This is Perl module Perlbal::Plugin::BackendHeaders.

INSTALLATION

Perlbal::Plugin::BackendHeaders installation is straightforward. If your CPAN shell is set up,
you should just be able to do

    % cpan Perlbal::Plugin::BackendHeaders

Download it, unpack it, then build it as per the usual:

    % perl Makefile.PL
    % make && make test

Then install it:

    % make install
    
Finally apply the modify_headers.patch to perlbal:
  
    % cat modify_headers.patch | patch -p0
    
Check to make sure it works:
  
    % curl -I http://mydomain.com/
    
    HTTP/1.0 200 OK
    Content-Type: text/html; charset=utf-8
    Content-Language: en
    Pragma: public
    X-Backend: mydomain:8880
    Connection: close
    
DOCUMENTATION

Perlbal::Plugin::BackendHeaders documentation is available as in POD. So you can do:

    % perldoc Perlbal::Plugin::BackendHeaders

to read the documentation online with your favorite pager.

Victor Igumnov