Swagger UI execute button not working when file is uploading - asp.net-core

Question

One of the endpoint in my API is for uploading a file and submitting details about the file . The API is implemented in ASP.Net Core. NSwag package is installed in my project. OAS 3 specification is implemented
On Swagger UI I can submit data without uploading file. if the file is chosen using file browser, the execute button is not working when clicked.
I checked Console and Network tab in Chrome Dev tools. There is no network movement. There is no request at all. Neither errors nor any logs were seen in console.
I used bearer token authorisation according to this. I tried in both cases of when in authorised and not authorised state. In both case Execute button not working when file is chosen. When bearer token was not given, and I execute with other parameters except file. I got 401 status response. If the file chosen , the click of execute button has no effect.
The swagger file is:
{
"x-generator": "NSwag v13.1.5.0 (NJsonSchema v10.0.27.0 (Newtonsoft.Json v12.0.0.0))",
"openapi": "3.0.0",
"info": {
"title": "My Title",
"version": "1.0.0"
},
"servers": [
{
"url": "https://localhost:5300"
}
],
"paths": {
"/api/Order": {
"post": {
"tags": [
"Order"
],
"operationId": "Order_Post",
"responses": {
"200": {
"description": "",
"content": {
"application/octet-stream": {
"schema": {
"type": "string",
"format": "binary"
}
}
}
}
}
}
},
"/api/Order/{action}/document": {
"post": {
"tags": [
"Order"
],
"operationId": "Order_CreateDocument",
"parameters": [
{
"name": "FileName",
"in": "formData",
"schema": {
"type": "string",
"nullable": true
},
"x-position": 1
},
{
"name": "FileType",
"in": "formData",
"schema": {
"type": "string",
"nullable": true
},
"x-position": 2
},
{
"name": "DocumentType",
"in": "formData",
"schema": {
"type": "string",
"nullable": true
},
"x-position": 3
},
{
"name": "Description",
"in": "formData",
"schema": {
"type": "string",
"nullable": true
},
"x-position": 4
},
{
"name": "Owners",
"in": "formData",
"collectionFormat": "multi",
"schema": {
"type": "array",
"nullable": true,
"items": {
"type": "string"
}
},
"x-position": 5
},
{
"type": "file",
"name": "SomeFile",
"in": "formData",
"schema": {
"type": "string",
"format": "binary",
"nullable": true
},
"nullable": true
}
],
"responses": {
"200": {
"description": "",
"content": {
"application/octet-stream": {
"schema": {
"type": "string",
"format": "binary"
}
}
}
}
}
}
},
"/api/Debug": {
"get": {
"tags": [
"Debug"
],
"operationId": "Debug_Get",
"parameters": [
{
"name": "message",
"in": "query",
"schema": {
"type": "string",
"nullable": true
},
"x-position": 1
}
],
"responses": {
"200": {
"description": "",
"content": {
"application/json": {
"schema": {
"type": "string"
}
}
}
}
}
}
}
},
"components": {
"securitySchemes": {
"authorization": {
"type": "apiKey",
"name": "authorization",
"in": "header"
}
}
},
"security": [
{
"authorization": []
}
]
}
I want to submit the file and other details as multipart form data.
ASP.Net Core code for the endpoint:
[HttpPost("document")]
public ActionResult CreateDocument([FromForm]Document request)
{ ... }
Document Class :
public class Document
{
public string FileName { get; set; }
public string FileType { get; set; }
public string DocumentType { get; set; }
public string Description { get; set; }
public List<string> Owners { get; set; } = new List<string>();
public Microsoft.AspNetCore.Http.IFormFile SomeFile { get; set; }
}
In Startup.cs :
public void ConfigureServices(IServiceCollection services)
{
....
...
// Register the Swagger services
services.AddOpenApiDocument(document =>
{
document.AddSecurity("authorization", Enumerable.Empty<string>(), new NSwag.OpenApiSecurityScheme
{
Type = NSwag.OpenApiSecuritySchemeType.ApiKey,
Name = "authorization",
In = NSwag.OpenApiSecurityApiKeyLocation.Header
});
document.OperationProcessors.Add(
new NSwag.Generation.Processors.Security.AspNetCoreOperationSecurityScopeProcessor("bearer"));
}); // registers a OpenAPI v3.0 document
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
. . . . . .
. . . . . .
// Register the Swagger generator and the Swagger UI middlewares
app.UseOpenApi();
app.UseSwaggerUi3();
}
Why is execute button in Swagger-UI not working ? How can i upload file from Swagger-UI ?

Answer 1

#Helen has commented and pointed the issue. It is NSwag.AspNetCore package/library.
It seems NSwag library has a bug in Swagger Generation for ASP.Core API in OpenAPI sepecification 3.0 . the issues for this error. It is only when using FromForm attribute for Model binding. In my case one of the property is Microsoft.AspNetCore.Http.IFormFile type that also may cause this error.
Changing to OAS 2.0 is temporary solution.