放入購物車腳本 - 一些設計的幫助，請

Question

我正在寫一個腳本，讓用戶放置物品在他們的籃子。到目前爲止，這是非常複雜的，我想和他人談一談，看看他們能否提出更好的設計或者整理當前的設計。這裏是我的代碼，這並不能很好地工作（即有，我還沒有得到解決的錯誤），以留言中顯示我的意圖：

<?php 
session_start(); 
include_once("db_include.php5"); 
doDB(); 


if(!$_GET["productid"] || !$_GET["qty"]) { 
//the user has entered the address directly into their address bar, send them away (if=1 to let me know where the script branched) 
header("Location:index.php5?if=1"); 
exit(); 
} 

**//do select query to verify item id is valid, in case they entered data into the query string or the item has been removed from db** 
$check_sql = "SELECT * FROM aromaProducts1 WHERE id='".$_GET["productid"]."'"; 
$check_res = mysqli_query($mysqli, $check_sql) or die(mysqli_error($mysqli)); 

if(mysqli_num_rows($check_res) == 0) { 
**//item doesn't exist, redirect user** 
header("Location:index.php5?if=2"); 
exit(); 
} else if(mysqli_num_rows($check_res) != 0) { 
**//item exists 
//do select query to check for item id already in basket - if this item is already in the table associated with the user's session id (which will be added every time an item is), then we want to change the quantity only** 
$duplicate_sql = "SELECT qty FROM sessionBasket WHERE product_id='".$_GET["productid"]."' AND usersessid='".$_SESSION["PHPSESSID"]."'"; 
$duplicate_res = mysqli_query($mysqli, $duplicate_sql) or die(mysqli_error($mysqli)); 

if(mysqli_num_rows($duplicate_res) != 0) { 
**//item in basket - add another - fetch current quantity and add new quantity** 
$basketInfo = mysqli_fetch_array($duplicate_res); 
$currQty = $basket_info["qty"]; 
$add_sql = "UPDATE sessionBasket SET qty='".($_GET["qty"]+$currQty)."' WHERE usersessid='".$_SESSION["PHPSESSID"]."'AND product_id='".$_GET["productid"]."'"; 
$add_res = mysqli_query($mysqli, $add_sql) or die(mysqli_error($mysqli)); 

if($add_res !== TRUE) { 
**//wasn't updated for some reason - this is where my script currently breaks** 
header("Location:basketfailredirect.php5?error=add"); 
exit(); 
} else if($add_res === TRUE) { 
**//was updated - send them away** 
header("basket.php5?res=add"); 
exit(); 
} 


} else if(mysqli_num_rows($duplicate_res) == 0) { 
**//no existing items in basket, so we want to add the current item info associated with the user's id/session id** 

**//fetch product id, passed in query string from the product info page** 
$productid = $_GET["productid"]; 

**//sanitize possible inputs, if set - notes is a field added to the product info page for custom products, and we want to sanitize it if it's set - note that check_chars_mailto() is a function I have in the db_include file** 
$notes = isset($_GET["notes"])?trim(mysqli_real_escape_string(check_chars_mailto($_GET["notes"]))):""; 
**//if the user is logged in, their userid is stored in the session variable** 
$userid = $_SESSION["userid"]?$_SESSION["userid"]:""; 
**//not sure about the keep alive option - i.e. store basket contents even if the user doesnt register/sign in, but keeping the option there** 
$alive = $_SESSION["alive"]?$_SESSION["alive"]:"no"; 


**//insert query** 
$insert_sql = "INSERT INTO sessionBasket (userid, usersessid, date_added, keep_alive, product_id, qty, notes) VALUES (
'".$userid."', 
'".$_SESSION["PHPSESSID"]."', 
now(), 
'".$alive."', 
'".$productid."', 
'".$_GET["qty"]."', 
'".htmlspecialchars($notes)."')"; 
$insert_res = mysqli_query($mysqli, $insert_sql) or die(mysqli_error($mysqli)); 

if($insert_res === TRUE) { 
**//success** 
header("Location:basket.php5?res=add"); 
exit(); 
} else if($insert_res !== TRUE) { 
**//fail** 
header("Location:basketfailredirect.php5?error=add2"); 
exit(); 
} 
} 
} 
?> 

這實在是太複雜了，我 - 我想允許空字段，添加用戶標識符（如果可用的話）（這在我的UPDATE查詢中是缺失的）......這是距離一個好設計百萬英里還是什麼？

此外，當我嘗試將項目添加到購物籃時，我現在得到一個錯誤：內部服務器錯誤500.我懷疑這是由於編碼錯誤，因爲我的搜索結果和產品查看頁面工作，並且他們使用相同的服務器和這個腳本一樣的數據庫。

Answer 1

您應該考慮使用PHP內置的僞對象定向樣式。

您還應該着眼於使用PHP框架，如Zend或CakePHP。即使你沒有使用PHP框架，你也應該能夠通過php的類和接口對象以面向對象的方式創建你的代碼。

通過將代碼分離到類和函數中，您可以使您的（和我們）的調試更加輕鬆，無論是現在還是將來在編輯代碼時。