Scala 如何使用Akka Http进行并行Http请求?
我是Scala新手,正在尝试实现一个库,在这个库中我将获得数千个URL。我的工作是从这些URL下载内容。我本来会选择simpleScala 如何使用Akka Http进行并行Http请求?,scala,akka,akka-http,Scala,Akka,Akka Http,我是Scala新手,正在尝试实现一个库,在这个库中我将获得数千个URL。我的工作是从这些URL下载内容。我本来会选择simplescalajhttplibrary,但它不符合我的目的。 我附带的代码是: class ProxyHttpClient { def get(url: String, proxy: ProxySettings,urlDownloaderConfig: UrlDownloaderConfig)(implicit ec: ExecutionCon
scalajhttp
library,但它不符合我的目的。
我附带的代码是:
class ProxyHttpClient {
def get(url: String, proxy: ProxySettings,urlDownloaderConfig:
UrlDownloaderConfig)(implicit ec: ExecutionContext): Either[HttpError,
HttpSuccessResponse] = {
implicit val system: ActorSystem = ActorSystem()
implicit val materializer: ActorMaterializer = ActorMaterializer()
val auth = headers.BasicHttpCredentials(proxy.userName,
proxy.secret)
val httpsProxyTransport =
ClientTransport.httpsProxy(InetSocketAddress.createUnresolved(
proxy.host, proxy.port), auth)
val settings =
ConnectionPoolSettings(system).withTransport(httpsProxyTransport)
val response: Future[HttpResponse] =
Http().singleRequest(HttpRequest().
withMethod(HttpMethods.GET).withUri(url), settings = settings)
val data: Future[Either[HttpError, HttpSuccessResponse]] = `response.map {`
case response@HttpResponse(StatusCodes.OK, _, _, _) => {
val content: Future[String] = Unmarshal(response.entity).to[String]
val finalContent = Await.ready(content, timeToWaitForContent).value.get.get.getBytes
Right(HttpSuccessResponse(url, response.status.intValue(), finalContent))
}
case errorResponse@HttpResponse(StatusCodes.GatewayTimeout, _, _, _) => Left(HttpError(url, errorResponse.status.intValue(), errorResponse.entity.toString))
}
val result: Try[Either[HttpError, HttpSuccessResponse]] = Await.ready(data, timeToWaitForResponse).value.get
val pop: Either[HttpError, HttpSuccessResponse] = try {
result.get
} catch {
case e: Exception => Left(HttpError(url, HttpStatus.SC_INTERNAL_SERVER_ERROR, e.getMessage))
}
pop
}
}
用于调用我正在使用的get
方法
val forkJoinPool = new scala.concurrent.forkjoin.ForkJoinPool(8)
picList.par.tasksupport = new ForkJoinTaskSupport(forkJoinPool)
picList.par.map(testUrl => {
val resp = get(url, Option(proxy))
})
它平稳地运行了几次,但当我试图调用1000个URL的方法来获取批量大小为100的图像时,它抛出了下面的错误。之后,即使是单个URL,我也会遇到同样的错误
**java.lang.OutOfMemoryError: unable to create new native thread**
val blockingExecutionContext = system.dispatchers.lookup("blocking-dispatcher")
但当我尝试时,system.dispatchers.lookup
返回的是messagedispatcher类型
implicit val system: ActorSystem = ActorSystem()
val ex: MessageDispatcher =system.dispatchers.lookup("io-blocking-dispatcher")
我是否缺少任何库或导入?您的问题很可能与为每个http调用创建actor系统有关。参与者系统通常是每个应用程序一个 做一个小的重构并尝试一下
class ProxyHttpClient() {
private implicit val system: ActorSystem = ActorSystem()
private implicit val materializer: ActorMaterializer = ActorMaterializer()
def get(url: String, proxy: ProxySettings,urlDownloaderConfig:
UrlDownloaderConfig)(implicit ec: ExecutionContext): Either[HttpError,
HttpSuccessResponse] = {???}
}
或者提取actor系统并将其作为隐式参数传递
class ProxyHttpClient() {
def get(url: String, proxy: ProxySettings,urlDownloaderConfig:
UrlDownloaderConfig)(implicit ec: ExecutionContext, system: ActorSystem, materializer: ActorMaterializer): Either[HttpError,
HttpSuccessResponse] = {???}
}
您的问题很可能与为每个http调用创建actor系统有关。参与者系统通常是每个应用程序一个 做一个小的重构并尝试一下
class ProxyHttpClient() {
private implicit val system: ActorSystem = ActorSystem()
private implicit val materializer: ActorMaterializer = ActorMaterializer()
def get(url: String, proxy: ProxySettings,urlDownloaderConfig:
UrlDownloaderConfig)(implicit ec: ExecutionContext): Either[HttpError,
HttpSuccessResponse] = {???}
}
或者提取actor系统并将其作为隐式参数传递
class ProxyHttpClient() {
def get(url: String, proxy: ProxySettings,urlDownloaderConfig:
UrlDownloaderConfig)(implicit ec: ExecutionContext, system: ActorSystem, materializer: ActorMaterializer): Either[HttpError,
HttpSuccessResponse] = {???}
}
所有URL都指向同一主机和端口吗?是的,它们通过同一个代理路由。所有URL都指向同一主机和端口吗?是的,它们通过同一个代理路由。是的,我怀疑是相同的,创建了一个对象,而系统现在只创建了一次。你的评论证实了我的怀疑。非常感谢。是的,我也怀疑这一点,我创建了一个对象,而系统现在只创建了一次。你的评论证实了我的怀疑。非常感谢。