读取Vert.x http客户端响应正文时引发的IllegalStateException

Question

当我试图从http客户端响应对象读取正文时，会出现以下错误。我并不总是得到异常，所以我想这是一个与完整未来相关的线程问题。你知道我做错了什么吗？我使用Vert.x3.8.1

java.lang.IllegalStateException
    at io.vertx.core.http.impl.HttpClientResponseImpl.checkEnded(HttpClientResponseImpl.java:134)
    at io.vertx.core.http.impl.HttpClientResponseImpl.endHandler(HttpClientResponseImpl.java:153)
    at io.vertx.core.http.impl.HttpClientResponseImpl.bodyHandler(HttpClientResponseImpl.java:193)
    at com.diagnostics.Response.body(Web.kt:116)
    at com.diagnostics.Response.bodyNow(Web.kt:111)
    at com.diagnostics.Response.bodyNow$default(Web.kt:110)
    at com.diagnostics.Main.postVerificationTest(Main.kt:73)
    at com.diagnostics.Main.main(Main.kt:52)
    at com.diagnostics.Main.main(Main.kt)

引发异常的代码：

val response = client.get(requestUri = "/api/info").get(3, TimeUnit.SECONDS)

val expectedStatus = 200
assertConditionOrExit(pvtLog, response.status == expectedStatus, "response status is ${response.status} expecting $expectedStatus")
val body = response.bodyNow()
assertConditionOrExit(pvtLog, body.isNotEmpty(), "body is empty expecting a non empty value")

http客户端响应对象由以下代码创建：

private fun request(
    method: HttpMethod,
    port: Int,
    host: String,
    requestUri: String
): CompletableFuture<Response> {
    val future = CompletableFuture<Response>()
    httpClient.request(method, port, host, requestUri)
        .exceptionHandler { future.completeExceptionally(it) }
        .handler { resp -> future.complete(Response(resp)) }
        .end()
    return future
}

尸体被找回...

fun bodyNow(timeout: Long = 10, unit: TimeUnit = SECONDS): String {
    return body().get(30000, SECONDS)
}

fun body(): CompletableFuture<String> {
    val future = CompletableFuture<String>()
    resp.bodyHandler { buff -> future.complete(buff.toString())}
    return future
}

Answer 1

body()函数在request()方法调用HttpClientRequest处理程序后设置BodyHandler。

因此，当主线程继续运行时，eventloop有可能接收内容并将其删除。如果内容很小，请求甚至可以在BodyHandler设置之前结束。

这就是为什么您只会时不时地看到异常。

如果以后要设置BodyHandler，必须暂停HttpClientResponse:

httpClient.request(method, port, host, requestUri)
    .exceptionHandler { future.completeExceptionally(it) }
    .handler { resp -> 
        resp.pause() // Pause the response
        future.complete(Response(resp))
    }
    .end()

然后在设置BodyHandler后继续：

resp.bodyHandler { buff -> future.complete(buff.toString())}
resp.resume()