仅在满足特定条件时节流

Question

我有一个订阅的可观察对象。这个可观察对象将返回一个具有ActivationType属性的对象，该属性可以被设置多次。

我想要实现的是日志消息每当ActivationType被设置为"Type1"。但是，如果ActivationType设置为"Type2"，则只记录一次消息，如果ActivationType设置为"Type2"，则等待30秒后再记录。

如果我输入:

myObservable
    .Where(o => o.ActivationType == "Type1" || o.ActivationType == "Type2")  //listen for types 1 and 2
    .Throttle() // ??? somehow only throttle if we are currently looking at Type2
    .Subscribe(Log); //log some stuff

我相信油门()是我正在寻找的，但我不确定如何有条件地触发它。

有什么建议吗?

Answer 1

啊，对于几乎无法理解的Window运算符来说，这是一个完美的例子!

编辑:我一个月发十几次这个链接，我发誓——这是我见过的最好的Window, Join, Buffer, GroupJoin等操作符:

Lee Campbell: Rx Part 9-Join、Window、Buffer和Group Join

var source = new Subject<Thing>();
var feed = source.Publish().RefCount();
var ofType1 = feed.Where(t => t.ActivationType == "Type1");
var ofType2 = feed
    // only window the type2s
    .Where(t => t.ActivationType == "Type2")
    // our "end window selector" will be a tick 30s off from start
    .Window(() => Observable.Timer(TimeSpan.FromSeconds(30)))
    // we want the first one in each window...
    .Select(lst => lst.Take(1))
    // moosh them all back together
    .Merge();
    // We want all "type 1s" and the buffered outputs of "type 2s"
    var query = ofType1.Merge(ofType2);
    // Let's set up a fake stream of data
    var running = true;
    var feeder = Task.Factory.StartNew(
       () => { 
         // until we say stop...
         while(running) 
         { 
             // pump new Things into the stream every 500ms
             source.OnNext(new Thing()); 
             Thread.Sleep(500); 
         }
    });
    using(query.Subscribe(Console.WriteLine))
    {               
        // Block until we hit enter so we can see the live output 
        // from the above subscribe 
        Console.ReadLine();
        // Shutdown our fake feeder
        running = false;
        feeder.Wait();
     }

Answer 2

为什么不使用两个流呢?

var baseStream = myObservable.Publish().RefCount(); // evaluate once
var type1 = baseStream.Where(o => o.ActivationType == "Type1");
var type2 = baseStream.Where(o => o.ActivationType == "Type2").Throttle(TimeSpan.FromSeconds(30));
type1.Merge(type2).Subscribe(Log);