The Shopping Basket [ 158 ] Service subscription payments: These are generally similar to one-click payments; you click on the subscription level, and then you pay. Most subscription services also make it easy to upgrade or downgrade accounts at any point, resulting in the customer being charged pro-rata based on how long their account was at each subscription level. Subscription sites give access to products or services for the duration of a subscription, from a business perspective. This often allows measurable recurring income, and can reduce transaction fees. For example, on a music download website, the customer may wish to make 25 purchases a month, and each purchase would incur a transaction fee. With a subscription payment method, the transaction fees apply to less regular, larger payments, which tend to work out less overall. Auctions: Auctions lead to bidding for products. This involves the customer committing to purchase the product at a certain price, provided no other customer commits to a higher price within the auction time window. Often, auction sites are automated, so the customer enters a maximum price, and over the duration of the auction, the website will increase the customer's bid, with respect to their maximum bid, as and when other bids come in. For our framework, a shopping basket is going to be the most appropriate option; however, this is a framework. After all, there is nothing stopping us from implementing other methods of facilitating purchases. Our basket At the end of this chapter, we will have a "shopping basket" page and a smaller shopping basket displayed on each page. Per-page basket If there is nothing in the customer's basket, they will be shown an empty basket message, like the following, on each page: • • This material is copyright and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 Chapter 6 [ 159 ] If the customer has products in their basket, the small basket message on each page reects something similar to this: And, our main basket page should look like this: Considerations for our shopping basket We discussed a number of considerations we need to take into account within our shopping basket in Chapter 4, Product Variations and User Uploads. Let's recap on those, and discuss how we shall implement those suggestions. Stock levels: In some cases, we need to determine if there is sufcient stock when a customer adds a product to their basket. When we add a product to the basket, we can simply query the products database, and ensure the level in stock is either more than the quantity the customer wishes to purchase, or is not relevant for that product (for example digital delivery products, services, and so on). • This material is copyright and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 The Shopping Basket [ 160 ] Product variations: When a customer adds a product variation to their basket, we need to record the variation that it is. The way products are maintained in an array for the basket must differentiate products and product variants, to ensure that when a customer adds a second instance of the product, the variant choices are preserved, allowing the customer to purchase any number of any different variations of a product. Product customizations: If the customer customizes a product, we need to record any customization data they have left, as with the product variations. Templates: We need a number of different templates to show the basket: an empty basket, a summary of the basket on every page, and so on. Subtotals: We need to calculate subtotals for each product in the basket. Creating a basket Let us create our shopping basket in stages, starting with basic functionality, and then extending it as we go along to support all of the considerations we have discussed. When to build a user's basket Our shopping basket will probably be stored on most pages, so we need to ensure that we can build up the contents of a shopping basket regardless of where a user is within the site being powered by our framework. Obviously, we may not always want to have this available, but more often than not, we would. Another consideration is with regards to user authentication: if the visitor is a logged-in user, then the basket will be built in a different way, so we need to ensure we build the basket after any authentication processing is done. Basket database We looked at creating a wish list in Chapter 5, Enhancing the User Experience; although the wish list was only suitable for standard products, which couldn't be customized and didn't have variants. The shopping basket needs to work in a similar way to this. A single database table is required that relates these products to the customers. Let's take the data from our wish-list table, and extend it to make it more suitable for a shopping basket. • • • • This material is copyright and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 Chapter 6 [ 161 ] Field Type Description ID Integer (Auto increment, Primary Key) Session_id Varchar To relate products in the basket to customers who are not logged into the site. User_id Integer To relate products in the basket to customers who are logged into the site. Quantity Integer The quantity of the particular product that the customer wishes to purchase. IPAddress Varchar This is also needed to help relate the products in the basket to users who are not logged in. Timestamp Timestamp To maintain active and expired contents. This is primarily for customers who are not logged in; after a certain period of time, we need to assume that the session ID and IP address now belong to another customer. This database is represented with the following SQL code: CREATE TABLE `book4database`.`basket_contents` ( `ID` INT NOT NULL AUTO_INCREMENT PRIMARY KEY, `session_id` VARCHAR( 50 ) NOT NULL, `user_id` INT NOT NULL , `product_id` INT NOT NULL, `quantity` INT NOT NULL, `ip_address` VARCHAR( 50 ) NOT NULL, `timestamp` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ) ENGINE = MYISAM; Basket contents We have a basket structure in our database, but we now need to allow our customers to control the contents of the basket. This involves allowing them to: View the basket Add products to their basket Add customizable products to their basket Add variations of a product to their basket Edit quantities of products in their basket Let's go through these requirements, and implement them into our framework. • • • • • This material is copyright and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 The Shopping Basket [ 162 ] Viewing the basket This may seem strange, discussing viewing the basket before our customers are even able to add products to the basket. However, the reason for this is that we need functionality in place for checking the basket contents before we can add a product to the basket. If a customer adds a product to their basket twice, the second instance should increment the quantity of the rst instance of the product, which means we need to be able to determine if a product exists in the basket. The following stages are involved in checking our shopping basket: 1. Select relevant data from the basket table in the database. 2. Build an array of data representing the contents of the basket. 3. Set some variables, including basket cost, if the basket is empty, and that we have checked the baskets contents. checkBasket method We need a function that performs all of the aspects of checking the basket, so that we can display the basket to our customers. /** * Checks for the users basket contents * @return void */ The rst stage is to generate a number of variables to use later. We indicate that the basket has been checked, which prevents the framework from unnecessarily calling this method again once it has already been called, and the data processed. We also need the user's session ID and IP address, primarily for customers who are not logged in, and if the user is logged in, we need to get their username. public function checkBasket() { // set out basket checked variable - this is to prevent this // function being called unnecessarily // if we run this on page load to generate a mini-basket, we // don't need to reload it to display the main basket! $this->basketChecked = true; // get user identifiable data $session_id = session_id(); $ip_address = $_SERVER ['REMOTE_ADDR']; // if the customer is logged in, our query is different if( $registry->getObject('authentication')-> isLoggedIn() == true ) This material is copyright and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 . and is licensed for the sole use by jackie tracey on 23rd February 2010 953 Quincy Drive, , Brick, , 08724 Chapter 6 [ 159 ] If the customer has products in their basket, the small basket message. PRIMARY KEY, `session_id` VARCHAR( 50 ) NOT NULL, `user_id` INT NOT NULL , `product_id` INT NOT NULL, `quantity` INT NOT NULL, `ip_address` VARCHAR( 50 ) NOT NULL, `timestamp` TIMESTAMP. The Shopping Basket [ 158 ] Service subscription payments: These are generally similar to one-click payments; you click