complicated requirement for iRule

Please help me to get a solution through the iRule for the complicated requirement.

 

 

Data flow description

 

 

client -1-> GW device -2-> F5 BIGIP -3-> Servers -4-> client -5-> GW device -6-> F5 BIGIP -7-> Server

 

 

1. Client send the request to GW.

 

2. GW insert an parameter into http header, named "ABC". then send the request to F5.

 

3. F5 make use of the http header "ABC" as the persistent uie. like as

 

persist uie [HTTP::header "X-Up-Calling-Line-ID"]

 

pool app-pool1

 

4. Server give the response to client.

 

5. client get the server response and trigger the next access request to GW.

 

6. GW device drop the "ABC" from the http header and add another parameter into request URL named "def". E.g http://aaa.com/4w;def=879543999.

 

 

7. the GW send the request with "def" in url to F5, further more, there is not "ABC" in the http header.

 

then we must change the persistent uie from "ABC" to "def".

 

 

After that, all request will be persistent base on "def"

 

 

Please help me draft the iRul for this complicted requriement.

 

 

Many thanks!