Drupal, as a content management system, allows you to create content types with date fields which means you can create events and calendars. There are many great modules which allow you to display content with date fields in calendars, forms, etc. But before you can fly, you must first learn to code... I think that's how the saying goes. Entering one, or even a couple of events into you site is not too difficult or cumbersome. The default node add forms are utilitarian if nothing else. I have even been know to gussy the forms up with some fieldsets, CSS and some occasional Jquery whiz-bang-iness. The challenge comes when you have to enter months worth of events at one sitting. After entering and saving a new event, the system will default to the current day (or whatever default relative date you set in the widget) the next time you add the next event. This means each time you add an event you have to set the month/day/year each time- and when this spans the next calendar year, or even several months, you finger may fall off from all the clicking needed.

The solution? Set the default date in the date widget programmatically, based on the last saved event date. This means if you are entering a lot of events in sequential order, you will have less clicking to do to set the date. It also means if you save an event several months in the future and later add a new event you will have to do the clicky-dance, but for adding many events at once, you will have saved yourself some time.

The way to change the default date in the form is to use the Drupal Forms API (formerly FAPI in D6). You will need to create a module, or add this code to an existing custom module. The Forms API, in simple terms, allows you to talk to Drupal and manipulate the forms through code. Instead of hacking away at a flat HTML file, editing <inputs> and trying to get form values to save in the right places, you can systematically address each form element and get/set values, change CSS attributes, add JS/Jquery and manipulate field settings/defaults. If you've ever installed Captcha, LoginToboggan or any other Drupal form altering module, that's exactly what they are doing. By 'hooking' into the Form API, they can perform all sorts of manipulation without rewriting or replacing the form's core- they simply alter it.

This function will find the currently displayed form and alter it if and only if it is the event form we want to alter. It next retrieves the date of the last event you saved and changes the sets that as the default value. If no date was last saved, then the form will default to the current date.

[cce_php]

function mymodule_form_alter($form, &$form_state, $form_id) {
switch ($form_id) {
case 'event_node_form' :
// Set the default start date for Events to the last saved event month
if ($form['#action'] == '/node/add/event') {
$date = variable_get('event_last_date', '');
$form['field_event_date']['und'][0]['#default_value']['value'] = $date['start'];
if (isset($date['end'])) {
$form['field_event_date']['und'][0]['#default_value']['value2'] = $date['end'];
}
}
break;
}
}

[/cce_php]

This next function reads the values of the event being saved and stores the date(s) as an array to the system table.

[cce_php]

function mymodule_node_presave($node) {
switch ($node->type) {
case 'event' :
$date['start'] = $node->field_event_date['und'][0]['value'];
if (isset($node->field_event_date['und'][0]['value2'])) {
$date['end'] = $node->field_event_date['und'][0]['value2'];
}
variable_set('event_last_date', $date);
break;
}
}

[/cce_php]

You will notice that there are 2 date fields being saved here, value and value2. If you have set the date field to allow an end date value to be set, it is called value2, and in this code is also saved. If you do not set it, or do not have it visible on the form, it will ignore it. The Second function calls hook_node_presave() which, like the Forms API, is an entry point into the Node API and allows you to interact with the node object via code. When any node is being processed for insertion/updating in Drupal, it will call this function and if it matches your 'event' type it will save the date field(s) to the system table for later retrieval by the first function. Place these two functions in a module and test it out. You will need to make sure your code matches  the content type name and CCK date field names of your site.

Modifications such as these can greatly improve the user experience of a site. When you are creating sites to be turned over to others for the content management, this attention to detail and usability can make their lives much easier.

Links:

• LogginToboggan
• Captcha

Recently we needed to implement a Next | Previous link feature for a site for two content types. For providing these links on a simple content type like a blog, the Flippy module may fit the bill. Flippy creates a themeable pager that gets its date from the node's 'created' date field. Blogs generally will benefit from this method of sorting and navigation, but what if your content type has a different, CCK, date field that you want to use for the links. The following code will take your CCK date field and use it to compare with same CCK date field of the current node:
[cce_php]
field_event_date['und'][0]['value']));
// Find the nid of the node with the timestamp just prior to $date
$prev_nid = db_query("SELECT n.nid FROM {node} n LEFT JOIN {field_data_field_event_date} f ON n.nid = f.entity_id WHERE type = 'event' AND UNIX_TIMESTAMP(f.field_event_date_value) < :posted ORDER BY field_event_date_value DESC LIMIT 1", array(':posted' => $date))->fetchField();
// Find the nid of the node with the timestamp just after $date
$next_nid = db_query("SELECT n.nid FROM {node} n LEFT JOIN {field_data_field_event_date} f ON n.nid = f.entity_id WHERE type = 'event' AND UNIX_TIMESTAMP(f.field_event_date_value) > :posted ORDER BY field_event_date_value ASC LIMIT 1", array(':posted' => $date))->fetchField();

if ($prev_nid > 0) {
$prev_link = l('Previous', "node/$prev_nid", array('html'=>TRUE, 'attributes' => array('title' => 'See Previous', 'class' => array('prev-link'))));
print($prev_link);
}

if ($next_nid > 0) {
$next_link = l('Next', "node/$next_nid", array('html'=>TRUE, 'attributes' => array('title' => 'See Previous', 'class' => array('next-link'))));
print(" | " . $next_link);
}
?>

[/cce_php]

The two db_query() calls in the code query the database for nodes based on their CCK Date field which is converted from a Mysql date (MM/DD/YY HH:MM:SS) to the unix epoch timestamp format for comparison. If there is a resulting nid, it is stored for output by drupal's l() function. The field we have is for an event and the field's name is 'field_date_event_value', seen in the SQL. You will have to dig into your content type to determine the exact name of the field you will use. Additionally you can see the syntax for the l() function for adding additional attributes to the generated link. The third argument takes a series of nested arrays that hold the 'title', 'class', 'id', etc.

This code could be extended to generate fuller pager with First, Last, Skip 5, or even Random links.

Links:

• Flippy

Drupal 7's commerce module is extremely powerful due in large part to being built on the new entity framework. One of the submodules under the hood of commerce is addressfield, which stores xNAL compliant addresses for customer profiles. It stores the basic street(s), city, state, zip/postal code, country. For the purposes of commerce, this is an appropriate solution. However, if you want to capture more data for taking orders, or use this field in a non-commerce application, you may want to have additional fields included.

To this end, we can add more fields as 'formatters' to the addressfield module. There is an example module which ships with addressfield and I also found a similar sandbox project which adds phone numbers to the addressfield- I based this project largely off of that project. For future development we'll add validation handlers and possibly extend it to include email contact information as well.

Here is a screenshot of the resulting field:

Addressfield Link

The project can be found here.

Links:

• commerce
• addressfield
• addressfield_phone