我正在关注本教程 - https://www.lagomframework.com/documentation/1.3.x/scala/ServiceImplementation.html
我创建了一个记录服务
//logged takes a ServerServiceCall as argument (serviceCall) and returns a ServerServiceCall.
//ServerServiceCall's compose method creates (composes) another ServerServiceCall
//we are returing the same ServerServiceCall that we received but are logging it using println
def logged[Request,Response](serviceCall:ServerServiceCall[Request,Response]) = {
println("inside logged");
//return new ServerServiceCall after logging request method and uri
ServerServiceCall.compose({
requestHeader=>println(s"Received ${requestHeader.method} ${requestHeader.uri}")
serviceCall
}
)}
我使用记录如下:
override def hello3 = logged(ServerServiceCall
{ (requestHeader,request) =>
println("inside ssc")
val incoming:Option[String] = requestHeader.getHeader("user");
val responseHeader = ResponseHeader.Ok.withHeader("status","authenticated")
incoming match {
case Some(s) => Future.successful((responseHeader,("hello3 found "+s)))
case None => Future.successful((responseHeader,"hello3 didn't find user"))
}
})
我预计inside ssc
会先打印,然后再打印,但事实恰恰相反。不应该首先评估传递给函数的参数吗?
我懂了。为什么?
inside logged
Received POST /hello3
inside ssc