Generating URL slugs in .NET Core

Updated: 5/5/17

• Better handling of diacritics in sample

I’ve just discovered what a Slug is:

Some systems define a slug as the part of a URL that identifies a page in human-readable keywords.

It is usually the end part of the URL, which can be interpreted as the name of the resource, similar to the basename in a filename or the title of a page. The name is based on the use of the word slug in the news media to indicate a short name given to an article for internal use.

I needed to know this as I’m particapting in the Realworld example projects and I’m doing a back end for ASP.NET Core.

The API spec kept saying slug, and I had a moment of “ohhh, that’s what that is.” Anyway, I needed to be able to generate one. Stackoverflow to the rescue!: https://stackoverflow.com/questions/2920744/url-slugify-algorithm-in-c

Also, decoding random characters from a lot of languages isn’t straight forward so I used one of the best effort implementations from the linked SO page: https://stackoverflow.com/questions/249087/how-do-i-remove-diacritics-accents-from-a-string-in-net

Now, here’s my Slug generator:

//https://stackoverflow.com/questions/2920744/url-slugify-algorithm-in-c
//https://stackoverflow.com/questions/249087/how-do-i-remove-diacritics-accents-from-a-string-in-net
public static class Slug
{
    public static string GenerateSlug(this string phrase)
    {
        string str = phrase.RemoveDiacritics().ToLower();
        // invalid chars           
        str = Regex.Replace(str, @"[^a-z0-9\s-]", "");
        // convert multiple spaces into one space   
        str = Regex.Replace(str, @"\s+", " ").Trim();
        // cut and trim 
        str = str.Substring(0, str.Length <= 45 ? str.Length : 45).Trim();
        str = Regex.Replace(str, @"\s", "-"); // hyphens   
        return str;
    }

    public static string RemoveDiacritics(this string text)
    {
        var s = new string(text.Normalize(NormalizationForm.FormD)
            .Where(c => CharUnicodeInfo.GetUnicodeCategory(c) != UnicodeCategory.NonSpacingMark)
            .ToArray());

        return s.Normalize(NormalizationForm.FormC);
    }
}