android - 如何在使用 MockWebServer 时使用 Dagger 2.0 支持多个端点

Question

对于一个 Android 项目，我使用 Dagger 2.6 配置了 Retrofit 2.1.0 和 OkHttp 3.4.1，如下面的 Dagger 模块所示。我的目标是使用@Named限定符支持多个后端。

@Module
public class ApiModule {

    private static final String GITHUB_QUALIFIER = "GitHub";

    private static final String TWITTER_QUALIFIER = "Twitter";

    @Provides
    GitHubClient provideGitHubClient(@Named(GITHUB_QUALIFIER) Retrofit retrofit) { /* ... */ }

    @Provides
    TwitterClient provideTwitterClient(@Named(TWITTER_QUALIFIER) Retrofit retrofit) { /* ... */ }

    @Named(GITHUB_QUALIFIER)
    @Provides
    @Singleton
    HttpUrl provideGitHubBaseUrl() { /* ... */ }

    @Named(TWITTER_QUALIFIER)
    @Provides
    @Singleton
    HttpUrl provideTwitterBaseUrl() { /* ... */ }

    @Named(GITHUB_QUALIFIER)
    @Provides
    @Singleton
    Retrofit getGitHubRetrofit(@Named(GITHUB_QUALIFIER) HttpUrl httpUrl, 
                               OkHttpClient okHttpClient) { /* ... */ }

    @Named(TWITTER_QUALIFIER)
    @Provides
    @Singleton
    Retrofit getTwitterRetrofit(@Named(TWITTER_QUALIFIER) HttpUrl httpUrl, 
                                OkHttpClient okHttpClient) { /* ... */ }

    private Retrofit getRetrofit(String baseUrl, 
                                 OkHttpClient okHttpClient) { /* ... */ }

    @Provides
    @Singleton
    public OkHttpClient provideOkHttpClient() { /* ... */ }

}

我想使用MockWebServer进行测试。但是，我不知道如何在支持多个后端的同时传入 MockWebServer 的 URL：

// From a unit test

mockWebServer = new MockWebServer();
mockWebServer.start();
ApiModule apiModule = new ApiModule();
OkHttpClient okHttpClient = new OkHttpClient.Builder().build();

String url = mockWebServer.url("/").toString();
// Here I cannot pass the URL to Retrofit
Retrofit retrofit = apiModule.provideRetrofit(/* HERE */ okHttpClient);

gitHubClient = apiModule.provideGitHubClient(retrofit);

Answer 1

可以使用 okhttp 拦截器覆盖基本 url。

public final class HostSelectionInterceptor implements Interceptor {
    private volatile String mHost;

    public void setHost(String host) {
        this.mHost = checkNotNull(host);
    }

    @Override
    public okhttp3.Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        String host = this.mHost;
        if (host != null) {
            HttpUrl overriddenBaseUrl = HttpUrl.parse(host);
            HttpUrl newUrl = request.url()
                    .newBuilder()
                    .host(overriddenBaseUrl.host())
                    .build();
            request = request.newBuilder()
                    .url(newUrl)
                    .build();
        }
        return chain.proceed(request);
    }
}

取自这里：https ://gist.github.com/swankjesse/8571a8207a5815cca1fb

您可以使用此拦截器来提供 MockWebServer url，甚至可以在登台端点之间切换以进行调试构建。