Collects an amount of HTTP body data, optionally specified with the length argument. When the system collects the specified amount of data, it calls the Tcl event HTTP_REQUEST_DATA or HTTP_RESPONSE_DATA.
The collected data can be accessed via the HTTP::payload command.


  • This command cannot be called after any Tcl command that sends an HTTP response (e.g. redirect, HTTP::redirect, and HTTP::respond). A run-time error will result.
  • If multiple iRules attached to the same virtual execute this command, the last collect wins, meaning the earlier one will be ignored. Having many HTTP::collect across multiple iRules is not a supported operation and should be avoided. The reason is that when performing actions with collected data (like HTTP::retry or HTTP::respond) it will implicitly cause the further operations against a collected data to break since it has been already released.

The BIG-IP API Reference documentation contains community-contributed content. F5 does not monitor or control community code contributions. We make no guarantees or warranties regarding the available code, and it may contain errors, defects, bugs, inaccuracies, or security vulnerabilities. Your access to and use of any code available in the BIG-IP API reference guides is solely at your own risk.