Removing Double Redirects or Redirect Chains form .htaccess files.

If you manage and large site using mod_rewrite or ISAPI_Rewrite 3 you will eventually run into issues maintaining the rewrite rules. After doing a few redesigns or moving things around repeatedly you can end up with situations where one page redirects to another page then another and so on in a chain. This is functional but inefficient, it can have a negative effect on user experience and on SEO value, and makes everything harder to maintain. This tool is a simple script you can pass you .htaccess file through to remove all these multi-step redirects and all pages redirect immediately on the first redirect to the final destination page.

This is a perl program that you will need to save along with a copy of your .htaccess file someplace with Perl installed.

	#!/usr/bin/perl
	# Get input file.
	my $file = $ARGV[0] or die "Need input file\n";
	open(my $data, '<', $file) or die "Could not open '$file' $!\n";
	open(my $out, '>', "$file.new");
	my $redir = 0;
	my $double = 0;
	my %adata;
	# Build a list of all rewrites.
	while (my $line = <$data>) {
	if( $line ~~ /^RewriteRule \^/ ) {
	my @parts = split(/\s+/, $line);
	my $source = $parts[1];
	$source =~ s/[\^\$]//g;
	$source = "/$source";
	my $destination = $parts[2];
	print "$source -> $destination\n";
	# Read all data and group by state then zipcode.
	$adata{$source} = $destination;
	$redir++;
	}
	}
	close $data;
	open(my $data, '<', $file) or die "Could not open '$file' $!\n";
	# Process the file again this time applying updates.
	while (my $line = <$data>) {
	if( $line ~~ /^RewriteRule \^/ ) {
	# Cehck each rewrite rule to see if it's destination has another rule.
	my @parts = split(/\s+/, $line);
	my $source = $parts[1];
	$source =~ s/[\^\$]//g;
	$source = "/$source";
	my $destination = $parts[2];
	if($adata{$destination}) {
	#print "$source -> $destination -> $adata{$destination}\n";
	# Print a replacment rule from the source to the real destination.
	print $out "$parts[0] $parts[1] $adata{$destination} $parts[3]\n";
	$double++;
	} else {
	# If not jsut print the line as is.
	print $out $line;
	}
	} else {
	# Output all non-rewrite likes as is.
	print $out $line;
	}
	}
	# Print some summary text.
	print "$redir Redirects Found, $double Double Redirect.\n";
	close $data;
	close $out;

view raw simplify-rewrites.pl hosted with ❤ by GitHub

Once saved you can run it by opening a terminal and running the following command:

perl simplify-rewrites filename

The Program will show a summary and a new filename.new file will be generated with the de-duping applied. You can use the following to get a list of all the changes for review.

diff -Na --unified=0 rw.txt rw.txt.new | less