.htaccess - htaccess multi language site with sub directories, and default 301

Question

I am having some issues setting up my htaccess to allow multiple languages utilising the sub directory method eg:

http://www.domain.com/en/
http://www.domain.com/sw/
http://www.domain.com/ie/

Also to complicate things, the project isn't currently live, its on a dev server. For example, I am currently accessing the project at:

http://dev.domain.com/devname/projectname/

And I want the above to automatically 301 redirect to:

http://dev.domain.com/devname/projectname/en/

Here is my htaccess:

Options +FollowSymLinks -MultiViews
RewriteEngine on

# ----------------------------------------------------------------------
# MULTI LANGUAGE SUB DIRECTORY
# ----------------------------------------------------------------------

RewriteCond %{REQUEST_URI} !^/(en|sw)/
RewriteRule ^(.*)$ en/$1 [R=301,L]

# ----------------------------------------------------------------------
# Rewrite rules
# ----------------------------------------------------------------------

## CASE STUDIES ##
RewriteRule ^casestudies/([^/.]+).html$ index.php?controller=contents&method=viewCasestudy&link=$1 [L,QSA]

## PRODUCTS ##
RewriteRule ^products/([^/.]+).html$ index.php?controller=contents&method=viewProduct&link=$1 [L,QSA]

RewriteRule ^([a-z{2}]+)(/)?$ index.php?controller=contents&method=viewHome&lang=$1 [L,QSA] # Default load
RewriteRule ^(/)?$ index.php?controller=contents&method=viewHome [L,QSA] # Default load

The above will actually redirect to:

http://dev.domain.com/home/webserver_dir/devname/projectname/en/

..and if I use RewriteBase it seems to just goto...

http://dev.domain.com/en/

So my question: How do I get the language URLs working correctly relative to the directory its in on my dev server, and then ideally will work when it goes live without any environment specific rules.

Bonus question: Do I need to add the ([a-z{2}]+) bit in front of all my subsequent rewrite rules or can I have a catch all that will effect all further rules?

EDIT -----------------------------

I have reduced it down to the following as suggested...

Options +FollowSymLinks -MultiViews
RewriteEngine on

RewriteBase /devname/projectname/

RewriteCond %{REQUEST_URI} !^/(en|sw)(/|$) [NC]
RewriteRule ^(.*)$ en/$1 [R=301,L]
RewriteRule ^([a-z]{2})/?$ index.php?controller=contents&method=viewHome&lang=$1 [NC,L,QSA] # Default load

... but now its redirecting to http://dev.domain.com/devname/projectname/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/en/, any ideas?

Answer 1

Have you tried the answer in the following link? It should do what you're trying to achieve.

Endless Redirect Loop by htaccess rules multi language

RewriteEngine On
RewriteBase /   

# empty url -> redirect to en/
RewriteCond %{QUERY_STRING} !lang=(en|de)
RewriteRule ^$ en/ [R=301,L]

# url is ONLY '/en' or '/de' -> redirect to /en/ or /de/ (adding slash)
RewriteRule ^(en|de)$  $1/ [R=301,L]

# now all urls have en/ de/ -> parse them
RewriteRule ^(en|de)/(.*)$  $2?lang=$1&%{query_STRING} [L]