Trouble Implementing OAuth2 Authorization Code Flow with Spring Boot and Keycloak
I'm wondering if anyone has experience with I've looked through the documentation and I'm still confused about I'm trying to implement the OAuth2 Authorization Code flow in my Spring Boot application using Keycloak as the identity provider..... Despite following the official documentation, I'm hitting a wall when it comes to exchanging the authorization code for an access token. After successfully redirecting to the Keycloak login page and back to my application, I receive the authorization code but when I attempt to use it, I get a `400 Bad Request` response from Keycloak. Here's a simplified version of the code I'm using to exchange the authorization code: ```java @Autowired private RestTemplate restTemplate; public String exchangeAuthorizationCode(String code) { UriComponentsBuilder uriBuilder = UriComponentsBuilder.fromHttpUrl("http://localhost:8080/auth/realms/myrealm/protocol/openid-connect/token") .queryParam("grant_type", "authorization_code") .queryParam("code", code) .queryParam("redirect_uri", "http://localhost:8081/login/oauth2/code/keycloak"); HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED); headers.setBasicAuth("client-id", "client-secret"); HttpEntity<String> entity = new HttpEntity<>(null, headers); ResponseEntity<String> response = restTemplate.exchange(uriBuilder.toUriString(), HttpMethod.POST, entity, String.class); return response.getBody(); } ``` I've double-checked the `client-id`, `client-secret`, and the redirect URI, and they all match what I configured in Keycloak. When I inspect the response, it shows `{"error":"invalid_grant","error_description":"Invalid code"}`. A few things I've tried: - I ensured that the authorization code is not being reused; I'm attempting to exchange it immediately after getting it. - Verified that the Keycloak server is running and accessible. - Checked the Keycloak logs for any additional error details, but nothing stands out. Additionally, I'm using Spring Security 5.4.6 and Keycloak 12.0.4. Could there be a configuration issue, or is there something I'm missing in the exchange process? Any insights would be greatly appreciated! What's the best practice here? I'm working on a application that needs to handle this. Has anyone else encountered this?