HTTP::payload replace

There is an example showing how to replace a string in a payload on the HTTP::payload page (Click here) which uses regsub -all. I suppose you could use string map for a more efficient replacement if don't need a regex to describe the search string(s).

Something like this...?

when HTTP_RESPONSE {
  if { [HTTP::header exists "Content-Length"] } {
     set content_length [HTTP::header "Content-Length"]
  } else {
     set content_length 1000000
  }
  if { $content_length > 0 } {
     HTTP::collect $content_length
  }
}
when HTTP_RESPONSE_DATA { 
     regsub -all "oursite" [HTTP::payload] "oursitedev" newdata  
    log "Replacing payload with new data."  
    HTTP::payload replace 0 $content_length [string map {oursite oursitedev} [HTTP::payload]}]
    HTTP::release
}  

Out of curiosity, do you have any idea of why the stream profile isn't working? What version are you running?

Aaron

they're running 9.4.1 HF1...let me try your solution, Thanks by the way!!!...I'll post back if it works...I do have a support case open on the stream profile..so far the feedback I've gotten after they checked the tcpdumps, qkview, and httpwatch captures is the stream profile should have worked and it's being escalated to see why it isn't...

 

so irule now looks like

 

 

when HTTP_RESPONSE {

 

if { [LB::server addr] eq "10.0.19.50" } {

 

HTTP::header replace Location [string map {nwte1jas7:8882 bob} [HTTP::header Location]]

 

log "replacing nwte1jas7:8882 in header with bob" }

 

elseif { [LB::server addr] eq "10.0.19.42" } {

 

HTTP::header replace Location [string map {nwte1jas6:8882 bob} [HTTP::header Location]]

 

log "replacing nwte1jas7:8882 in header with bob" }

 

if { [HTTP::header exists "Content-Length"] } {

 

set content_length [HTTP::header "Content-Length"] }

 

else {

 

set content_length 1000000 }

 

if { $content_length > 0 } {

 

HTTP::collect $content_length }

 

}

 

 

when HTTP_RESPONSE_DATA {

 

if { [LB::server addr] eq "10.0.19.50" } {

 

regsub -all "nwte1jas7:8882" [HTTP::payload] "bob" newdata

 

log "Replacing nwtejas7:8882 with bob in the payload."

 

HTTP::payload replace 0 $content_length [string map {nwte1jas7:8882 bob} [HTTP::payload]]

 

HTTP::release }

 

elseif { [LB::server addr] eq "10.0.19.42" } {

 

regsub -all "nwte1jas6:8882" [HTTP::payload] "bob" newdata

 

log "Replacing nwtejas6:8882 with bob in the payload."

 

HTTP::payload replace 0 $content_length [string map {nwte1jas7:8882 bob} [HTTP::payload]]

 

HTTP::release }

 

}

 

 

I'm seeing error in log shown below

 

TCL error: Rule jas_redirect2 HTTP_RESPONSE_DATA - Out of bounds line 1 invoked from within HTTP::payload replace 0 $content_length [string map {nwte1jas7:8882 bob} [HTTP::payload]]

From the wiki page and Deb's post (Click here), it looks like you need to use the original content length (what's been collected so far). LTM should then recalculate the new length and update the Content-Length header it sends (in 9.4.0 and later).

 

 

As $content_length should be the amount of bytes collected so far, I'm not sure why you're seeing the out of bounds error.

 

 

Anyone have ideas on this?

 

 

Thanks,

 

Aaron

I think I'm getting the out of bounds because there is no content length set w/in the original http header...so the irule is using 10000 when the content may only be 100,200, etc...

Ah. Can you try this then?

 

 

HTTP::payload replace 0 [HTTP::payload length] [string map {nwte1jas7:8882 bob} [HTTP::payload]]

 

 

Aaron

I get wrong of args for those lines when I do that..

 

 

line 28: [wrong args] [HTTP::payload replace 0 [string map {nwte1jas7:8882 bob} [HTTP::payload]]]

 

line 33: [wrong args] [HTTP::payload replace 0 [string map {nwte1jas7:8882 bob} [HTTP::payload]]]

There should be '[HTTP::payload length]' after the 0. Also, I think nwte1jas7 should be nwteljas6 is the second HTTP::payload replace command.

 

 

Aaron

Aaron, I'm not getting errors anymore but it appears like none of the HTTP_RESPONSE_DATA section is even running. I put a log entry at the beginning of it to see if I got anything and I didn't. Here's what I have in teh irule now...

 

 

when HTTP_RESPONSE {

 

if { [HTTP::status] starts_with "301" } {

 

if { [LB::server addr] eq "10.0.19.50" } {

 

HTTP::header replace Location [string map {nwte1jas7:8882 E1NP.crocs.com} [HTTP::header Location]]

 

log "replacing nwte1jas7:8882 in header with E1NP" }

 

elseif { [LB::server addr] eq "10.0.19.42" } {

 

HTTP::header replace Location [string map {nwte1jas6:8882 E1NP.crocs.com} [HTTP::header Location]]

 

log "replacing nwte1jas7:8882 in header with E1NP" }

 

}

 

}

 

when HTTP_RESPONSE_DATA {

 

if { [LB::server addr] eq "10.0.19.50" } {

 

regsub -all "nwte1jas7:8882" [HTTP::payload] "bob" newdata

 

log "Replacing nwtejas7:8882 with bob in the payload."

 

HTTP::payload replace 0 [HTTP::payload length] [string map {nwte1jas7:8882 E1NP.crocs.com} [HTTP::payload]]

 

HTTP::release }

 

elseif { [LB::server addr] eq "10.0.19.42" } {

 

regsub -all "nwte1jas6:8882" [HTTP::payload] "bob" newdata

 

log "Replacing nwtejas6:8882 with bob in the payload."

 

HTTP::payload replace 0 [HTTP::payload length] [string map {nwte1jas6:8882 E1NP.crocs.com} [HTTP::payload]]

 

HTTP::release }

 

}

 

It looks like you removed the HTTP::collect command from the HTTP_RESPONSE event. This is what dictates that LTM should buffer the HTTP data in the response. The HTTP_RESPONSE_DATA event is triggered when the amount of data specified in the HTTP::collect command has been collected.

 

 

If there isn't a Content-Length header (like when the server is sending chunked responses) to use in the collect command, you could specify something smaller than one million bytes. Can you add the collect command back in and try with 100?

 

 

 

Does anyone else have ideas on how best to collect response data when there isn't a content length header? If you specify a smaller number of bytes than what is sent, does the HTTP::payload command only return what you've collect? If so, don't you miss the change to perform the replacement in any subsequent response data that wasn't collected?

 

 

Aaron