Asked  7 Months ago    Answers:  5   Viewed   49 times

What is a good complete regular expression or some other process that would take the title:

How do you change a title to be part of the URL like Stack Overflow?

and turn it into


that is used in the SEO-friendly URLs on Stack Overflow?

The development environment I am using is Ruby on Rails, but if there are some other platform-specific solutions (.NET, PHP, Django), I would love to see those too.

I am sure I (or another reader) will come across the same problem on a different platform down the line.

I am using custom routes, and I mainly want to know how to alter the string to all special characters are removed, it's all lowercase, and all whitespace is replaced.



Here's how we do it. Note that there are probably more edge conditions than you realize at first glance.

This is the second version, unrolled for 5x more performance (and yes, I benchmarked it). I figured I'd optimize it because this function can be called hundreds of times per page.

/// <summary>
/// Produces optional, URL-friendly version of a title, "like-this-one". 
/// hand-tuned for speed, reflects performance refactoring contributed
/// by John Gietzen (user otac0n) 
/// </summary>
public static string URLFriendly(string title)
    if (title == null) return "";

    const int maxlen = 80;
    int len = title.Length;
    bool prevdash = false;
    var sb = new StringBuilder(len);
    char c;

    for (int i = 0; i < len; i++)
        c = title[i];
        if ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9'))
            prevdash = false;
        else if (c >= 'A' && c <= 'Z')
            // tricky way to convert to lowercase
            sb.Append((char)(c | 32));
            prevdash = false;
        else if (c == ' ' || c == ',' || c == '.' || c == '/' || 
            c == '\' || c == '-' || c == '_' || c == '=')
            if (!prevdash && sb.Length > 0)
                prevdash = true;
        else if ((int)c >= 128)
            int prevlen = sb.Length;
            if (prevlen != sb.Length) prevdash = false;
        if (i == maxlen) break;

    if (prevdash)
        return sb.ToString().Substring(0, sb.Length - 1);
        return sb.ToString();

To see the previous version of the code this replaced (but is functionally equivalent to, and 5x faster), view revision history of this post (click the date link).

Also, the RemapInternationalCharToAscii method source code can be found here.

Tuesday, June 1, 2021
answered 7 Months ago

The slugs make the URL more user-friendly and you know what to expect when you click a link. Search engines such as Google, rank the pages higher if the searchword is in the URL.

Friday, June 11, 2021
answered 6 Months ago

Check out friendly_id gem. It is exactly what you need.

Thursday, July 29, 2021
answered 5 Months ago


Options +FollowSymLinks
RewriteEngine On
RewriteRule ^folder/file/(.*)/(.*)/ /folder/file.php?x=$1&y=$2 [L]
RewriteRule ^folder/(.*)/ /folder/index.php?x=$1 [L]

The order of the rules is important. You should always put the one with the most rules first as your way was getting to the first rule and then stopping because it was always true due to the (.*) which was capturing the file.

Saturday, July 31, 2021
answered 5 Months ago

I've only been working with CodeIgniter for the past couple of months in my spare time, so I'm still learning, but I'll take a shot at this (be gentle):

There is a url_title() function in the URL Helper (which will need loaded, of course) that will change Foo Bar to foo-bar.

$name = 'Foo Bar';
$seo_name = url_title($name, TRUE);
// Produces: foo-bar

The URL helper strips illegal characters and throws in the hyphens by default (underscores, by parameter) and the TRUE parameter will lowercase everything.

To solve your problem, I suppose you could either do a foreach statement in your routes.php file or pass the url_title() value to the URL, rather than the ID, and modify your code to match the url_title() value with its category name in the DB.

Tuesday, October 19, 2021
answered 2 Months ago
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