Why You Should Always Salt Your Hashes

Hashes are used almost everywhere on the web, behind the scenes, to protect your passwords. Learn why it's important to always add salt to your hashes.

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16 December 2009   |   18 comments   |   security, database, passwords, programming, webdev

Rex Swain HTTP Viewer Bookmarklet

Rex Swain's HTTP Viewer is a great tool for checking HTTP status codes, redirection, and so on. I've been unable to find a bookmarklet, though, for sending the URL I am viewing to the viewer automatically, so I put one together:

Rex Swain's HTTP Viewer

26 January 2007   |   1 comments   |   http, webdev, bookmarklet

RSS to iCal

I have been looking for a way to convert the BBC weather feed for my area to iCal, so I can subscribe to it. It's date-based, after all, and RSS never seemed to me to be an appropriate format for subscribing to weather information. iCal always struck me as being "better" for that purpose. Of course, the BBC only have an RSS feed for local weather. What I needed was a converter.

After some hunting, I discovered that Dean Sanvitale had written a PHP script to convert RSS feeds to iCal format. However, his site (codent.com) appears to be long since abandoned and the script is no longer available from there. Fortunately, the Wayback Machine did have a copy. Dean originally released the script under a Creative Commons License which, fortunately, allows me to make the script available to download from this site (note: the script is available from this site under the same license).

So, if you're looking for a way to convert an RSS feed to iCal, this PHP script will do the job. Thanks Dean!

Source: rss2ical.txt

19 October 2006   |   15 comments   |   rss, weather, php, bbc, ical, convert, tools, web, webdev, code, rss2ical

Internet Country Codes

A list of country level domain names, ordered by country or domain name.

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07 October 2005   |   21 comments   |   cheatsheet, webdev, reference, domain, domains, tld, codes, dns, internet, resources, country

Block Referrer Spam (Updated)

Referrer spam is becoming increasingly common. At best, it will only render your log files useless. At worst, it can cause your site to be dropped by search engines and your running costs to skyrocket. Here's how to block spurious referrers.

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14 September 2005   |   41 comments   |   howto, webdev, server, spam, referrer, wordpress, htaccess, admin, apache

Block Prefetching

Mozilla and Google's prefetching functions are a nice addition to browser technology in many ways. Unsurprisingly, they are not very well thought through. The main two problems with the prefetching idea are that it messes with log files and it means every link on a page could potentially be followed despite the consequences (dangerous in a site administration context).

It appears from the FAQ that Google only intends their accelerator to prefetch specific pages, that have been specified with the <link> tag. However, many people are claiming that normal links have been prefetched.

To prevent prefetching of a page is simple: add the following PHP to the page you do not want prefetched:

if ((isset($_SERVER['HTTP_X_MOZ'])) && ($_SERVER['HTTP_X_MOZ'] == 'prefetch')) {
    // This is a prefetch request. Block it.
    header('HTTP/1.0 403 Forbidden');
    echo '403: Forbidden<br><br>Prefetching not allowed here.';
    die();
}

This will serve a "forbidden" header to the prefetcher. Normal browsing should be unaffected.

20 April 2005   |   3 comments   |   webdev, block, mozilla, prefetching, google, reference, php

Password Protect a Directory with .htaccess

A tutorial explaining how to retrict access to a directory on a web server using .htaccess.

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15 March 2005   |   84 comments   |   howto, webdev, security, programming, php, password, protect, sysadmin, htaccess, website, apache, directory, generator

Preload Images with CSS

How to preload images using CSS and so avoid delays with rollover effects.

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23 December 2004   |   57 comments   |   code, rollover, webdev, howto, preload, web, design, image, webdesign, images, css

Flesch-Kincaid Reading Level

Functions to count the number of syllables in a word or sentence, and work out the readability of text.

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07 July 2004   |   14 comments   |   reading, webdev, text, programming, reference, php, writing, readability, language, accessibility, algorithm

28k and 56k Modem Emulator

Regardless of your connection speed, this will show you how your site loads on PCs with older connections.

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29 June 2004   |   65 comments   |   webdev, development, web, design, usability, modem, webdesign, tools, accessibility, optimization, testing

Ternary Conditionals

Ternary conditionals (using the "ternary operator", sometimes known as the "trinary operator") are a part of PHP that many simply steer clear of, despite their usefulness. They can save a great deal of time when writing code and can make for much easier code to read and edit later on. They look strange to many people though, which might explain why they are not as widely used as they could be.

Consider a normal conditional statement, like the following. It begins by evaluating a condition. If that condition is true, it follows one path. Sometimes, an alternate path is specified if the condition is not true (the 'else' section). Sometimes, you can have a list of several possible conditions in a row (using 'if ... elseif ... else' or 'switch ... case').

if (condition) {
    variable = value-if-true;
} else {
    variable = value-if-false;
}

However, a simple situation like the above is a perfect candidate to convert to a ternary conditional. You have one condition, and if it is true, the variable is given a certain value - if false, a different value. A ternary conditional can accomplish the same thing, concatenating it into one simple line of code.

variable = (condition) ? value-if-true : value-if-false;

Ternary conditionals take the above form. You do not necessarily need to have a "variable = " section (as you will see later on), but usually that is what this is used for. The above does exactly the same thing as the 'if ... else' statement earlier. If the condition evaluates to true, the variable will be assigned the value in the "value-if-true" section, otherwise it will receive the "value-if-false" value.

In practice, you could use the ternary conditional to, for example, greet a user depending on whether it is currently morning or afternoon. Using traditional code ('if ... else'), you might write something like this:

if (date("G") < 12) {
    echo 'Good morning';
} else {
    echo 'Good afternoon';
}

The same statement, using a ternary conditional, would look like this:

echo (date("G") < 12) ? 'Good morning' : 'Good afternoon';

Note that in this example, we've used "echo", rather than assigning a value to a variable. The above is exactly the same as this, which does make use of a variable:

$greeting = (date("G") < 12) ? 'Good morning' : 'Good afternoon';
echo $greeting;

Another situation in which I often use ternary conditionals is when displaying rows of data. It can often be much easier for a user to see what is going in if the rows alternate background colour, and the following code can be useful for that:

$i = 1;
echo '<table>';
while ($data = mysql_fetch_array($result)) {
    echo '    <tr>';
    echo '        <td bgcolor="';
    echo (($i % 2) == 0) ? '#eee' : '#ddd' ;
    echo '">';
    echo $data['field'];
    echo '        </td>';
    echo '    </tr>';
    $i++;
}
echo '</table>';

The above code will cycle through a result set, displaying each item in a new row. The background colour of the row will alternate between shades of grey, controlled by the ternary conditional on the bold line.

Ternary conditionals make for tidier code. Use them - if not for yourself, then for whoever is going to end up editing your scripts!

02 June 2004   |   27 comments   |   webdev, development, tutorial, programming, ternary, tips, php, coding

PHP DateDiff Function

VBScript's DateDiff function is a powerful way to express differences between dates, and PHP lacks a similar function. Here's a replica of VBScript's DateDiff function in PHP.

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20 April 2004   |   74 comments   |   webdev, php, datediff, date, script, webdesign, programming

US States Select Box

A populated select list (input box) with the states of the USA as options.

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14 February 2004   |   26 comments   |   select, webdev, development, html, reference, resource, design, forms, webdesign, states, resources