support websocket snapshot (#157)

Author: mlapaglia

OpenAlprWebhookProcessor.Server/Features/ImageRelay/ImageRelayController.cs

@@ -4,6 +4,7 @@
 using OpenAlprWebhookProcessor.Features.ImageRelay.GetCropImage;
 using OpenAlprWebhookProcessor.Features.ImageRelay.GetImage;
 using OpenAlprWebhookProcessor.Features.ImageRelay.SnapshotRelay;
+using OpenAlprWebhookProcessor.Features.ImageRelay.WebsocketSnapshotRelay;
 using System;
 using System.Threading;
 using System.Threading.Tasks;
@@ -75,5 +76,24 @@ public async Task<IActionResult> GetSnapshot(
                 return NotFound();
             }
         }
+
+        [HttpGet("websocket/{agentId}/{cameraId}/snapshot")]
+        public async Task<IActionResult> GetWebsocketSnapshot(
+            string agentId,
+            long cameraId,
+            CancellationToken cancellationToken)
+        {
+            try
+            {
+                var query = new GetWebsocketSnapshotQuery(agentId, cameraId);
+                var snapshot = await _mediator.Send(query, cancellationToken);
+
+                return File(snapshot, "image/jpeg");
+            }
+            catch
+            {
+                return NotFound();
+            }
+        }
     }
 }

OpenAlprWebhookProcessor.Server/Features/ImageRelay/WebsocketSnapshotRelay/GetWebsocketSnapshotQuery.cs

@@ -0,0 +1,19 @@
+using Mediator;
+using System;
+using System.IO;
+
+namespace OpenAlprWebhookProcessor.Features.ImageRelay.WebsocketSnapshotRelay
+{
+    public class GetWebsocketSnapshotQuery : IQuery<Stream>
+    {
+        public string AgentId { get; set; }
+        
+        public long CameraId { get; set; }
+
+        public GetWebsocketSnapshotQuery(string agentId, long cameraId)
+        {
+            AgentId = agentId;
+            CameraId = cameraId;
+        }
+    }
+}

OpenAlprWebhookProcessor.Server/Features/ImageRelay/WebsocketSnapshotRelay/GetWebsocketSnapshotQueryHandler.cs

@@ -0,0 +1,47 @@
+using Mediator;
+using OpenAlprWebhookProcessor.Features.Webhooks.WebhookProcessor.OpenAlprWebsocket;
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace OpenAlprWebhookProcessor.Features.ImageRelay.WebsocketSnapshotRelay
+{
+    public class GetWebsocketSnapshotQueryHandler : IQueryHandler<GetWebsocketSnapshotQuery, Stream>
+    {
+        private readonly IWebsocketClientOrganizer _websocketClientOrganizer;
+
+        public GetWebsocketSnapshotQueryHandler(IWebsocketClientOrganizer websocketClientOrganizer)
+        {
+            _websocketClientOrganizer = websocketClientOrganizer ?? throw new ArgumentNullException(nameof(websocketClientOrganizer));
+        }
+
+        public async ValueTask<Stream> Handle(GetWebsocketSnapshotQuery request, CancellationToken cancellationToken)
+        {
+            var response = await _websocketClientOrganizer.GetCameraSnapshotAsync(
+                request.AgentId,
+                request.CameraId,
+                cancellationToken);
+
+            if (response == null)
+            {
+                throw new InvalidOperationException("Failed to get snapshot from agent");
+            }
+
+            if (string.IsNullOrWhiteSpace(response.Image))
+            {
+                throw new InvalidOperationException("Agent returned empty image data");
+            }
+
+            try
+            {
+                var imageBytes = Convert.FromBase64String(response.Image);
+                return new MemoryStream(imageBytes);
+            }
+            catch (FormatException ex)
+            {
+                throw new InvalidOperationException("Invalid image data received from agent", ex);
+            }
+        }
+    }
+}

OpenAlprWebhookProcessor.Server/Features/LicensePlates/Commands/UpdatePlateNumber/UpdatePlateNumberCommand.cs

@@ -9,3 +9,5 @@ public class UpdatePlateNumberCommand : ICommand
 
     public string PlateNumber { get; set; }
 }
+
+

OpenAlprWebhookProcessor.Server/Features/LicensePlates/Commands/UpdatePlateNumber/UpdatePlateNumberCommandHandler.cs

@@ -32,3 +32,5 @@ public async ValueTask<Unit> Handle(UpdatePlateNumberCommand request, Cancellati
         return Unit.Value;
     }
 }
+
+

OpenAlprWebhookProcessor.Server/Features/Webhooks/WebhookProcessor/OpenAlprWebsocket/IOpenAlprWebsocketClient.cs

@@ -23,7 +23,8 @@ Task SendGetAgentStatusRequestAsync(
 
         Task SendGetImageRequestAsync(
             Guid transactionId,
-            long cameraId,
+            long cameraId,
+            string imageUuid,
             CancellationToken cancellationToken = default);
 
         Task SendSaveMaskRequestAsync(

OpenAlprWebhookProcessor.Server/Features/Webhooks/WebhookProcessor/OpenAlprWebsocket/IWebsocketClientOrganizer.cs

@@ -1,3 +1,4 @@
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -29,6 +30,11 @@ Task<bool> UpsertCameraMaskAsync(
             string openAlprName,
             CancellationToken cancellationToken = default);
 
+        Task<ImageDownloadResponse> GetCameraSnapshotAsync(
+            string agentId,
+            long cameraId,
+            CancellationToken cancellationToken = default);
+
         Task DisconnectAllClientsAsync(CancellationToken cancellationToken = default);
     }
 }

OpenAlprWebhookProcessor.Server/Features/Webhooks/WebhookProcessor/OpenAlprWebsocket/ImageDownloadRequest.cs

@@ -7,15 +7,20 @@ public class ImageDownloadRequest
     {
         public ImageDownloadRequest() { }
 
-
         [JsonPropertyName("type")]
         public string RequestType { get; set; }
+
+        [JsonPropertyName("uuid")]
+        public string Uuid { get; set; }
 
         [JsonPropertyName("direction")]
         public string Direction { get; set; }
 
         [JsonPropertyName("camera_id")]
         public long CameraId { get; set; }
+
+        [JsonPropertyName("size")]
+        public ImageDownloadRequestSize Size { get; set; }
 
         [JsonPropertyName("transaction_id")]
         public Guid TransactionId { get; set; }

OpenAlprWebhookProcessor.Server/Features/Webhooks/WebhookProcessor/OpenAlprWebsocket/ImageDownloadRequestSize.cs

@@ -0,0 +1,21 @@
+using System.Text.Json.Serialization;
+
+namespace OpenAlprWebhookProcessor.Features.Webhooks.WebhookProcessor.OpenAlprWebsocket
+{
+    public class ImageDownloadRequestSize
+    {
+        public ImageDownloadRequestSize() { }
+
+        [JsonPropertyName("type")]
+        public string X { get; set; }
+
+        [JsonPropertyName("uuid")]
+        public string Y { get; set; }
+
+        [JsonPropertyName("direction")]
+        public int Width { get; set; }
+
+        [JsonPropertyName("camera_id")]
+        public int Height { get; set; }
+    }
+}

OpenAlprWebhookProcessor.Server/Features/Webhooks/WebhookProcessor/OpenAlprWebsocket/OpenAlprWebsocketClient.cs

@@ -82,6 +82,7 @@ public async Task ConsumeMessagesAsync(CancellationToken cancellationToken = def
         public async Task SendGetImageRequestAsync(
             Guid transactionId,
             long cameraId,
+            string imageUuid = null,
             CancellationToken cancellationToken = default)
         {
             var imageRequest = new ImageDownloadRequest()
@@ -90,6 +91,7 @@ public async Task SendGetImageRequestAsync(
                 Direction = "request",
                 RequestType = RequestType.GetRequestType(OpenAlprRequestType.ImageDownload),
                 TransactionId = transactionId,
+                Uuid = imageUuid,
             };
 
             var message = Encoding.UTF8.GetBytes(JsonSerializer.Serialize(imageRequest));