Asp.Net Core 自动适应Windows服务、Linux服务、手动启动时的内容路径的扩展方法

      public static IWebHostBuilder UseContentRootAsEnv(this IWebHostBuilder hostBuilder)
        {
            bool IsWindowsService = false;
            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                using (var process = GetParent(Process.GetCurrentProcess()))
                {
                    IsWindowsService = process != null && process.ProcessName == "services";
                }
            }
            if ( Environment.CommandLine.Contains("--usebasedirectory") || (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && IsWindowsService))
            {
                hostBuilder.UseContentRoot(AppContext.BaseDirectory);
            }
            else
            {
                if (!Debugger.IsAttached)
                {
                    hostBuilder.UseContentRoot(System.IO.Directory.GetCurrentDirectory());
                }
            }
            return hostBuilder;
        }

        public static void RunAsEnv(this IWebHost host)
        {
            bool IsWindowsService = false;

            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                using (var process = GetParent(Process.GetCurrentProcess()))
                {
                    IsWindowsService = process != null && process.ProcessName == "services";
                }
            }
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && IsWindowsService)
            {
                System.IO.Directory.SetCurrentDirectory(AppContext.BaseDirectory);
                host.RunAsService();
            }
            else
            {
                if (Environment.CommandLine.Contains("--usebasedirectory"))
                {
                    System.IO.Directory.SetCurrentDirectory(AppContext.BaseDirectory);
                }
                host.Run();
            }
        }

        private static Process GetParent(Process child)
        {
            var parentId = ;

            var handle = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, );

            if (handle == IntPtr.Zero)
            {
                return null;
            }

            var processInfo = new PROCESSENTRY32
            {
                dwSize = (uint)Marshal.SizeOf(typeof(PROCESSENTRY32))
            };

            if (!Process32First(handle, ref processInfo))
            {
                return null;
            }

            do
            {
                if (child.Id == processInfo.th32ProcessID)
                {
                    parentId = (int)processInfo.th32ParentProcessID;
                }
            } while (parentId ==  && Process32Next(handle, ref processInfo));

            if (parentId > )
            {
                return Process.GetProcessById(parentId);
            }
            return null;
        }

        private static uint TH32CS_SNAPPROCESS = ;

        [DllImport("kernel32.dll")]
        public static extern bool Process32Next(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern IntPtr CreateToolhelp32Snapshot(uint dwFlags, uint th32ProcessID);

        [DllImport("kernel32.dll")]
        public static extern bool Process32First(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

        [StructLayout(LayoutKind.Sequential)]
        public struct PROCESSENTRY32
        {
            public uint dwSize;
            public uint cntUsage;
            public uint th32ProcessID;
            public IntPtr th32DefaultHeapID;
            public uint th32ModuleID;
            public uint cntThreads;
            public uint th32ParentProcessID;
            public int pcPriClassBase;
            public uint dwFlags;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = )]
            public string szExeFile;
        }

使用方法:

    public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().RunAsEnv();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
                        WebHost.CreateDefaultBuilder(args)
                        .UseContentRootAsEnv()
                        .UseStartup<Startup>();