How to Run a Silent Auction using Drupal

We’re in the middle of the second year of online bidding for the Prince Street School Silent Auction and it seems like a good time to peel off a little more of the wrapping and talk about the technical side of the process so that others can do the same thing (I took a first stab at this last year with just the basics).

The Silent Auction is run through a slightly-modified Drupal website: the modifications that support the auction are not dramatic, and should be within the realm of anyone with some basic Drupal savvy.  Here’s what I did.

Install some Drupal Modules

• CCK
• Views
• FileField
• Formatted Number CCK
• ImageField
• ImageCache
• PathAuto
• String Overrides
• CAPTCHA
• reCAPTCHA

Set up some ImageCache Presets

I created two ImageCache presets:

1. display – scale to width 500 pixels
2. thumbnail – scale to height 150 pixels

I’ll use the display preset when I want to display the full-sized image and the thumbnail preset when I’m displaying a list of items with thumbnail images.

Create a Silent Auction Item Content Type

We need to keep track of a few additional items for each auction item in addition to the title and description that a standard Drupal node supports. So I installed the CCK module and created a new content type called Silent Auction Item.

I set up the content type with comments turned on, newest comments displayed first, allowed anonymous comments (but checked Anonymous posters must leave their contact information) and set comments to display Display below post or comments.

Next I added three new fields to the Silent Auction Item content type:

• Item Number – field_itemnumber – Integer
• Donated By – field_donatedby – Text
• Estimated Value – field_value – Formatted decimal
• Photo – field_photo – File

The result looks like this:

Finally, I set the Display Fields settings for the new content type so that:

• Item Number field is excluded – we use this for internal purposes only.
• Donated By and Estimated Value have their labels displayed in-line.
• Photo is displayed as thumbnail image linked to node for the Teaser and as display image for the Full Node.

Create a Silent Auction Categories Taxonomy

To allow auction items to be categorized, I created a new Silent Auction Categories taxonomy, and added some terms:

I set this new Taxonomy to apply to the Silent Auction Item content type I created earlier.

Add some Silent Auction Items

Next I was ready to add some actual content to the site, so I started adding Silent Auction items using the regular Drupal Create Content mechanism. For each item I entered the Item Number (assigned manually when the item was received at the school), the title of the item (“Goalie Stick”), a category (“Sports”), a description (if I was given one), who the item was donated by, and its estimated value. I then uploaded a file (taken by the school secretary and sent to me as a JPEG) and saved the new item.

The result was something like this:

Turn “Comments” into “Bids”

With the content pretty well taken care of, now I turned my attention to setting up a way for people to bid on the items. I decided that rather than building out a more complicated dedicated Drupal module for this, I’d simply harness the already-in-place Drupal comments system and turn it into a “bids” system.

First I made some entries in the String Overrides module’s settings, changing appearances of the “comments” terminology to “bids.” I made the following entries:

• Add new comment became Place a bid
• Comments became Bids
• New comments became New bids
• Post new comment became Place a bid

Setup reCAPTCHA

To reduce the possibility of “spam bids” – not that this was a huge concern, but why create extra work for ourselves – I set up the CAPTCHA and reCAPTCHA modules (the latter required setting up a free account at recaptcha.net) so that a CAPTCHA would appear on the form with form_id of comment_form:

Hack the Comment Form

To customize the comment form itself, I created a module called customsite and in it I used the hook_form_alter to change the form:

function customsite_form_comment_form_alter(&$form, &$form_state) {
  unset($form['_author']);
  unset($form['homepage']);

  $form['name'] = array(
    '#type' => 'textfield',
    '#title' => t('Your full name'),
    '#maxlength' => 60,
    '#size' => 30,
    '#default_value' => '',
    '#required' => TRUE,
    );

  $form['comment_filter']['comment'] = array(
    '#type' => 'textfield',
    '#size' => '10',
    '#title' => t('Your bid for this item.'),
    '#default_value' => '$',
    '#required' => TRUE,
  );

    $form['comment_filter']['format'][$i]['#value'] = '';
}

This had the effect of making the comment form look like this:

Create some Views

With the display of items and the handling of bidding completed, my final step was to create a couple of Views to display items and bids.

I created a view with a Page display called auction items that drives this page of the auction website; it displays all of the auction items, sorted by item number, showing the category, donated by, estimated value, and number of bids (which is just the “comment count”).

I also modified the stock node_comments view a little to customize the Recent Bids block that I display in the left-hand sidebar of the site; it shows the 5 most recent bids, with the item name, bid amount and bidding time.

Add Polish

That’s essentially it: a CCK content type holds auction item information; comments become bids. With the addition of some stock Drupal polish – menus pointing to each taxonomy item page to allow browsing by category, for example – the only additional tweak was to create an additional block in the customsite module to show how much we’d raised so far (the total of the high bids for all items):

function customsite_totalraised() {
   
    $result = db_query("select nid,max(comment) as maxbid
                            from {comments} group by nid");
   
    $total = '';
    while ($onerow = db_fetch_object($result)) {
        $bid = str_replace("$","",$onerow->maxbid);
        $total = $total + $bid ;
      }
    $block .= "<p>So far we've raised <b>\$" .
                        number_format($total,2) .
                        "</b>. Thank you (and keep bidding!)</p>";

    return $block;
}

Questions or Suggestions?

This solution has worked well over two years, but there’s always room for improvements. If you’d like to try something like this for your own silent auction and run into any stumbling blocks, feel free to ask questions here.