feat: add ERP agent pet bridge and startup guide

插件库/Lskj.AgentBridge/DeadlineFrameCodec.cs

@@ -0,0 +1,187 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Threading;
+
+namespace Lskj.AgentBridge
+{
+    /// <summary>
+    /// Length-prefixed bridge framing with one total deadline for the header
+    /// and body. A stalled asynchronous operation closes the owning stream so
+    /// a local client cannot retain a server worker indefinitely.
+    /// </summary>
+    internal static class DeadlineFrameCodec
+    {
+        internal const int MaximumMessageBytes = 1024 * 1024;
+
+        internal static byte[] ReadFrame(Stream stream, TimeSpan timeout)
+        {
+            if (stream == null) throw new ArgumentNullException("stream");
+            ValidateTimeout(timeout);
+            Stopwatch stopwatch = Stopwatch.StartNew();
+            byte[] header = ReadExactly(stream, 4, timeout, stopwatch);
+            int length = header[0]
+                | (header[1] << 8)
+                | (header[2] << 16)
+                | (header[3] << 24);
+            if (length <= 0 || length > MaximumMessageBytes)
+                throw new InvalidDataException("请求长度无效或超过 1 MB 限制。");
+            return ReadExactly(stream, length, timeout, stopwatch);
+        }
+
+        internal static void WriteFrame(Stream stream, byte[] body, TimeSpan timeout)
+        {
+            if (stream == null) throw new ArgumentNullException("stream");
+            ValidateTimeout(timeout);
+            if (body == null || body.Length == 0 || body.Length > MaximumMessageBytes)
+                throw new InvalidDataException("响应长度无效或超过 1 MB 限制。");
+            Stopwatch stopwatch = Stopwatch.StartNew();
+            int length = body.Length;
+            byte[] header = new[]
+            {
+                (byte)(length & 0xff),
+                (byte)((length >> 8) & 0xff),
+                (byte)((length >> 16) & 0xff),
+                (byte)((length >> 24) & 0xff)
+            };
+            WriteWithDeadline(stream, header, 0, header.Length, timeout, stopwatch);
+            WriteWithDeadline(stream, body, 0, body.Length, timeout, stopwatch);
+            stream.Flush();
+        }
+
+        private static byte[] ReadExactly(
+            Stream stream,
+            int length,
+            TimeSpan timeout,
+            Stopwatch stopwatch)
+        {
+            byte[] buffer = new byte[length];
+            int offset = 0;
+            while (offset < length)
+            {
+                int read = ReadWithDeadline(
+                    stream,
+                    buffer,
+                    offset,
+                    length - offset,
+                    timeout,
+                    stopwatch);
+                if (read <= 0)
+                    throw new EndOfStreamException("客户端在完整消息到达前断开连接。");
+                offset += read;
+            }
+            return buffer;
+        }
+
+        private static int ReadWithDeadline(
+            Stream stream,
+            byte[] buffer,
+            int offset,
+            int count,
+            TimeSpan timeout,
+            Stopwatch stopwatch)
+        {
+            RemainingMilliseconds(timeout, stopwatch);
+            IAsyncResult pending = stream.BeginRead(buffer, offset, count, null, null);
+            Func<int> complete = delegate { return stream.EndRead(pending); };
+            int remaining;
+            try
+            {
+                remaining = RemainingMilliseconds(timeout, stopwatch);
+            }
+            catch (TimeoutException)
+            {
+                AbortPending(stream, pending, complete);
+                throw;
+            }
+            return CompleteWithDeadline(stream, pending, remaining, complete);
+        }
+
+        private static void WriteWithDeadline(
+            Stream stream,
+            byte[] buffer,
+            int offset,
+            int count,
+            TimeSpan timeout,
+            Stopwatch stopwatch)
+        {
+            RemainingMilliseconds(timeout, stopwatch);
+            IAsyncResult pending = stream.BeginWrite(buffer, offset, count, null, null);
+            Func<int> complete = delegate
+            {
+                stream.EndWrite(pending);
+                return 0;
+            };
+            int remaining;
+            try
+            {
+                remaining = RemainingMilliseconds(timeout, stopwatch);
+            }
+            catch (TimeoutException)
+            {
+                AbortPending(stream, pending, complete);
+                throw;
+            }
+            CompleteWithDeadline(stream, pending, remaining, complete);
+        }
+
+        private static int CompleteWithDeadline(
+            Stream stream,
+            IAsyncResult pending,
+            int remaining,
+            Func<int> complete)
+        {
+            WaitHandle waitHandle = pending.AsyncWaitHandle;
+            if (!waitHandle.WaitOne(remaining, false))
+            {
+                AbortPending(stream, waitHandle, complete);
+                throw new TimeoutException("命名管道帧传输超时。");
+            }
+            try
+            {
+                return complete();
+            }
+            finally
+            {
+                waitHandle.Close();
+            }
+        }
+
+        private static void AbortPending(
+            Stream stream,
+            IAsyncResult pending,
+            Func<int> complete)
+        {
+            AbortPending(stream, pending.AsyncWaitHandle, complete);
+        }
+
+        private static void AbortPending(
+            Stream stream,
+            WaitHandle waitHandle,
+            Func<int> complete)
+        {
+            try { stream.Dispose(); }
+            finally
+            {
+                try { complete(); }
+                catch { }
+                waitHandle.Close();
+            }
+        }
+
+        private static int RemainingMilliseconds(TimeSpan timeout, Stopwatch stopwatch)
+        {
+            double value = (timeout - stopwatch.Elapsed).TotalMilliseconds;
+            if (value <= 0) throw new TimeoutException("命名管道帧传输超时。");
+            return Math.Max(1, (int)Math.Min(int.MaxValue, Math.Ceiling(value)));
+        }
+
+        private static void ValidateTimeout(TimeSpan timeout)
+        {
+            if (timeout <= TimeSpan.Zero || timeout > TimeSpan.FromMinutes(1))
+                throw new ArgumentOutOfRangeException(
+                    "timeout",
+                    "命名管道帧超时必须在 1 分钟以内。");
+        }
+    }
+}