PHP-Scripts Blog » PHP 3.x

Using header to redirect the browser

TDavid — Fri, 23 Sep 2005 02:16:31 +0000

The PHP header function allows redirection of the browser, among other cool things.

Example redirecting the browser to php-scripts.com homepage:

header(”Location: http://www.php-scripts.com/”);
?>

Using floor and time to calculate number of days elapsed from UNIX timestamp

TDavid — Wed, 21 Sep 2005 20:06:51 +0000

Finding out the number of days elapsed from a UNIX timestamp is actually pretty straightforward. If you only know two dates then first you’ll need to convert the date to a UNIX timestamps and then subtract the most recent timestamp from the older timestamp like this:

$old_timestamp = 1102971600;
$elapsed_seconds = time() - $old_timestamp;
print ‘Seconds elapsed since ‘ . date(“m-d-Y H:i:s”,$old_timestamp) . “: $elapsed_seconds”;
?>

Now, let’s convert those seconds to days using the floor() function, by just adding the following code to the code above:

/*
divide #seconds by 60 for minutes
divide #of minutes by 60 for hours
divide #of hours by 24 for days
use floor to get integer for day
*/
$elapsed_days = floor(($elapsed_seconds / 60) / 60 / 24);
print “
Number of days elapsed: $elapsed_days”;

How to join an ID list using IN MySQL function

TDavid — Thu, 15 Sep 2005 02:12:21 +0000

How to create a query list of ID numbers using join from an $array and put into a string that can be used in a MySQL query:

$id_numbers = array(1,6,14,32,84,27,49,77);
$complist = join(”,”, $id_numbers);
$query = “SELECT id from tablename WHERE id IN($complist)”;

How to strip off last two characters from string using substr

TDavid — Tue, 13 Sep 2005 18:54:09 +0000

substr comes in handy if you need to strip characters off the end of a string.

$test_string = ‘item 1, item 2, item 3, ‘;
$test_string = substr($test_string,0,-2);
echo($test_string); // returns “item 1, item 2, item 3″
?>

Colorized pretty source code htaccess method

TDavid — Sat, 10 Sep 2005 00:12:27 +0000

Tired of black and whit coding that looks like what’s above? Want to colorize it to look like this instead:

Here is how to make colorized pretty source code using the .htacess method for .phps files:

Step 1. create a text file and save it as .htaccess. Put the following code in the file:

AddType application/x-httpd-php-source .phps

Step 2. change the filename to .phps from .php
Step 3. navigate with your browser to the .phps and voila!

The nice thing about the htacess method is it works with PHP version 3 files, whereas the two function methods only work with version 4.xx and 5.xx. But who is running PHP version 3 any more? Anybody?

Other ways to highlight PHP source code
If you can’t or don’t want to use the htaccess method for some reason then there are a couple PHP functions that will colorize code called: highlight_string() (PHP 4, 5 only) and highlight_file() (PHP 4, 5 only)

How to find the location of php.ini on the server

TDavid — Fri, 09 Sep 2005 14:50:47 +0000

Using the phpinfo() function you can easily find the location of the php.ini file on the server. Here’s the code to generate the phpinfo information pictured above:

phpinfo();
?>

Shown with the red arrows in the screenshot above:

#1 - this is the version of PHP
#2 - these are the configured library. For example ‘–with-mcrypt=/usr/lib’ means the mcrypt library is enabled
#3 - the full path location to the php.ini file. In the screenshot above the location is /usr/local/Zend/etc/php.ini

Most likely the php.ini file will be owned by root, so unless you have root you’ll probably have to ask your hosting company to make changes to this unless you have root. Also PHP will need to be restarted after changing these settings.

PHP Hello world!

TDavid — Wed, 07 Sep 2005 00:22:16 +0000

Welcome to the PHP-scripts blog. Though I’m not a huge fan of ‘Hello World’ stuff, it seems that is where most things in the programming world start out. So here we go with examples using print and echo

Hello World using print statement

print ‘Hello World!’;
?>

Hello World using echo

echo ‘Hello World!’;
?>

What is the difference between print and echo? print behaves like a function and can be used in expressions like this, where echo cannot:

$returns = print ‘Hello World’; // $returns = 1

echo is a tiny bit faster since it doesn’t set a return value.

Programming tips
Pick one format and stick to it. For example, I like to use echo for echoing variable values like this:

echo($name); // outputs value of string $name

But I prefer print for mixing text and variables like this:

$name = ‘TDavid’;
print “My name is: $name”; // outputs: My name is TDavid

Since you can use or not use parenthesis, it’s important to determine a style that is consistent throughout coding projects to keep code easy to read.