getSessionToken() not working in Parse - parse-platform

Question

Below is my parse cloud code. I am unable to get user session even when I am using master key. Is it not possible to get User session even if we use mater key to retrieve user?
Parse.Cloud.define("getFSUserSession", getFSUserSession);
function getFSUserSession(request, response) {
Parse.Cloud.useMasterKey();
//Removed some codes here to make it short
var someID = request.params.user;
var query = new Parse.Query(Parse.User);
query.equalTo('familySearchID', someID);
query.ascending('createdAt');
query.first({useMasterKey: true}).then(function (user) {
console.log(typeof user.getSessionToken());//this returns function
console.log(user.getSessionToken()); //this logs No Message provided
response.success(user.getSessionToken());
})
}

Answer 1

I had to disable Require Revocable Sessions to make this work. After disabling Require Revocable Sessions in settings we can make an api request to /1/upgradeToRevocableSession to get the upgraded session token.
Parse.Cloud.define("getFSUserSession", getFSUserSession);
function getFSUserSession(request, response) {
Parse.Cloud.useMasterKey();
//Removed some codes here to make it short
var someID = request.params.user;
var query = new Parse.Query(Parse.User);
query.equalTo('familySearchID', someID);
query.ascending('createdAt');
query.first({useMasterKey: true}).then(function (user) {
return Parse.Cloud.httpRequest({
method: 'POST',
url: 'https://api.parse.com/1/upgradeToRevocableSession',
headers: {
'X-Parse-Application-Id': Parse.applicationId,
'X-Parse-REST-API-Key': restKey,
'X-Parse-Session-Token': user.getSessionToken()
}
});
}).then(function (httpResponse) {
var sessionObject = httpResponse.data;
if (sessionObject.sessionToken) {
return Parse.Promise.as(sessionObject.sessionToken);
}
return Parse.Promise.error('Unable to get Session token');
});
}