ReWrite rule to add .html extension

Question

I need a rule that will add an .html extension whenever there is 'not' a trailing slash.

A new client recently changed ecommerce scripts and the new version handles SEO differently and changed all of their 16,000+ product links. This was not caught prior to the site being re-indexed so we need to redirect the old to the new..

All products used to have links like this domain.com/category/productname but are now domain.com/category/productname.html

Category links did not change and all are like this domain.com/category/ (with trailing slash)

Answer 1

There's a lot of answers here that sort of work, but by far the easiest way since apache 2.4 is to just enable MultiViews, see official docs https://httpd.apache.org/docs/2.4/content-negotiation.html

All I had to do was:

<Directory /var/www/html>
  Options +MultiViews
</Directory>

This means that if I go to my site e.g. example.com/dashboard it just serves dashboard.html without needing any redirects, and it keeps the original URL as it was (so it doesn't append the extension).

I couldn't really find specifics in the docs about which file extensions get priority, so not sure what happens if you have both dashboard.html and dashboard.php living in the directory, or whether it's easy to change the priority order.

Answer 2

The answer from @david-wolever redirects everything that does not end in .html (or the root) to the same URL with an added .html extension, meaning it appends a .html extension to things like CSS and JavaScripts files, e.g. it will redirect /style.css to /style.css.html which is not likely what you want. It also has the spaces after ! character which will likely caused @greggles 500s

This redirects URLs which do not end in a dot followed by 3 or 4 alphanumeric characters:

RewriteEngine On
RewriteCond %{REQUEST_URI} !\.[a-zA-Z0-9]{3,4}
RewriteCond %{REQUEST_URI} !/$
RewriteRule ^(.*)$ $1.html

Or for finer grain control, whitelist the extensions you do not want .html appended to e.g.

RewriteCond %{REQUEST_URI} !\.(html|css|js|less|jpg|png|gif)$