第一阶段迁移已完成。

已实现： ASP.NET Core 10 分层解决方案：[Eis.slnx](C:/Users/BI/Documents/EIS-dotnet/Eis.slnx) ASP.NET Core 统一入口与健康检查：[Program.cs](C:/Users/BI/Documents/EIS-dotnet/src/Eis.Web/Program.cs) 原前端静态资源无修改托管未迁移 API 自动转发至旧 Node 服务，兼容 JSON、Cookie、请求体和文件下载可重复执行的端到端测试：[smoke-dotnet-migration.ps1](C:/Users/BI/Documents/EIS-dotnet/scripts/smoke-dotnet-migration.ps1) 迁移进度与运行说明：[MIGRATION.md](C:/Users/BI/Documents/EIS-dotnet/MIGRATION.md) 验证结果：
2026-07-22 18:45:54 +08:00
parent ecb3dc63ed
commit 241fa8a6d7
20 changed files with 680 additions and 0 deletions
@@ -0,0 +1,135 @@
+using System.Net;
+using System.Net.Http.Headers;
+using Microsoft.Extensions.Options;
+
+namespace Eis.Web.Legacy;
+
+public sealed class LegacyApiProxy(
+    HttpClient httpClient,
+    IOptions<LegacyNodeOptions> options,
+    ILogger<LegacyApiProxy> logger)
+{
+    private static readonly HashSet<string> HopByHopHeaders = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "Connection",
+        "Keep-Alive",
+        "Proxy-Authenticate",
+        "Proxy-Authorization",
+        "TE",
+        "Trailer",
+        "Transfer-Encoding",
+        "Upgrade"
+    };
+
+    private readonly LegacyNodeOptions _options = options.Value;
+
+    public async Task ForwardAsync(HttpContext context)
+    {
+        if (!_options.Enabled)
+        {
+            context.Response.StatusCode = StatusCodes.Status501NotImplemented;
+            await context.Response.WriteAsJsonAsync(new
+            {
+                ok = false,
+                message = "该接口尚未迁移到 ASP.NET Core",
+                migration = new { native = false, legacyProxyEnabled = false }
+            }, context.RequestAborted);
+            return;
+        }
+
+        var target = new Uri(_options.BaseUrl, $"{context.Request.PathBase}{context.Request.Path}{context.Request.QueryString}");
+        using var outbound = CreateRequest(context, target);
+
+        try
+        {
+            using var upstream = await httpClient.SendAsync(
+                outbound,
+                HttpCompletionOption.ResponseHeadersRead,
+                context.RequestAborted);
+
+            context.Response.StatusCode = (int)upstream.StatusCode;
+            CopyResponseHeaders(upstream, context.Response);
+
+            if (context.Request.Method != HttpMethods.Head && upstream.StatusCode != HttpStatusCode.NoContent)
+            {
+                await upstream.Content.CopyToAsync(context.Response.Body, context.RequestAborted);
+            }
+        }
+        catch (HttpRequestException exception)
+        {
+            logger.LogWarning(exception, "Legacy Node API at {Target} is unavailable", target);
+            if (context.Response.HasStarted)
+            {
+                context.Abort();
+                return;
+            }
+
+            context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
+            await context.Response.WriteAsJsonAsync(new
+            {
+                ok = false,
+                message = "迁移期间的旧版 API 服务暂时不可用",
+                migration = new { native = false, legacyProxyEnabled = true }
+            }, context.RequestAborted);
+        }
+    }
+
+    public async Task<bool> IsAvailableAsync(CancellationToken cancellationToken)
+    {
+        if (!_options.Enabled)
+        {
+            return true;
+        }
+
+        try
+        {
+            using var response = await httpClient.GetAsync("api/public/home", cancellationToken);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException)
+        {
+            return false;
+        }
+    }
+
+    private static HttpRequestMessage CreateRequest(HttpContext context, Uri target)
+    {
+        var request = new HttpRequestMessage(new HttpMethod(context.Request.Method), target);
+        var hasBody = context.Request.ContentLength > 0 || context.Request.Headers.TransferEncoding.Count > 0;
+        if (hasBody)
+        {
+            request.Content = new StreamContent(context.Request.Body);
+        }
+
+        foreach (var (name, values) in context.Request.Headers)
+        {
+            if (name.Equals("Host", StringComparison.OrdinalIgnoreCase) || HopByHopHeaders.Contains(name))
+            {
+                continue;
+            }
+
+            var valueArray = values.ToArray();
+            if (!request.Headers.TryAddWithoutValidation(name, valueArray) && request.Content is not null)
+            {
+                request.Content.Headers.TryAddWithoutValidation(name, valueArray);
+            }
+        }
+
+        request.Headers.TryAddWithoutValidation("X-Forwarded-Host", context.Request.Host.Value);
+        request.Headers.TryAddWithoutValidation("X-Forwarded-Proto", context.Request.Scheme);
+        return request;
+    }
+
+    private static void CopyResponseHeaders(HttpResponseMessage upstream, HttpResponse response)
+    {
+        foreach (var header in upstream.Headers.Concat(upstream.Content.Headers))
+        {
+            if (!HopByHopHeaders.Contains(header.Key))
+            {
+                response.Headers.Append(header.Key, header.Value.ToArray());
+            }
+        }
+
+        response.Headers.Remove("transfer-encoding");
+    }
+}