iRule to drop HTTP GET requests that don't have zero content length header

Are you looking for requests that have any content length (like a POST):

when HTTP_REQUEST {
    if { [HTTP::header exists Content-Length] } {
        drop
    }
}

Or something that specifically has a content length of zero:

when HTTP_REQUEST {
    if { ( [HTTP::header exists Content-Length] ) and ( [HTTP::header Content-Length] == 0 ) } {
        drop
    }
}

I'm looking to drop only GET requests that don't have 0 content-length. If the GET request is properly formatted with a zero content-length, I want to allow it.

when HTTP_REQUEST {
    if { ( [HTTP::method] equals "GET" ) and ( [HTTP::header exists Content-Length] ) and ( [HTTP::header Content-Length] == 0 ) } {
         do nothing
    } else {
        reject
    }
}

What if the request doesn't have a Content-Length header?

That's a good question....is "not exist" a valid qualifier? so...would this work?

when HTTP_REQUEST { if { ( [HTTP::method] equals "GET" ) and ((( [HTTP::header exists Content-Length] ) and ( [HTTP::header Content-Length] == 0 )) or ( [HTTP::header not exist Content-Length] )) } { do nothing } else { reject } }

Well, it would be:

 if { not ( [HTTP::header exists Content-Length] ) } {
    ...
 } 

Thanks Kevin!!!

So does this look like the right way to implement it?

when HTTP_REQUEST { if { ( [HTTP::method] equals "GET" ) and ( [HTTP::header exists Content-Length] ) and ( [HTTP::header Content-Length] == 0 ) } or { not ( [HTTP::header exists Content-Length] ) } do nothing } else { reject } }

I think this will work... 😉

when HTTP_REQUEST {
    if { ( [HTTP::method] equals "GET" ) and ( ( ( [HTTP::header exists Content-Length] ) and ( [HTTP::header Content-Length] == 0 ) ) or ( not [HTTP:::header exists Content-Length] ) ) } {
         do nothing
    } else {
        reject
    }
}