PHP - Split ugly date string and then do date maths on it?

Question

I'm a PHP beginner and been struggling unsuccessfully with the php documentation. Seems a lot of ways to do what I want.

Basically I need a php page to check an "ugly" date/time variable appended to a URL - it must convert it into a usable format and subtract it from the current date/time. If the result is less than 48hrs then the page should redirect to "Page A" otherwise it should redirect to "Page B"

This is what the URL and variable looks like.

http://mysite.com/special-offer.php?date=20130527212930

The $date variable is the YEAR,MONTH,DAY,HOUR,MINUTE,SECOND. I can't change the format of this variable.

I'm guessing PHP can't use that string as it is. So I need to split it somehow into a date format PHP can use. Then subtract that from the current server date/time.

Then put the result into an if/else depending on whether the result is more or less than 48hrs.

Am I right in theory? Can anyone help me with the "practise"?

Thanks!

Answer 1

Take a look at the DateTime class and specifically the createFromFormat method (php 5.3+):

$date = DateTime::createFromFormat('YmdHis', '20130527212930');
echo $date->format('Y-m-d');

You might need to adjust the format depending on the use of leading zeros.

Answer 2

PHP 5 >= 5.3.0

$uglydate = '20130527212930';

// change ugly date to date object
$date_object = DateTime::createFromFormat('YmdHis', $uglydate);

// add 48h
$date_object->modify('+48 hours');

// current date
$now = new DateTime();

// compare dates
if( $date_object < $now ) {
    echo "It was more than 48h ago";
}

Answer 3

You can use a regular expression to read your string and construct a meaningful value.

for example

$uglydate = "20130527212930";
preg_match("/([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{2})([0-9]{2})([0-9]{2})/", $uglydate, $matches);

$datetime = $matches[1] . "-" . $matches[2] . "-" . $matches[3] . " " . $matches[4] . ":" . $matches[5] . ":" . $matches[6];

//then u can use $datetime in functions like strtotime etc

Answer 4

Whoa! you all have WAY too much time on your hands... Nice answers... oh well, i'll pop-in a complete solution...

<?php

$golive = true;

if (preg_match('|^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})|', $_GET['date'], $matches)) {

    list($whole, $year, $month, $day, $hour, $minute, $second) = $matches;

    // php: mktime function (using parameters derived
    $timestamp = mktime($hour,$minute,$second,$month,$day,$year);

    $diff = time()-$timestamp;
    $diffInHours = $diff / 3600 ;

    // if less, than 48
    if ( $diffInHours < 48 ) {
        $location = "http://bing.com";
    } else {
        $location = "http://google.com";
    }

    //
    if ( $golive ) {
        header("Location: ".$location);
        exit();
    } else {
        echo "<p>You are would be sending the customer to:<br><strong>$location</strong>";
    }

} else {

    echo "<p>We're not sure how you got here, but... 'Welcome!'???</p>";

}

That oughta do it.

By the way, on another note, I'd heavily suggest you go back to the sending party of that URL and definitely reconsider how this is being done. As this is VERY easily tweakable (URL date= value), thus not really protecting anything, but merely putting the keys on the front porch next to the 'Guardian Alarms Installed at This House' {sign} :).

Answer 5

Assuming the input is in the correct format (correct number of characters and all of them digits) you'll need 1 substring of length 4 and the rest of lenght 2. For simplicity I'll ignore the first 2 chars (the 20 part from 2013) with substr

$input=substr($input, 2, strlen($input));

Now I can treat all the remaining elements in the string as 2-char pairs:

$mydate=array(); //I'll store everything in here
for($i=0; $i<=strlen($input)-2; $i+=2){
    $mydate[$a]=substr($input, $i, $i+2);
    $a++;
}

Now I have year, month, day etc. in an array indexed from 0 to 5. For the date difference I'll put the array into mktime:

$timestamp = mktime(mydate[3], mydate[4], mydate[5], mydate[1], mydate[2], mydate[0]);

Finally compare the two timestamps:

if($old_ts - $timestamp > (60*60*48)){
//more than 48 hours
}else{ ... }