ServiceHost 和 IIS 之间缺少链接

Question

当我设置多个 ServiceHost 实例时，我只能将一个主机用于一个端口。

Uri baseAddressHttps = new Uri("https://localhost/myservice.svc");
ServiceHost host = new ServiceHost(typeof(MyService), baseAddressHttps);
...
host.Open(); //OK

ServiceHost host2 = new ServiceHost(typeof(MyService), baseAddressHttps);
...
host2.Open();   //Fail

对 host2.Open() 的第二次调用按预期失败。

最近我偶然发现了ServiceHost的一个奇怪的行为。 一台机器 (Windows Server 2012 R2) 正在运行覆盖https://localhost 的 IIS。没有托管站点，IIS 基本上什么也没做。 当我在地址 https://localhost/myservice.svc 上安装使用 WCF ServiceHost 的程序（普通 Windows 服务）时，它可以正常工作。

我既没有配置 IIS，也没有“告诉”ServiceHost 有一个正在运行的 IIS。怎么可能没有任何端口冲突？ ServiceHost 使用哪种黑魔法？只是想了解发生了什么。

Answer 1

监听 http 的不是 IIS，而是 http.sys 驱动程序（HTTP 服务）正在 Windows 操作系统上执行此操作。这个魔法是在 http.sys 级别。你也可以这样做，看看是什么应用程序 监听 .IIS（w3wp.exe 进程）或您的 Windows 服务（使用 HTTP 侦听器）从 HTTP.sys 提供的队列接收请求。

要查看实际情况，您可以运行 netsh 命令

C:\windows\system32>netsh http show servicestate

Snapshot of HTTP service state (Server Session View):
-----------------------------------------------------

Server session ID: FF00000020000001
    Version: 2.0
    State: Active
    Properties:
        Max bandwidth: 4294967295
        Timeouts:
            Entity body timeout (secs): 120
            Drain entity body timeout (secs): 120
            Request queue timeout (secs): 65535
            Idle connection timeout (secs): 120
            Header wait timeout (secs): 120
            Minimum send rate (bytes/sec): 240
    URL groups:
    URL group ID: FE00000040000001
        State: Active
        Request queue name: DefaultAppPool
        Properties:
            Max bandwidth: inherited
            Max connections: 4294967295
            Timeouts:
                Entity body timeout (secs): 120
                Drain entity body timeout (secs): 120
                Request queue timeout (secs): 65535
                Idle connection timeout (secs): 120
                Header wait timeout (secs): 0
                Minimum send rate (bytes/sec): 0
            Logging information:
                Log directory: C:\inetpub\logs\LogFiles\W3SVC1
                Log format: 0
            Authentication Configuration:
                Authentication schemes enabled:
    URL group ID: FD00000040000001
        State: Active
        Request queue name: testweb
        Properties:
            Max bandwidth: inherited
            Max connections: inherited
            Timeouts:
                Timeout values inherited
            Authentication Configuration:
                Authentication schemes enabled:
            Number of registered URLs: 1
            Registered URLs:
                HTTP://*:80/BUGGYBITS/
    URL group ID: FF00000240000001
        State: Active
        Request queue name: testweb
        Properties:
            Max bandwidth: inherited
            Max connections: 4294967295
            Timeouts:
                Entity body timeout (secs): 120
                Drain entity body timeout (secs): 120
                Request queue timeout (secs): 65535
                Idle connection timeout (secs): 120
                Header wait timeout (secs): 0
                Minimum send rate (bytes/sec): 0
            Logging information:
                Log directory: C:\inetpub\logs\LogFiles\W3SVC2
                Log format: 0
            Authentication Configuration:
                Authentication schemes enabled:
            Number of registered URLs: 1
            Registered URLs:
                HTTP://*:80/

Server session ID: FF00000120000001
    Version: 2.0
    State: Active
    Properties:
        Max bandwidth: 4294967295
        Timeouts:
            Entity body timeout (secs): 120
            Drain entity body timeout (secs): 120
            Request queue timeout (secs): 120
            Idle connection timeout (secs): 120
            Header wait timeout (secs): 120
            Minimum send rate (bytes/sec): 150
    URL groups:
    URL group ID: FE00000140000001
        State: Active
        Request queue name: Request queue is unnamed.
        Properties:
            Max bandwidth: inherited
            Max connections: inherited
            Timeouts:
                Timeout values inherited
            Number of registered URLs: 1
            Registered URLs:
                HTTP://*:5357/B5B45532-3676-4316-BBB8-9DBB35BACAB4/

Request queues:
    Request queue name: DefaultAppPool
        Version: 2.0
        State: Active
        Request queue 503 verbosity level: Limited
        Max requests: 1000
        Number of active processes attached: 0
        Controller process ID: 3016
        Process IDs:

    Request queue name: testweb
        Version: 2.0
        State: Active
        Request queue 503 verbosity level: Limited
        Max requests: 1000
        Number of active processes attached: 0
        Controller process ID: 3016
        Process IDs:

正如您在上面的输出中看到的，查看 Registered URLS，特定进程可以在其中侦听 URL 的一部分。所以在这种情况下 HTTP://:80/BUGGYBITS/ 将进入一个特定的进程，而 HTTP://:80/ 将进入另一个进程。

希望这一切都清楚。您可以找到有关 netsh 命令here 的更多详细信息