Postman pre-request script to automatically get a bearer token from Auth0 and save it for reuse

postman-pre-request.js

const echoPostRequest = {
  url: 'https://<my url>.auth0.com/oauth/token',
  method: 'POST',
  header: 'Content-Type:application/json',
  body: {
    mode: 'application/json',
    raw: JSON.stringify(
        {
        	client_id:'<your client ID>',
        	client_secret:'<your client secret>',
        	audience:'<my audience>',
        	grant_type:'client_credentials'
        })
  }
};

var getToken = true;

if (!pm.environment.get('accessTokenExpiry') || 
    !pm.environment.get('currentAccessToken')) {
    console.log('Token or expiry date are missing')
} else if (pm.environment.get('accessTokenExpiry') <= (new Date()).getTime()) {
    console.log('Token is expired')
} else {
    getToken = false;
    console.log('Token and expiry date are all good');
}

if (getToken === true) {
    pm.sendRequest(echoPostRequest, function (err, res) {
    console.log(err ? err : res.json());
        if (err === null) {
            console.log('Saving the token and expiry date')
            var responseJson = res.json();
            pm.environment.set('currentAccessToken', responseJson.access_token)
    
            var expiryDate = new Date();
            expiryDate.setSeconds(expiryDate.getSeconds() + responseJson.expires_in);
            pm.environment.set('accessTokenExpiry', expiryDate.getTime());
        }
    });
}

Good script, thx all.
One can also get the expiry from the token (if not returned explicitly by the API):

const payload = JSON.parse(atob(responseJson.access_token.split('.')[1]));
console.log(new Date(payload.exp * 1000));

Details:

• Split the token by '.'
• Take the payload (second element between [0]: header and [2]: signature)
• Base 64 decode the string with atob()
• JSON.parse() the decoded payload
• Expiration timestamp can be found in the exp key
• Eventually exp can be converted to a Date() multiplying it by 1000

Very nice, I was struggling trying to do something like this, and then decided to search and see if anybody had done it already. Found it and it works great. Thank you!

Here is my trick:

1. Created an environment and variable Authorization inside it.
   https://monosnap.com/file/Vn4WvhXMNsnOFPmB4sC8GU4gilfMPz

2. Added a folder called "User". In folder settings I defined pre-request:
   https://monosnap.com/file/AWMMTcSs6TtJw3Eqet3gMBLmOdcDA5

pm.sendRequest({
    url: 'https://' + pm.variables.get('api_domain') + '/api/auth/login',
    method: 'POST',
    header: {
        'content-type': 'application/json',
    },
    body: {
        mode: 'raw',
        raw: JSON.stringify({ 
            email: pm.variables.get('admin_email'),
            password: pm.variables.get('admin_password'),
            captcha_token: "no_for_local"
        })
    }
}, function (err, res) {
    pm.environment.set("Authorization", "Bearer " + res.json().token);
});

3. In request created inside this folder I set this header:
   https://monosnap.com/file/H0n2VnrxU1cwriJokXvlJU7I2f6qGl

4. Each request you created inside this folder will run above script before execution:
   https://monosnap.com/file/KK3qzgDKXj27iQqlCOgdyxDFuBtl9e

amazing!

@bcnzer - I am trying to figure out if similar script could work for auth code flow. I need user to sign in, based on which need to generate the access token. Unfortunately, postman "Authorization" tab does not expose the access_token as variable and they are still working on it (since long 4 years). Have you ever faced this situation? Do you have any workarounds in mind?

It works perfectly! Time & Effort saving
Thanks a lot

thx a lot,
I use it in postman pre-request script but unfortunately I couldn't pass the currentAccessToken to the second request
how to do it?

thx a lot, I use it in postman pre-request script but unfortunately I couldn't pass the currentAccessToken to the second request how to do it?

@sayuri-sam What do you mean, 2nd request? Have you specified the currentAccessToken as a variable in the Authorization tab of the request?

bo55vxr
yes, I use this code as pre-request script in postman.
and I want to pass the value in currentAccessToken to Auth token.

the request result

can you figure it out?

@sayuri-sam you need to use double curly braces {{currentAccessToken}}

@sayuri-sam you need to use double curly braces {{currentAccessToken}}

^^^ This...

@Solksjaer thanks for the snippet just what i needed 👍

Tks! 👍

Hi @anantyadunath. Quick question, did you ever get auth code flow working with Postman?

Unfortunately, nope. I was supposed to use this for Automation testing, however dropped the research since something different came up. But do post your method if you are successful.Thanks and Regards,Anant KulkarniOn 09-Jun-2023, at 11:39 AM, Troy Holland ***@***.***> wrote:Re: ***@***.*** commented on this gist.Hi @anantyadunath. Quick question, did you ever get auth code flow working with Postman?—Reply to this email directly, view it on GitHub or unsubscribe.You are receiving this email because you were mentioned.Triage notifications on the go with GitHub Mobile for iOS or Android.                                                           

Hi, Do you have a solution if our authorization is with Grant Type: Authorization Code (with PKCE).
we don`t use client secret, and we put it blank.
I turn on Auto-refresh token and every API works great, but in monitor I get No response.