How to rewrite the status from 205 to 200

Hmm good question! Unfortunately for some reason our HTTP developer did not provide any way to change the response code, but that does not mean you can’t do it. There are a couple of approaches to this problem.

 

 

If you know ahead of time that you will be getting a 205 request (special request method, request cookie etc) then you can do a TCP::collect on the server side and replace the response code using TCP::payload replace.

 

 

If if you don’t have the priveledge of knowing this ahead of time, you will need to write some thing like this ...

 

 

when HTTP_RESPONSE {
   if {[HTTP::status] == 205}{
      HTTP::collect [HTTP::header Content-Length]
   }
}
when HTTP_RESPONSE_DATA {
   HTTP::respond 200 content [HTTP::payload]
}

 

 

The first approach while a little bit more difficult, can be more superior because you will not be buffering unnecessary payload. But if the 205 response payload size is not very large then I would go with the second one.

Thanks for your help. However ,the bad thing is that server do not write the content-length information in the header .

I have a rule like this , It works sometimes , however, sometime do not , And got an error in /var/log/ltm like this

 

 

--- http_process_state_prepend - Invalid action EV_INGRESS_DATA during ST_HTTP_PREPEND_HEADERS --------------

 

 

rule httpcodechange {

 

when SERVER_CONNECTED {

 

TCP::collect

 

}

 

when SERVER_DATA {

 

TCP::collect 100

 

set httpcodeheader [findstr [TCP::payload] "HTTP/1.0" 9 "\r"]

 

if { $httpcodeheader eq "205 Reset Content" } {

 

log local0. "error=($httpcodeheader)"

 

TCP::payload replace 9 17 "200 OK"

 

}

 

TCP::release

 

}

 

}

 

How about some thing like this. It appears to work for me.

when HTTP_REQUEST_SEND {
   TCP::collect 12
}
when SERVER_DATA {
   if {[findstr [TCP::payload 12] "200"] == "200"} {
      TCP::payload replace 9 3 "205"
   }
}

Note that I have the response codes logic reversed but it should still demonstrate the point.

You shouldn't need the "TCP::collect 100" in the SERVER_DATA event.

 

That might be causing the error you are seeing.