I don't understand this part:
[...] "And if I specify a 'response object variable' in the routing
invoke, I can not access the content (json) of this variable in the
following steps." [...]
Why can't you access the content of this variable in the following steps?
Save copy of the request...
... that you received. What I'd do is always save a copy of the data received in the invoke to a processed variable instead of the (raw) original request.
In your GatewayScript try something like this:
let objRequest = apim.getvariable("request");
let body = null;
Here I recommend you to change the body (if json) to a standard js object
if(objRequest && objRequest.hasOwnProperty("body")){
try{
body = JSON.parse(objRequest.body);
}catch(e){
body = objRequest.body;
}
}
Remember to stringify the complete object before saving it as global variable. Is the only way to store it (because you can only store a string value in this kind of variables)
apim.setvariable("objRequest", JSON.stringify(objRequest));
Retrieve copy of the request...
...that you have saved in global variables you can get it from any other GatewayScript that you want this way:
let objRequest = JSON.parse(apim.getvariable("objRequest"));
Be careful not to assign an existent name to the apim.setvariable(name, value) because if you use "request" as name instead of "objRequest" (or other), you'll be replacing the original request element, and we don't want that to happen.
If you need to set or retrieve the status.code...
...you can do it with:
let statusCode = objRequest.body.status.code;
