Create human friendly URL using preg_replace and regular expression in PHP

Published on July 12th, 2012 - by chanon Categorized in Backendphpwordpress

This post explain how can you generate human readable URL (friendly URL for SEO) from the given string. Using regular expression and preg_replace in PHP.

Concept

The concept below are applied to the given string in order to create the friendly URL using PHP script.

• URL must be lower case
• ‘&’ or ‘&’ (html special character to display ‘&’) must be converted to ‘-and-‘
• Any characters except English letters or numbers must be converted to ‘-‘
• en dash (-) is not allowed to be repeated (E.g. no ‘—-‘)
• en dash is not allowed at the start or ending of URL phase (e.g. no ‘-friendly-url-‘)

For example the string ‘convert “php.net” title into human readable url‘ will be converted to ‘convert-php-net-title-into-human-readable-url‘ Coding

Coding

The code below show PHP function that return human readable URL from the given string. The further section explain the work flow of this code.

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function friendlyURL($inputString){
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    $url = strtolower($inputString);
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    $patterns = $replacements = array();
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    $patterns[0] = '/(&|&)/i';
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    $replacements[0] = '-and-';
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    $patterns[1] = '/[^a-zA-Z01-9]/i';
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    $replacements[1] = '-';
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    $patterns[2] = '/(-+)/i';
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    $replacements[2] = '-';
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    $patterns[3] = '/(-$|^-)/i';
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    $replacements[3] = '';
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    $url = preg_replace($patterns, $replacements, $url);
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    return $url;
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    }

How it works?

• line 2 – lower case the input using PHP build-in function strtolower
• line 3 – declare $patterns and $replacement as Array
• line 4,5 – match ‘& or &’ and replace with ‘-and-‘
• line 6,7 – match non Alphabets or number and replace with ‘-‘
• line 8,9 – match the single or repeated en dash (—-) and replace with single en dash (-)
• line 10,11 – match en dash at the beginning of phase ($-) or en dash the end of phase (^-) and delete

That’s all it is, please use the comment below if you have any questions.