feat(shared-web): add shared swagger and tracing utilities

src/Core/TakeoutSaaS.Shared.Web/Middleware/CorrelationIdMiddleware.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+using TakeoutSaaS.Shared.Abstractions.Diagnostics;
+
+namespace TakeoutSaaS.Shared.Web.Middleware;
+
+/// <summary>
+/// 统一 TraceId/CorrelationId，贯穿日志与响应。
+/// </summary>
+public sealed class CorrelationIdMiddleware
+{
+    private const string TraceHeader = "X-Trace-Id";
+    private const string RequestHeader = "X-Request-Id";
+
+    private readonly RequestDelegate _next;
+    private readonly ILogger<CorrelationIdMiddleware> _logger;
+
+    public CorrelationIdMiddleware(RequestDelegate next, ILogger<CorrelationIdMiddleware> logger)
+    {
+        _next = next;
+        _logger = logger;
+    }
+
+    public async Task InvokeAsync(HttpContext context)
+    {
+        var traceId = ResolveTraceId(context);
+        context.TraceIdentifier = traceId;
+        TraceContext.TraceId = traceId;
+
+        context.Response.OnStarting(() =>
+        {
+            context.Response.Headers[TraceHeader] = traceId;
+            return Task.CompletedTask;
+        });
+
+        using (_logger.BeginScope(new Dictionary<string, object>
+               {
+                   ["TraceId"] = traceId
+               }))
+        {
+            try
+            {
+                await _next(context);
+            }
+            finally
+            {
+                TraceContext.Clear();
+            }
+        }
+    }
+
+    private static string ResolveTraceId(HttpContext context)
+    {
+        if (TryGetHeader(context, TraceHeader, out var traceId))
+        {
+            return traceId;
+        }
+
+        if (TryGetHeader(context, RequestHeader, out var requestId))
+        {
+            return requestId;
+        }
+
+        return Guid.NewGuid().ToString("N");
+    }
+
+    private static bool TryGetHeader(HttpContext context, string headerName, out string value)
+    {
+        if (context.Request.Headers.TryGetValue(headerName, out var values))
+        {
+            var headerValue = values.ToString();
+            if (!string.IsNullOrWhiteSpace(headerValue))
+            {
+                value = headerValue;
+                return true;
+            }
+        }
+
+        value = string.Empty;
+        return false;
+    }
+}