Postman pre-request script for authentication with Keycloak

This is a javascript-Script for use with Postman's pre-request script feature. It makes POST request to Keycloak Token Endpoint to get a valid token and automatically set the token for all requests in Postman collection. This will enable to make request as if a logged in user would make them to an API.

Usage

1. Create a new client in Keycloak. This client is mostly default. Important are just these few:

• Client ID: Choose a name
• Client Protocol: openid-connect
• Access Type: confidential
• Valid Redirect URIs: http://localhost:8080/*

This client will only be used for Postman then. Btw. don´t forget to hit "save".

2. Go now into the second tab "Credentials" of your new created Client. Here you can find the Clientsecret in the field Secret. Copy that to you clipboard.

3. Now head on to Postman. Create a new collection. Every query you want to make to the API which is protected by Keycloak, has to be in this collection then. On a already existing collection click edit (behind the 3 vertical dots). In the new appearing window choose a name and copy the content of keycloak-fetch-token-postman-pre-request.js into the "Pre-request Script" tab in Postman. No fill in all the variables in the beginning of the script. Remember you already copied the Clientsecret. If you dont know a variable, some of them can be found in Keycloak under the previously created Client and then in the tab Installation. In the screenshot below you can see an example. These are my development values. Never post production clientsecrets or something! With username and password you can choose a user. This is good for testing roles. Leave the rest as is.

4. In the Authorization tab set the Type to Bearer Token and Token to {{token}}. This is the token that get send back from Keycloak via the pre-request script.

5. For all API requests: In the Authorization tab select Type - Inherit auth from parent. You can see an example below. Keep in mind that the queries you want to execute has to be saved into the configured collection

6. ENJOY