如何在 Retrofit 中动态处理错误

Question

在我的应用程序中，我使用 Retrofit 库连接到服务器，有时会显示验证错误或其他原因......
报错信息格式如下：

{
  "message": "The given data was invalid.",
  "errors": {
    "login": [
      "Email or phone is not valid"
    ]
  }
}

login 对象在其他 API 中发生变化，可能显示 password、basket 或其他...
我知道我可以使用上面的 Json 创建错误类并使用 Gson 库转换 errorBody 并显示它！
但我不想为每个 API 创建一个新类！
我想创建一个通用类并从 Json 的错误字段中获取所有错误消息并将其显示给用户！

我的网络响应类：

open class NetworkResponse<T>(private val response: Response<T>) {

    fun generalNetworkResponse(): NetworkRequest<T> {
        return when {
            response.code() == 401 -> NetworkRequest.Error("You are not authorized")
            response.code() == 422 -> NetworkRequest.Error("Api key not found!")
            response.code() == 500 -> NetworkRequest.Error("Try again")
            response.isSuccessful -> NetworkRequest.Success(response.body()!!)
            else -> NetworkRequest.Error(response.message())
        }
    }
}

Config改造代码：

@Module
@InstallIn(SingletonComponent::class)
object NetworkProviders {

    @Provides
    @Singleton
    fun provideBaseUrl() = BASE_URL

    @Provides
    @Singleton
    fun provideNetworkTime() = CONNECTION_TIME

    @Provides
    @Singleton
    fun provideGson(): Gson = GsonBuilder().setLenient().create()

    @Provides
    @Singleton
    fun provideInterceptor() = HttpLoggingInterceptor().apply {
        level = HttpLoggingInterceptor.Level.BODY
    }

    @Provides
    @Singleton
    fun provideClient(time: Long, interceptor: HttpLoggingInterceptor) = OkHttpClient.Builder()
        .addInterceptor(interceptor)
        .writeTimeout(time, TimeUnit.SECONDS)
        .readTimeout(time, TimeUnit.SECONDS)
        .connectTimeout(time, TimeUnit.SECONDS)
        .build()

    @Provides
    @Singleton
    fun provideRetrofit(baseUrl: String, gson: Gson, client: OkHttpClient): ApiServices =
        Retrofit.Builder()
            .baseUrl(baseUrl)
            .client(client)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .build()
            .create(ApiServices::class.java)
}

如何使用 Retrofit 动态处理错误？

Answer 1

创建一个名为 ApiError

的类

data class ApiError(
    val message: String?,
    val errors: Map<String, List<String>>?
)

在您的 Retrofit Callback 实现中，您可以使用 Gson 库将错误响应解析为 ApiError 的实例。这是一个例子：

class MyCallback : Callback<MyResponse> {

    override fun onResponse(call: Call<MyResponse>, response: Response<MyResponse>) {
        // handle success response...
    }

    override fun onFailure(call: Call<MyResponse>, t: Throwable) {
        // handle network error...
    }

    override fun onFailure(call: Call<MyResponse>, response: Response<MyResponse>) {
        if (response.errorBody() != null) {
            try {
                val apiError = Gson().fromJson(response.errorBody()!!.string(), ApiError::class.java)
                // handle API error...
                val errorMessage = apiError.message
                val errors = apiError.errors
                // You can iterate through the map of errors and display them to the user
                errors?.forEach { (field, fieldErrors) ->
                    // display field errors to user
                }
            } catch (e: IOException) {
                // handle parsing error...
            }
        } else {
            // handle unexpected error...
        }
    }
}