[okhttp-gson] Add support for OAuth access token retry (#1058)

* Add support for access token retry in okhttp-gson lib

* Update expected number of generated files in test

* Update samples

* Update security samples

* Fix default user-agent and update samples

samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java

@@ -23,6 +23,9 @@ import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.threeten.bp.format.DateTimeFormatter;
 
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest.TokenRequestBuilder;
+import org.apache.oltu.oauth2.common.message.types.GrantType;
+
 import javax.net.ssl.*;
 import java.io.File;
 import java.io.IOException;
@@ -49,6 +52,7 @@ import org.openapitools.client.auth.Authentication;
 import org.openapitools.client.auth.HttpBasicAuth;
 import org.openapitools.client.auth.ApiKeyAuth;
 import org.openapitools.client.auth.OAuth;
+import org.openapitools.client.auth.RetryingOAuth;
 
 public class ApiClient {
 
@@ -77,6 +81,39 @@ public class ApiClient {
      * Constructor for ApiClient
      */
     public ApiClient() {
+        init();
+
+        // Setup authentications (key: authentication name, value: authentication).
+        authentications.put("api_key", new ApiKeyAuth("header", "api_key"));
+        authentications.put("api_key_query", new ApiKeyAuth("query", "api_key_query"));
+        authentications.put("http_basic_test", new HttpBasicAuth());
+        authentications.put("petstore_auth", new OAuth());
+        // Prevent the authentications from being modified.
+        authentications = Collections.unmodifiableMap(authentications);
+    }
+    
+    /*
+     * Constructor for ApiClient to support access token retry on 401/403
+     */
+    public ApiClient(
+            String clientId,
+            String clientSecret,
+            Map<String, String> parameters
+    ) {
+        init();
+
+        RetryingOAuth retryingOAuth = new RetryingOAuth("", clientId, GrantType.valueOf("implicit"), clientSecret, parameters);
+        authentications.put(
+                "petstore_auth",
+                retryingOAuth
+        );
+        httpClient.interceptors().add(retryingOAuth);
+
+        // Prevent the authentications from being modified.
+        authentications = Collections.unmodifiableMap(authentications);
+    }
+    
+    private void init() {
         httpClient = new OkHttpClient();
 
 
@@ -87,14 +124,7 @@ public class ApiClient {
         // Set default User-Agent.
         setUserAgent("OpenAPI-Generator/1.0.0/java");
 
-        // Setup authentications (key: authentication name, value: authentication).
         authentications = new HashMap<String, Authentication>();
-        authentications.put("api_key", new ApiKeyAuth("header", "api_key"));
-        authentications.put("api_key_query", new ApiKeyAuth("query", "api_key_query"));
-        authentications.put("http_basic_test", new HttpBasicAuth());
-        authentications.put("petstore_auth", new OAuth());
-        // Prevent the authentications from being modified.
-        authentications = Collections.unmodifiableMap(authentications);
     }
 
     /**
@@ -484,6 +514,20 @@ public class ApiClient {
         return this;
     }
 
+    /**
+     * Helper method to configure the token endpoint of the first oauth found in the apiAuthorizations (there should be only one)
+     * @return Token request builder
+     */
+    public TokenRequestBuilder getTokenEndPoint() {
+        for (Authentication apiAuth : authentications.values()) {
+            if (apiAuth instanceof RetryingOAuth) {
+                RetryingOAuth retryingOAuth = (RetryingOAuth) apiAuth;
+                return retryingOAuth.getTokenRequestBuilder();
+            }
+        }
+        return null;
+    }
+
     /**
      * Format the given parameter object into string.
      *

samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/OAuthOkHttpClient.java

@@ -0,0 +1,68 @@
+package org.openapitools.client.auth;
+
+import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.MediaType;
+import com.squareup.okhttp.Request;
+import com.squareup.okhttp.RequestBody;
+import com.squareup.okhttp.Response;
+
+import org.apache.oltu.oauth2.client.HttpClient;
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest;
+import org.apache.oltu.oauth2.client.response.OAuthClientResponse;
+import org.apache.oltu.oauth2.client.response.OAuthClientResponseFactory;
+import org.apache.oltu.oauth2.common.exception.OAuthProblemException;
+import org.apache.oltu.oauth2.common.exception.OAuthSystemException;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Map.Entry;
+
+public class OAuthOkHttpClient implements HttpClient {
+    private OkHttpClient client;
+
+    public OAuthOkHttpClient() {
+        this.client = new OkHttpClient();
+    }
+
+    public OAuthOkHttpClient(OkHttpClient client) {
+        this.client = client;
+    }
+
+    @Override
+    public <T extends OAuthClientResponse> T execute(OAuthClientRequest request, Map<String, String> headers,
+                                                     String requestMethod, Class<T> responseClass)
+            throws OAuthSystemException, OAuthProblemException {
+
+        MediaType mediaType = MediaType.parse("application/json");
+        Request.Builder requestBuilder = new Request.Builder().url(request.getLocationUri());
+
+        if(headers != null) {
+            for (Entry<String, String> entry : headers.entrySet()) {
+                if (entry.getKey().equalsIgnoreCase("Content-Type")) {
+                    mediaType = MediaType.parse(entry.getValue());
+                } else {
+                    requestBuilder.addHeader(entry.getKey(), entry.getValue());
+                }
+            }
+        }
+
+        RequestBody body = request.getBody() != null ? RequestBody.create(mediaType, request.getBody()) : null;
+        requestBuilder.method(requestMethod, body);
+
+        try {
+            Response response = client.newCall(requestBuilder.build()).execute();
+            return OAuthClientResponseFactory.createCustomResponse(
+                    response.body().string(),
+                    response.body().contentType().toString(),
+                    response.code(),
+                    responseClass);
+        } catch (IOException e) {
+            throw new OAuthSystemException(e);
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        // Nothing to do here
+    }
+}

samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/RetryingOAuth.java

@@ -0,0 +1,147 @@
+package org.openapitools.client.auth;
+
+import com.squareup.okhttp.Interceptor;
+import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.Request;
+import com.squareup.okhttp.Response;
+
+import org.apache.oltu.oauth2.client.OAuthClient;
+import org.apache.oltu.oauth2.client.request.OAuthBearerClientRequest;
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest;
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest.TokenRequestBuilder;
+import org.apache.oltu.oauth2.client.response.OAuthJSONAccessTokenResponse;
+import org.apache.oltu.oauth2.common.exception.OAuthProblemException;
+import org.apache.oltu.oauth2.common.exception.OAuthSystemException;
+import org.apache.oltu.oauth2.common.message.types.GrantType;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.util.Map;
+
+public class RetryingOAuth extends OAuth implements Interceptor {
+    private OAuthClient oAuthClient;
+
+    private TokenRequestBuilder tokenRequestBuilder;
+
+    public RetryingOAuth(OkHttpClient client, TokenRequestBuilder tokenRequestBuilder) {
+        this.oAuthClient = new OAuthClient(new OAuthOkHttpClient(client));
+        this.tokenRequestBuilder = tokenRequestBuilder;
+    }
+
+    public RetryingOAuth(TokenRequestBuilder tokenRequestBuilder) {
+        this(new OkHttpClient(), tokenRequestBuilder);
+    }
+
+    public RetryingOAuth(
+            String tokenUrl,
+            String clientId,
+            GrantType grantType,
+            String clientSecret,
+            Map<String, String> parameters
+    ) {
+        this(OAuthClientRequest.tokenLocation(tokenUrl)
+                .setClientId(clientId)
+                .setGrantType(grantType)
+                .setClientSecret(clientSecret));
+
+        if (parameters != null) {
+            for (String paramName : parameters.keySet()) {
+                tokenRequestBuilder.setParameter(paramName, parameters.get(paramName));
+            }
+        }
+    }
+
+    @Override
+    public Response intercept(Chain chain) throws IOException {
+        return retryingIntercept(chain, true);
+    }
+
+    private Response retryingIntercept(Chain chain, boolean updateTokenAndRetryOnAuthorizationFailure) throws IOException {
+        Request request = chain.request();
+
+        // If the request already has an authorization (e.g. Basic auth), proceed with the request as is
+        if (request.header("Authorization") != null) {
+            return chain.proceed(request);
+        }
+
+        // Get the token if it has not yet been acquired
+        if (getAccessToken() == null) {
+            updateAccessToken(null);
+        }
+
+        OAuthClientRequest oAuthRequest;
+        if (getAccessToken() != null) {
+            // Build the request
+            Request.Builder requestBuilder = request.newBuilder();
+
+            String requestAccessToken = getAccessToken();
+            try {
+                oAuthRequest =
+                        new OAuthBearerClientRequest(request.urlString()).
+                                setAccessToken(requestAccessToken).
+                                buildHeaderMessage();
+            } catch (OAuthSystemException e) {
+                throw new IOException(e);
+            }
+
+            Map<String, String> headers = oAuthRequest.getHeaders();
+            for (String headerName : headers.keySet()) {
+                requestBuilder.addHeader(headerName, headers.get(headerName));
+            }
+            requestBuilder.url(oAuthRequest.getLocationUri());
+
+            // Execute the request
+            Response response = chain.proceed(requestBuilder.build());
+
+            // 401/403 response codes most likely indicate an expired access token, unless it happens two times in a row
+            if (
+                    response != null &&
+                            (   response.code() == HttpURLConnection.HTTP_UNAUTHORIZED ||
+                                    response.code() == HttpURLConnection.HTTP_FORBIDDEN     ) &&
+                            updateTokenAndRetryOnAuthorizationFailure
+            ) {
+                try {
+                    if (updateAccessToken(requestAccessToken)) {
+                        response.body().close();
+                        return retryingIntercept(chain, false);
+                    }
+                } catch (Exception e) {
+                    response.body().close();
+                    throw e;
+                }
+            }
+            return response;
+        }
+        else {
+            return chain.proceed(chain.request());
+        }
+    }
+
+    /*
+     * Returns true if the access token has been updated
+     */
+    public synchronized boolean updateAccessToken(String requestAccessToken) throws IOException {
+        if (getAccessToken() == null || getAccessToken().equals(requestAccessToken)) {
+            try {
+                OAuthJSONAccessTokenResponse accessTokenResponse =
+                        oAuthClient.accessToken(tokenRequestBuilder.buildBodyMessage());
+                if (accessTokenResponse != null && accessTokenResponse.getAccessToken() != null) {
+                    setAccessToken(accessTokenResponse.getAccessToken());
+                    return !getAccessToken().equals(requestAccessToken);
+                }
+            } catch (OAuthSystemException | OAuthProblemException e) {
+                throw new IOException(e);
+            }
+        }
+
+        return false;
+    }
+
+    public TokenRequestBuilder getTokenRequestBuilder() {
+        return tokenRequestBuilder;
+    }
+
+    public void setTokenRequestBuilder(TokenRequestBuilder tokenRequestBuilder) {
+        this.tokenRequestBuilder = tokenRequestBuilder;
+    }
+}