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I need to recover a token from amazon cognito service. I tried to use Spring RestTemplate, but when I request the URL in Java I got the following error:

org.springframework.web.client.HttpClientErrorException$MethodNotAllowed: 405 Method Not Allowed: [no body]
at org.springframework.web.client.HttpClientErrorException.create(HttpClientErrorException.java:117)
at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:186)
at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:125)
at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:819)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:777)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711)
at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:602)

Below is my code (okay compagny and aHash were removed for this ticket):

Map<String, String> params = new LinkedHashMap<>();
params.put("grant_type", "client_credentials");

// build the url with params
UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl("https://company.auth.eu-west-1.amazoncognito.com/oauth2/token");
for (Map.Entry<String, String> entry : params.entrySet()) {
    builder.queryParam(entry.getKey(), entry.getValue());
}

Map<String, String> headers = new LinkedHashMap<>();
headers.put(AUTHORIZATION, "Basic aHash==");
headers.put("Content-Type", "application/x-www-form-urlencoded");
log.error("GenerateRemoteTokenURI requesting: {}", builder.toUriString());

HttpEntity<String> tokenResponseEntity = restTemplate.exchange(builder.toUriString(), HttpMethod.POST, new HttpEntity<>(headers),
        String.class);

If I use a curl with that:

curl --location --request POST 'https://company.eu-west-1.amazoncognito.com/oauth2/token?grant_type=client_credentials' \                         [14:28:53]
--header 'Content-Type: application/x-www-form-urlencoded' \
--header 'Authorization: Basic aHash=='

I got my access_token without any problem.

Do you know why I got this error from Spring, and how I can resolve the problem, please?

Thank you a lot and best regards

João Dias
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Adrien Ruffié
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  • can you try to move the parameter "grant_type" to the body? it should works! – Franco Berardi Nov 19 '21 at 15:33
  • I did that but same error: HttpEntity request = new HttpEntity<>("grant_type=client_credentials", httpHeaders); HttpEntity tokenResponseEntity = restTemplate.postForEntity(builder.build(params), new HttpEntity<>(request), String.class); – Adrien Ruffié Nov 19 '21 at 15:37
  • Adrien, i think that you nesting the httpEntity in another httpentity and that doesnt look good. Check out this example to send the request https://stackoverflow.com/questions/38372422/how-to-post-form-data-with-spring-resttemplate – Franco Berardi Nov 19 '21 at 15:40
  • It seems Cognito will response 405 on various reasons (https://stackoverflow.com/questions/55800666/405-method-not-allowed-error-in-aws-cognito-oauth2-token-endpoint). And from my experience, Spring tend to modify your request with some default standard behind the scene. May be printing raw request log of RestTemplate will help you detect some suspicious content in the request (logging.level.org.springframework.web.client.RestTemplate=DEBUG) – asinkxcoswt Nov 19 '21 at 15:46

0 Answers0