Forum Discussion

Carl_Weiss_1340

Nimbostratus

Jun 28, 2016

String Scan question ... trying to do something really simple

Its just not working...

Given a string - "/part1/part2/part3/part4" I want the result to be: p1 = part1 p2 = part2 p3 = /part3/part4

which led me to write the following:

when HTTP_REQUEST { set foo "/part1/part2/part3/part4"

if { [ scan $foo {/%s/%s/%s} part1 part2 part3 ] == 3 } { log local0. "testing part1 = $part1; part2= $part2; part3 = $part3" } else { log local0. "did not scan properly" } log local0. "exit irule" }

I tried scan $foo {/%[^/]/%[^/]/%s} - which did not work either. So its something in the expression that I have wrong...

I keep getting "did not scan properly" in the logs

Any help or pointers appreciated.

Thanks Carl

String matchers are "greedy", so %s will match everything up to the next whitespace. That's why ~~/%s/%s/%s~~ won't work; everything ends up in ~~$part1~~.

The second construct should work. Indeed, on 11.5.4, I do the following:

when CLIENT_ACCEPTED {
    set path "/foo/bar/baz/bing"
    
    set x [scan $path {/%[^/]/%[^/]/%s} part1 part2 part3]
    if { $x == 3 } {
        log local0. "part1 = $part1; part2 = $part2; part3 = $part3"
    }
    else {
        log local0. "scan returned ($x) elements"
    }
}

And it works as I expect. In the logs, I get:

Jun 27 19:00:01 b201 info tmm[13446]: Rule /Common/test_scan : part1 = foo; part2 = bar; part3 = baz/bing

VernonWells
Employee
Jun 28, 2016
String matchers are "greedy", so %s will match everything up to the next whitespace. That's why ~~/%s/%s/%s~~ won't work; everything ends up in ~~$part1~~.

The second construct should work. Indeed, on 11.5.4, I do the following:

when CLIENT_ACCEPTED { set path "/foo/bar/baz/bing" set x [scan $path {/%[^/]/%[^/]/%s} part1 part2 part3] if { $x == 3 } { log local0. "part1 = $part1; part2 = $part2; part3 = $part3" } else { log local0. "scan returned ($x) elements" } }

And it works as I expect. In the logs, I get:

Jun 27 19:00:01 b201 info tmm[13446]: Rule /Common/test_scan : part1 = foo; part2 = bar; part3 = baz/bing
- Carl_Weiss_1340
  Nimbostratus
  Jul 12, 2016
  sorry for the tardiness - I tried the alternative again and viola! it worked (not sure what happened when I tested it before).
Vernon_97235
Historic F5 Account
Jun 28, 2016
String matchers are "greedy", so %s will match everything up to the next whitespace. That's why ~~/%s/%s/%s~~ won't work; everything ends up in ~~$part1~~.

The second construct should work. Indeed, on 11.5.4, I do the following:

when CLIENT_ACCEPTED { set path "/foo/bar/baz/bing" set x [scan $path {/%[^/]/%[^/]/%s} part1 part2 part3] if { $x == 3 } { log local0. "part1 = $part1; part2 = $part2; part3 = $part3" } else { log local0. "scan returned ($x) elements" } }

And it works as I expect. In the logs, I get:

Jun 27 19:00:01 b201 info tmm[13446]: Rule /Common/test_scan : part1 = foo; part2 = bar; part3 = baz/bing
- Carl_Weiss_1340
  Nimbostratus
  Jul 12, 2016
  sorry for the tardiness - I tried the alternative again and viola! it worked (not sure what happened when I tested it before).