Swagger 2 Feign client code oAuth flow throwing error url values must be not be absolute - oauth

Question

I exposed Rest APIs, and I generated client code using Swagger 2 Java language with Feign library. The code gen generated the below OAuth RequestInterceptor. I am getting the below error when I use the oAuth as auth.
Error
feign.RetryableException: url values must be not be absolute.
at com.sam.feign.auth.OAuth.updateAccessToken(OAuth.java:95)
at com.sam.feign.auth.OAuth.apply(OAuth.java:83)
at feign.SynchronousMethodHandler.targetRequest(SynchronousMethodHandler.java:161)
at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:110)
at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:89)
at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:100)
at com.sun.proxy.$Proxy9.getUser(Unknown Source)
at com.sam.feign.clients.UserApiTest.getUserTest(UserApiTest.java:38)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: java.lang.IllegalArgumentException: url values must be not be absolute.
at feign.RequestTemplate.uri(RequestTemplate.java:434)
at feign.RequestTemplate.uri(RequestTemplate.java:421)
at feign.RequestTemplate.append(RequestTemplate.java:388)
at com.sam.feign.auth.OAuth$OAuthFeignClient.execute(OAuth.java:163)
at org.apache.oltu.oauth2.client.OAuthClient.accessToken(OAuthClient.java:65)
at org.apache.oltu.oauth2.client.OAuthClient.accessToken(OAuthClient.java:55)
at org.apache.oltu.oauth2.client.OAuthClient.accessToken(OAuthClient.java:71)
at com.sam.feign.auth.OAuth.updateAccessToken(OAuth.java:93)
... 34 more
Swagger Generated oAuth supporting file
public class OAuth implements RequestInterceptor {
static final int MILLIS_PER_SECOND = 1000;
public interface AccessTokenListener {
void notify(BasicOAuthToken token);
}
private volatile String accessToken;
private Long expirationTimeMillis;
private OAuthClient oauthClient;
private TokenRequestBuilder tokenRequestBuilder;
private AuthenticationRequestBuilder authenticationRequestBuilder;
private AccessTokenListener accessTokenListener;
public OAuth(Client client, TokenRequestBuilder requestBuilder) {
this.oauthClient = new OAuthClient(new OAuthFeignClient(client));
this.tokenRequestBuilder = requestBuilder;
}
public OAuth(Client client, OAuthFlow flow, String authorizationUrl, String tokenUrl, String scopes) {
this(client, OAuthClientRequest.tokenLocation(tokenUrl).setScope(scopes));
switch(flow) {
case accessCode:
case implicit:
tokenRequestBuilder.setGrantType(GrantType.AUTHORIZATION_CODE);
break;
case password:
tokenRequestBuilder.setGrantType(GrantType.PASSWORD);
break;
case application:
tokenRequestBuilder.setGrantType(GrantType.CLIENT_CREDENTIALS);
break;
default:
break;
}
authenticationRequestBuilder = OAuthClientRequest.authorizationLocation(authorizationUrl);
}
public OAuth(OAuthFlow flow, String authorizationUrl, String tokenUrl, String scopes) {
this(new Client.Default(null, null), flow, authorizationUrl, tokenUrl, scopes);
}
#Override
public void apply(RequestTemplate template) {
// If the request already have an authorization (eg. Basic auth), do nothing
if (template.headers().containsKey("Authorization")) {
return;
}
// If first time, get the token
if (expirationTimeMillis == null || System.currentTimeMillis() >= expirationTimeMillis) {
updateAccessToken(template);
}
if (getAccessToken() != null) {
template.header("Authorization", "Bearer " + getAccessToken());
}
}
public synchronized void updateAccessToken(RequestTemplate template) {
OAuthJSONAccessTokenResponse accessTokenResponse;
try {
accessTokenResponse = oauthClient.accessToken(tokenRequestBuilder.buildBodyMessage());
} catch (Exception e) {
throw new RetryableException(400, e.getMessage(), template.request().httpMethod(), e, null, template.request());
}
if (accessTokenResponse != null && accessTokenResponse.getAccessToken() != null) {
setAccessToken(accessTokenResponse.getAccessToken(), accessTokenResponse.getExpiresIn());
if (accessTokenListener != null) {
accessTokenListener.notify((BasicOAuthToken) accessTokenResponse.getOAuthToken());
}
}
}
public synchronized void registerAccessTokenListener(AccessTokenListener accessTokenListener) {
this.accessTokenListener = accessTokenListener;
}
public synchronized String getAccessToken() {
return accessToken;
}
public synchronized void setAccessToken(String accessToken, Long expiresIn) {
this.accessToken = accessToken;
this.expirationTimeMillis = System.currentTimeMillis() + expiresIn * MILLIS_PER_SECOND;
}
public TokenRequestBuilder getTokenRequestBuilder() {
return tokenRequestBuilder;
}
public void setTokenRequestBuilder(TokenRequestBuilder tokenRequestBuilder) {
this.tokenRequestBuilder = tokenRequestBuilder;
}
public AuthenticationRequestBuilder getAuthenticationRequestBuilder() {
return authenticationRequestBuilder;
}
public void setAuthenticationRequestBuilder(AuthenticationRequestBuilder authenticationRequestBuilder) {
this.authenticationRequestBuilder = authenticationRequestBuilder;
}
public OAuthClient getOauthClient() {
return oauthClient;
}
public void setOauthClient(OAuthClient oauthClient) {
this.oauthClient = oauthClient;
}
public void setOauthClient(Client client) {
this.oauthClient = new OAuthClient( new OAuthFeignClient(client));
}
public static class OAuthFeignClient implements HttpClient {
private Client client;
public OAuthFeignClient() {
this.client = new Client.Default(null, null);
}
public OAuthFeignClient(Client client) {
this.client = client;
}
public <T extends OAuthClientResponse> T execute(OAuthClientRequest request, Map<String, String> headers,
String requestMethod, Class<T> responseClass)
throws OAuthSystemException, OAuthProblemException {
RequestTemplate req = new RequestTemplate()
.append(request.getLocationUri())
.method(requestMethod)
.body(request.getBody());
for (Entry<String, String> entry : headers.entrySet()) {
req.header(entry.getKey(), entry.getValue());
}
Response feignResponse;
String body = "";
try {
feignResponse = client.execute(req.request(), new Options());
body = Util.toString(feignResponse.body().asReader());
} catch (IOException e) {
throw new OAuthSystemException(e);
}
String contentType = null;
Collection<String> contentTypeHeader = feignResponse.headers().get("Content-Type");
if(contentTypeHeader != null) {
contentType = StringUtil.join(contentTypeHeader.toArray(new String[0]), ";");
}
return OAuthClientResponseFactory.createCustomResponse(
body,
contentType,
feignResponse.status(),
responseClass
);
}
public void shutdown() {
// Nothing to do here
}
}
}
ApiClient.java have the below absolute URL which configured in swagger spec
public ApiClient() {
objectMapper = createObjectMapper();
apiAuthorizations = new LinkedHashMap<String, RequestInterceptor>();
feignBuilder = Feign.builder()
.encoder(new FormEncoder(new JacksonEncoder(objectMapper)))
.decoder(new JacksonDecoder(objectMapper))
.logger(new Slf4jLogger());
}
public ApiClient(String[] authNames) {
this();
for(String authName : authNames) {
RequestInterceptor auth = null;
if ("client-credentils-oauth2".equals(authName)) {
auth = new OAuth(OAuthFlow.application, "", "http://localhost:8080/app/oauth/token", "user.create");
} else if ("password-oauth2".equals(authName)) {
auth = new OAuth(OAuthFlow.password, "", "http://localhost:8080/app/oauth/token", "openid");
} else {
throw new RuntimeException("auth name \"" + authName + "\" not found in available auth names");
}
addAuthorization(authName, auth);
}
}
Used the below dependencies
swagger-codegen-maven-plugin v2.4.28
feign-version 11.6
feign-form-version 3.8.0
oltu-version 1.0.1
Java 8
I am invoking the client by using below code
UserApi api = new ApiClient("client-credentils-oauth2","admin", "admin", null, null).buildClient(UserApi.class);
api.getUser(login, tenant)
I made the few changes in the generated oAuth.java file to make it work. Expecting the client generated code should work without making any manual changes.
public <T extends OAuthClientResponse> T execute(OAuthClientRequest request, Map<String, String> headers,
String requestMethod, Class<T> responseClass)
throws OAuthSystemException, OAuthProblemException {
// Added the below 3 lines
URI targetUri = URI.create(uri);
String target = targetUri.getScheme() + "://" + targetUri.getAuthority() ;
String path = targetUri.getPath();
RequestTemplate req = new RequestTemplate()
.uri(path)
.method(requestMethod)
.body(request.getBody())
.target(target); // Added this line
for (Entry<String, String> entry : headers.entrySet()) {
req.header(entry.getKey(), entry.getValue());
}
req = req.resolve(new HashMap<String, Object>()); // Added this line
Response feignResponse;
String body = "";
try {
feignResponse = client.execute(req.request(), new Options());
body = Util.toString(feignResponse.body().asReader());
} catch (IOException e) {
throw new OAuthSystemException(e);
}
String contentType = null;
Collection<String> contentTypeHeader = feignResponse.headers().get("Content-Type");
if(contentTypeHeader != null) {
contentType = StringUtil.join(contentTypeHeader.toArray(new String[0]), ";");
}
return OAuthClientResponseFactory.createCustomResponse(
body,
contentType,
feignResponse.status(),
responseClass
);
}
Appreciate if someone can assist me with this issue