Haproxy redirect request base on body

haproxy-redirect-base-on-payload

Based on this guide
https://stackoverflow.com/questions/23259843/how-to-route-traffic-reverse-proxy-with-haproxy-based-on-request-body

frontend http-in
             bind *:80
             option http-buffer-request
             acl redirect_pingpong req.body -m reg [insert your regular expression here]
             use_backend pingpong_backend if redirect_pingpong

             default_backend web_bk

We use regex to redirect request
Example

frontend kifarunixlb
        bind localhost:8088
        acl redirect_app2 req.body -m reg \"data\":.*\"test1\"
        use_backend app2 if redirect_app2
        default_backend app1
        option forwardfor
backend app1
        balance roundrobin
        server  app01   localhost:8080 check
backend app2
        balance roundrobin
        server  app02   localhost:8081 check


when body request contain "data":"test0", the request will be processed by server02
remember string to hex upper case

check in both body and header  
acl redirect_app2 req.payload(0,0),hex -m sub 7573657231   // 7573657231 -> user1
Cache-Control: no-cache -> ok
Content-Type: application/json
user: user2


or we can use pare keyvalue
user:user1 // attendtion remove space between key and value


the best way is use header 
acl redirect_app2 hdr_val(user_id) eq my_user_id