88 lines
3 KiB
C#
88 lines
3 KiB
C#
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using System.Text.Json;
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using Microsoft.AspNetCore.Mvc;
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using w4c_workflows.Services;
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namespace w4c_workflows.Controllers;
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/// <summary>
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/// Tenant-scoped server-sent-events stream: <c>GET /api/workflows/events</c> pushes
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/// <c>data: {"kind":"workflow","id":"<path>","at":"<iso>"}</c> frames whenever a workflow file is
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/// written server-side. The client re-fetches the touched file; no payload is pushed.
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/// The full literal route avoids colliding with <c>api/workflows/{id}</c> and routes to this service
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/// through the SPA proxy (<c>/api/workflows</c> prefix).
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/// </summary>
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[ApiController]
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[Route("api/workflows/events")]
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public class RealtimeController : ControllerBase
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{
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private static readonly JsonSerializerOptions JsonOptions = new() { PropertyNamingPolicy = JsonNamingPolicy.CamelCase };
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private static readonly TimeSpan HeartbeatInterval = TimeSpan.FromSeconds(15);
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private readonly RealtimeEventHub _hub;
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private readonly ILogger<RealtimeController> _logger;
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public RealtimeController(RealtimeEventHub hub, ILogger<RealtimeController> logger)
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{
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_hub = hub;
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_logger = logger;
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}
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private string TenantId =>
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(string?)HttpContext.Items["TenantId"]
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?? throw new InvalidOperationException("TenantId not resolved by auth middleware");
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[HttpGet]
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public async Task Stream(CancellationToken ct)
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{
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var tid = TenantId;
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Response.Headers["Content-Type"] = "text/event-stream";
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Response.Headers["Cache-Control"] = "no-cache";
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Response.Headers["Connection"] = "keep-alive";
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Response.Headers["X-Accel-Buffering"] = "no";
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await Response.Body.FlushAsync(ct);
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var (id, reader) = _hub.AddClient(tid);
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try
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{
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while (!ct.IsCancellationRequested)
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{
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using var readCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
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readCts.CancelAfter(HeartbeatInterval);
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bool hasItem;
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try
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{
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hasItem = await reader.WaitToReadAsync(readCts.Token);
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}
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catch (OperationCanceledException) when (!ct.IsCancellationRequested)
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{
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await Response.WriteAsync(": ping\n\n", ct);
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await Response.Body.FlushAsync(ct);
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continue;
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}
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if (!hasItem) break;
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while (reader.TryRead(out var evt))
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{
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var json = JsonSerializer.Serialize(evt, JsonOptions);
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await Response.WriteAsync($"data: {json}\n\n", ct);
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}
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await Response.Body.FlushAsync(ct);
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}
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}
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catch (OperationCanceledException)
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{
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// Client disconnected — normal terminal state.
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}
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catch (Exception ex)
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{
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_logger.LogWarning(ex, "Realtime SSE stream ended for tenant {Tenant}", tid);
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}
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finally
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{
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_hub.RemoveClient(tid, id);
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}
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}
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}
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