Http::collect to parse some data in the http request

I am having troubles on some http payload (xml soap) that I can't see in an irule (once I see it, i'd be able to parse some data and allow or drop traffic).

I have tried to tcpdumpo the traffic (-s0) and I see all the soap request sent from a device to the server that is behind the Bigip, there's no limit, the soap request is complete with tcpdump.

In this xml soap (a sequence of values in this format):

(value)16(/value)

(value2)222(/value2)

.

.

.

I need to parse a specific field and then to compare it with a string, if they match, go otherwise drop, not too difficult.

Issue is that with my irule I can see only a part of the soap xml, and more than the last half of it is missing and not collected:

Here my Irule:

when HTTP_REQUEST {

HTTP::collect 2151

}

when HTTP_REQUEST_DATA {

log local0. " payload [HTTP::payload]"

}

When I'll be able to see the payoad in full, then I could use findstr to parse the string I need and do my tests.

As told, in /var/log/ltm I see just part of the Soap xml, the rest is just "not collected, and not logged".

Any reason why ?

Even replacing the value (that I saw with the tcpdump) of 2151 did not solve:

HTTP::collect [HTTP::header Content-Length]

I am stuck :/

Thx a lot to anyone who has some tips.

Nicola