fix(webi): Add missing type on ETag response headers (#1666)

<!--- Provide a general summary of your changes in the Title above -->

## Description

<!--- Describe your changes in detail -->

## Related Issue(s)

- #1665 

## Verification

- [ ] **Your** code builds clean without any errors or warnings
- [ ] Manual testing done (required)
- [ ] Relevant automated test added (if you find this hard, leave it and
we'll help out)

## Documentation

- [ ] Documentation is updated (either in `docs`-directory, Altinnpedia
or a separate linked PR in
[altinn-studio-docs.](https://github.com/Altinn/altinn-studio-docs), if
applicable)

Co-authored-by: Knut Haug <knut.espen.haug@digdir.no>

docs/schema/V1/swagger.verified.json

@@ -5866,7 +5866,11 @@
             "description": "The UUID of the created dialog aggregate. A relative URL to the newly created activity is set in the \u0022Location\u0022 header.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },
@@ -5940,7 +5944,11 @@
             "description": "The dialog aggregate was deleted successfully.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },
@@ -6101,7 +6109,11 @@
             "description": "Patch was successfully applied.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },
@@ -6201,7 +6213,11 @@
             "description": "The dialog aggregate was updated successfully.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },
@@ -6504,7 +6520,11 @@
             "description": "The UUID of the created dialog activity. A relative URL to the newly created activity is set in the \u0022Location\u0022 header.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },
@@ -6872,7 +6892,11 @@
             "description": "The UUID of the created dialog transmission. A relative URL to the newly created activity is set in the \u0022Location\u0022 header.",
             "headers": {
               "Etag": {
-                "description": "The new UUID ETag of the dialog"
+                "description": "The new UUID ETag of the dialog",
+                "example": "123e4567-e89b-12d3-a456-426614174000",
+                "schema": {
+                  "type": "string"
+                }
               }
             }
           },

src/Digdir.Domain.Dialogporten.WebApi/Endpoints/V1/Common/Headers/HttpResponseHeaderExamples.cs

@@ -9,5 +9,6 @@ public static ResponseHeader NewDialogETagHeader(int statusCode)
         => new(statusCode, Constants.ETag)
         {
             Description = "The new UUID ETag of the dialog",
+            Example = "123e4567-e89b-12d3-a456-426614174000"
         };
 }

src/Digdir.Domain.Dialogporten.WebApi/Endpoints/V1/ServiceOwner/Dialogs/Patch/PatchDialogsController.cs

@@ -60,7 +60,7 @@ public PatchDialogsController(ISender sender, IMapper mapper)
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status412PreconditionFailed)]
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status422UnprocessableEntity)]
-    [ProducesResponseHeader(StatusCodes.Status204NoContent, Constants.ETag, "The new UUID ETag of the dialog")]
+    [ProducesResponseHeader(StatusCodes.Status204NoContent, Constants.ETag, "The new UUID ETag of the dialog", "123e4567-e89b-12d3-a456-426614174000")]
     public async Task<IActionResult> Patch(
         [FromRoute] Guid dialogId,
         [FromHeader(Name = Constants.IfMatch)] Guid? etag,

src/Digdir.Domain.Dialogporten.WebApi/Endpoints/V1/ServiceOwner/Dialogs/Patch/ProducesResponseHeaderAttribute.cs

@@ -1,16 +1,24 @@
+using NJsonSchema;
+
 namespace Digdir.Domain.Dialogporten.WebApi.Endpoints.V1.ServiceOwner.Dialogs.Patch;
 
 [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
 public sealed class ProducesResponseHeaderAttribute : Attribute
 {
-    public ProducesResponseHeaderAttribute(int statusCode, string headerName, string description)
+    public ProducesResponseHeaderAttribute(int statusCode, string headerName,
+        string description, string example, JsonObjectType type = JsonObjectType.String)
     {
         HeaderName = headerName;
         StatusCode = statusCode;
         Description = description;
+        Example = example;
+        Type = type;
     }
 
     public string HeaderName { get; }
     public int StatusCode { get; }
     public string Description { get; }
+    public string Example { get; }
+
+    public JsonObjectType Type { get; }
 }

src/Digdir.Domain.Dialogporten.WebApi/Endpoints/V1/ServiceOwner/Dialogs/Patch/ProducesResponseHeaderOperationProcessor.cs

@@ -1,5 +1,6 @@
 using System.Globalization;
 using System.Reflection;
+using NJsonSchema;
 using NSwag;
 using NSwag.Generation.Processors;
 using NSwag.Generation.Processors.Contexts;
@@ -21,6 +22,11 @@ public bool Process(OperationProcessorContext context)
         var header = new OpenApiHeader
         {
             Description = headerAttribute.Description,
+            Example = headerAttribute.Example,
+            Schema = new JsonSchema
+            {
+                Type = headerAttribute.Type
+            }
         };
 
         response.Headers.Add(headerAttribute.HeaderName, header);

src/Digdir.Domain.Dialogporten.WebApi/OpenApiDocumentExtensions.cs

@@ -5,6 +5,25 @@ namespace Digdir.Domain.Dialogporten.WebApi;
 
 public static class OpenApiDocumentExtensions
 {
+    /// <summary>
+    /// FastEndpoints generates a title for headers with the format "System_String", which is a C# specific type.
+    /// </summary>
+    /// <param name="openApiDocument"></param>
+    public static void RemoveSystemStringHeaderTitles(this OpenApiDocument openApiDocument)
+    {
+        const string systemString = "System_String";
+        var headers = openApiDocument.Paths
+            .SelectMany(path => path.Value
+                .SelectMany(operation => operation.Value.Responses
+                    .SelectMany(response => response.Value.Headers
+                        .Where(header => header.Value.Schema.Title == systemString))));
+
+        foreach (var header in headers)
+        {
+            header.Value.Schema.Title = null;
+        }
+    }
+
     /// <summary>
     /// To have this be validated in BlackDuck, we need to lower case the bearer scheme name.
     /// From editor.swagger.io:

src/Digdir.Domain.Dialogporten.WebApi/Program.cs

@@ -214,6 +214,7 @@ static void BuildAndRun(string[] args, TelemetryConfiguration telemetryConfigura
                 document.ReplaceProblemDetailsDescriptions();
                 document.MakeCollectionsNullable();
                 document.FixJwtBearerCasing();
+                document.RemoveSystemStringHeaderTitles();
             };
         }, uiConfig =>
         {