HAProxy reverse proxy configuration with URL rewriting for two backends

reverse-urlrewrite.haproxy.cfg

global
    log                       127.0.0.1 local2
    maxconn                   2048
    tune.ssl.default-dh-param 2048

defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s

frontend fe-test
    bind *:80
    acl ac-web1 path_beg /web1
    acl ac-web2 path_beg /web2
    use_backend be-web1 if ac-web1
    use_backend be-web2 if ac-web2

backend be-web1
    server static web-a:80 check
    reqrep ^([^\ :]*)\ /web1[/]?(.*)  \1\ /aaa/\2

backend be-web2
    server static web-b:80 check
reqrep ^([^\ :]*)\ /web2[/]?(.*) \1\ /bbb/\2