How to remove the specific character in between using Apache rewrite rule - regex

Question

I have a URL like http://example.com/abc+def+cde+ndk
Unfortunately the number of capturing groups in the URI (abc, def,cde..) are not in a fixed number.
I tried writing a rule like the below but it is matching and replacing only three groups(two character groups and one + in between).
RewriteCond %{REQUEST_URI} ^/(.*?)(\+{1,})(.*)$ [NC]
RewriteRule . http://example.com/%1%3 [R=301,L]
Example given below:
Source: example.com/abc+def+cde+x+y(n number of strings separated by +)
Destination Must be: example.com/abccdexy...till n

Answer 1

If you can add a directive to the main config, the best solution is to use a RewriteMap that processes the URL rewriting through an external script, which you write. You can find details on that here.
Basically you do something like:
RewriteMap convertUrl "prg:/www/bin/convertUrl.pl"
RewriteRule \+ ${convertUrl:%{REQUEST_URI}} [R=301,L]
(only the RewriteMap needs to go in your main config, the RewriteRule can go in your .htaccess)
Where /www/bin/convertUrl.pl is a script you write to process the substitution, as described on the above link. It should take the URL on STDIN (without any buffering), strip out the plus signs, and return it on STDOUT.
Something like this should work:
#!/usr/bin/perl
$| = 1; # Turn off I/O buffering
while (<STDIN>) {
s/\+//g; # Replace dashes with underscores
print $_;
}

Answer 2

Here is a pure .htaccess solution.
# Remove a plus sign on each iteration of the rule
RewriteRule ^help/col/([^+/]+)\+([^/]+)$ help/col/$1$2 [E=REMOVED_PLUS_SIGNS:1]
# For URLs that were processed, redirect once all the plus signs are removed
RewriteCond %{ENV:REMOVED_PLUS_SIGNS} =1
RewriteRule ^help/col/([^+/]+)$ /help/col/$1 [R=301,L]