Struggling with .htaccess (Godaddy Linux Hosting) - linux

Question

I would really appreciate your help with the below. I have been both googling and testing code via trial an error, I believe that I'm slowly figuring things out but I would appreciate the fast track assistance in both the result and my learning development.
I currently have a website hosted on a shared resource on a apache Linux server through GoDaddy. I am trying to achieve the following;-
1) Redirect non www traffic to www.
2) Remove the .html file extension and add a trailing slash on the web address.
I currently have the code below, the 301 www. redirect is working and the trailing slash is also working. However I am getting 404 errors on the subpages ie www.swiftcomm.co.uk/contact/;-
How do I go about resolving this issue with the code?
Options +FollowSymlinks -MultiViews -Indexes
RewriteEngine on
# Redirect to domain with www.
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule .* http://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
# Same for HTTPS:
RewriteCond %{HTTPS} on
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule .* https://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
# Ensure all directory URLs have a trailing slash.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !\/$
RewriteCond %{REQUEST_URI} !\/[^\/]*\.[^\/]+$
RewriteRule .* http://%{HTTP_HOST}%{REQUEST_URI}/ [L,R=301]
# Same for HTTPS:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !\/$
RewriteCond %{REQUEST_URI} !\/[^\/]*\.[^\/]+$
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI}/ [L,R=301]

Answer 1

Please try the following code - it can replace your entire file. The comments explain what each ruleset does.
Options +FollowSymlinks -MultiViews -Indexes
RewriteEngine on
RewriteBase /
# Force www. prefix - http/https
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=302,L]
# Remove .html extension suffix from URI only if it matches an existing file.
# Add trailing slash simultaneously.
RewriteCond %{REQUEST_FILENAME} -f
RewriteCond %{THE_REQUEST} \s\/(.+)\.html\s [NC]
RewriteRule ^ %1/ [R=302,L]
# Force trailing slash if it has'nt been forced already.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} ^\/(.+[^/])$
RewriteRule ^ %{REQUEST_URI}/ [R=302,L]
# Rewrite non-existing files to their .html counterparts.
# If the .html file does not exist, Apache will gracefully degrade to a 404.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)/$ $1.html [L]