Add logic for downloading attachment for A2 GUI

src/Altinn.Correspondence.API/Controllers/LegacyCorrespondenceController.cs

@@ -1,18 +1,11 @@
+using System.Runtime.CompilerServices;
 using Altinn.Correspondence.API.Models;
-using Altinn.Correspondence.API.Models.Enums;
 using Altinn.Correspondence.Application;
 using Altinn.Correspondence.Application.Configuration;
 using Altinn.Correspondence.Application.DownloadCorrespondenceAttachment;
-using Altinn.Correspondence.Application.GetCorrespondenceDetails;
 using Altinn.Correspondence.Application.GetCorrespondenceHistory;
 using Altinn.Correspondence.Application.GetCorrespondenceOverview;
 using Altinn.Correspondence.Application.GetCorrespondences;
-using Altinn.Correspondence.Application.InitializeCorrespondences;
-using Altinn.Correspondence.Application.PurgeCorrespondence;
-using Altinn.Correspondence.Application.UpdateCorrespondenceStatus;
-using Altinn.Correspondence.Application.UpdateMarkAsUnread;
-using Altinn.Correspondence.Core.Models.Enums;
-using Altinn.Correspondence.Helpers;
 using Altinn.Correspondence.Mappers;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
@@ -115,6 +108,30 @@ public async Task<ActionResult<CorrespondencesExt>> GetCorrespondences(
             );
         }
 
+        /// <summary>
+        /// Download an attachment from a Correspondence
+        /// </summary>
+        [HttpGet]
+        [Route("{correspondenceId}/attachment/{attachmentId}/download")]
+        [ApiExplorerSettings(IgnoreApi = true)]
+        public async Task<ActionResult> DownloadCorrespondenceAttachment(
+            Guid correspondenceId,
+            Guid attachmentId,
+            [FromServices] LegacyDownloadCorrespondenceAttachmentHandler handler,
+            CancellationToken cancellationToken)
+        {
+            var commandResult = await handler.Process(new DownloadCorrespondenceAttachmentRequest()
+            {
+                CorrespondenceId = correspondenceId,
+                AttachmentId = attachmentId
+            }, cancellationToken);
+
+            return commandResult.Match<ActionResult>(
+                result => File(result.Stream, "application/octet-stream", result.FileName),
+                Problem
+            );
+        }
+
         private ActionResult Problem(Error error) => Problem(detail: error.Message, statusCode: (int)error.StatusCode);
     }
 }

src/Altinn.Correspondence.Application/DependencyInjection.cs

@@ -58,6 +58,7 @@ public static void AddApplicationHandlers(this IServiceCollection services)
         services.AddScoped<LegacyGetCorrespondencesHandler>();
         services.AddScoped<LegacyGetCorrespondenceOverviewHandler>();
         services.AddScoped<LegacyGetCorrespondenceHistoryHandler>();
+        services.AddScoped<LegacyDownloadCorrespondenceAttachmentHandler>();
 
         // Migration
         services.AddScoped<MigrateInitializeAttachmentHandler>();

src/Altinn.Correspondence.Application/DownloadCorrespondenceAttachment/LegacyDownloadCorrespondenceAttachmentHandler.cs

@@ -0,0 +1,69 @@
+using Altinn.Correspondence.Application.Helpers;
+using Altinn.Correspondence.Core.Repositories;
+using Altinn.Correspondence.Core.Services;
+using Altinn.Correspondence.Core.Services.Enums;
+using Hangfire;
+using OneOf;
+
+namespace Altinn.Correspondence.Application.DownloadCorrespondenceAttachment;
+
+public class LegacyDownloadCorrespondenceAttachmentHandler : IHandler<DownloadCorrespondenceAttachmentRequest, DownloadCorrespondenceAttachmentResponse>
+{
+    private readonly ICorrespondenceRepository _correspondenceRepository;
+    private readonly IStorageRepository _storageRepository;
+    private readonly IAttachmentRepository _attachmentRepository;
+    private readonly IAltinnRegisterService _altinnRegisterService;
+    private readonly UserClaimsHelper _userClaimsHelper;
+    private readonly IBackgroundJobClient _backgroundJobClient;
+
+    public LegacyDownloadCorrespondenceAttachmentHandler(IStorageRepository storageRepository, IAttachmentRepository attachmentRepository, ICorrespondenceRepository correspondenceRepository, UserClaimsHelper userClaimsHelper, IBackgroundJobClient backgroundJobClient, IAltinnRegisterService altinnRegisterService)
+    {
+        _correspondenceRepository = correspondenceRepository;
+        _storageRepository = storageRepository;
+        _attachmentRepository = attachmentRepository;
+        _altinnRegisterService = altinnRegisterService;
+        _userClaimsHelper = userClaimsHelper;
+        _backgroundJobClient = backgroundJobClient;
+    }
+
+    public async Task<OneOf<DownloadCorrespondenceAttachmentResponse, Error>> Process(DownloadCorrespondenceAttachmentRequest request, CancellationToken cancellationToken)
+    {
+        var partyId = _userClaimsHelper.GetPartyId();
+        if (partyId is null)
+        {
+            return Errors.InvalidPartyId;
+        }
+        var party = await _altinnRegisterService.LookUpPartyByPartyId(partyId.Value, cancellationToken); 
+        if (party is null || (string.IsNullOrEmpty(party.SSN) && string.IsNullOrEmpty(party.OrgNumber)))
+        {
+            return Errors.CouldNotFindOrgNo;
+        }
+
+        var correspondence = await _correspondenceRepository.GetCorrespondenceById(request.CorrespondenceId, true, false, cancellationToken);
+        if (correspondence is null)
+        {
+            return Errors.CorrespondenceNotFound;
+        }
+        var attachment = await _attachmentRepository.GetAttachmentByCorrespondenceIdAndAttachmentId(request.CorrespondenceId, request.AttachmentId, cancellationToken);
+        if (attachment is null)
+        {
+            return Errors.AttachmentNotFound;
+        }
+        bool isRecipient = correspondence.Recipient == ("0192:"+party.OrgNumber) || correspondence.Recipient == party.SSN;
+        if (!isRecipient)
+        {
+            return Errors.CorrespondenceNotFound;
+        }
+        var latestStatus = correspondence.GetLatestStatus();
+        if (!latestStatus.Status.IsAvailableForRecipient())
+        {
+            return Errors.CorrespondenceNotFound;
+        }
+        var attachmentStream = await _storageRepository.DownloadAttachment(attachment.Id, cancellationToken);
+        _backgroundJobClient.Enqueue<IDialogportenService>((dialogportenService) => dialogportenService.CreateInformationActivity(request.CorrespondenceId, DialogportenActorType.Recipient, DialogportenTextType.DownloadStarted, attachment.FileName ?? attachment.Name));
+        return new DownloadCorrespondenceAttachmentResponse(){
+            FileName = attachment.FileName ?? attachment.Name,
+            Stream = attachmentStream
+        };
+    }
+}

src/Altinn.Correspondence.Application/Helpers/UserClaimsHelper.cs

@@ -18,6 +18,7 @@ public class UserClaimsHelper
         private const string _consumerClaim = "consumer";
         private const string _IdProperty = "ID";
         private const string _dialogportenOrgClaim = "p";
+        private const string _partyIdClaim = "urn:altinn:partyid";
 
         public UserClaimsHelper(IHttpContextAccessor httpContextAccessor, IOptions<DialogportenSettings> dialogportenSettings, IOptions<IdportenSettings> idportenSettings)
         {
@@ -26,6 +27,13 @@ public UserClaimsHelper(IHttpContextAccessor httpContextAccessor, IOptions<Dialo
             _dialogportenSettings = dialogportenSettings.Value;
             _idportenSettings = idportenSettings.Value;
         }
+        public int? GetPartyId()
+        {
+            var partyId = _claims.FirstOrDefault(c => c.Type == _partyIdClaim)?.Value;
+            if (partyId is null) return null;
+            if (int.TryParse(partyId, out int id)) return id;
+            return null;
+        }
         public bool IsAffiliatedWithCorrespondence(string recipientId, string senderId)
         {
             return IsRecipient(recipientId) || IsSender(senderId);