ExpressionEngine Docs

Getting Started

The Fundamentals

Advanced Usage

Best Practices

Community

Simple Commerce

The Simple Commerce Module is a basic but flexible module that easily integrates ExpressionEngine with PayPal.

Simple Commerce Purchase Tag

The Simple Commerce Purchase tag is the primary tag used to display information about items in your store. It is designed to be used within a Channel Entries tag, as store items are actually Channel Entries.

Here is a simple example:

{exp:simple_commerce:purchase entry_id="{entry_id}" success="site/success" cancel="site/index"}
 <h3>{item_name}</h3>

 <p><strong>{item_sale_price}</strong></p>

 {if item_type == "purchase"}
   <p><a href="{buy_now_url}" onclick="window.open(this.href);return false;">Buy Now</a></p>
   <p><a href="{add_to_cart_url}" onclick="window.open(this.href);return false;">Add to Cart</a></p>
   <p><a href="{view_cart_url}" onclick="window.open(this.href);return false;">View Cart</a></p>
 {/if}
 {if item_type == "subscription"}
   <p><a href="{subscribe_now_url}" onclick="window.open(this.href);return false;">Subscribe Now</a></p>
 {/if}
{/exp:simple_commerce:purchase}

Parameters

cancel= 

cancel="store/cancel"

You may specify a particular Template to display if a purchase is cancelled mid-transaction. This takes a standard “Template_Group/Template” as input, or you may provide a full URL, e.g. https://example.com/store/cancel/. If this parameter is not supplied, your site’s main index template will be displayed.

country_code= 

country_code="DE"

This parameter controls the language that will be used on the initial PayPal shopping cart / log in screen when someone makes a purchase from your store. Use the two letter country abbreviation, following the ISO 3166 standard. If no parameter is given, a default of ‘US’ will be used.

currency= 

currency="USD"

The three letter representation of the currency for the item prices in the store, using the ISO 4217 standard. Default is “USD” (U.S. Dollars). For other currencies, please refer to Wikipedia’s ISO 4127 listing.

decimal= 

decimal=","

Change the decimal separator for display. For example, instead of display 3.95, you can have the price outputted as 3,95.

entry_id= 

entry_id="{entry_id}"

REQUIRED. As the Simple Commerce Purchase tag is designed to be used inside a Channel Entries tag, the {entry_id} variable of the Channel Entries tag will normally be used to provide the value. You may also use a specific entry id to display an item’s information outside of a Channel Entries tag.

show_disabled= 

show_disabled="yes"

Allows the Simple Commerce Purchase tag to output information for store items that are not enabled. This can be used in conjunction with an item_enabled conditional to display information for enabled / disabled items. e.g.:

{if item_enabled == 'n'}
  <p><strong>NOT AVAILABLE</strong></p>
{if:else}
  <p>{item_sale_price}</p>
  <p><a href="{buy_now_url}" onclick="window.open(this.href);return false;">Buy Now</a></p>
  <p><a href="{add_to_cart_url}" onclick="window.open(this.href);return false;">Add to Cart</a></p>
  <p><a href="{view_cart_url}" onclick="window.open(this.href);return false;">View Cart</a></p>
{/if}

success= 

success="store/thank_you"

REQUIRED. You must specify a particular Template to display after a successful purchase transaction. This takes a standard “Template_Group/Template” as input, or you may provide a full URL, e.g. https://example.com/store/thank\_you/.

Variables

Item Details

{item_id}

The store item’s id.

{item_name}

The descriptive name of the item.

{item_enabled}

Whether or not the store item is enabled (y/n). This can be useful if you use custom queries to access information about your store items. If the item is not enabled (“n”), the {exp:simple_commerce:purchase} tag will not output information for that item.

{item_purchases}

The number of times the item has been purchased.

{item_regular_price}

The item’s regular price.

{item_sale_price}

The item’s sale price.

{item_use_sale}

Whether or not the item is on sale (y/n). Useful in conditionals and custom queries. If the item is marked as on sale, the PayPal purchase links will automatically use the sale price.

{item_type}

Whether item is a recurring item (subscription/purchase). Useful in conditionals and custom queries.

Note: Recurring payments cannot be made using the shopping cart. Thus item_type conditionals should be used if you offer cart links and are mixing recurring and non-recurring items.

Purchase Links

{add_to_cart_url} 

<a href="{add_to_cart_url}" onclick="window.open(this.href);return false;">Add to Cart</a>

The PayPal URL to add the item to the PayPal shopping cart. The example shown is a typical usage as a popup link. Recurring payments cannot be made using the cart.

Note: If using encrypted payments, this link may be cutoff in some browsers. Purchase buttons are recommended as an alternative.

{buy_now_url} 

<a href="{buy_now_url}" onclick="window.open(this.href);return false;">Buy Now</a>

Note: If using encrypted payments, this link may be cutoff in some browsers. Purchase buttons are recommended as an alternative.

{view_cart_url} 

<a href="{view_cart_url}" onclick="window.open(this.href);return false;">View Cart</a>

The PayPal URL to view the contents of the shopping cart. The example shown is a typical usage as a popup link.

{subscribe_now_url} 

<a href="{subscribe_now_url}" onclick="window.open(this.href);return false;">Subscribe Now</a>

The “Subscribe Now” PayPal URL. The example shown is a typical usage as a popup link.

Note: If using encrypted payments, this link may be cutoff in some browsers. Purchase buttons are recommended as an alternative.

Purchase Buttons

Purchase buttons are variable pairs, and enclose the text used for the button label.

{add_to_cart_button} 

{add_to_cart_button}Add to Cart{/add_to_cart_button}

A button that adds the item to the PayPal shopping cart.

{buy_now_button} 

{buy_now_button}Buy Now{/buy_now_button}

A “Buy Now” PayPal button.

{view_cart_button} 

{view_cart_button}View Cart{/view_cart_button}

A button to view the contents of the shopping cart.

Recurring Payments

The Simple Commerce Module supports Paypal Subscriptions and Recurring Payments (offsite link). Using recurring payments, you can offer your users automatically recurring subscriptions. For purchases managed through the module, you can specify emails to be sent upon a recurring purchase, emails to be sent when a recurring payment is canceled, and alter a member’s group assignment based on their subscription status.

Note: Automatic emails and member role changes rely on Instant Payment Notification. New subscription automated features will only work for purchases made by logged-in members of your site. Subscription termination automatic features will only work for purchases made by members.

Recurring Payment Variables in Template Tags

Paypal does not allow recurring payments to be added to the shopping cart. It is therefore important to use the item_type variable in a conditional if you use shopping cart links.

Recurring Payment Subscription Expiration Date

There is no set expiration date for a recurring payment. In the control panel display, ongoing recurring payments will be marked as such. An expiration date is provided only for subscriptions that have been terminated.

How Recurring Payments may be terminated

PayPal will send an instant payment notification if the purchaser has canceled their subscription. You may also cancel a subscription through the PayPal control panel, triggering an instant payment notification. See the PayPal documentation for details.

Testing Purchases

When setting up your Simple Commerce store, it can be valuable to test your settings by running fake purchases through your store. PayPal makes this possible with a “sandbox” area, where fictitious purchases can be made without anyone’s credit card or PayPal account actually being used.

Setting up a Developer Account with PayPal

To use the sandbox area, you will have to set up a free developer account with PayPal.

  1. Point your browser to https://developer.paypal.com/
  2. Click “Sandbox” and then “Create Test Accounts”. Sandbox accounts are not tied to your PayPal account on www.paypal.com in any way.
    1. Create a Premier Account for Merchant. You can usually use the same information that your real merchant account uses. Remember that nothing on the Sandbox is tied to real world information or accounts.
    2. Create a Personal Account for a test purchaser. Keep this account’s login information handy, as you will be using it to make test purchases.
  3. Launch Sandbox for the Premier Account
    1. Set up Instant Payment Notification.
    2. Add a Bank Account. Enter a fictional name, PayPal will automatically create fake account numbers for you.
    3. Confirm the Bank Account. Simply click confirm–no test deposits are made.
  4. Launch Sandbox for the Personal Account
    1. Add a Credit Card. Again, you can use fictitious information, and allow PayPal to provide the false account numbers automatically.

Debug Mode

In order for the Simple Commerce module to create purchase links that utilize PayPal’s Sandbox area instead of the real PayPal site, you need to enable the module’s debug mode. To do so, open mod.simple_commerce.php, and near the top where the class variables are defined, set $debug to TRUE.

var $debug                = TRUE;

Remember to set this variable to FALSE when you wish to take your store live and route purchases to the real PayPal website.

Encrypted Website Payments

The Simple Commerce Module has the ability to utilize PayPal’s Encrypted Website Payments feature. In order to use these features, there are some additional steps you will need to take to set up Encrypted Website Payments with PayPal. A brief background on the process will also be beneficial.

How Encrypted Payments Work

After exchanging public certificates with PayPal, the button or link parameters of a purchase are encrypted with PayPal’s public key, and digitally signed with the merchant’s private key. When a purchase request is made from the encrypted form or link, PayPal checks the authenticity of the information by using the merchant’s uploaded public certificate. PayPal then decrypts the information with their private key, and the purchase transaction is allowed to continue.

The steps required to use Encrypted Website Payments with PayPal are to:

  1. Generate a private key
  2. Generate a public certificate
  3. Upload your public certificate to PayPal
  4. Update your Certificate ID in your Simple Commerce control panel
  5. Download PayPal’s public certificate
  6. Update the paths to the files in your Simple Commerce control panel

For the most security, you may also wish to set up your PayPal account so that it only accepts encrypted payments.

PayPal accepts only X.509 public certificates in OpenSSL PEM format, from any established certificate authority, such as VeriSign You can also create your own private key and public certificate using the open source software OpenSSL. Most *nix based operating systems (including Macintosh OS X) will already have this software compiled and ready to use. If you are running Windows, there are pre-compiled binaries available. The sections that follow describe creating your public certificate and private key using OpenSSL.

Generate a private key

The private key is the portion of the encryption method that is kept secret and not sent to anyone. To create your private key, key in the following at the command line:

openssl genrsa -out private_key.pem 1024

“private_key.pem” is the name of the file that will be created in the directory you are running the command from. You will need to upload this file to your server only.

Note: ExpressionEngine must have read access to the directory you upload the private key to, but for security it is highly recommended that you use a location above the public HTML folder on your account so that it is not accessible via the web.

Generate a public certificate

The public certificate is the portion of the encryption method that you provide PayPal to enable them to accept encrypted payments for you. To create your public certificate, key in the following at the command line:

openssl req -new -key private_key.pem -x509 -days 730 -out public_certificate.pem

“private_key.pem” is the name of the private key file generated in step one. This command needs to be ran from the same directory, or provide a path to the private key file. “public_certificate.pem” is the name of the public certificate file that will be created in the directory you are running the command from.

You will be prompted to answer some questions. You should answer these questions with the same information used by the PayPal merchant account. Once the public certificate is created, you must upload it to your server.

Note: ExpressionEngine must have read access to the directory you upload the public certificate to, but for security it is highly recommended that you use a location above the public HTML folder on your account so that it is not accessible via the web.

Upload your public certificate to PayPal

You must also upload your public certificate to PayPal at the following URL: https://www.paypal.com/us/cgi-bin/webscr?cmd=_profile-website-cert, or as follows:

  1. Log into your PayPal account
  2. Click the Profile subtab
  3. In the Seller Preferences column, click Encrypted Payment Settings.
  4. Click Add
  5. Click browse and select the public certificate file you just created

When you have successfully uploaded your public certificate to PayPal, it will be displayed under “Your Public Certificates”. You will need information from this screen in the following step.

Update your Certificate ID

In the Encrypted Payment Settings section of your PayPal Seller Preferences, the “Cert ID” column of the table showing your uploaded public certificates displays the certificate ID that PayPal assigned to the certificate. In your Simple Commerce control panel PayPal Settings, key in your certificate ID to the field marked ID Given to Public Certificate by PayPal.

Download PayPal’s public certificate

In the same area of PayPal’s website that you used in step 3 to upload your public certificate, download PayPal’s public certificate. Upload this file to your server.

Note: ExpressionEngine must have read access to the directory you upload the public certificate to, but for security it is highly recommended that you use a location above the public HTML folder on your account so that it is not accessible via the web.

Update paths to your certificates and key

In your Simple Commerce control panel PayPal Settings, update the paths for the certificates and key, as well as the folder used to temporarily store encrypted files. As indicated in the notes, this path must be readable by ExpressionEngine, but should not be accessible from the web.

Accept encrypted payments only

For maximum security, you may wish to set up PayPal so that your account only accepts encrypted payments. This will make it impossible for people to alter the price or information for a purchase unless they obtain your public certificate and private key (keep them safe!).

To block unencrypted payments, log in to PayPal and navigate to My Selling Tools > Website preferences (under “Selling online” heading) > Encrypted Website Payments, and then select “On” next to “Block Non-encrypted Website Payments”.

Control Panel

See the Simple Commerce Control Panel page for more information on:

ExpressionEngine 6 Docs
©2002–2022 Packet Tide,LLC. Edit this page