Fixes hot reload of CRUD API data file. Closes dotnet#1390 (dotnet#1484)

* Fixes hot reload of CRUD API data file. Closes dotnet#1390

* Update DevProxy.Plugins/Mocking/CrudApiDataLoader.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: waldekmastykarz

DevProxy.Abstractions/Plugins/BaseLoader.cs

@@ -79,7 +79,9 @@ private async Task<bool> ValidateFileContentsAsync(string fileContents, Cancella
         using var document = JsonDocument.Parse(fileContents, ProxyUtils.JsonDocumentOptions);
         var root = document.RootElement;
 
-        if (!root.TryGetProperty("$schema", out var schemaUrlElement))
+        // Schema validation only applies to JSON objects, not arrays
+        if (root.ValueKind != JsonValueKind.Object ||
+            !root.TryGetProperty("$schema", out var schemaUrlElement))
         {
             Logger.LogDebug("Schema reference not found in file {File}. Skipping schema validation", FilePath);
             return true;

DevProxy.Plugins/Mocking/CrudApiDataLoader.cs

@@ -0,0 +1,47 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using DevProxy.Abstractions.Plugins;
+using DevProxy.Abstractions.Proxy;
+using DevProxy.Abstractions.Utils;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json.Linq;
+
+namespace DevProxy.Plugins.Mocking;
+
+internal sealed class CrudApiDataLoader(
+    HttpClient httpClient,
+    ILogger<CrudApiDataLoader> logger,
+    CrudApiConfiguration configuration,
+    IProxyConfiguration proxyConfiguration,
+    Action<JArray?> onDataLoaded) :
+    BaseLoader(httpClient, logger, proxyConfiguration)
+{
+    private readonly CrudApiConfiguration _configuration = configuration;
+    private readonly Action<JArray?> _onDataLoaded = onDataLoaded;
+
+    protected override string FilePath =>
+        Path.GetFullPath(
+            ProxyUtils.ReplacePathTokens(_configuration.DataFile),
+            Path.GetDirectoryName(_configuration.ApiFile) ?? string.Empty
+        );
+
+    protected override void LoadData(string fileContents)
+    {
+        try
+        {
+            var data = JArray.Parse(fileContents);
+            _onDataLoaded(data);
+            Logger.LogInformation(
+                "Data for CRUD API loaded from {DataFile} for API {ApiFile}",
+                _configuration.DataFile,
+                _configuration.ApiFile);
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError(ex, "An error has occurred while reading {DataFile}", _configuration.DataFile);
+            _onDataLoaded(null);
+        }
+    }
+}

DevProxy.Plugins/Mocking/CrudApiPlugin.cs

@@ -90,7 +90,8 @@ public sealed class CrudApiPlugin(
         proxyConfiguration,
         pluginConfigurationSection)
 {
-    private CrudApiDefinitionLoader? _loader;
+    private CrudApiDefinitionLoader? _definitionLoader;
+    private CrudApiDataLoader? _dataLoader;
     private JArray? _data;
     private OpenIdConnectConfiguration? _openIdConnectConfiguration;
 
@@ -104,8 +105,8 @@ public override async Task InitializeAsync(InitArgs e, CancellationToken cancell
 
         Configuration.ApiFile = ProxyUtils.GetFullPath(Configuration.ApiFile, ProxyConfiguration.ConfigFile);
 
-        _loader = ActivatorUtilities.CreateInstance<CrudApiDefinitionLoader>(e.ServiceProvider, Configuration);
-        await _loader.InitFileWatcherAsync(cancellationToken);
+        _definitionLoader = ActivatorUtilities.CreateInstance<CrudApiDefinitionLoader>(e.ServiceProvider, Configuration);
+        await _definitionLoader.InitFileWatcherAsync(cancellationToken);
 
         if (Configuration.Auth == CrudApiAuthType.Entra &&
             Configuration.EntraAuthConfig is null)
@@ -126,7 +127,13 @@ public override async Task InitializeAsync(InitArgs e, CancellationToken cancell
             return;
         }
 
-        LoadData();
+        _dataLoader = ActivatorUtilities.CreateInstance<CrudApiDataLoader>(
+            e.ServiceProvider,
+            Configuration,
+            (Action<JArray?>)(data => _data = data)
+        );
+        await _dataLoader.InitFileWatcherAsync(cancellationToken);
+
         await SetupOpenIdConnectConfigurationAsync();
     }
 
@@ -200,27 +207,6 @@ private async Task SetupOpenIdConnectConfigurationAsync()
         }
     }
 
-    private void LoadData()
-    {
-        try
-        {
-            var dataFilePath = Path.GetFullPath(ProxyUtils.ReplacePathTokens(Configuration.DataFile), Path.GetDirectoryName(Configuration.ApiFile) ?? string.Empty);
-            if (!File.Exists(dataFilePath))
-            {
-                Logger.LogError("Data file '{DataFilePath}' does not exist. The {APIUrl} API will be disabled.", dataFilePath, Configuration.BaseUrl);
-                Configuration.Actions = [];
-                return;
-            }
-
-            var dataString = File.ReadAllText(dataFilePath);
-            _data = JArray.Parse(dataString);
-        }
-        catch (Exception ex)
-        {
-            Logger.LogError(ex, "An error has occurred while reading {ConfigFile}", Configuration.DataFile);
-        }
-    }
-
     private (Action<SessionEventArgs, CrudApiAction, IDictionary<string, string>> handler, CrudApiAction action, IDictionary<string, string> parameters)? GetMatchingActionHandler(Request request)
     {
         if (Configuration.Actions is null ||