We are using Retrofit in our Android app, to communicate with an OAuth2 secured server. Everything works great, we use the RequestInterceptor to include the access token with each call. However there will be times, when the access token will expire, and the token needs to be refreshed. When the token expires, the next call will return with an Unauthorized HTTP code, so that's easy to monitor. We could modify each Retrofit call the following way: In the failure callback, check for the error code, if it equals Unauthorized, refresh the OAuth token, then repeat the Retrofit call. However, for this, all calls should be modified, which is not an easily maintainable, and good solution. Is there a way to do this without modifying all Retrofit calls?


当前回答

如果你正在使用Retrofit >= 1.9.0,那么你可以使用OkHttp的新拦截器,它是在OkHttp 2.2.0中引入的。您可能希望使用Application Interceptor,它允许您重试并进行多个调用。

你的拦截器可以看起来像这样的伪代码:

public class CustomInterceptor implements Interceptor {

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();

        // try the request
        Response response = chain.proceed(request);

        if (response shows expired token) {
            // close previous response
            response.close()

            // get a new token (I use a synchronous Retrofit call)

            // create a new request and modify it accordingly using the new token
            Request newRequest = request.newBuilder()...build();

            // retry the request
            return chain.proceed(newRequest);
        }

        // otherwise just pass the original response on
        return response;
    }

}

定义拦截器之后,创建OkHttpClient并将拦截器添加为应用程序拦截器。

    OkHttpClient okHttpClient = new OkHttpClient();
    okHttpClient.interceptors().add(new CustomInterceptor());

最后,在创建RestAdapter时使用这个OkHttpClient。

    RestService restService = new RestAdapter().Builder
            ...
            .setClient(new OkClient(okHttpClient))
            .create(RestService.class);

警告:正如杰西威尔逊(来自Square)在这里提到的,这是一个危险的电量。

话虽如此,我绝对认为这是现在处理这种事情的最好方法。如果你有任何问题,请不要犹豫在评论中提问。

其他回答

给任何人谁想解决并发/并行调用时刷新令牌。这里有一个变通办法

class TokenAuthenticator: Authenticator {

    override fun authenticate(route: Route?, response: Response?): Request? {
        response?.let {
            if (response.code() == 401) {
                while (true) {
                    if (!isRefreshing) {
                        val requestToken = response.request().header(AuthorisationInterceptor.AUTHORISATION)
                        val currentToken = OkHttpUtil.headerBuilder(UserService.instance.token)

                        currentToken?.let {
                            if (requestToken != currentToken) {
                                return generateRequest(response, currentToken)
                            }
                        }

                        val token = refreshToken()
                        token?.let {
                            return generateRequest(response, token)
                        }
                    }
                }
            }
        }

        return null
    }

    private fun generateRequest(response: Response, token: String): Request? {
        return response.request().newBuilder()
                .header(AuthorisationInterceptor.USER_AGENT, OkHttpUtil.UA)
                .header(AuthorisationInterceptor.AUTHORISATION, token)
                .build()
    }

    private fun refreshToken(): String? {
        synchronized(TokenAuthenticator::class.java) {
            UserService.instance.token?.let {
                isRefreshing = true

                val call = ApiHelper.refreshToken()
                val token = call.execute().body()
                UserService.instance.setToken(token, false)

                isRefreshing = false

                return OkHttpUtil.headerBuilder(token)
            }
        }

        return null
    }

    companion object {
        var isRefreshing = false
    }
}

如果你正在使用Retrofit >= 1.9.0,那么你可以使用OkHttp的新拦截器,它是在OkHttp 2.2.0中引入的。您可能希望使用Application Interceptor,它允许您重试并进行多个调用。

你的拦截器可以看起来像这样的伪代码:

public class CustomInterceptor implements Interceptor {

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();

        // try the request
        Response response = chain.proceed(request);

        if (response shows expired token) {
            // close previous response
            response.close()

            // get a new token (I use a synchronous Retrofit call)

            // create a new request and modify it accordingly using the new token
            Request newRequest = request.newBuilder()...build();

            // retry the request
            return chain.proceed(newRequest);
        }

        // otherwise just pass the original response on
        return response;
    }

}

定义拦截器之后,创建OkHttpClient并将拦截器添加为应用程序拦截器。

    OkHttpClient okHttpClient = new OkHttpClient();
    okHttpClient.interceptors().add(new CustomInterceptor());

最后,在创建RestAdapter时使用这个OkHttpClient。

    RestService restService = new RestAdapter().Builder
            ...
            .setClient(new OkClient(okHttpClient))
            .create(RestService.class);

警告:正如杰西威尔逊(来自Square)在这里提到的,这是一个危险的电量。

话虽如此,我绝对认为这是现在处理这种事情的最好方法。如果你有任何问题,请不要犹豫在评论中提问。

经过长时间的研究,我自定义Apache客户端来处理刷新AccessToken For Retrofit,其中您发送访问令牌作为参数。

使用cookie持久客户端启动适配器

restAdapter = new RestAdapter.Builder()
                .setEndpoint(SERVER_END_POINT)
                .setClient(new CookiePersistingClient())
                .setLogLevel(RestAdapter.LogLevel.FULL).build();

Cookie持久客户端,为所有请求维护Cookie,并检查每个请求响应,如果是未经授权的访问ERROR_CODE = 401,刷新访问令牌并召回请求,否则仅处理请求。

private static class CookiePersistingClient extends ApacheClient {

    private static final int HTTPS_PORT = 443;
    private static final int SOCKET_TIMEOUT = 300000;
    private static final int CONNECTION_TIMEOUT = 300000;

    public CookiePersistingClient() {
        super(createDefaultClient());
    }

    private static HttpClient createDefaultClient() {
        // Registering https clients.
        SSLSocketFactory sf = null;
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore
                    .getDefaultType());
            trustStore.load(null, null);

            sf = new MySSLSocketFactory(trustStore);
            sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
        } catch (KeyManagementException e) {
            e.printStackTrace();
        } catch (UnrecoverableKeyException e) {
            e.printStackTrace();
        } catch (KeyStoreException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (CertificateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        HttpParams params = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(params,
                CONNECTION_TIMEOUT);
        HttpConnectionParams.setSoTimeout(params, SOCKET_TIMEOUT);
        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("https", sf, HTTPS_PORT));
        // More customization (https / timeouts etc) can go here...

        ClientConnectionManager cm = new ThreadSafeClientConnManager(
                params, registry);
        DefaultHttpClient client = new DefaultHttpClient(cm, params);

        // Set the default cookie store
        client.setCookieStore(COOKIE_STORE);

        return client;
    }

    @Override
    protected HttpResponse execute(final HttpClient client,
            final HttpUriRequest request) throws IOException {
        // Set the http context's cookie storage
        BasicHttpContext mHttpContext = new BasicHttpContext();
        mHttpContext.setAttribute(ClientContext.COOKIE_STORE, COOKIE_STORE);
        return client.execute(request, mHttpContext);
    }

    @Override
    public Response execute(final Request request) throws IOException {
        Response response = super.execute(request);
        if (response.getStatus() == 401) {

            // Retrofit Callback to handle AccessToken
            Callback<AccessTockenResponse> accessTokenCallback = new Callback<AccessTockenResponse>() {

                @SuppressWarnings("deprecation")
                @Override
                public void success(
                        AccessTockenResponse loginEntityResponse,
                        Response response) {
                    try {
                        String accessToken =  loginEntityResponse
                                .getAccessToken();
                        TypedOutput body = request.getBody();
                        ByteArrayOutputStream byte1 = new ByteArrayOutputStream();
                        body.writeTo(byte1);
                        String s = byte1.toString();
                        FormUrlEncodedTypedOutput output = new FormUrlEncodedTypedOutput();
                        String[] pairs = s.split("&");
                        for (String pair : pairs) {
                            int idx = pair.indexOf("=");
                            if (URLDecoder.decode(pair.substring(0, idx))
                                    .equals("access_token")) {
                                output.addField("access_token",
                                        accessToken);
                            } else {
                                output.addField(URLDecoder.decode(
                                        pair.substring(0, idx), "UTF-8"),
                                        URLDecoder.decode(
                                                pair.substring(idx + 1),
                                                "UTF-8"));
                            }
                        }
                        execute(new Request(request.getMethod(),
                                request.getUrl(), request.getHeaders(),
                                output));
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                }

                @Override
                public void failure(RetrofitError error) {
                    // Handle Error while refreshing access_token
                }
            };
            // Call Your retrofit method to refresh ACCESS_TOKEN
            refreshAccessToken(GRANT_REFRESH,CLIENT_ID, CLIENT_SECRET_KEY,accessToken, accessTokenCallback);
        }

        return response;
    }
}

正如Brais Gabin在评论中所说,我遇到了TokenAuthenticator依赖于服务类的问题。服务类依赖于OkHttpClient实例,要创建OkHttpClient,我需要TokenAuthenticator。

那么我是如何打破这个循环的呢?

我创建了一个新的okHttpClient对象,一个新的Retrofit对象,并使用该对象调用refreshToken来获得新的令牌(检查getUpdatedToken()函数)

class TokenAuthenticator : Authenticator {

    override fun authenticate(route: Route?, response: Response): Request? {
        return runBlocking {

            // 1. Refresh your access_token using a synchronous api request
           val response = getUpdatedToken(refreshToken)

           //2. In my case here I store the new token and refreshToken into SharedPreferences

           response.request.newBuilder()
                        .header("Authorization", "Bearer   ${tokenResponse.data?.accessToken}")
                        .build()

           // 3. If there's any kind of error I return null
           
        }
    }

    private suspend fun getUpdatedToken( refreshToken: String): TokenResponse {
        val okHttpClient = OkHttpClient().newBuilder()
            .addInterceptor(errorResponseInterceptor)
            .build()

        val retrofit = Retrofit.Builder()
            .baseUrl(BuildConfig.BASE_URL)
            .client(okHttpClient)
            .addConverterFactory(MoshiConverterFactory.create())
            .build()


        val service = retrofit.create(RefreshTokenApi::class.java)
        return service.refreshToken(refreshToken)

    }

}

RefreshTokenApi

interface RefreshTokenApi {

    @FormUrlEncoded
    @POST("refreshToken")
    suspend fun refreshToken(
        @Field("refresh_token") refreshToeken: String
    ): TokenResponse
}

在这个项目中,我使用Koin,我这样配置:

object RetrofigConfig {
    fun provideRetrofit(okHttpClient: OkHttpClient): Retrofit {
        return Retrofit.Builder()
            .baseUrl(BuildConfig.BASE_URL)
            .client(okHttpClient)
            .addConverterFactory(MoshiConverterFactory.create())
            .build()
    }

    fun provideOkHttpClient(
        tokenAuthenticator: TokenAuthenticator
    ): OkHttpClient {

        return OkHttpClient().newBuilder()
            .authenticator(tokenAuthenticator)
            .build()
    }

    fun provideServiceApi(retrofit: Retrofit): ServiceApi {
        return retrofit.create(ServiceApi::class.java)
    }
}

重要的一行是OkHttpClient().newBuilder().authenticator(tokenAuthenticator)

因为这是我第一次实现这个,我不知道这是否是最好的方式,但这是它在我的项目中工作的方式。

您可以尝试为所有的加载器创建一个基类,在这个基类中您可以捕获特定的异常,然后根据需要进行操作。 让所有不同的加载器从基类扩展,以传播行为。