Is there a way to know from which servlet a request has been redirected or dispatched ?

[Baaziz Hamza]

Hello there !
As i said in the title, if I have a controller servlet that accepts requests and redirections from multiple servlets (or any resource in general).
Is there any ways I could determine which jsp send that request or which servlet did that redirection/dispatching, without sending an extra param (origin="ServletName" for example) with every request ?

[Bear Bibeault]

That's a red flag for a bad design.



Why do you need to know this? This creates strong coupling between the components, which can make your design fragile and easily broken.

If you need to make a decision based upon this info, rather than trying to find out where things came from, define a parameter that can be used to pass info that can be used to make the decision.

[Baaziz Hamza]

Bear Bibeault wrote:That's a red flag for a bad design.



Why do you need to know this? This creates strong coupling between the components, which can make your design fragile and easily broken.

If you need to make a decision based upon this info, rather than trying to find out where things came from, define a parameter that can be used to pass info that can be used to make the decision.

Thanks for the quick reply , I already know this solution, I'm just asking if there's a method or something in Servlet API, that does this automatically ?

[Bear Bibeault]

So you want to create a bad design?

[Baaziz Hamza]

Bear Bibeault wrote:So you want to create a bad design?

No ! I guess sending an extra param holding the name of the servlet with every request, and making hidden inputs in the jsp forms will do it, i was just afraid this solution was somehow dumb and heavy

[Bear Bibeault]

Baaziz Hamza wrote:

Bear Bibeault wrote:So you want to create a bad design?

No ! I guess sending an extra param holding the name of the servlet with every request, and making hidden inputs in the jsp forms will do it, i was just afraid this solution was somehow dumb and heavy

You're instinct there is right -- sending the name of the Servlet is not a good approach.

Step back. Take a deep breath.

What is it that you really need to know? It's not the name of the sending the servlet. Abstract what you're trying to do in your mind and figure out what it is you really need to know. Where you "came from" is never going to be the right answer.

[Pat Farrell]

Baaziz Hamza wrote: making hidden inputs in the jsp forms will do it

Note, having importent values be hidden form fields from the jsp/html form is bad as well.

The first rule of security is to never trust the user's browser. You think it may be IE or Firefox or Chrome, but it could be a rogue program that is pretending to be a browser but is really trying to crack into your system.

Put the data into the session, and do not send it to and from the browser.

[Wendy L Gibbons]

Bear Bibeault wrote:

Baaziz Hamza wrote:

Bear Bibeault wrote:So you want to create a bad design?

No ! I guess sending an extra param holding the name of the servlet with every request, and making hidden inputs in the jsp forms will do it, i was just afraid this solution was somehow dumb and heavy

You're instinct there is right -- sending the name of the Servlet is not a good approach.

Step back. Take a deep breath.

What is it that you really need to know? It's not the name of the sending the servlet. Abstract what you're trying to do in your mind and figure out what it is you really need to know. Where you "came from" is never going to be the right answer.

One example is:
If called from form A i need to restrict the search on database to only include the current users records, if I am calling from form B i need to search for every user.

create a parameter called restrictSearchToCurrentUser (i like snappy variable names).

which means that if later on form B gets a check box saying "restrict to current user" it is a simple matter of passing the correct boolean to the method.