Display License file from blob storage/local files (#6675)

* Display license file from blob storage

* fix some reviews and add tests

* Support local license files and add more tests

* Interface for ServiceDiscoveryClient and some changes

* Update

* some updates

Author: zhhyu

src/NuGet.Services.Search.Client/Client/IServiceDiscoveryClient.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace NuGet.Services.Search.Client
+{
+    /// <summary>
+    /// This interface is used to discover the service client.
+    /// </summary>
+    public interface IServiceDiscoveryClient
+    {
+        /// <summary>
+        /// The function is used to retrieve the endpoint for the resource type.
+        /// </summary>
+        /// <param name="resourceType"> The resource type needed for retrieval</param>
+        Task<IEnumerable<Uri>> GetEndpointsForResourceType(string resourceType);
+    }
+}

src/NuGet.Services.Search.Client/Client/ServiceDiscoveryClient.cs

@@ -10,7 +10,7 @@
 
 namespace NuGet.Services.Search.Client
 {
-    public class ServiceDiscoveryClient
+    public class ServiceDiscoveryClient : IServiceDiscoveryClient
     {
         private readonly HttpClient _httpClient;
         private readonly Uri _serviceDiscoveryEndpoint;

src/NuGet.Services.Search.Client/NuGet.Services.Search.Client.csproj

@@ -48,6 +48,7 @@
     <Compile Include="Client\BaseUrlHealthIndicatorStore.cs" />
     <Compile Include="Client\IEndpointHealthIndicatorStore.cs" />
     <Compile Include="Client\IHealthIndicatorLogger.cs" />
+    <Compile Include="Client\IServiceDiscoveryClient.cs" />
     <Compile Include="Client\NullHealthIndicatorLogger.cs" />
     <Compile Include="Client\RetryingHttpClientWrapper.cs" />
     <Compile Include="Client\SearchClient.cs" />

src/NuGetGallery.Core/Services/CorePackageFileService.cs

@@ -13,8 +13,6 @@ namespace NuGetGallery
 {
     public class CorePackageFileService : ICorePackageFileService
     {
-        private const string LicenseFileName = "license";
-
         private readonly ICoreFileStorageService _fileStorageService;
         private readonly IFileMetadataService _metadata;
 
@@ -263,7 +261,7 @@ public Task DeleteLicenseFileAsync(string id, string version)
             return _fileStorageService.DeleteFileAsync(_metadata.PackageContentFolderName, fileName);
         }
 
-        private string LicensePathTemplate => $"{_metadata.PackageContentPathTemplate}/{LicenseFileName}";
+        private string LicensePathTemplate => $"{_metadata.PackageContentPathTemplate}/{CoreConstants.LicenseFileName}";
 
         private string BuildLicenseFileName(Package package)
             => BuildFileName(package, LicensePathTemplate, string.Empty);

src/NuGetGallery/App_Start/DefaultDependenciesModule.cs

@@ -25,6 +25,7 @@
 using NuGet.Services.Logging;
 using NuGet.Services.Messaging;
 using NuGet.Services.Messaging.Email;
+using NuGet.Services.Search.Client;
 using NuGet.Services.ServiceBus;
 using NuGet.Services.Sql;
 using NuGet.Services.Validation;
@@ -332,6 +333,14 @@ protected override void Load(ContainerBuilder builder)
                 .As<ITyposquattingCheckListCacheService>()
                 .SingleInstance();
 
+            builder.RegisterType<FlatContainerService>()
+                .As<IFlatContainerService>()
+                .InstancePerLifetimeScope();
+
+            builder.Register<ServiceDiscoveryClient>(c =>
+                    new ServiceDiscoveryClient(c.Resolve<IAppConfiguration>().ServiceDiscoveryUri))
+                .As<IServiceDiscoveryClient>();
+
             RegisterMessagingService(builder, configuration);
 
             builder.Register(c => HttpContext.Current.User)

src/NuGetGallery/App_Start/Routes.cs

@@ -227,6 +227,11 @@ public static void RegisterUIRoutes(RouteCollection routes)
                 "account/ConfirmationRequired",
                 new { controller = "Users", action = "ConfirmationRequired" });
 
+            routes.MapRoute(
+                RouteName.License,
+                "packages/{id}/{version}/license",
+                new { controller = "Packages", action = "License" });
+            
             //Redirecting v1 Confirmation Route
             routes.Redirect(
                 r => r.MapRoute(

src/NuGetGallery/Controllers/PackagesController.cs

@@ -94,6 +94,7 @@ public partial class PackagesController
         private readonly IContentObjectService _contentObjectService;
         private readonly ISymbolPackageUploadService _symbolPackageUploadService;
         private readonly IDiagnosticsSource _trace;
+        private readonly IFlatContainerService _flatContainerService;
 
         public PackagesController(
             IPackageService packageService,
@@ -118,7 +119,8 @@ public PackagesController(
             IPackageOwnershipManagementService packageOwnershipManagementService,
             IContentObjectService contentObjectService,
             ISymbolPackageUploadService symbolPackageUploadService,
-            IDiagnosticsService diagnosticsService)
+            IDiagnosticsService diagnosticsService,
+            IFlatContainerService flatContainerService)
         {
             _packageService = packageService;
             _uploadFileService = uploadFileService;
@@ -143,6 +145,7 @@ public PackagesController(
             _contentObjectService = contentObjectService;
             _symbolPackageUploadService = symbolPackageUploadService;
             _trace = diagnosticsService?.SafeGetSource(nameof(PackagesController)) ?? throw new ArgumentNullException(nameof(diagnosticsService));
+            _flatContainerService = flatContainerService;
         }
 
         [HttpGet]
@@ -663,6 +666,36 @@ public virtual async Task<ActionResult> DisplayPackage(string id, string version
             return View(model);
         }
 
+        public virtual async Task<ActionResult> License(string id, string version)
+        {
+            var package = _packageService.FindPackageByIdAndVersionStrict(id, version);
+            if (package == null)
+            {
+                return HttpNotFound();
+            }
+
+            if (package.EmbeddedLicenseType == EmbeddedLicenseFileType.Absent)
+            {
+                return HttpNotFound();
+            }
+
+            if (!_config.AsynchronousPackageValidationEnabled)
+            {
+                try
+                {
+                    var licenseFileContent = await _packageFileService.DownloadLicenseFileAsync(package);
+                    return new FileStreamResult(licenseFileContent, "text/plain");
+                }
+                catch (Exception ex)
+                {
+                    _telemetryService.TraceException(ex);
+                    return HttpNotFound();
+                }
+            }
+
+            return Redirect(await _flatContainerService.GetLicenseFileFlatContainerUrlAsync(package.Id, package.NormalizedVersion));
+        }
+
         public virtual async Task<ActionResult> ListPackages(PackageListSearchViewModel searchAndListModel)
         {
             var page = searchAndListModel.Page;

src/NuGetGallery/GalleryConstants.cs

@@ -60,6 +60,8 @@ public static class GalleryConstants
         public const string UrlValidationRegEx = @"(https?):\/\/[^ ""]+$";
         public const string UrlValidationErrorMessage = "This doesn't appear to be a valid HTTP/HTTPS URL";
 
+        public const string PackageBaseAddress = "PackageBaseAddress/3.0.0";
+
         // Note: regexes must be tested to work in JavaScript
         // We do NOT follow strictly the RFCs at this time, and we choose not to support many obscure email address variants.
         // Specifically the following are not supported by-design:

src/NuGetGallery/NuGetGallery.csproj

@@ -443,6 +443,8 @@
     <Compile Include="Services\ITyposquattingService.cs" />
     <Compile Include="Services\IValidationMessage.cs" />
     <Compile Include="Services\JsonValidationMessage.cs" />
+    <Compile Include="Services\IFlatContainerService.cs" />
+    <Compile Include="Services\FlatContainerService.cs" />
     <Compile Include="Services\LicenseUrlDeprecationValidationMessage.cs" />
     <Compile Include="Services\PackageShouldNotBeSignedUserFixableValidationMessage.cs" />
     <Compile Include="Services\PlainTextOnlyValidationMessage.cs" />

src/NuGetGallery/RouteName.cs

@@ -98,5 +98,6 @@ public static class RouteName
         public const string GetOrganizationCertificate = "GetOrganizationCertificate";
         public const string GetOrganizationCertificates = "GetOrganizationCertificates";
         public const string SetRequiredSigner = "SetRequiredSigner";
+        public const string License = "License";
     }
 }