Generated client code does not replace/set route parameters with 14.0.0-preview010

[vas6ili]

For a path template like /odata/QueueRetention({key}) generated client code does not replace {key} url route parameter. Used net80/dotnet-nswag.exe from https://github.com/RicoSuter/NSwag/releases/tag/v14.0.0-preview010 with net8 (which is the reason I'm upgrading to 14)

Generated client code snippet

var urlBuilder_ = new System.Text.StringBuilder();

urlBuilder_.Append("odata");
urlBuilder_.Append('/');
urlBuilder_.Append("QueueRetention({key})");

PrepareRequest(client_, request_, urlBuilder_);

var url_ = urlBuilder_.ToString();
request_.RequestUri = new System.Uri(url_, System.UriKind.RelativeOrAbsolute);

PrepareRequest(client_, request_, url_);

API definition snippet

    "/odata/QueueRetention({key})": {
        "delete": {
            "description": "",
            "operationId": "QueueRetention_Delete",
            "parameters": [
                {
                    "in": "path",
                    "name": "key",
                    "required": true,
                    "schema": {
                        "format": "int64",
                        "type": "integer"
                    },
                    "x-position": 1
                },
                {
                    "in": "header",
                    "name": "api-version",
                    "schema": {
                        "nullable": true,
                        "type": "string"
                    },
                    "x-position": 2
                }
            ],
            "responses": {
                "204": {
                    "description": ""
                }
            },
            "tags": [
                "QueueRetention"
            ]
        }
    }

test-swag.json
NswagClient.zip

Probably related to #4579 @paulomorgado

[paulomorgado]

OOPS! I'll work on that tomorrow.

@RicoSuter, what's the best way to add a unit test for this?

[lahma]

NJsonSchema uses Verify whici is IMO a nice way to test as snapshots are produced and VCS controlled and you can see differences in pull request when output changes. I think this hasn't been taken into use (yet) on NSwag's side though.

[paulomorgado]

I've added corrections to my draft PR: #4585.

Please, checkout if that solves the issue.

[vas6ili]

It did solve the issue. I'm inspecting a quite large 8 MB generated client from a 2.5 MB swagger file and haven't found any other issue yet.

[RicoSuter]

Can you confirm that the latest preview works fine for you?

[vas6ili]

Can confirm with latest RC3 the issue no longer reproduces

[bzwieratinnovadis]

@RicoSuter @vas6ili I'm having a similar issue with route parameters with the stable release (v14.0.0) in a .NET 8 project.
I'm using NSwag.MSBuild to generate a CSharp client.

I have the following controller action:

[HttpGet("confirm/{batch}")]
public Task<MessageBoxConfirmBatchModel> ConfirmAsync(Guid batch) => _batchService.ConfirmAsync(batch);

OpenAPI definition:

"/api/message-box-batch/confirm/{batch}": {
  "get": {
    "tags": [
      "MessageBoxBatch"
    ],
    "parameters": [
      {
        "name": "OrganizationReference",
        "in": "header",
        "required": true,
        "schema": {
          "type": "string",
          "format": "uuid"
        }
      },
      {
        "name": "batch",
        "in": "path",
        "required": true,
        "schema": {
          "type": "string",
          "format": "uuid"
        }
      }
    ],
    "responses": {
      "200": {
        "description": "Success",
        "content": {
          "text/plain": {
            "schema": {
              "$ref": "#/components/schemas/MessageBoxConfirmBatchModel"
            }
          },
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/MessageBoxConfirmBatchModel"
            }
          },
          "text/json": {
            "schema": {
              "$ref": "#/components/schemas/MessageBoxConfirmBatchModel"
            }
          }
        }
      },
      "204": {
        "description": "No Content"
      },
      "400": {
        "description": "Bad Request",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/ValidationProblemDetails"
            }
          }
        }
      },
      "500": {
        "description": "Internal Server Error",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/ProblemDetails"
            }
          }
        }
      }
    }
  }
}

The resulting client:

var urlBuilder_ = new System.Text.StringBuilder();
urlBuilder_.Append("api/message-box-batch/confirm/{batch}");
urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(batch, System.Globalization.CultureInfo.InvariantCulture)));

The request URI ends up being: api/message-box-batch/confirm/{batch}462995b7-433b-4382-b4d7-5f84599cf732

When the client is called the API returns a 400 Bad Request response due to the malformed URI.

In v13.20.0 the client was generated correctly:

var urlBuilder_ = new System.Text.StringBuilder();
urlBuilder_.Append("api/message-box-batch/confirm/{batch}");
urlBuilder_.Replace("{batch}", System.Uri.EscapeDataString(ConvertToString(batch, System.Globalization.CultureInfo.InvariantCulture)));

Is there some workaround in terms of configuration? Or should I wait for the next minor/patch version?

[paulomorgado]

Thanks for the concrete example, @bzwieratinnovadis.

Which tooling and version are you using?

I just tried that example on NSwagStudio v14.0.0.0 and got this generated code:

var urlBuilder_ = new System.Text.StringBuilder();
if (!string.IsNullOrEmpty(BaseUrl)) urlBuilder_.Append(BaseUrl);
// Operation Path: "api/message-box-batch/confirm/{batch}"
urlBuilder_.Append("api/message-box-batch/confirm/");
urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(batch, System.Globalization.CultureInfo.InvariantCulture)));

[bzwieratinnovadis]

Thanks for the concrete example, @bzwieratinnovadis.

Which tooling and version are you using?

I just tried that example on NSwagStudio v14.0.0.0 and got this generated code:

var urlBuilder_ = new System.Text.StringBuilder();
if (!string.IsNullOrEmpty(BaseUrl)) urlBuilder_.Append(BaseUrl);
// Operation Path: "api/message-box-batch/confirm/{batch}"
urlBuilder_.Append("api/message-box-batch/confirm/");
urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(batch, System.Globalization.CultureInfo.InvariantCulture)));

So I've been messing around with NSwagStudio to reproduce the issue and figured out why the code was being generated incorrecly. Apparently there was a template being used that causes the issue because without it everything is fine and path/route parameters are handled correctly.

I closed related #4683

[lfderm]

Hi @bzwieratinnovadis, I am still getting this error in NSwag 14.1. Can you elaborate what you mean with "a template being used"? I do nothing special, just generate a C# client from a valid openapi spec. But the generated code is obviously broken, the generated url contains names of the placeholders instead of just the values.

                    if (offset != null)
                    {
                        urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(offset, System.Globalization.CultureInfo.InvariantCulture)));
                    }
                    else
                        if (urlBuilder_.Length > 0) urlBuilder_.Length--;
                    urlBuilder_.Append("{offset}");
                    urlBuilder_.Append('/');
                    if (limit != null)
                    {
                        urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(limit, System.Globalization.CultureInfo.InvariantCulture)));
                    }
                    else
                        if (urlBuilder_.Length > 0) urlBuilder_.Length--;
                    urlBuilder_.Append("{limit}");

URL: .../0{offset}/1{limit}

Is there any fix or workaround available? I am surprised this issue is still open after almost one year.

[paulomorgado]

Hi @bzwieratinnovadis, I am still getting this error in NSwag 14.1. Can you elaborate what you mean with "a template being used"? I do nothing special, just generate a C# client from a valid openapi spec. But the generated code is obviously broken, the generated url contains names of the placeholders instead of just the values.

                    if (offset != null)
                    {
                        urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(offset, System.Globalization.CultureInfo.InvariantCulture)));
                    }
                    else
                        if (urlBuilder_.Length > 0) urlBuilder_.Length--;
                    urlBuilder_.Append("{offset}");
                    urlBuilder_.Append('/');
                    if (limit != null)
                    {
                        urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(limit, System.Globalization.CultureInfo.InvariantCulture)));
                    }
                    else
                        if (urlBuilder_.Length > 0) urlBuilder_.Length--;
                    urlBuilder_.Append("{limit}");

URL: .../0{offset}/1{limit}

Is there any fix or workaround available? I am surprised this issue is still open after almost one year.

@lfderm, can you provide a sample swagger/openapi spec that has this issue, And the full set of options used? You can use NSwag Studio for that and post the nswag file.

[dkone]

Hi @paulomorgado, i reproduced that when i was manually generating a schema. Adding an OpenApiParameter with a OpenApiParameterKind.Path that has no IsRequired = true will broke code generation.

getOperation.Parameters.Add(new OpenApiParameter
{
    Name = "websitecode",
    Kind = OpenApiParameterKind.Path,
    Description = "code of the website",
    Type = JsonObjectType.String,
    IsRequired = true // Needed to avoid error in code generation
});
getOperation.Parameters.Add(new OpenApiParameter
{
    Name = "id",
    Description = "id of the resource",
    Type = JsonObjectType.Integer,
    Kind = OpenApiParameterKind.Path,
    IsRequired = true // Needed to avoid error in code generation
});
getItem["get"] = getOperation;
doc.Paths.Add("/resources/whatever/{websitecode}/{id}", getItem);

Thank you for all your amazing work.
Regards,

[lfderm]

I can confirm that making the route parameter mandatory fixes the issue. Still, this seems like a bug to me. The generated code for an optional parameter (here "offset") does not make sense:

                    if (offset != null)
                    {
                        urlBuilder_.Append(System.Uri.EscapeDataString(ConvertToString(offset, System.Globalization.CultureInfo.InvariantCulture)));
                    }
                    else
                        if (urlBuilder_.Length > 0) urlBuilder_.Length--;
                    urlBuilder_.Append("{offset}");

There is already the if/else clause for the parameter. The last method call is absolutely wrong and should be removed from code generation. Then, I think optional route parameters would work fine.

[paulomorgado]

@dkone, a proper OpenAPI document would go a long way to expedite the fix. Better yet, adding unit tests exposing this.

Although this can be "fixed", "path parameters are always required" (in https://swagger.io/docs/specification/v3_0/describing-parameters/#path-parameters). If you want them optional, you should specify them as query parameters.