Hi, We are trying to implement the following scenario and would like to know if the LTM can do the following: An application execute an HTTP POST request with parameters inside the HTML bodyLTM sends back a 302 redirect request back to the client to another local url How can LTM sends back in the 302 redirect with the same parameters that were availble in the initial packet (see 1))? Can LTM look into HTML body and use them in packet 2) with an iRule? In initial packet 1) these parameters can be a small text or a large file that is being posted to the servers behind LTM Thanks, Giulio.

What do the parameters in the body look like?

Hi, This is the initial packet with the POST DATA https://dl.dropboxusercontent.com/u/11374616/first%20request.png and this is the second, after the 302, with empty parameters https://dl.dropboxusercontent.com/u/11374616/redirect%20without%20parameters.png

Hi 2funky, I normally step a bit back, and ask, why do we get the redirect ? Wouldn't it make sense, that if the user sends the post to a the wrong URL, that BIG-IP would change the inital Post to point to the right backend URL ? ie: your post goes to www.test.com/login.php redirect sends you to www.test.com/prod/login.php Browser sends the request to www.test.com/prod/login.php (without Parameters) iRule would need to add it. What you could do very easy would be to change the inital post www.test.com/login.php to www.test.com/prod/login.php without changing the Parameters. So the Backend System would not need to send a redirect, and could consume the Parameters and Values as needed. Wiesmann

Generally speaking, if you need to do a redirect and keep all post parameters, you will have to create a postback form which then has the client actually post to the new URL. If the form that generates the POST is flowing through your LTM and you can't get the developers to update the target URL of the form, you may be able to use a stream replacement to change it on the way out of the LTM to the browser before they make the first post.

Hi, Thanks for the answers. Indeed, we have a redirection iRule in place that we can not really change, as it is linked with GLB in case of servers unavailability. So, if I get it well, LTM can parse HTML body and push it back the initial POST parameters inside the HTTP302? Do you have an example somewhere? Is it CPU intensive?

Forum Discussion

2funky_105078

Cirrus

Oct 08, 2013

How to preserve data in a HTTP 302 redirect of a POST

Hi,

We are trying to implement the following scenario and would like to know if the LTM can do the following:

An application execute an HTTP POST request with parameters inside the HTML body
LTM sends back a 302 redirect request back to the client to another local url

How can LTM sends back in the 302 redirect with the same parameters that were availble in the initial packet (see 1))?

Can LTM look into HTML body and use them in packet 2) with an iRule?

In initial packet 1) these parameters can be a small text or a large file that is being posted to the servers behind LTM

Thanks, Giulio.

Jaz_170005
Nimbostratus
Oct 02, 2018
Hello, I am facing similar challenge. I insert a new value to request header before redirect. seems that F5 drops the new value somehow.

HTTP::header insert "appKey" "$app_key" HTTP::redirect "https://$NewHost[HTTP::uri]"

if I log header into logs, I can see that appKey gets inserted. however when I check at NewHost, I see the request came in with no appKey value in the header.

in other cases when I had to do the same, it worked but there was no redirect. so I am certain that redirect has something to do with it. it's just wont let through any newly added name/value in request-header.

any idea how can I insert new name/value into request header and make redirect call right after ( without losing new added value).?

thank you in advance.
Kevin_Stewart
Employee
Oct 02, 2018
Jaz, use HTTP::respond instead.

HTTP::respond 302 Location "https://$NewHost[HTTP::uri]" "appKey" "$app_key"

This command allows you to insert an arbitrary set of headers (most important the "Location" header).