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Sajid's avatar
Sajid
Icon for Cirrostratus rankCirrostratus
Sep 15, 2019

External Posting to APM with dynamic URL

Hi Guys,   I have a requirement to pass url with username/password.   Simple username/password working fine, when trying to pass the url as variable. It maks password empty.   Working sol...
application delivery
BIG-IP Access Policy Manager (APM)
security
  • youssef1's avatar
    youssef1
    Sep 16, 2019

    Hi Sajid,

    In fact we have to decoded payload using "[URI::decode [HTTP::payload]]"

    Payload:

    is=txtURL=https%3A%2F%2Ftrnapp01.example.com%3A443%2Fappmanager%2Fabc&username=user123&password=%40password123

    decoded raw:

    is=txtURL=https://trnapp01.example.com:443/appmanager/abc&username=user123&password=@password123

    now we have to set the right regex in your irule:

    https://regex101.com/

    when HTTP_REQUEST_DATA {
 
set payload [URI::decode [HTTP::payload]]
 
set username [URI::query "?[HTTP::payload]" username]
set password [URI::query [URI::decode "?[HTTP::payload]"] password]
 
regexp {^.*txtURL=([^&]+).*$} $payload -> gotURL
 
log local0. "Username: $username - password : $password - gotURL: $gotURL"
 
HTTP::release
 
}

    keep me in touch.

    regards

youssef1's avatar
youssef1
Icon for Cumulonimbus rankCumulonimbus
Sep 16, 2019

Hi Sajid,

 

I work as follows. when I write an Irule I do it at the simplest I validate that it works. and afterwards I optimize it.

 

In order to retrieve URL, I used “regexp”, Because I noticed that you post a form auth. So that’s mean that I have to retrieve information needed in Post Data.

 

How “regexp” work:

 

So first of you have to retrieve all payload (Post Data):

set payload [HTTP::payload]

 

In this payload you have to extract URL or other information (In our case URL)

So we can use “regexp” function, it allow us to retrieve a specific string of characters

 

 

regexp {^.*name=\"txtURL\" value=\"([^\"]+).*$} $payload -> posturl

 

 

^ and $:  match the begin/end of the payload

.*: matches any character

() : between parentheses is what we want to recover and put in the variable “posturl”

([^\"]+): means recover all the characters until “

$payload: payload where my regex applies

\: Since “ is used in the regular expressions I am obliged to the despecialized like this \”

 

Hope it’s clear.

Form more info check this:

http://www.tcl.tk/man/tcl8.4/TclCmd/regexp.htm

 

so if you have an Control service you can modify your Irule adding this line:

 

set payload [HTTP::payload]

regexp {^.*name=\"txtURL\" value=\"([^\"]+).*$} $payload -> posturl

 

regards