Add config.expireInactiveSession to add support for non-expiring inactive sessions (#1536)

* Create non-expiring session when sessionLength is zero

* Introduce expireInactiveSessions setting

spec/RestCreate.spec.js

@@ -352,4 +352,31 @@ describe('rest create', () => {
         done();
       });
   });
+
+  it("can create a session with no expiration", (done) => {
+    var user = {
+      username: 'asdf',
+      password: 'zxcv',
+      foo: 'bar'
+    };
+    config.expireInactiveSessions = false;
+
+    rest.create(config, auth.nobody(config), '_User', user)
+      .then((r) => {
+        expect(Object.keys(r.response).length).toEqual(3);
+        expect(typeof r.response.objectId).toEqual('string');
+        expect(typeof r.response.createdAt).toEqual('string');
+        expect(typeof r.response.sessionToken).toEqual('string');
+        return rest.find(config, auth.master(config),
+          '_Session', {sessionToken: r.response.sessionToken});
+      })
+      .then((r) => {
+        expect(r.results.length).toEqual(1);
+
+        var session = r.results[0];
+        expect(session.expiresAt).toBeUndefined();
+
+        done();
+      });
+  });
 });

spec/index.spec.js

@@ -332,6 +332,29 @@ describe('server', () => {
       sessionLength: '0'
     })).toThrow('Session length must be a value greater than 0.');
     done();
+  });
+
+  it('ignores the session length when expireInactiveSessions set to false', (done) => {
+    expect(() => setServerConfiguration({
+      serverURL: 'http://localhost:8378/1',
+      appId: 'test',
+      appName: 'unused',
+      javascriptKey: 'test',
+      masterKey: 'test',
+      sessionLength: '-33',
+      expireInactiveSessions: false
+    })).not.toThrow();
+
+    expect(() => setServerConfiguration({
+      serverURL: 'http://localhost:8378/1',
+      appId: 'test',
+      appName: 'unused',
+      javascriptKey: 'test',
+      masterKey: 'test',
+      sessionLength: '0',
+      expireInactiveSessions: false
+    })).not.toThrow();
+    done();
   })
 
   it('fails if you try to set revokeSessionOnPasswordReset to non-boolean', done => {