iRule to restrict the Parameter Value Length in a Particular URL

Hi Experts,

 

I have this requirement to look for a Particular Parameter in a URL and restrict access to the URL if the Parameter value length exceeds 50 characters. For example in URL /index.html I have this parameter called "db" in the POST request body whose value length shouldn't exceed 50 characters.

 

Could some through some light on the logic to parse the HTTP Payload and read the Parameter value length for a specific parameter and apply the restrictions.

 

Thank you in Advance !

 

Best Regards, Saneesh