Forum Discussion
Rory_Hewitt_139
Nimbostratus
NimbostratusDetermining processing based on flags in a URL
I have a URL which will come in as
/features?features=10010001
where each '1' or '0' is a 'flag'. I need to check each flag in turn and depending on its value, XOR it with a matching flag stored as a preset in my iRule, and eventually return the result. The presets will be stored as variables called e.g. 'flag1', 'flag2' etc. So my processing would be to split the '10--01-00---01' string into an array of flags, process each element in the array, match it with the related preset variable, do the XOR and then return the XOR'ed string as a 200 response.
As a start, I'm trying to figure out the best way to convert the '10--01-00---01' string into an array of flags that I can process.
I hope the above makes sense.
that kinda works, except that the characters could potentially be 0, 1 or -
may we remove - before scanning?
% scan [string map {"-" ""} 10--01-00---01] %2d%2d%2d%2d a b c d 4 % put "$a $b $c $d" 10 1 0 1by the way, if flag is only one digit each, can we use split?
% split [string map {"-" ""} 10--01-00---01] {} 1 0 0 1 0 0 0 1
nitassEmployee
what about scan or regexp?
scan % scan 10010001 %2d%2d%2d%2d a b c d 4 % put "$a $b $c $d" 10 1 0 1 % time "scan 10010001 %2d%2d%2d%2d a b c d" 1000 5.319 microseconds per iteration regexp % regexp {(\d\d)(\d\d)(\d\d)(\d\d)} 10010001 m a b c d 1 % put "$a $b $c $d" 10 01 00 01 % time "regexp {(\d\d)(\d\d)(\d\d)(\d\d)} 10010001 m a b c d" 1000 3.077 microseconds per iteration
Rory_Hewitt_139Hey @nitass, that kinda works, except that the characters could potentially be 0, 1 or -, so I can't use %d in scan or \d in regex. I can use %c in scan, but it converts them to a Unicode integer. So for instance, scan $flags %c%c%c%c%c%c%c%c flag1 flag2 flag3 flag4 flag5 flag6 flag7 flag8 gives me "49 45 48 45 45 45 45 49". Any way to simply chop them out as single characters?
JGCumulonimbus
The test results here seem to go contrary to the prevalent view that prefers "scan" to "regexp" for performance.
nitass_89166Noctilucent
what about scan or regexp?
scan % scan 10010001 %2d%2d%2d%2d a b c d 4 % put "$a $b $c $d" 10 1 0 1 % time "scan 10010001 %2d%2d%2d%2d a b c d" 1000 5.319 microseconds per iteration regexp % regexp {(\d\d)(\d\d)(\d\d)(\d\d)} 10010001 m a b c d 1 % put "$a $b $c $d" 10 01 00 01 % time "regexp {(\d\d)(\d\d)(\d\d)(\d\d)} 10010001 m a b c d" 1000 3.077 microseconds per iteration- Rory_Hewitt_139Hey @nitass, that kinda works, except that the characters could potentially be 0, 1 or -, so I can't use %d in scan or \d in regex. I can use %c in scan, but it converts them to a Unicode integer. So for instance, scan $flags %c%c%c%c%c%c%c%c flag1 flag2 flag3 flag4 flag5 flag6 flag7 flag8 gives me "49 45 48 45 45 45 45 49". Any way to simply chop them out as single characters?
- JGThe test results here seem to go contrary to the prevalent view that prefers "scan" to "regexp" for performance.
- nitass_89166
that kinda works, except that the characters could potentially be 0, 1 or -
may we remove - before scanning?
% scan [string map {"-" ""} 10--01-00---01] %2d%2d%2d%2d a b c d 4 % put "$a $b $c $d" 10 1 0 1by the way, if flag is only one digit each, can we use split?
% split [string map {"-" ""} 10--01-00---01] {} 1 0 0 1 0 0 0 1- Rory_Hewitt_139Nope, we need the '-' in there - it implies 'null'. Although, of course, split would work fine -I don't know why I didn't think of it - probably because I'm not a Tcl programmer :) In any event, I have this working - using substr: for {set x 0} {$x < 8} {incr x} { set flag [string index $flags $x] switch $flag { "0" {...} "1" {...} default {...} } which seems to do the job rather nicely. Thanks for the help!
- nitass
that kinda works, except that the characters could potentially be 0, 1 or -
may we remove - before scanning?
% scan [string map {"-" ""} 10--01-00---01] %2d%2d%2d%2d a b c d 4 % put "$a $b $c $d" 10 1 0 1by the way, if flag is only one digit each, can we use split?
% split [string map {"-" ""} 10--01-00---01] {} 1 0 0 1 0 0 0 1- Rory_Hewitt_139Nope, we need the '-' in there - it implies 'null'. Although, of course, split would work fine -I don't know why I didn't think of it - probably because I'm not a Tcl programmer :) In any event, I have this working - using substr: for {set x 0} {$x < 8} {incr x} { set flag [string index $flags $x] switch $flag { "0" {...} "1" {...} default {...} } which seems to do the job rather nicely. Thanks for the help!