Single click donations with CiviCRM

From Creative Commons
Revision as of 17:14, 18 March 2010 by Nkinkade (talk | contribs) (Usage)
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OneClickDonate.php is one of the PHP scripts that is behind CC's one-click-like donation process. The buttons on CC's donation page all lead to this script, which processes any submitted variables and then sends the contributor off to PayPal. Contributor's won't generally even be aware that they have passed through this script; it will appear to them that they went directly from the donation page to PayPal.

There are a number of possible benefits to using this method as opposed to regular contribution pages in CiviCRM:

  • The contributor makes a single click to donate on your site. The less clicks/keystrokes the better chance someone will complete a contribution. I believe this has been empirically tested and demonstrated (??).
  • You are no longer limited to designing your contribution pages within the confines/scope of Drupal and CiviCRM. You can create pages the way you want, wherever you want. This is especially nice for widgets, or anyone else wanting to help your campaign. Potentially, people can create their own donate links on their own sites ... it doesn't matter. And if you run multiple sites, you can place Donate links wherever you want on any of those sites, and it makes no difference whether it's run by Drupal, Wordpress, Joomla, or even made with static HTML.
  • Tired of Pending (Incomplete Transaction) contribution statuses and bogus contacts for people who never completed a transaction? This method eliminates those 100% because no contact or contribution will ever end up in the database until a contribution has been completed at PayPal.

The script is located in CC's public git repository.

Special Considerations

This method is known to work with CiviCRM version 3.1.1. It should work fine with any version in the 2.2.x line (we used it for a long time with 2.2.7).

It currently only works with PayPal and Google Checkout.

OneClickDonate.php will not work without modifications to a couple other CiviCRM files: CRM/Contribute/BAO/Contribution/Utils.php and bin/ContributionProcessor.php. The necessary patches for those files are here:

Some of the modifications in the above patches are specific to CC and will need to be changed for other installations.

Once the scripts are in place and modified to suit your unique setup and needs, then you simply need to run bin/ContributionProcessor.php periodically to pull new contributions into CiviCRM. CC does this via a cronjob that looks something like:

*/15 * * * * wget -O - -q -t 1 " \
name=XXXXXXXX&pass=XXXXXXXX&key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXX&ppID=5&ppMode=live&type=paypal" &> /dev/null"

Static variables

There are a couple variables that are statically defined in the script. They are presumed to not need changing on a flexible basis:

# Valid groups that contributors can join.  This is just a safeguard
# to prevent contributors from joining arbitrary groups.  This should
# be an array of group names as they are seen in the CiviCRM admin
# interface, not as they are in the database.  Example:
$pp_config['valid_groups'] = array(
    "CC Newsletter",
    "CC Events"

# The base PayPal URL for the request (minus the query string)
$pp_config['paypal_base_url'] = "";

# Email address of site's PayPal account
$pp_config['paypal_business'] = "";

Predefined variables

There are a few variables that need a default value because they are too important to leave to chance, yet can be overridden by one of the variables under Usage.

// Valid groups that users can join.  This is just a safeguard to prevent users
// from joining arbitrary groups
$pp_config['valid_groups'] = array(
    "CC Newsletter",
    "CC Events"

// Base URL for PayPal request (minus the query string)
$pp_config['paypal_base_url'] = "";

// Email address of site's PayPal account
$pp_config['paypal_business'] = "";

// Base URL for Google Checkout request
$pp_config['gc_base_url'] = "";

// Default name of item as contributor sees it and as recorded in CiviCRM. Can be overidden by passing $_REQUEST['source'].
$pp_config['item_name'] = "Online Contribution: Support Creative Commons";

// Where contributor goes if they cancel contribution at payment processor. Can be overidden by passing $_REQUEST['cancel_return'].
$pp_config['cancel_return'] = "";

// Where user goes when they click "Return to Merchant Site". Can be overidden by passing $_REQUEST['return'].
$pp_config['return'] = "";

// The minimum amount someone can donate.
$pp_config['min_amount'] = '5';


Anyone can make use of the script from anywhere, but the script expects certain variables to be passed to it. The only variables which are absolutely necessary are pp and amount. Here is a summary of the possible variables, which can be sent by either a GET or POST request:

  • pp (required): The payment processor to use. Presently it can be one of paypal and gc (for Google Checkout). Example: ?pp=paypal
  • amount (required): The amount of the contribution, with no currency symbol. It can be a floating number, but will get rounded to two decimal places if for some reason it has more. Example: ?amount=150
  • cancel_return (optional): This is the URL the contributor will be directed to should they for some reason click a Cancel link on the payment processor's site without having completed the transaction. Will always have a predefined default value should it not be passed. Example (urlencoded): ?
  • groups (optional): A colon separated list of groups that the user should be subscribed to. The group names are the exact names as they are found in the CiviCRM database, spaces and all. The script will not let users join arbitrary groups. Passed groups that are not in the predefined groups list in OneClickDonate.php will be ignored. Example (urlencoded): ?groups=CC+Newsletter:CC+Events
  • pcpid (optional): If this contribution originated from a Personal Campaign Page (PCP), this is the CiviCRM database ID of the PCP page. Example: ?pcpid=8
  • premium (optional): If the user has opted for a gift/premium, this is the CiviCRM database ID of the premium they will get. Example: ?premium=12
    • size (optional): If the premium includes a t-shirt, this is a free-text description of the size. This option is ignored if premium is not set. Example (urlencoded): ?size=Adult+Large
  • receipt (optional): This is the database ID of the message template to use when generating a receipt email to the contributor. These are the message templates found in CiviCRM at CiviCRM -> Administer CiviCRM -> Configure -> Message Templates. This functionality allow you to send a different receipt message based on various criteria, whatever they may be. You can use any, all or none of a few variable tokens in the templates. They are pretty much self-explanatory and they are these:
    • %{amount}
    • %{date}
    • %{trxn_id}
    • %{first_name}
    • %{last_name}
  • return (optional): This is the URL the contributor will be directed to if/when they click on some link directing them back to your site after having completed the transaction. Will always have a predefined default value should it not be passed. Example (urlencoded): ?
  • recur (optional): Defines whether this is to be a recurring contribution, and if so of what type. A passed value of 1 means that the amount will charged to the contributor's account every month for 12 months. A passed value of 2 means that the amount will be charged to the contributor's account every month indefinitely. Example: ?recur=1
  • sloptout (optional): If this variable is present in the request the contributor's name will not be included in the public supporter list on the CC support site. If the contribution originated from a PCP, the contributor will not show up in the "honor roll" list on the PCP page. The value doesn't matter. If this variable is not passed, the contributor's name will by default be displayed in public supporter listings. Example: ?slopout=LOL
  • source (optional): When the contributor is sent to the payment processor there is a description displayed letting them know what the payment is for. If this value is passed it will be the text that is displayed to the contributor. It is also the text that will be stored in the CiviCRM contribution field "Source," so it can used to identify where the contribution originated such as from the CC Network, a regular donation, a donation widget, etc. A default value is set in the script which will be used if this variable isn't passed. Will always have a predefined default value should it not be passed. Example (urlencoded): ?source=CC+Network+Annual+Membership