Retrofit builder to handle calls with authorization requirements and interceptor with refresh token.

ApiRefreshToken.kt

interface ApiRefreshToken {
    companion object {
        private const val REFRESH_TOKEN = "/refreshToken"
    }

    @FormUrlEncoded
    @POST(REFRESH_TOKEN)
    fun refreshToken(@Field("refreshToken") refreshToken: String?): Call<TokenModel>
}

AuthenticationInterceptorRefreshToken.kt

class AuthenticationInterceptorRefreshToken @Inject constructor(private val retrofitBuilder: RetrofitBuilder, private val userManager: UserManager) : Interceptor {
    @Throws(IOException::class)
    override fun intercept(chain: Interceptor.Chain): Response? {
            val originalRequest = chain.request()
            val authenticationRequest = request(originalRequest)
            val initialResponse = chain.proceed(authenticationRequest)

            when {
                initialResponse.code() == 403 || initialResponse.code() == 401 -> {
                    val responseNewTokenLoginModel = retrofitBuilder.retrofit().create(ApiRefreshToken::class.java).refreshToken(userManager.load()?.refreshToken).execute()

                    return when {
                        responseNewTokenLoginModel == null || responseNewTokenLoginModel.code() != 200 -> {
                            AuthManager().authExpiredAndGoLogin(AndroidApplication().getContext())
                            null
                        }
                        else -> {
                            responseNewTokenLoginModel.body()?.accessToken?.let {
                                userManager.updateToken(it)
                            }
                            val newAuthenticationRequest = originalRequest.newBuilder().addHeader("Authorization", "Bearer " + responseNewTokenLoginModel.body()?.accessToken).build()
                            chain.proceed(newAuthenticationRequest)
                        }
                    }
                }
                else -> return initialResponse
            }

    }

requestHeaders.kt

 private fun request(originalRequest: Request): Request {
        return originalRequest.newBuilder()
                .addHeader("Authorization", "Bearer ${userManager.load()?.accessToken}")
                .addHeader("appVersion", BuildConfig.VERSION_NAME).build()

    }

RetrofitBuilder.kt

class RetrofitBuilder {

    fun retrofitAuth(): Retrofit {
        return Retrofit.Builder()
                .baseUrl(BuildConfig.BASE_URL)
                .client(createClientAuth())
                .addConverterFactory(GsonConverterFactory.create())
                .build()
    }

    private fun createClientAuth(): OkHttpClient {
        val okHttpClientBuilder: OkHttpClient.Builder = OkHttpClient.Builder()
     
        okHttpClientBuilder.addInterceptor(AuthenticationInterceptorRefreshToken(this, UserManager()))
        return okHttpClientBuilder.build()
    }
}