Ensure rewrite-rule is used - .htaccess

Question

I have created a simple rewrite URL like this:
RewriteRule ^messages$ /messages.php [L]
How do I force the user to use /messages and not /messages.php? I.e., if user queries messages.php, he'll be 301 redirected to /messages.
I have a long list of rewrite rules, like the one above.
RewriteEngine On
RewriteRule ^messages$ /messages.php [L]
RewriteRule ^events$ /events.php [L]
RewriteRule ^cv$ /cv.php [L]
RewriteRule ^profile/([^/]*)$ /profile.php?id=$1 [L]
RewriteRule ^ratings$ /ratings.php [L]
RewriteRule ^newsfeed$ /newsfeed.php [L]
RewriteRule ^logout$ /logout.php [L]
RewriteRule ^profile$ /profile.php [L]
RewriteRule ^ranking$ /rank.php [L]
RewriteRule ^find-study$ /search.php [L]
RewriteRule ^search/$ /search.php [L]
RewriteRule ^search$ /search.php [L]
RewriteRule ^invite-friends$ /invite-friends.php [L]
RewriteRule ^profile/([^/]*)$ /profile.php?id=$1 [L]
RewriteRule ^profile/([^/]*)/([^/]*)$ /profile.php?id=$1&programme=$2 [L]
RewriteRule ^student-requests$ /student-requests.php [L]
# Q&A
# view question
RewriteRule ^question(?:/([^/]+)(?:/([^/]*))?)?/?$ /question.php?id=$1&permalink=$2 [L]
RewriteRule ^question/([^/]*)/([^/]*)/([^/]*)$ /question.php?id=$1&permalink=$2&answer=$3 [L]
# manage question
RewriteRule ^ask(?:/([^/]+)(?:/([^/]*))?)?/?$ /manageQuestion.php?tag_id=$1&tag_type=$2 [L]
RewriteRule ^ask/([^/]*)/([^/]*)/([^/]*)$ /manageQuestion.php?tag_id=$1&tag_type=$2&tag_name=$3 [L]
RewriteRule ^editquestion(?:/([^/]+)(?:/([^/]*))?)?/?$ /manageQuestion.php?id=$1&second=$2 [L]
# questions
RewriteRule ^questions$ /questions.php [L]
RewriteRule ^questions/([^/]*)$ /questions.php?first=$1 [L]
RewriteRule ^questions/([^/]*)/([^/]*)$ /questions.php?first=$1&second=$2 [L]
RewriteRule ^questions/([^/]*)/([^/]*)/([^/]*)$ /questions.php?first=$1&second=$2&third=$3 [L]
RewriteRule ^questions/([^/]*)/([^/]*)/([^/]*)/([^/]*)$ /questions.php?first=$1&second=$2&third=$3&fourth=$4 [L]

Answer 1

When trying to solve this problem you probably encountered the problem of infinite loops. One way to prevent this is to use %{THE_REQUEST}, since this variable doesn't change on a rewrite. Therefore, if you use the following rule, it will change every url ending on .php to an url without it:
RewriteCond %{THE_REQUEST} ^(GET|POST)\ /(messages|events|cv|ratings|etc)\.php\ HTTP
RewriteRule ^ %2 [R,L]
After testing that the rule works correctly, change [R,L] to [R=301,L] to make the redirect permanent. Doing this before everything works correctly makes testing a pain.
Edit: Instead of using (.*) you could use /(page1|page2|page3) for all the simple redirects. For each of the more complex ones you probably need to have a single redirect each in the form of:
RewriteCond %{THE_REQUEST} ^(GET|POST)\ /questions\.php\?id=([^&]+)&permalink=([^&]+)&answer=([^&]+)\ HTTP
RewriteRule ^ questions/%2/%3/%4 [R,L]