问题
With the foreach loop I'm trying to connect to my database and display in a list the products that have been added to the cart. Each product has a product ID which is correctly working and being stored in the session variable through the cart.php. I can't figure out how to connect to the database to display the information gathered about the product added - I also tried doing var_dump $SESSION['cart'] and its prints out null even after I use the "Add" button in cart.php.
<div class="row">
<h4>Shopping Cart</h4>
<?php
foreach($_SESSION['cart'] as $proid => $proq) {
// $proid is product id and $proq is quantity
// use $proid to select the product detail from database
}
?>
</div>
<!--Below is my cart.php page-->
<?php
session_start();
$productID = $_GET['product'];
$action = $_GET['action'];
switch($action) {
case "add":
$_SESSION['cart'][$productID]++;
break;
case "remove":
$_SESSION['cart'][$productID]--;
if($_SESSION['cart'][$productID] == 0) unset($_SESSION['cart'][$productID]);
break;
case "empty":
unset($_SESSION['cart']);
break;
}
header("Location: browse.php");
?>
回答1:
Based on your explanation, you are trying to retrieve data from a session value to populate a database query.
However, when your for loop executes, you have not de-serialized the session data into memory (so it cannot be accessed and you get null values).
You need to start the session before your for loop:
session_start();
foreach($_SESSION['cart'] as $proid => $proq) {
Please see more information in the php manual
Also, you can configure PHP to start the session automatically if desired (see more details in the manual linked above), however keep in mind that this will have a performance impact even on pages which do not rely on session data.
回答2:
For product view (index.php)
<?php
//current URL of the Page. cart_update.php redirects back to this URL
$current_url = base64_encode($url="http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
$results = $mysqli->query("SELECT * FROM products");
if ($results) {
//fetch results set as object and output HTML
while($obj = $results->fetch_object())
{
echo '<div class="product">';
echo '<form method="post" action="update_cart.php">';
echo '<div class="product-content">';
echo '<div class="product-info">';
echo 'Price '.$currency.$obj->price.' | ';
echo 'Qty <input type="text" name="product_qty" value="1" size="3" />';
echo '<button class="add_to_cart">Add To Cart</button>';
echo '</div></div>';
echo '<input type="hidden" name="product_code" value="'.$obj->product_code.'" />';
echo '<input type="hidden" name="type" value="add" />';
echo '<input type="hidden" name="return_url" value="'.$current_url.'" />';
echo '</form>';
echo '</div>';
}
}
?>
For Update cart (Update_cart.php)
//add item in shopping cart
if(isset($_POST["type"]) && $_POST["type"]=='add')
{
$product_code = filter_var($_POST["product_code"], FILTER_SANITIZE_STRING); //product code
$product_qty = filter_var($_POST["product_qty"], FILTER_SANITIZE_NUMBER_INT); //product code
$return_url = base64_decode($_POST["return_url"]); //return url
ySqli query - get details of item from db using product code
$results = $mysqli->query("SELECT product_name,price FROM products WHERE product_code='$product_code' LIMIT 1");
$obj = $results->fetch_object();
if ($results) { //we have the product info
//prepare array for the session variable
$new_product = array(array('name'=>$obj->product_name, 'code'=>$product_code, 'qty'=>$product_qty, 'price'=>$obj->price));
if(isset($_SESSION["products"])) //if we have the session
{
$found = false; //set found item to false
foreach ($_SESSION["products"] as $cart_itm) //loop through session array
{
if($cart_itm["code"] == $product_code){ //the item exist in array
$product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$product_qty, 'price'=>$cart_itm["price"]);
$found = true;
}else{
//item doesn't exist in the list, just retrive old info and prepare array for session var
$product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$cart_itm["qty"], 'price'=>$cart_itm["price"]);
}
}
if($found == false) //we didn't find item in array
{
//add new user item in array
$_SESSION["products"] = array_merge($product, $new_product);
}else{
//found user item in array list, and increased the quantity
$_SESSION["products"] = $product;
}
}else{
//create a new session var if does not exist
$_SESSION["products"] = $new_product;
}
}
//redirect back to original page
header('Location:'.$return_url);
}
For View Cart(View_cart.php)
<?php
$current_url = base64_encode($url="http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
if(isset($_SESSION["products"]))
{
$total = 0;
echo '<form method="post" action="checkout.php">';
echo '<ul>';
$cart_items = 0;
foreach ($_SESSION["products"] as $cart_itm)
{
$product_code = $cart_itm["code"];
$results = $mysqli->query("SELECT product_name,product_desc, price FROM products WHERE product_code='$product_code' LIMIT 1");
$obj = $results->fetch_object();
echo '<li class="cart-itm">';
echo '<span class="remove-itm"><a href="cart_update.php?removep='.$cart_itm["code"].'&return_url='.$current_url.'">×</a></span>';
echo '<div class="p-price">'.$currency.$obj->price.'</div>';
echo '<div class="product-info">';
echo '<h3>'.$obj->product_name.' (Code :'.$product_code.')</h3> ';
echo '<div class="p-qty">Qty : '.$cart_itm["qty"].'</div>';
echo '<div>'.$obj->product_desc.'</div>';
echo '</div>';
echo '</li>';
$subtotal = ($cart_itm["price"]*$cart_itm["qty"]);
$total = ($total + $subtotal);
echo '<input type="hidden" name="item_name['.$cart_items.']" value="'.$obj->product_name.'" />';
echo '<input type="hidden" name="item_code['.$cart_items.']" value="'.$product_code.'" />';
echo '<input type="hidden" name="item_desc['.$cart_items.']" value="'.$obj->product_desc.'" />';
echo '<input type="hidden" name="item_qty['.$cart_items.']" value="'.$cart_itm["qty"].'" />';
$cart_items ++;
}
echo '</ul>';
echo '<span class="check-out-txt">';
echo '<strong>Total : '.$currency.$total.'</strong> ';
echo '</span>';
echo '</form>';
}
?>
Need remove product from cart
use this in update cart (update_cart.php)
//remove item from shopping cart
if(isset($_GET["removep"]) && isset($_GET["return_url"]) && isset($_SESSION["products"]))
{
$product_code = $_GET["removep"]; //get the product code to remove
$return_url = base64_decode($_GET["return_url"]); //get return url
foreach ($_SESSION["products"] as $cart_itm) //loop through session array var
{
if($cart_itm["code"]!=$product_code){ //item does,t exist in the list
$product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$cart_itm["qty"], 'price'=>$cart_itm["price"]);
}
//create a new product list for cart
$_SESSION["products"] = $product;
}
//redirect back to original page
header('Location:'.$return_url);
}
Create database connection
<?php
$db_username = 'root';//username
$db_password = '';//password
$db_name = '';//database name
$db_host = 'localhost';//your host
$mysqli = new mysqli($db_host, $db_username, $db_password,$db_name);
?>
> Important Use this in every page
<?php
error_reporting(0);
include("config.php");
session_start();
?>
来源：https://stackoverflow.com/questions/29859822/display-item-list-in-shopping-cart-using-php