Magento custom module date field saving date to one day before the selected date

Question

i followed steps on this link to add a date field to my custom module :

http://magentomechanic.blogspot.com/2010/01/to-add-custom-date-field-in-custom.html

Every

Answer 1

I stumbled on this post, while browsing for similar question about dates in Magento. Unfortunately, these answers didn’t help me, but I came back to share a couple of things about dates which I hope will be useful for someone else.

First of all, Magento stores dates in DB in UTC timezone. This way it requires the same code and same logic to display info for your customers in UK, US or AU. Check carefully, it saves it not "one day before", but 8 hours before (25 Jan, 2012 00:00:00 => 2012-01-26 16:00:00).

Second important thing: Magento provides standard dynamically generated getters and setters for database fields. So if you have added your custom fields to Product or Customer you don’t need to define your own methods to read/write to database. Your class, something like: class MyOrg_MyModule_Model_Customer extends Mage_Customer_Model_Customer will have methods $this->getStart_date() and $this->setStart_date($datetime) even for your custom fields. You also can use method $this-setData('start_date', $datetime); and then $this->save();

This information will help you understand what TimeZone parameters are required by standard Magento functions:

$current_datetime_utc_in_timestamp_format = time();

$start_datetime_utc_in_text_format = $this->getStart_date();
$start_datetime_utc_in_timestamp_format = Varien_Date::toTimestamp($start_datetime_utc_in_text_format);

//check Mage/Core/Model/Date.php
// timestamp()  adds TimeZone to datetime, see also gmtTimestamp() – it deducts TimeZone from datetime
$start_datetime_local_in_timestamp_format = Mage::getModel('core/date')->timestamp($start_datetime_utc_in_text_format) );
//Timestamp() also accepts parameter in timestamp format
$start_datetime_local_in_timestamp_format = Mage::getModel('core/date')->timestamp($current_datetime_utc_in_timestamp_format) );

$displayTime = true;
$start_datetime_local_in_text_format = Mage::helper('core')->formatDate($start_datetime_utc_in_text_format, 'medium', $displayTime);
//or
$start_datetime_local_in_text_format = Mage::getModel('core/date')->date("Y-m-d H:i:s", $start_datetime_utc_in_timestamp_format);

$start_datetime_utc_in_text_format = Mage::getModel('core/date')->gmtdate("Y-m-d H:i:s", $start_datetime_local_in_timestamp_format);
//similar to timestamp()/gmtTimestamp(), date() – adds TimeZone and gmtDate() – deducts TimeZone from time

$this->setStart_date( $start_datetime_utc_in_timestamp_format );

For simplicity and speed, I suggest you to use timestamps for your date calculations and comparisons. And convert time in your timezone only in order to display it.