Stream Profile: Replace String

You need to either escape or use a different expression separator. The example below uses the character '' as the expression separator.

 

 

/uri1/uri2//uri3/uri4/

Am I missing something? How are you setting the expression separator? (Is this set in the profile?)

 

 

-Brian

Also, what is the default context of STREAM_REPLACED?

 

 

Thanks,

 

Brian

STREAM::replace [] - Can be used to change the target replacement string specified in the profile. This call is not sticky and will be applied only once during the current match. If the ‘target’ expression is missing, the replacement will be skipped.

 

 

Does this mean that if I execute "STREAM::replace" without any arguements, the stream profile default action won't take effect?

 

 

Thanks,

 

Brian

Thanks for the information. I tried with and this is the error I am getting when I try to update the stream profile

 

 

Bad Characters. Only the following special characters are allowed: period, asterisk, forward slash, dash, colon, underscore, question mark, equals, at sign, comma, ampersand and space (.*/-:_?=@,&

 

 

/http://testbigip/https://testbigip/

 

 

The configuration is still handled from the stream profile. Adding the expression to the ‘target’ profile value and leaving the ‘source’ empty triggers the new behavior.

 

 

Calling STREAM::replace without any arguments will skip the replacement.

 

 

The new event is stream STREAM_MATCHED and can be fired both on the client and/or server side depending on your profile configuration.

 

 

Finally, the *first* character of the expression is treated as the expression separator. If you are having trouble with the ‘’ character, give this a try @/http://testbigip@https://testbigip/@

 

I have found something like this seems to work for replacing multiple items within a stream

 

 

when HTTP_RESPONSE {

 

STREAM::enable

 

STREAM::expression @IE@Apache@@Windows@Linux@

 

}

 

 

 

This would replace IE with Apache and Windows with Linux

 

 

9.2 is required as well as a stream profile defined within the Virtual Server. Just a blank stream profile works.

 

Hmm...

 

 

Is there any way to make the replacement sting a variable (e.g. [HTTP::header host])

 

 

H

Hi Hamish,

Yes, STREAM::expression accepts variables. Just make sure to wrap the string in double quotes instead of curly braces.

Also, I think you'll need to save the HTTP::host value in HTTP_REQUEST. And it would be good to only enable the stream filter for text responses when the client used a host header.

http://devcentral.f5.com/Wiki/default.aspx/iRules/STREAM__expression.html

 
 when HTTP_REQUEST { 
     Save the host header value 
    set host [HTTP::host] 
 } 
 when HTTP_RESPONSE { 
  
     Disable the stream filter by default 
    STREAM::disable 
  
     Check if response type is text 
    if {[HTTP::header value Content-Type] contains "text" && $host ne ""}{ 
  
        Replace any instance of the requested with newhost.example.com 
       STREAM::expression "@$host@newhost.example.com@" 
  
        Enable the stream filter for this response only 
       STREAM::enable 
    } 
 } 
 

Aaron

Ah. Thanks.

 

 

FWIW after asking the question I found the rather excellent ProxyPass iRule in the codeshare... Brilliant piece of code.

 

 

I also found that variables are shared between iRules for a single connection... Ouch... I wasn't expecting that feature...

 

 

H