在Kotlin中处理Spring WebFlux WebClient超时

Question

我正在Kotlin(1.4.30)中使用Spring WebFlux WebClient（引导2.4.3)执行一个get http调用。当请求超时时，它以异常方式失败，但我希望返回一个默认值。我看到对onerror、onstatus等的引用在retrieve()之后使用，但在我的示例中似乎没有这些引用（只有body、toentity、awaitexchange)

电话：

suspend fun conversation(id: String): Conversation =
    client.get().uri("/conversation/{id}", id).retrieve().awaitBody()

连接和读取超时的WebClient配置：

fun webClient(url: String, connectTimeout: Int, readTimeout: Long, objectMapper: ObjectMapper): WebClient =
    WebClient.builder()
      .baseUrl(url)
      .exchangeStrategies(
        ExchangeStrategies.builder()
          .codecs { configurer -> configurer.defaultCodecs().jackson2JsonDecoder(Jackson2JsonDecoder(objectMapper)) }
          .build())
      .clientConnector(
        ReactorClientHttpConnector(
          HttpClient.create()
            .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, connectTimeout)
            .doOnConnected { connection ->
              connection.addHandlerLast(ReadTimeoutHandler(readTimeout, TimeUnit.MILLISECONDS))
            }))
      .build()

响应模型：

kotlin prettyprint-override">@JsonIgnoreProperties(ignoreUnknown = true)
data class Conversation(
  val replyTimestamp: Map<String, String>,
)

  private val defaultConversation = Conversation(emptyMap())

  suspend fun conversation(id: String): Conversation =
    client.get()
      .uri("/conversation/{id}", id)
      .awaitExchange {
          response -> if (response.statusCode() == HttpStatus.OK)  response.awaitBody() else defaultConversation
      }

回应：

{
  "replyTimestamp": {
    "1": "2021-02-23T15:30:28.753Z",
    "2": "2021-02-23T16:30:28.753Z"
  }
}

它的模拟配置：

{
  "mappings":
  [
    {
      "priority": 1,
      "request": {
        "method": "GET",
        "urlPathPattern": "/conversation/1"
      },
      "response": {
        "status": 200,
        "fixedDelayMilliseconds": 1010,
        "headers": {
          "content-type": "application/json;charset=utf-8"
        },
        "bodyFileName": "conversation1.json"
      }
    }
  ]
}

Answer 1

之所以出现异常，是因为在您的方法中，您希望得到一个类型为Conversation的响应，但由于您接收到一个错误，所以正文不同。在本例中，处理响应的方式应该是首先查看HTTP状态代码，然后相应地转换正文。下面是Spring.io https://docs.spring.io/spring-framework/docs/current/reference/html/web-reactive.html中的一个示例

在您的情况下，当您收到错误的状态代码时，您应该创建一个新的空对话并返回它

val entity = client.get()
  .uri("/conversation/{id}", id)
  .accept(MediaType.APPLICATION_JSON)
  .awaitExchange {
        if (response.statusCode() == HttpStatus.OK) {
             return response.awaitBody<Conversation>()
        }
        else if (response.statusCode().is4xxClientError) {
             return response.awaitBody<ErrorContainer>()
        }
        else {
             throw response.createExceptionAndAwait()
        }
  }