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
TokenAuthenticator依赖于服务类。服务类依赖于OkHttpClient实例。要创建OkHttpClient，我需要TokenAuthenticator。我该如何打破这个循环?两个不同的OkHttpClients?它们将有不同的连接池..
如果你有一个你需要在你的Authenticator内部的Retrofit TokenService，但是你只想建立一个OkHttpClient，你可以使用TokenServiceHolder作为TokenAuthenticator的依赖项。您必须在应用程序(单例)级别维护对它的引用。如果你使用匕首2，这很容易，否则只是在你的应用程序中创建类字段。
在TokenAuthenticator.java
public class TokenAuthenticator implements Authenticator {
private final TokenServiceHolder tokenServiceHolder;
public TokenAuthenticator(TokenServiceHolder tokenServiceHolder) {
this.tokenServiceHolder = tokenServiceHolder;
}
@Override
public Request authenticate(Proxy proxy, Response response) throws IOException {
//is there a TokenService?
TokenService service = tokenServiceHolder.get();
if (service == null) {
//there is no way to answer the challenge
//so return null according to Retrofit's convention
return null;
}
// Refresh your access_token using a synchronous api request
newAccessToken = service.refreshToken().execute();
// Add new header to rejected request and retry it
return response.request().newBuilder()
.header(AUTHORIZATION, newAccessToken)
.build();
}
@Override
public Request authenticateProxy(Proxy proxy, Response response) throws IOException {
// Null indicates no attempt to authenticate.
return null;
}
在TokenServiceHolder.java:
public class TokenServiceHolder {
TokenService tokenService = null;
@Nullable
public TokenService get() {
return tokenService;
}
public void set(TokenService tokenService) {
this.tokenService = tokenService;
}
}
客户端设置:
//obtain instance of TokenServiceHolder from application or singleton-scoped component, then
TokenAuthenticator authenticator = new TokenAuthenticator(tokenServiceHolder);
OkHttpClient okHttpClient = new OkHttpClient();
okHttpClient.setAuthenticator(tokenAuthenticator);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://api.github.com/")
.client(okHttpClient)
.build();
TokenService tokenService = retrofit.create(TokenService.class);
tokenServiceHolder.set(tokenService);
如果你正在使用Dagger 2或类似的依赖注入框架，这里有一些例子可以回答这个问题
其他回答
请不要使用拦截器来处理身份验证。
目前，处理身份验证的最佳方法是使用新的Authenticator API，它是专门为此目的设计的。
当响应为401未授权重试最后一次失败的请求时，OkHttp将自动向验证者请求凭据。
public class TokenAuthenticator implements Authenticator {
@Override
public Request authenticate(Proxy proxy, Response response) throws IOException {
// Refresh your access_token using a synchronous api request
newAccessToken = service.refreshToken();
// Add new header to rejected request and retry it
return response.request().newBuilder()
.header(AUTHORIZATION, newAccessToken)
.build();
}
@Override
public Request authenticateProxy(Proxy proxy, Response response) throws IOException {
// Null indicates no attempt to authenticate.
return null;
}
将验证器附加到OkHttpClient，方法与拦截器相同
OkHttpClient okHttpClient = new OkHttpClient();
okHttpClient.setAuthenticator(authAuthenticator);
在创建您的Retrofit RestAdapter时使用此客户端
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint(ENDPOINT)
.setClient(new OkClient(okHttpClient))
.build();
return restAdapter.create(API.class);
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。
TokenAuthenticator依赖于服务类。服务类依赖于OkHttpClient实例。要创建OkHttpClient，我需要TokenAuthenticator。我该如何打破这个循环?两个不同的OkHttpClients?它们将有不同的连接池..
如果你有一个你需要在你的Authenticator内部的Retrofit TokenService，但是你只想建立一个OkHttpClient，你可以使用TokenServiceHolder作为TokenAuthenticator的依赖项。您必须在应用程序(单例)级别维护对它的引用。如果你使用匕首2，这很容易，否则只是在你的应用程序中创建类字段。
在TokenAuthenticator.java
public class TokenAuthenticator implements Authenticator {
private final TokenServiceHolder tokenServiceHolder;
public TokenAuthenticator(TokenServiceHolder tokenServiceHolder) {
this.tokenServiceHolder = tokenServiceHolder;
}
@Override
public Request authenticate(Proxy proxy, Response response) throws IOException {
//is there a TokenService?
TokenService service = tokenServiceHolder.get();
if (service == null) {
//there is no way to answer the challenge
//so return null according to Retrofit's convention
return null;
}
// Refresh your access_token using a synchronous api request
newAccessToken = service.refreshToken().execute();
// Add new header to rejected request and retry it
return response.request().newBuilder()
.header(AUTHORIZATION, newAccessToken)
.build();
}
@Override
public Request authenticateProxy(Proxy proxy, Response response) throws IOException {
// Null indicates no attempt to authenticate.
return null;
}
在TokenServiceHolder.java:
public class TokenServiceHolder {
TokenService tokenService = null;
@Nullable
public TokenService get() {
return tokenService;
}
public void set(TokenService tokenService) {
this.tokenService = tokenService;
}
}
客户端设置:
//obtain instance of TokenServiceHolder from application or singleton-scoped component, then
TokenAuthenticator authenticator = new TokenAuthenticator(tokenServiceHolder);
OkHttpClient okHttpClient = new OkHttpClient();
okHttpClient.setAuthenticator(tokenAuthenticator);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://api.github.com/")
.client(okHttpClient)
.build();
TokenService tokenService = retrofit.create(TokenService.class);
tokenServiceHolder.set(tokenService);
如果你正在使用Dagger 2或类似的依赖注入框架，这里有一些例子可以回答这个问题
使用一个拦截器(注入令牌)和一个验证器(刷新操作)完成工作，但是:
我也有一个双重呼叫的问题:第一个呼叫总是返回401: 在第一次调用(拦截器)时没有注入令牌，并且调用验证器:发出了两个请求。
修复只是在拦截器中重新影响对构建的请求:
之前:
private Interceptor getInterceptor() {
return (chain) -> {
Request request = chain.request();
//...
request.newBuilder()
.header(AUTHORIZATION, token))
.build();
return chain.proceed(request);
};
}
后:
private Interceptor getInterceptor() {
return (chain) -> {
Request request = chain.request();
//...
request = request.newBuilder()
.header(AUTHORIZATION, token))
.build();
return chain.proceed(request);
};
}
在一个街区:
private Interceptor getInterceptor() {
return (chain) -> {
Request request = chain.request().newBuilder()
.header(AUTHORIZATION, token))
.build();
return chain.proceed(request);
};
}
希望能有所帮助。
编辑:我没有找到一种方法来避免第一次调用总是返回401，只使用验证器而不使用拦截器
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。
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