;
break;
}
$check->MoveNext();
}
if ($check_flag == false) {
$this->enabled = false;
}
}
}
function javascript_validation() {
return false;
}
function selection() {
$text = MODULE_PAYMENT_SIMPLE_PAYPAL_TEXT_CATALOG_LOGO."  ".MODULE_PAYMENT_PAYPAL_SIMPLE_TEXT_TITLE . "<br/><br/>    <span class="smallText">" . MODULE_PAYMENT_PAYPAL_SIMPLE_ACCEPTANCE_MARK_TEXT . "</span><br/><br/>";
return array("id" => $this->code,
"module" => $text
);
}
function pre_confirmation_check() {
return false;
}
function confirmation() {
return false;
}
function process_button() {
return false;
}
function before_process() {
return false;
}
function after_process() {
return false;
}
function get_error() {
return false;
}
function check() {
global $db;
if (!isset($this->_check)) {
$check_query = $db->Execute("select configuration_value from " . TABLE_CONFIGURATION . " where configuration_key = "MODULE_PAYMENT_PAYPAL_SIMPLE_STATUS"");
$this->_check = $check_query->RecordCount();
}
return $this->_check;
}
function install() {
global $db;
$db->Execute("insert into " . TABLE_CONFIGURATION . " (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, set_function, date_added) values ("Enable PayPal-Simple Module", "MODULE_PAYMENT_PAYPAL_SIMPLE_STATUS", "True", "Do you want to accept PayPal-Simple payments?", "6", "0", "zen_cfg_select_option(array("True", "False"), ", now())");
$db->Execute("insert into " . TABLE_CONFIGURATION . " (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, date_added) values ("Sort order of display.", "MODULE_PAYMENT_PAYPAL_SIMPLE_SORT_ORDER", "0", "Sort order of display. Lowest is displayed first.", "6", "8", now())");
$db->Execute("insert into " . TABLE_CONFIGURATION . " (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, use_function, set_function, date_added) values ("Payment Zone", "MODULE_PAYMENT_PAYPAL_SIMPLE_ZONE", "0", "If a zone is selected, only enable this payment method for that zone.", "6", "2", "zen_get_zone_class_title", "zen_cfg_pull_down_zone_classes(", now())");
$db->Execute("insert into " . TABLE_CONFIGURATION . " (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, set_function, use_function, date_added) values ("Set Order Status", "MODULE_PAYMENT_PAYPAL_SIMPLE_ORDER_STATUS_ID", "0", "Set the status of orders made with this payment module to this value", "6", "0", "zen_cfg_pull_down_order_statuses(", "zen_get_order_status_name", now())");
$db->Execute("insert into " . TABLE_CONFIGURATION . " (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, set_function, date_added) values ("Mode for PayPal web services<br /><br />Default:<br /><code>www.paypal.com/cgi-bin/webscr</code><br />or<br /><code>www.paypal.com/us/cgi-bin/webscr</code><br />or for the UK,<br /><code>www.paypal.com/uk/cgi-bin/webscr</code>", "MODULE_PAYMENT_PAYPAL_SIMPLE_HANDLER", "www.paypal.com/cgi-bin/webscr", "Choose the URL for PayPal live processing", "6", "73", "", now())");
}
function remove() {
global $db;
$db->Execute("delete from " . TABLE_CONFIGURATION . " where configuration_key in ("" . implode("", "", $this->keys()) . "")");
}
function keys() {
return array("MODULE_PAYMENT_PAYPAL_SIMPLE_STATUS","MODULE_PAYMENT_PAYPAL_SIMPLE_SORT_ORDER","MODULE_PAYMENT_PAYPAL_SIMPLE_ZONE","MODULE_PAYMENT_PAYPAL_SIMPLE_ORDER_STATUS_ID", "MODULE_PAYMENT_PAYPAL_SIMPLE_HANDLER");
}
function paynow_button($order_id){
global $db, $order, $currencies, $currency;
require_once(DIR_WS_CLASSES . "order.php");
$order = new order($order_id);
$options = array();
$optionsCore = array();
$optionsPhone = array();
$optionsShip = array();
$optionsLineItems = array();
$optionsAggregate = array();
$optionsTrans = array();
$buttonArray = array();
$this->totalsum = $order->info["total"];
// save the session stuff permanently in case paypal loses the session
$_SESSION["ppipn_key_to_remove"] = session_id();
$db->Execute("delete from " . TABLE_PAYPAL_SESSION . " where session_id = "" . zen_db_input($_SESSION["ppipn_key_to_remove"]) . """);
$sql = "insert into " . TABLE_PAYPAL_SESSION . " (session_id, saved_session, expiry) values (
"" . zen_db_input($_SESSION["ppipn_key_to_remove"]) . "",
"" . base64_encode(serialize($_SESSION)) . "",
"" . (time() + (1*60*60*24*2)) . "")";
$db->Execute($sql);
$my_currency = select_pp_currency();
$this->transaction_currency = $my_currency;
$this->transaction_amount = ($this->totalsum * $currencies->get_value($my_currency));
$telephone = preg_replace("/D/", "", $order->customer["telephone"]);
if ($telephone != "") {
$optionsPhone["H_PhoneNumber"] = $telephone;
if (in_array($order->customer["country"]["iso_code_2"], array("US","CA"))) {
$optionsPhone["night_phone_a"] = substr($telephone,0,3);
$optionsPhone["night_phone_b"] = substr($telephone,3,3);
$optionsPhone["night_phone_c"] = substr($telephone,6,4);
$optionsPhone["day_phone_a"] = substr($telephone,0,3);
$optionsPhone["day_phone_b"] = substr($telephone,3,3);
$optionsPhone["day_phone_c"] = substr($telephone,6,4);
} else {
$optionsPhone["night_phone_b"] = $telephone;
$optionsPhone["day_phone_b"] = $telephone;
}
}
$optionsCore = array(
"charset" => CHARSET,
"lc" => $order->customer["country"]["iso_code_2"],
"page_style" => MODULE_PAYMENT_PAYPAL_PAGE_STYLE,
"custom" => zen_session_name() . "=" . zen_session_id(),
"business" => MODULE_PAYMENT_PAYPAL_BUSINESS_ID,
"return" => zen_href_link(FILENAME_PAY_SUCCESS, "referer=paypal", "SSL"),
"cancel_return" => zen_href_link(FILENAME_PAY_FAILED, "", "SSL"),
"shopping_url" => zen_href_link(FILENAME_SHOPPING_CART, "", "SSL"),
"notify_url" => zen_href_link("ipn_main_handler.php", "", "SSL",false,false,true),
"redirect_cmd" => "_xclick",
"rm" => 2,
"bn" => "zencart",
"mrb" => "R-6C7952342H795591R",
"pal" => "9E82WJBKKGPLQ",
);
$optionsCust = array(
"first_name" => replace_accents($order->customer["firstname"]),
"last_name" => replace_accents($order->customer["lastname"]),
"address1" => replace_accents($order->customer["street_address"]),
"city" => replace_accents($order->customer["city"]),
"state" => zen_get_zone_code($order->customer["country"]["id"], $order->customer["zone_id"], $order->customer["zone_id"]),
"zip" => $order->customer["postcode"],
"country" => $order->customer["country"]["iso_code_2"],
"email" => $order->customer["email_address"],
);
if ($order->customer["suburb"] != "") $optionsCust["address2"] = $order->customer["suburb"];
if (MODULE_PAYMENT_PAYPAL_ADDRESS_REQUIRED == 2) $optionsCust = array(
"address_name" => replace_accents($order->customer["firstname"] . " " . $order->customer["lastname"]),
"address_street" => replace_accents($order->customer["street_address"]),
"address_city" => replace_accents($order->customer["city"]),
"address_state" => zen_get_zone_code($order->customer["country"]["id"], $order->customer["zone_id"], $order->customer["zone_id"]),
"address_zip" => $order->customer["postcode"],
"address_country" => $order->customer["country"]["title"],
"address_country_code" => $order->customer["country"]["iso_code_2"],
"payer_email" => $order->customer["email_address"],
);
$optionsShip = array(
//"address_override" => MODULE_PAYMENT_PAYPAL_ADDRESS_OVERRIDE,
"no_shipping" => MODULE_PAYMENT_PAYPAL_ADDRESS_REQUIRED,
);
if (MODULE_PAYMENT_PAYPAL_DETAILED_CART == "Yes") $optionsLineItems = ipn_getLineItemDetails();
if (sizeof($optionsLineItems) > 0) {
$optionsLineItems["cmd"] = "_cart";
// $optionsLineItems["num_cart_items"] = sizeof($order->products);
if (isset($optionsLineItems["shipping"])) {
$optionsLineItems["shipping_1"] = $optionsLineItems["shipping"];
unset($optionsLineItems["shipping"]);
}
if (isset($optionsLineItems["handling"])) {
$optionsLineItems["handling_1"] = $optionsLineItems["handling"];
unset($optionsLineItems["handling"]);
}
unset($optionsLineItems["subtotal"]);
// if line-item details couldn"t be kept due to calculation mismatches or discounts etc, default to aggregate mode
if (!isset($optionsLineItems["item_name_1"])) $optionsLineItems = array();
//if ($optionsLineItems["amount"] != $this->transaction_amount) $optionsLineItems = array();
ipn_debug_email("Line Item Details (if blank, this means there was a data mismatch, and thus bypassed): " . " " . print_r($optionsLineItems, true));
}
$products_name_display = "";
/*
for ($i=0, $n=sizeof($order->products); $i<$n; $i++) {
if(i > 0) {
$products_name_display.= ", ";
}
$products_name_display.= $order->products[$i]["name"]. "(". $order->products[$i]["qty"] .",".$order->products[$i]["dhisys_web_order_number"].")";
}*/
$optionsAggregate = array(
"cmd" => "_ext-enter",
"item_name" => $products_name_display,
"item_number" => $order_id,
"num_cart_items" => sizeof($order->products),
"amount" => number_format($this->transaction_amount, $currencies->get_decimal_places($my_currency)),
"shipping" => "0.00",
);
if (MODULE_PAYMENT_PAYPAL_TAX_OVERRIDE == "true") $optionsAggregate["tax"] = "0.00";
if (MODULE_PAYMENT_PAYPAL_TAX_OVERRIDE == "true") $optionsAggregate["tax_cart"] = "0.00";
$optionsTrans = array(
"upload" => (int)(sizeof($order->products) > 0),
"currency_code" => $my_currency,
// "paypal_order_id" => $paypal_order_id,
//"no_note" => "1",
//"invoice" => "",
);
// if line-item info is invalid, use aggregate:
if (sizeof($optionsLineItems) > 0) $optionsAggregate = $optionsLineItems;
// prepare submission
$options = array_merge($optionsCore, $optionsCust, $optionsPhone, $optionsShip, $optionsTrans, $optionsAggregate);
ipn_debug_email("Keys for submission: " . print_r($options, true));
if(sizeof($order->products) > 0){
$options["cmd"] = "_cart";
for ($i=0, $n=sizeof($order->products); $i<$n; $i++) {
$options["item_name_". (string)($i+1)] = $order->products[$i]["name"];
$options["item_number_". (string)($i+1)] = $order->products[$i]["dhisys_web_order_number"];
$options["amount_". (string)($i+1)] = number_format((float)$order->products[$i]["final_price"],2);
$options["quantity_". (string)($i+1)] = $order->products[$i]["qty"];
}
}
// build the button fields
foreach ($options as $name => $value) {
// remove quotation marks
$value = str_replace(""", "", $value);
// check for invalid chars
if (preg_match("/[^a-zA-Z_0-9]/", $name)) {
ipn_debug_email("datacheck - ABORTING - preg_match found invalid submission key: " . $name . " (" . $value . ")");
break;
}
// do we need special handling for & and = symbols?
//if (strpos($value, "&") !== false || strpos($value, "=") !== false) $value = urlencode($value);
$buttonArray[] = zen_draw_hidden_field($name, $value);
}
$_SESSION["paypal_transaction_info"] = array($this->transaction_amount, $this->transaction_currency);
$process_button_string = implode(" ", $buttonArray) . " ";
return $process_button_string;
}
}
?>

3. 在checkout_success页面中显示pay now按钮。打开文件"includes/modules/pages/checkout_success/header.php"，在文件的末尾添加下面的代码（如果你已经掌握zen-cart中的通知者/观察者模式，并且又不想破坏zen-cart核心代码的话，也可以创建一个观察类来监听NOTIFY_HEADER_END_CHECKOUT_SUCCESS来实现）。
复制代码 代码如下:
require_once(DIR_WS_CLASSES . "order.php");
require_once(DIR_WS_CLASSES . "payment.php");
$payment_modules = new payment($orders->fields["payment_module_code"]);

打开文件"includes/modules/templates/template_default/templates/tpl_checkout_success_default.php"，并在适当的位置加上如下的代码，这里对订单的状态进行了一个判断，当只有订单的状态在未付款状态，才显示该按钮，
复制代码 代码如下:
<div id="pay_now">
<?php
//&& $orders->fields["orders_status"] == "1"
if(isset($payment_modules->paynow_action_url) && $payment_modules->paynow_action_url != ""&& $orders->fields["orders_status"] == "1"){
echo("<fieldset id="csNotifications">");
echo("<legend>".TEXT_PAYNOW."</legend>");
echo zen_draw_form("checkout_paynow", $payment_modules->paynow_action_url, "post", "id="checkout_confirmation" onsubmit="submitonce();"");
$selection = $payment_modules->selection();
echo("<div class="buttonRow payment_method">".$selection[0]["module"]."</div>");
echo("<div class="buttonRow forward paynow">");
if (is_array($payment_modules->modules)) {
echo $payment_modules->paynow_button($orders_id);
}
echo(zen_image_submit(BUTTON_IMAGE_PAYNOW, BUTTON_IMAGE_PAYNOW_ALT, "name="btn_paynow" id="btn_paynow""));
echo("</div>");
echo("</form>");
echo("</fieldset>");
}
?>
</div>

4. 在历史订单中显示pay now按钮。需要显示pay now按钮的页面有三个：account, account_history,account_history_info，这里的实现和checkout_success页面的实现大同小异，只是传给$payment_modules的函数paynow_button的参数不一样而已，这里就不再赘述。
总结：
经过上面的修改，我们的流程如下：
1. 购物车(shopping cart)
2. [货运方式(delivery method)]
3. 支付方式(payment method)
4. 订单确认(confirmation)
5. 订单处理(checkout process)
6. 下单成功(checkout success)
7. [第三方网站支付]
因为从订单确认到订单处理，都是在我们自己的网站完成的，并且进入支付网站之前，订单已经存在了，这样就不会出现掉单的情况了。