Forum Discussion

avp4's avatar
avp4
Icon for Nimbostratus rankNimbostratus
Dec 14, 2022

Google Tag Manager

I've been asked to implement Google Tag Manager via an iRule. I have the Google code but am unsure how to implement. Does anyone have experience with this and can point me in the right direction? This seems a bit different than the standard Google Analytics found here - Google Analytics script injection - DevCentral (f5.com)

application delivery
  • JRahm's avatar
    JRahm
    Dec 16, 2022

    Seems you would just need 2 substitutions instead of one, like:

    when HTTP_RESPONSE_DATA { 
    set search1 "<head>"
    set search2 "<body>"
    set tracking_id [class match -value -- $host equals HOST_TRACKING_MAPPING]
    if { $tracking_id eq "" } {
        set tracking_id $static::default_trackingid
    }
    HTTP::payload replace 0 $content_length [string map [list $search1 "<head>[subst -nocommands -nobackslashes [ifile get gtm_head.js]]" $search2 "<body>[subst -nocommands -nobackslashes [ifile get gtm_body.js]]"] [HTTP::payload]]
    HTTP::release
}

    Note: I'm just interpreting literally the notes here: https://developers.google.com/tag-platform/tag-manager/web. If there's a reason it should not be at the top of head for performance or other reasons, find the slot you want it to sit and then make the line in head above that as your first search term.

    Just working in the tlcsh with substitute values, this works out like this:

    % set http_payload "<html><head><title>Hi there</title></head><body><p>This is a sentence</p></body></html>"
<html><head><title>Hi there</title></head><body><p>This is a sentence</p></body></html>
% set search1 <head>
<head>
% set search2 <body>
<body>
% set insert1 "<script>GTM_head_script_here</script>"
<script>GTM_head_script_here</script>
% set insert2 "<script>GTM_body_script_here</script>"
<script>GTM_body_script_here</script>
% string map [list $search1 "<head>[subst -nocommands -nobackslashes $insert1]" $search2 "<body>[subst -nocommands -nobackslashes $insert2]"] $http_payload
<html><head><script>GTM_head_script_here</script><title>Hi there</title></head><body><script>GTM_body_script_here</script><p>This is a sentence</p></body></html>
  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Dec 16, 2022

    Seems you would just need 2 substitutions instead of one, like:

    when HTTP_RESPONSE_DATA { 
    set search1 "<head>"
    set search2 "<body>"
    set tracking_id [class match -value -- $host equals HOST_TRACKING_MAPPING]
    if { $tracking_id eq "" } {
        set tracking_id $static::default_trackingid
    }
    HTTP::payload replace 0 $content_length [string map [list $search1 "<head>[subst -nocommands -nobackslashes [ifile get gtm_head.js]]" $search2 "<body>[subst -nocommands -nobackslashes [ifile get gtm_body.js]]"] [HTTP::payload]]
    HTTP::release
}

    Note: I'm just interpreting literally the notes here: https://developers.google.com/tag-platform/tag-manager/web. If there's a reason it should not be at the top of head for performance or other reasons, find the slot you want it to sit and then make the line in head above that as your first search term.

    Just working in the tlcsh with substitute values, this works out like this:

    % set http_payload "<html><head><title>Hi there</title></head><body><p>This is a sentence</p></body></html>"
<html><head><title>Hi there</title></head><body><p>This is a sentence</p></body></html>
% set search1 <head>
<head>
% set search2 <body>
<body>
% set insert1 "<script>GTM_head_script_here</script>"
<script>GTM_head_script_here</script>
% set insert2 "<script>GTM_body_script_here</script>"
<script>GTM_body_script_here</script>
% string map [list $search1 "<head>[subst -nocommands -nobackslashes $insert1]" $search2 "<body>[subst -nocommands -nobackslashes $insert2]"] $http_payload
<html><head><script>GTM_head_script_here</script><title>Hi there</title></head><body><script>GTM_body_script_here</script><p>This is a sentence</p></body></html>
    • Kai_Wilke's avatar
      Kai_Wilke
      Icon for MVP rankMVP
      Jan 20, 2023

      HI Jason,

      [subst] is one of the most broken commands in TCL, try to stay away from it and use alternatives. Even with -nocommand option a [subst] will still perform command execution during varibale expansions. 

      For your examples I actually dont see any usecase to even use subst at all...

      set search1 <head>
set search2 <body>
set insert1 "<head><script>GTM_head_script_here</script>"
set insert2 "<body><script>GTM_body_script_here</script>"
set http_payload [string map [list $search1 $insert1 $search2 $insert2] $http_payload]

       Cheers, Kai