Tutorial Cross Domain GET Forwarding

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When you do an AJAX request on a website, the URL you request from needs to reside on the same domain as where the request was made from. This is a security restriction imposed by the browser. There is a way to sneak around this by using a bit of a "man in the middle" approach.

PHP, being a server-side language, has the ability to pull content from any URL. So a PHP file can become the man in the middle. The contents of the PHP file can be set up to accept a URL as a parameter and then return the contents of that URL. 

<?php

    echo file_get_contents($_GET['url']);
    // WARNING: You REALLY should write something to whitelist or otherwise limit what the function will accept, or it could be a security danger to your server (people could read any file).

?>

With that in place, we can do an AJAX request directly to that URL, passing it the URL we actually want the data from as a parameter. See how we are passing "http://google.com" as data below.

<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js?ver=1.3.2'></script>
<script type='text/javascript'>
    $(function() {
       $.ajax({
            type: "GET",
            dataType: 'html',
            data: 'url=http://google.com',
            url: 'get.php',
            success: function(data){
                // Yah! Do something cool with data
            },
            error: function(){
                // Boo! Handle the error.
            }
        }); 
    });
</script>

This is an extremely simple example. If you are interested in a more robust version, check out the Simple PHP Proxy.

Tutorial Crop Image

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Displays a selected chunk of an image. In the example provided, the upper left 100px x 100px are shown.

<?php

$filename= "test.jpg";
list($w, $h, $type, $attr) = getimagesize($filename);
$src_im = imagecreatefromjpeg($filename);

$src_x = '0';   // begin x
$src_y = '0';   // begin y
$src_w = '100'; // width
$src_h = '100'; // height
$dst_x = '0';   // destination x
$dst_y = '0';   // destination y

$dst_im = imagecreatetruecolor($src_w, $src_h);
$white = imagecolorallocate($dst_im, 255, 255, 255);
imagefill($dst_im, 0, 0, $white);

imagecopy($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h);

header("Content-type: image/png");
imagepng($dst_im);
imagedestroy($dst_im);

?>

Tutorial Create URL Slug from Post Title

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Regular expression function that replaces spaces between words with hyphens.

<?php
function create_slug($string){
   $slug=preg_replace('/[^A-Za-z0-9-]+/', '-', $string);
   return $slug;
}
echo create_slug('does this thing work or not');
//returns 'does-this-thing-work-or-not'
?>

Tutorial Create Unique AlphaNumeric

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function MakeUnique($length=16) {
           $salt       = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
           $len        = strlen($salt);
           $makepass   = '';
           mt_srand(10000000*(double)microtime());
           for ($i = 0; $i < $length; $i++) {
               $makepass .= $salt[mt_rand(0,$len - 1)];
           }
       return $makepass;
}

Tutorial Create Data URI’s

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These can be useful for embedding images into HTML/CSS/JS to save on HTTP requests, at the cost of maintainability. More information. There are online tools to do it, but if you want your own very simple utility, here's some PHP to do it:

function data_uri($file, $mime) {
  $contents=file_get_contents($file);
  $base64=base64_encode($contents);
  echo "data:$mime;base64,$base64";
}

Tutorial Count Script Excecution Time

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$execution_time = microtime(); # Start counting

# Your code

$execution_time = microtime() - $execution_time;
$execution_time = sprintf('It took %.5f sec', $execution_time);

Tutorial Convert HEX to RGB

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Give function hex code (e.g. #eeeeee), returns array of RGB values.

function hex2rgb( $colour ) {
        if ( $colour[0] == '#' ) {
                $colour = substr( $colour, 1 );
        }
        if ( strlen( $colour ) == 6 ) {
                list( $r, $g, $b ) = array( $colour[0] . $colour[1], $colour[2] . $colour[3], $colour[4] . $colour[5] );
        } elseif ( strlen( $colour ) == 3 ) {
                list( $r, $g, $b ) = array( $colour[0] . $colour[0], $colour[1] . $colour[1], $colour[2] . $colour[2] );
        } else {
                return false;
        }
        $r = hexdec( $r );
        $g = hexdec( $g );
        $b = hexdec( $b );
        return array( 'red' => $r, 'green' => $g, 'blue' => $b );
}