Archive for category: PHP

AJAX Requests and PHP

Recently I’ve seen a lot of questions on stackoverflow about how to detect/respond to AJAX requests. It’s actually quite simple. Most of the major players in the javascript framework will send a specific header(X-REQUESTED-WITH) to the requested page. You can check this header to detect AJAX requests.

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if (
    isset( $_SERVER['HTTP_X_REQUESTED_WITH'] ) &&
    strtolower( $_SERVER['HTTP_X_REQUESTED_WITH'] ) == 'xmlhttprequest'
) {
    // AJAX request
}
else {
    // Normal request
}

You can add this to your request object or define a constant

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define(
    'IS_AJAX_REQUEST',
    (bool)isset( $_SERVER['HTTP_X_REQUESTED_WITH'] ) && strtolower( $_SERVER['HTTP_X_REQUESTED_WITH'] ) == 'xmlhttprequest';
);

Example usage

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// Get an array of contacts for a user
$contacts = Contacts::getForUser( $user_id );
 
// If the page was requested via ajax, json encode the array and exit the script
if ( IS_AJAX_REQUEST ) {
    die( json_encode( $contacts ) );
}
 
// Normal request, require the view
require( 'views/contacts.php' );

Frameworks verified to use the X-REQUESTED_WITH header: Prototype, Jquery, Dojo, Mootools, YUI

PHP template engines and why they’re unnecessary

For the past 4 or 5 years I’ve been a proponent of using PHP as it’s own template engine. I cringe every time I see someone using smarty, btemplate, fastTemplate, etc… because I’ve never had to do anything in my html that couldn’t be done with PHP. Never! Why add a layer to your app if you don’t have to?

To illustrate this I’m going to show you a template written in a template engine, and then in PHP.

Here’s an example from the Smarty website

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<table border="0" width="300">
    <tr>
        <th colspan="2" bgcolor="#d1d1d1">Guestbook Entries (<a href="{$SCRIPT_NAME}?action=add">add</a>)</th>
    </tr>
    {foreach from=$data item="entry"}
        <tr bgcolor="{cycle values="#dedede,#eeeeee" advance=false}">
            <td>{$entry.Name|escape}</td>        
            <td align="right">{$entry.EntryDate|date_format:"%e %b, %Y %H:%M:%S"}</td>        
        </tr>
        <tr>
            <td colspan="2" bgcolor="{cycle values="#dedede,#eeeeee"}">{$entry.Comment|escape}</td>
        </tr>
    {foreachelse}
        <tr>
            <td colspan="2">No records</td>
        </tr>
    {/foreach}
</table>

Here’s an example using PHP. e() is an escaping function you write yourself.

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<table border="0" width="300">
    <tr>
        <th colspan="2" bgcolor="#d1d1d1">Guestbook Entries (<a href="{$SCRIPT_NAME}?action=add">add</a>)</th>
    </tr>
    <?php if ( count( $data ) ): ?>
    <?php foreach( $data as $entry ): ?>
        <tr bgcolor="<?php if( $i++ % 2 ): ?>#dedede<?php else: ?>#eeeeee<?php endif; ?>">
            <td><?= e( $entry['name'] ) ?></td>        
            <td align="right"><?= date( $entry['entryDate'], 'e b Y H M S' ) ?></td>        
        </tr>
        <tr>
            <td colspan="2" bgcolor="<?php if( $i % 2 ): ?>#dedede<?php else: ?>#eeeeee<?php endif; ?>"><?= e( $entry['comment'] ) ?></td>
        </tr>
     <?php endforeach; ?>
     <?php else: ?>
        <tr>
            <td colspan="2">No records</td>
        </tr>
     <?php endif; ?>
</table>

As you can see there is only 2 added lines of code. I had to add an if statement to account for smarty’s foreachelse. No added layer. No extra work for the interpreter. Just as readable (unless you’re a PHP developer, then it will be more readable)

In closing read this post on the sitepoint forums. Pay particular attention to Voostind’s replies (#1, #2, #3)

Setting mysql connection charset with PDO

Recently while creating a store locator for a Chinese website I ran into a problem. Some Chinese characters were being displayed correctly and some weren’t. First thing I did was check the charset of the HTTP headers and the database… both were set correctly to utf-8. I figured it had to be a database issue so I began googling and found this.

Apparently you have to set the character set of the connection as well via:

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SET NAMES 'utf-8'

SET NAMES indicates what character set the client will use to send SQL statements to the server. Thus, SET NAMES ‘cp1251′ tells the server “future incoming messages from this client are in character set cp1251.” It also specifies the character set that the server should use for sending results back to the client. (For example, it indicates what character set to use for column values if you use a SELECT statement.)

Great!

The only issue remaining was the fact that I didn’t want to have to run that query on every page.

I use PDO, and I found out you can use the driver_options argument of PDO to run an initial command.

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$dsn = sprintf( 'mysql:dbname=%s;host=%s', DB_NAME, DB_HOST );
$driver_options = array( PDO::MYSQL_ATTR_INIT_COMMAND =&gt; 'SET NAMES utf-8' );
try {
    $dbc = new pdo($dsn, $user, $pw, $driver_options);
}
catch (PDOException $e) {
    // Handle exception
}

Good reads about character sets

Returning an instance of a class from PDO

PDO can create and return an object(s) of a specific class. It can be a little tricky getting it to work though…

With fetchAll() you can pass ( PDO:FETCH_CLASS, ‘class_name’ ) directly

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$sql = sprintf( 'select * from %s where prod_id=:prod_id', TABLE );
$findProducts = $this->db->prepare( $sql );
$findProduct->execute();
$products = $findProducts->fetchAll( PDO::FETCH_CLASS, 'Product' );

But with fetch() you must initiate it with setFetchMode()

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$sql = sprintf( 'select * from %s where prod_id=:prod_id', TABLE );
$findProduct = $this->db->prepare( $sql );
$findProduct->setFetchMode( PDO::FETCH_CLASS, 'Product' );
$findProduct->execute();
$product = $findProduct->fetch( PDO::FETCH_CLASS );
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