Is it possible?: Yes
Is it a good idea: No

Proof of concept of bad idea:

Class Rest.BadExample Extends %CSP.Page
{

Parameter CHARSET = "utf-8";

Parameter CONTENTTYPE = "application/json";

ClassMethod OnPage() As %Status
{

  Set String = "[ {code:1,description:'cat'},{code:2,description:'lyon'}]"
  Write String

  Quit $$$OK
}

}

As Eduard said, you should make your own class that inherits from %CSP.REST

A new problem..

In my country we speak in spanish. My developing machine uses windows 8.1

I made a nice looking html mock-up using angular material (in Atom, writing in UTF-8). I just moved that mock-up to the CSP folder inside Ensemble and it shows the typical weird characters of character encoding problems.

Have you had an issue like this before?

My temporal solution for the html files: I just configured Atom to read the files in Windows 1252 encoding
However I still see weird characters on a query to the DB (I made a rest service that returns a json than in turn I use to fill a select input in the html)

I change the names of the files in order to do that, like this:

csp file:

<!DOCTYPE html>
<html>
<head>
<csp:include page="includes/libraries.csp"/>
<title></title>
</head>

inside the includes/libraries.csp file, rename the file as "jquery-1.11.3.min.js" instead of just use the file as "jquery.min.js" :

 <script src="jquery/jquery-1.11.3.min.js"></script> 

this in order to avoid the server to load the old file

Thank you very much Eduard!

I've been reading w3c's angular tutorial and also from angular site itself, and from them I got the perception that Angular 1 is similar to using jquery. Also the video on angular 1's page seems to point that way:

Video: https://www.youtube.com/watch?v=uFTFsKmkQnQ

W3C's angular tutorials: http://www.w3schools.com/angular/angular_intro.asp

Angular 1 webpage: https://angularjs.org/

Recently I stumbled upon the same problem, the need to use bcrypt from within caché. I did the following:

1. Install pip, the python package manager:
http://sharadchhetri.com/2014/05/30/install-pip-centos-rhel-ubuntu-debian/

2. Install bcrypt with pip

sudo pip install bcrypt

3. Call bcrypt from Caché Code. The Encrypted String is pOutput

BCrypt
    Set password = "password"
    set tSC = ##class(EnsLib.JavaGateway.Service).RunCommandViaCPIPE("python -c 'import bcrypt; print(bcrypt.hashpw("_$c(34)_password_$c(34)_", bcrypt.gensalt()))'",.pDevice,.pOutput)
    Write pOutput,!
    Quit