FDC3 AppDirectory implementation

src/fdc3/dotnet/AppDirectory/AppDirectory.sln

@@ -0,0 +1,46 @@
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+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "AppDirectory", "src\AppDirectory\AppDirectory.csproj", "{4B8CA047-2023-4E1A-BD73-85F7EB1D56B3}"
+EndProject
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+EndProject
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+EndProject
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+EndProject
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src/fdc3/dotnet/AppDirectory/src/AppDirectory/AppDirectory.cs

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+// Morgan Stanley makes this available to you under the Apache License,
+// Version 2.0 (the "License"). You may obtain a copy of the License at
+// 
+//      http://www.apache.org/licenses/LICENSE-2.0.
+// 
+// See the NOTICE file distributed with this work for additional information
+// regarding copyright ownership. Unless required by applicable law or agreed
+// to in writing, software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions
+// and limitations under the License.
+
+using System.Collections.Concurrent;
+using System.IO.Abstractions;
+using System.Reactive.Disposables;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Primitives;
+using MorganStanley.Fdc3.AppDirectory;
+using MorganStanley.Fdc3.NewtonsoftJson.Serialization;
+using Newtonsoft.Json;
+
+namespace MorganStanley.ComposeUI.Fdc3.AppDirectory;
+
+public class AppDirectory : IAppDirectory
+{
+    public AppDirectory(
+        IOptions<AppDirectoryOptions> options,
+        IMemoryCache? cache = null,
+        IFileSystem? fileSystem = null,
+        ILogger<AppDirectory>? logger = null)
+    {
+        _options = options.Value;
+        _cache = cache ?? new MemoryCache(new MemoryCacheOptions());
+        _fileSystem = fileSystem ?? new FileSystem();
+        _logger = logger ?? NullLogger<AppDirectory>.Instance;
+    }
+
+    public async Task<IEnumerable<Fdc3App>> GetApps()
+    {
+        return (await GetAppsCore()).Values;
+    }
+
+    public async Task<Fdc3App?> GetApp(string appId)
+    {
+        if (!(await GetAppsCore()).TryGetValue(appId, out var app))
+            throw new AppNotFoundException(appId);
+
+        return app;
+    }
+
+    private readonly IFileSystem _fileSystem;
+    private readonly ILogger<AppDirectory> _logger;
+    private readonly AppDirectoryOptions _options;
+    private readonly IMemoryCache _cache;
+
+    private static readonly string GetAppsCacheKey = typeof(AppDirectory).FullName + "." + nameof(GetApps);
+
+    private Task<Dictionary<string, Fdc3App>> GetAppsCore()
+    {
+        return _cache.GetOrCreateAsync(
+            GetAppsCacheKey,
+            async entry =>
+            {
+                var result = await LoadApps();
+                entry.ExpirationTokens.Add(result.ChangeToken);
+
+                // Assuming that appIds are case-insensitive (not specified by the standard)
+                return result.Apps.ToDictionary(
+                    app => app.AppId,
+                    StringComparer.OrdinalIgnoreCase);
+            });
+    }
+
+    private Task<(IEnumerable<Fdc3App> Apps, IChangeToken ChangeToken)> LoadApps()
+    {
+        if (_fileSystem.File.Exists(_options.Source?.LocalPath))
+        {
+            return LoadAppsFromFile(_options.Source.LocalPath);
+        }
+        // TODO: add provider for online static files and FDC3 AppD API
+
+        _logger.LogWarning("The configured source is empty or not supported");
+
+        return Task.FromResult<(IEnumerable<Fdc3App>, IChangeToken)>(
+            (
+                Enumerable.Empty<Fdc3App>(),
+                NullChangeToken.Singleton));
+    }
+
+    private Task<(IEnumerable<Fdc3App>, IChangeToken)> LoadAppsFromFile(string fileName)
+    {
+        using var stream = _fileSystem.File.OpenRead(fileName);
+
+        return Task.FromResult<(IEnumerable<Fdc3App>, IChangeToken)>(
+            (
+                LoadAppsFromStream(stream),
+                new FileSystemChangeToken(fileName, _fileSystem)));
+    }
+
+    private static IEnumerable<Fdc3App> LoadAppsFromStream(Stream stream)
+    {
+        var serializer = JsonSerializer.Create(new Fdc3JsonSerializerSettings());
+        using var textReader = new StreamReader(stream, leaveOpen: true);
+        using var jsonReader = new JsonTextReader(textReader);
+
+        return serializer.Deserialize<IEnumerable<Fdc3App>>(jsonReader) ?? Enumerable.Empty<Fdc3App>();
+    }
+
+    private sealed class FileSystemChangeToken : IChangeToken
+    {
+        public FileSystemChangeToken(string path, IFileSystem fileSystem)
+        {
+            var fileSystemWatcher = fileSystem.FileSystemWatcher.New(
+                fileSystem.Path.GetDirectoryName(path)!,
+                fileSystem.Path.GetFileName(path));
+
+            fileSystemWatcher.Changed += (sender, args) =>
+            {
+                if (!args.ChangeType.HasFlag(WatcherChangeTypes.Changed))
+                    return;
+
+                fileSystemWatcher.Dispose();
+                HasChanged = true;
+
+                foreach (var item in _callbacks)
+                {
+                    item.Value();
+                }
+
+                _callbacks.Clear(); // Change tokens are only fired once
+            };
+
+            fileSystemWatcher.EnableRaisingEvents = true;
+        }
+
+        public bool HasChanged { get; private set; }
+        public bool ActiveChangeCallbacks => true;
+
+        public IDisposable RegisterChangeCallback(Action<object> callback, object state)
+        {
+            if (HasChanged)
+            {
+                callback(state);
+
+                return Disposable.Empty;
+            }
+
+            var action = () => callback(state);
+
+            _callbacks.TryAdd(action, action);
+
+            return Disposable.Create(() => _callbacks.Remove(action, out _));
+        }
+
+        private readonly ConcurrentDictionary<object, Action> _callbacks = new();
+    }
+
+    private sealed class NullChangeToken : IChangeToken
+    {
+        public bool HasChanged => false;
+        public bool ActiveChangeCallbacks => true;
+
+        public IDisposable RegisterChangeCallback(Action<object> callback, object state)
+        {
+            return Disposable.Empty;
+        }
+
+        public static readonly NullChangeToken Singleton = new();
+    }
+}

src/fdc3/dotnet/AppDirectory/src/AppDirectory/AppDirectory.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFramework>net6.0</TargetFramework>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
+		<AssemblyName>MorganStanley.ComposeUI.Fdc3.AppDirectory</AssemblyName>
+		<RootNamespace>MorganStanley.ComposeUI.Fdc3.AppDirectory</RootNamespace>
+		<LangVersion>preview</LangVersion>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="6.0.1" />
+		<PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="6.0.0" />
+		<PackageReference Include="Microsoft.Extensions.Options" Version="6.0.0" />
+		<PackageReference Include="MorganStanley.Fdc3.AppDirectory" Version="2.0.0-alpha.6" />
+		<PackageReference Include="MorganStanley.Fdc3.NewtonsoftJson" Version="2.0.0-alpha.6" />
+		<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+		<PackageReference Include="Roslyn.System.IO.Abstractions.Analyzers" Version="12.2.19">
+		  <PrivateAssets>all</PrivateAssets>
+		  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+		</PackageReference>
+		<PackageReference Include="System.Reactive" Version="6.0.0" />
+		<PackageReference Include="TestableIO.System.IO.Abstractions" Version="19.2.69" />
+		<PackageReference Include="TestableIO.System.IO.Abstractions.Wrappers" Version="19.2.69" />
+	</ItemGroup>
+
+	<ItemGroup>
+	  <Folder Include="DependencyInjection\" />
+	</ItemGroup>
+</Project>

src/fdc3/dotnet/AppDirectory/src/AppDirectory/AppDirectoryOptions.cs

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+// Morgan Stanley makes this available to you under the Apache License,
+// Version 2.0 (the "License"). You may obtain a copy of the License at
+// 
+//      http://www.apache.org/licenses/LICENSE-2.0.
+// 
+// See the NOTICE file distributed with this work for additional information
+// regarding copyright ownership. Unless required by applicable law or agreed
+// to in writing, software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions
+// and limitations under the License.
+
+using Microsoft.Extensions.Options;
+using MorganStanley.Fdc3.AppDirectory;
+
+namespace MorganStanley.ComposeUI.Fdc3.AppDirectory;
+
+/// <summary>
+///     Configuration options for <see cref="AppDirectory" />
+/// </summary>
+public sealed class AppDirectoryOptions : IOptions<AppDirectoryOptions>
+{
+    /// <summary>
+    ///     Gets or sets the source URL of a static JSON file.
+    /// </summary>
+    /// <remarks>
+    ///     Supported schemes are <c>file</c>, <c>http</c> and <c>https</c>.
+    ///     The static file must contain a single array of <see cref="Fdc3App" /> objects,
+    ///     using the schema defined by the FDC3 AppDirectory API specification
+    ///     (https://fdc3.finos.org/schemas/2.0/app-directory.html#tag/Application/paths/~1v2~1apps~1%7BappId%7D/get)
+    ///     UTF8 encoding is assumed unless a byte order mark or encoding header is present.
+    /// </remarks>
+    public Uri? Source { get; set; }
+
+    // TODO: Implement fetching from AppD REST API
+    ///// <summary>
+    ///// Gets or sets the name of the <see cref="HttpClient"/> that is used to fetch
+    ///// the application definitions from a REST API defined by the FDC3 AppDirectory API specification (https://fdc3.finos.org/schemas/2.0/app-directory.html)
+    ///// </summary>
+    ///// <remarks>
+    ///// This property is only used when <see cref="Source"/> is set to <c>null</c>.
+    ///// When this property is set, an <see cref="IHttpClientFactory"/> instance must be provided as a constructor parameter
+    ///// for <see cref="AppDirectory"/>, with a matching HTTP client configured.
+    ///// </remarks>
+    //public string? HttpClientName { get; set; }
+
+    /// <inheritdoc />
+    public AppDirectoryOptions Value => this;
+}

src/fdc3/dotnet/AppDirectory/src/AppDirectory/AppNotFoundException.cs

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+// Morgan Stanley makes this available to you under the Apache License,
+// Version 2.0 (the "License"). You may obtain a copy of the License at
+// 
+//      http://www.apache.org/licenses/LICENSE-2.0.
+// 
+// See the NOTICE file distributed with this work for additional information
+// regarding copyright ownership. Unless required by applicable law or agreed
+// to in writing, software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions
+// and limitations under the License.
+
+namespace MorganStanley.ComposeUI.Fdc3.AppDirectory;
+
+public class AppNotFoundException : Exception
+{
+    public AppNotFoundException(string appId) : base($"Could not find app with id '{appId}'")
+    {
+    }
+}

src/fdc3/dotnet/AppDirectory/src/AppDirectory/DependencyInjection/ServiceCollectionAppDirectoryExtensions.cs

@@ -0,0 +1,40 @@
+// Morgan Stanley makes this available to you under the Apache License,
+// Version 2.0 (the "License"). You may obtain a copy of the License at
+// 
+//      http://www.apache.org/licenses/LICENSE-2.0.
+// 
+// See the NOTICE file distributed with this work for additional information
+// regarding copyright ownership. Unless required by applicable law or agreed
+// to in writing, software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions
+// and limitations under the License.
+
+// ReSharper disable CheckNamespace
+// ReSharper disable UnusedMember.Global
+
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using MorganStanley.ComposeUI.Fdc3.AppDirectory;
+using MorganStanley.Fdc3.AppDirectory;
+
+namespace Microsoft.Extensions.DependencyInjection;
+
+public static class ServiceCollectionAppDirectoryExtensions
+{
+    public static IServiceCollection AddFdc3AppDirectory(this IServiceCollection serviceCollection)
+    {
+        serviceCollection.TryAddSingleton<IAppDirectory, AppDirectory>();
+
+        return serviceCollection;
+    }
+
+    public static IServiceCollection AddFdc3AppDirectory(
+        this IServiceCollection serviceCollection,
+        Action<AppDirectoryOptions> configureOptions)
+    {
+        serviceCollection.AddFdc3AppDirectory();
+        serviceCollection.AddOptions().Configure(configureOptions);
+
+        return serviceCollection;
+    }
+}