how to convert php date formats to GMT and vice versa?

Question 1

i am new to php. i want to write a function where i need user to input date in any date format including DST,into GMT format and again later back into the original entered format.please any body help me.

Question 2

Although the gmdate functions are available. If you are using PHP 5.2 or greater, then consider using the DateTime object.

Here's code to switch to GMT

$date = new DateTime();
$date->setTimezone(new DateTimeZone('GMT'));

and back to the default timezone...

$date = new DateTime('2011-01-01', new DateTimeZone('GMT'));
$date->setTimezone(new DateTimeZone(date_default_timezone_get()));

Using the DateTime object lets your create a datetime, just like the procedural functions, except that you keep a reference to an instance.

e.g.

// Get a reference to Christmas of 2011, at lunch time.
$date = new DateTime('2011-12-25 13:00:00');

// Print the date for people to see, in whatever format we specify.
echo $date->format('D jS M y');

// Change the timezone to GMT.
$date->setTimezone(new DateTimeZone('GMT'));

// Now print the date/time it would in the GMT timezone
// as opposed to the default timezone it was created with.
echo $date->format('Y-m-d H:i:s');

// Just to show of some more, get the previous Sunday
$date->modify('previous Sunday');

There's a whole lot of functions you can use, that are much more readable that the procedural functions.

Explicit example of converting from a timezone to GMT

$melbourne = new DateTimeZone('Australia/Melbourne');
$gmt = new DateTimeZone('GMT');

$date = new DateTime('2011-12-25 00:00:00', $melbourne);
$date->setTimezone($gmt);
echo $date->format('Y-m-d H:i:s');
// Output: 2011-12-24 13:00:00
// At midnight on Christmas eve in Melbourne it will be 1pm on Christmas Eve GMT.

echo '<br/>';

// Convert it back to Australia/Melbourne
$date->setTimezone($melbourne);
echo $date->format('Y-m-d H:i:s');

Using your Asia/Kolkata to America/New_York

date_default_timezone_set('Asia/Kolkata');
$date = new DateTime('2011-03-28 13:00:00');
$date->setTimezone(new DateTimeZone('America/New_York'));
echo $date->format("Y-m-d H:i:s");
//Outputs: 2011-03-28 03:30:00

Question 3

Passing data from PHP is easy, you can generate JavaScript with it. The other way is a bit harder - you have to invoke the PHP script by a Javascript request.

An example (using traditional event registration model for simplicity):

<!-- headers etc. omitted -->
<script>
function callPHP(params) {
    var httpc = new XMLHttpRequest(); // simplified for clarity
    var url = "get_data.php";
    httpc.open("POST", url, true); // sending as POST

    httpc.onreadystatechange = function() { //Call a function when the state changes.
        if(httpc.readyState == 4 && httpc.status == 200) { // complete and no errors
            alert(httpc.responseText); // some processing here, or whatever you want to do with the response
        }
    };
    httpc.send(params);
}
</script>
<a href="#" onclick="callPHP('lorem=ipsum&foo=bar')">call PHP script</a>
<!-- rest of document omitted -->

Whatever get_data.php produces, that will appear in httpc.responseText. Error handling, event registration and cross-browser XMLHttpRequest compatibility are left as simple exercises to the reader ;)

See also Mozilla's documentation for further examples

Question 4

You don't have to repeat those format identifiers . For yyyy you just need to have Y, etc.

gmdate('Y-m-d h:i:s GMT', time());

In fact you don't even need to give it a default time if you want current time

gmdate('Y-m-d h:i:s GMT');  // This is fine for your purpose

Manual

You can get that list of identifiers Here

Question 5

you need to escape the a and t as both have special meaning when used as formatting options in date()

echo date('M j at h:i a');

See it in action

Question 6

use Base64.encodeToString() try this http://developer.android.com/reference/android/util/Base64.html#encodeToString%28byte%5B%5D,%20int%29

File file = new File(Environment.getExternalStorageDirectory() + "/hello-4.wav");
byte[] bytes = FileUtils.readFileToByteArray(file);

String encoded = Base64.encodeToString(bytes, 0);                                       
Utilities.log("~~~~~~~~ Encoded: ", encoded);

byte[] decoded = Base64.decode(encoded, 0);
Utilities.log("~~~~~~~~ Decoded: ", Arrays.toString(decoded));

try
{
    File file2 = new File(Environment.getExternalStorageDirectory() + "/hello-5.wav");
    FileOutputStream os = new FileOutputStream(file2, true);
    os.write(decoded);
    os.close();
}
catch (Exception e)
{
    e.printStackTrace();
}



public class FileUtils {

    /**
     * Instances should NOT be constructed in standard programming.
     */
    public FileUtils() { }

    /**
     * The number of bytes in a kilobyte.
     */
    public static final long ONE_KB = 1024;

    /**
     * The number of bytes in a megabyte.
     */
    public static final long ONE_MB = ONE_KB * ONE_KB;

    /**
     * The number of bytes in a gigabyte.
     */
    public static final long ONE_GB = ONE_KB * ONE_MB;



    public static String readFileToString(
            File file, String encoding) throws IOException {
        InputStream in = new java.io.FileInputStream(file);
        try {
            return IOUtils.toString(in, encoding);
        } finally {
            IOUtils.closeQuietly(in);
        }
    }



    }

}

how to convert php date formats to GMT and vice versa?

Answers

php,date,gmt