Yes, you can use a custom function to decode JWT tokens in Azure Logic Apps. However, Logic Apps does not natively support decoding JWT tokens through built-in actions. Instead, you can achieve this by using a combination of Logic Apps' string manipulation functions and possibly integrating with Azure Functions for more complex operations.
Here's how you can approach it:
1. Split and Base64 Decode: You can use Logic Apps' built-in functions to split the JWT token by the '.' character and then base64 decode each part. This will give you the header and payload as JSON strings. You can use the `split` function to divide the token into its parts and then apply `base64ToString` to decode them[1][3].
2. Parse JSON: After decoding the payload, you can use the `json` function to parse it into a JSON object that you can work with in your Logic App[1].
3. Custom Function via Azure Functions: If you need more advanced processing or validation of the JWT token, consider creating an Azure Function. This function can handle the decoding and validation logic, and you can call it from your Logic App. This approach is particularly useful if you need to validate the token's signature or perform other complex operations[5].
4. Child Logic App: Another strategy is to create a child Logic App specifically designed to parse JWT tokens. This child app can be reused across multiple Logic Apps, making it easier to manage and maintain your workflow[3].
While using a custom function or Azure Functions might seem like an extra step, it provides flexibility and scalability for handling JWT tokens in Logic Apps.
Citations:
[1] https://stackoverflow.com/questions/54257879/how-to-decode-a-jwt-token-in-azure-logic-app
[2] https://adevait.com/laravel/implementing-jwt-authentication-in-laravel
[3] https://autosysops.com/blog/parse-jwt-tokens-in-azure-logic-apps
[4] https://www.criipto.com/blog/jwt-validation-guide
[5] https://www.reddit.com/r/AZURE/comments/u4alct/blog_parse_jwt_token_with_azure_logic_apps/
[6] https://auth0.com/blog/how-to-validate-jwt-dotnet/
[7] https://community.flutterflow.io/ask-the-community/post/custom-action-for-decoding-jwt-and-saving-info-in-shared-preferences-zvLf9RxdY02epbd
[8] https://hasura.io/blog/best-practices-of-using-jwt-with-graphql
[9] https://community.auth0.com/t/custom-client-side-custom-jwt-inputs/97936
[10] https://github.com/auth0/jwt-decode
[11] https://techcommunity.microsoft.com/blog/azuredevcommunityblog/part-4-secure-your-logic-app-using-api-management-8211-validate-jwt-access-restr/336802