HMAC in Autorization headers in web services

Hello.

I have a web services API that requires an Id and an hmac generated with the request parameters and an API Key to be placed in its authorization header.

Is there a way to obtain the call body to perform the HMAC?

In postman I have been able to make the call successfully with a pre-request which is the following:

const apiKey = pm.collectionVariables.get("apiKey");;
const webId = pm.collectionVariables.get("webId");
const crypto = require('crypto-js');
 
if(pm.request.method === 'POST') {
 
    const parsedBody = JSON.parse(pm.request.body.raw);
    const jsonParams = JSON.stringify(parsedBody);
 
    // Create HMAC
 
    const hmac = crypto.HmacSHA256(jsonParams, apiKey);
    const hmacb64 = crypto.enc.Base64.stringify(hmac);
 
    // Set computed HMAC as an environment variable (or you could add it directly to the headers)
    pm.environment.set('hmacb64', hmacb64);
 
    // Construct the Authorization header
    const authorizationHeader = "signmage " + webId + ":" + hmacb64;
    pm.environment.set('Authorization', authorizationHeader);
} else if(pm.request.method === 'GET') {
 
    const url = pm.request.url.getPathWithQuery();
 
    const hmac = crypto.HmacSHA256(url, apiKey);
    const hmacb64 = crypto.enc.Base64.stringify(hmac);
 
    // Set computed HMAC as an environment variable (or you could add it directly to the headers)
    pm.environment.set('hmacb64', hmacb64);
 
    // Construct the Authorization header
    const authorizationHeader = "signmage " + webId + ":" + hmacb64;
    pm.environment.set('Authorization', authorizationHeader);
}

But in Creatio I'm a little lost if it's possible to do something similar.

I would appreciate it if you could help me know if this is possible. Thank you.