Why OAuth2AccessTokenSupport always send POST request ?? - spring-boot

Question

I'm working with a Spring Boot + Spring Security OAuth2 to consume the Restful Oauth2 service.
Our Oauth2 service is always expects HTTP GET But OAuth2AccessTokenSupport always sending HTTP POST.
Result:
resulted in 405 (Method Not Allowed); invoking error handler
protected OAuth2AccessToken retrieveToken(AccessTokenRequest request, OAuth2ProtectedResourceDetails resource,
MultiValueMap<String, String> form, HttpHeaders headers) throws OAuth2AccessDeniedException {
try {
this.authenticationHandler.authenticateTokenRequest(resource, form, headers);
this.tokenRequestEnhancer.enhance(request, resource, form, headers);
AccessTokenRequest copy = request;
ResponseExtractor delegate = getResponseExtractor();
ResponseExtractor extractor = new ResponseExtractor(copy, delegate) {
public OAuth2AccessToken extractData(ClientHttpResponse response) throws IOException {
if (response.getHeaders().containsKey("Set-Cookie")) {
this.val$copy.setCookie(response.getHeaders().getFirst("Set-Cookie"));
}
return ((OAuth2AccessToken) this.val$delegate.extractData(response));
}
};
return ((OAuth2AccessToken) getRestTemplate().execute(getAccessTokenUri(resource, form), getHttpMethod(),
getRequestCallback(resource, form, headers), extractor, form.toSingleValueMap()));
} catch (OAuth2Exception oe) {
throw new OAuth2AccessDeniedException("Access token denied.", resource, oe);
} catch (RestClientException rce) {
throw new OAuth2AccessDeniedException("Error requesting access token.", resource, rce);
}
}
<b>protected HttpMethod getHttpMethod() {
return HttpMethod.POST;
}</b>
protected String getAccessTokenUri(OAuth2ProtectedResourceDetails resource, MultiValueMap<String, String> form) {
String accessTokenUri = resource.getAccessTokenUri();
if (this.logger.isDebugEnabled()) {
this.logger.debug(new StringBuilder().append("Retrieving token from ").append(accessTokenUri).toString());
}
StringBuilder builder = new StringBuilder(accessTokenUri);
String separator;
if (getHttpMethod() == HttpMethod.GET) {
separator = "?";
if (accessTokenUri.contains("?")) {
separator = "&";
}
for (String key : form.keySet()) {
builder.append(separator);
builder.append(new StringBuilder().append(key).append("={").append(key).append("}").toString());
separator = "&";
}
}
return builder.toString();
}
Can Anyone explain me why OAuth2AccessTokenSupport always returns POST and
How to send HTTP GET request

Answer 1

To enable GET requests for the token endpoint, you need to add the following in your AuthorizationServerConfigurerAdapter:
#Override
public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
endpoints.allowedTokenEndpointRequestMethods(HttpMethod.GET, HttpMethod.POST);
}
As for why only POST by default: I think that is due to GET requests potentially sending username and password information as request params (this is certainly the case for password grant). These may well be visible in web server logs, while POST body data is not.
Indeed the RFC for OAuth2 declares that the client must use HTTP POST when requesting an access token (https://www.rfc-editor.org/rfc/rfc6749#section-3.2)