title: Reduce duplication in haproxy acl with multiple frontend sections
body: <p>I'm using haproxy with stunnel handling SSL (and using the proxy mode to preserve the original IP from haproxy).</p>
  
  <p>I have several acl tests that redirect to different backends depending on the domain, headers, or path.</p>
  
  <p>The problem is that these are identical whether you're coming in via http or https, but I have to duplicate them in the config. Is there any way to reduce the duplication?</p>
  
  <p>Here's a sample config:</p>
  
  <pre><code>global
      user haproxy
      group haproxy
      #etc...
  
  frontend http-in
      bind *:80
  
      acl files_path path_beg /files/
      acl beta_host hdr_beg(host) -i beta.
  
      use_backend files if files_path
      use backend beta_host
      default_backend appservers
  
  frontend https-in
      bind *:442 accept-proxy
  
      acl files_path path_beg /files/
      acl beta_host hdr_beg(host) -i beta.
  
      use_backend files if files_path
      use backend beta_host
      default_backend appservers
  
  
  backend appservers
      balance roundrobin
      option forwardfor
  
      server appserver_1 localhost:8080 weight 1
      server appserver_2 192.168.1.101:8080 weight 1
  
  backend files
      balance roundrobin
      option forwardfor
      server file1 192.168.1.102 weight 1
      server file2 192.168.1.103 weight 1
  
  backend beta
      balance roundrobin
      server beta1 192.168.1.104 weight 1
  </code></pre>
  
  <p>The http-in and https-in have different ports, and the https-in has to sepcify accept-proxy so that stunnel can use the proxy protocol to pass it the original IP of the user. But other than that they are identical, and should always be identical. Is there any way to reduce this duplication? (haproxy 1.5-dev)</p>