5/24/2023 Admin

Create a C# OpenAI ChatGPT Plugin

In the ever-evolving world of artificial intelligence, OpenAI's ChatGPT has emerged as a powerful tool for creating dynamic and engaging conversational experiences.

However, integrating this technology into your own applications may seem daunting.

Fear not! In this blog post, we will guide you through the process of creating a simple ChatGPT plug-in using C#.

In this article we will create a C# version of the OpenAI plugin TO DO example.

A special thanks to this article: How to Build a ChatGPT Weather Plugin with C# and ASP.NET Web API for demonstrating how to create the required .yaml file automatically.

Video

https://www.youtube.com/watch?v=8k3OZwAvC7w

Requirements

OpenAI Account: You can sign up for an OpenAI account by following this link.
ChatGPT Plugin Access: If you haven't obtained access through a paid account, you can join the waitlist by clicking here.

Create The Application

Use Visual Studio to create the application.

Create a Blazor Server app named BlazorChatGPTPlugin.

Right-click on the Project node and select Manage NuGet Packages..

Install the following NuGet packages:

Microsoft.AspNetCore.OpenApi
Swashbuckle.AspNetCore
Swashbuckle.AspNetCore.Annotations

Open the Program.cs file.

Add the following code before the var app = builder.Build() line:

            // ** Create CORS policy called OpenAI
            // to allow OpenAI to access the API
            builder.Services.AddCors(options =>
            {
                options.AddPolicy("OpenAI", policy =>
                {
                    policy.WithOrigins(
                        "https://chat.openai.com",
                        "http://localhost:5165")
                    .AllowAnyHeader()
                    .AllowAnyMethod();
                });
            });
            // ** Add controllers to the application
            builder.Services.AddControllers();
            // ** Add Swagger/OpenAPI to the application
            // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
            builder.Services.AddEndpointsApiExplorer();
            builder.Services.AddSwaggerGen(options =>
            {
                options.CustomOperationIds(e => $"{e.ActionDescriptor.RouteValues["controller"]}_{e.HttpMethod}");
                options.SwaggerDoc("v1", new OpenApiInfo
                {
                    Title = "Blazor TODO Plugin (no auth)",
                    Version = "v1",
                    Description = "Plugin for managing a TODO list, you can add, remove and view your TODOs."
                });
            });

Next, disable this line:

            // Disable this so that OpenAI can access the API
            // without using https  (which is not supported by OpenAI)
            //app.UseHttpsRedirection();

Also, add the following code before the app.MapFallbackToPage("/_Host") line:

    app.MapControllers();

Add the following code before the app.Run() line:

            // ** CORS to allow OpenAI to access the API
            app.UseCors("OpenAI");
            // ** Serve the .well-known folder for OpenAI
            app.UseStaticFiles(new StaticFileOptions
            {
                FileProvider = new PhysicalFileProvider(
                    Path.Combine(Directory.GetCurrentDirectory(), ".well-known")),
                RequestPath = "/.well-known"
            });
            // ** UseSwagger
            app.UseSwagger(c =>
            {
                c.PreSerializeFilters.Add((swaggerDoc, httpReq) =>
                {
                    swaggerDoc.Servers = new List<OpenApiServer> {
                        new OpenApiServer {
                            Url = $"{httpReq.Scheme}://{httpReq.Host.Value}"
                        }
                    };
                });
            });
            // ** UseSwaggerUI
            app.UseSwaggerUI(x =>
            {
                x.SwaggerEndpoint(
                    "/swagger/v1/swagger.yaml", 
                    "Blazor TODO Plugin (no auth)"
                    );
            });

Add a Controllers folder, and a TodosController.cs file with the following code:

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
namespace BlazorChatGPTPlugin.Controllers
{
    [ApiController]
    [ApiExplorerSettings(GroupName = "v1")]
    [Produces("application/json")]
    [Route("[controller]")]
    public class TodosController : ControllerBase
    {
        private static readonly Dictionary<string, List<string>> 
            _TODOS = new Dictionary<string, List<string>>();
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [HttpPost("{username}")]
        public IActionResult AddTodo(string username, 
            [FromBody] TodoRequest request)
        {
            if (!_TODOS.ContainsKey(username))
            {
                _TODOS[username] = new List<string>();
            }
            _TODOS[username].Add(request.Todo);
            return Ok();
        }
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [HttpGet("{username}")]
        public IActionResult GetTodos(string username)
        {
            if (!_TODOS.TryGetValue(username, out var todos))
            {
                todos = new List<string>();
            }
            return Ok(todos);
        }
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [HttpDelete("{username}")]
        public IActionResult DeleteTodo(string username, 
            [FromBody] TodoIndexRequest request)
        {
            if (_TODOS.TryGetValue(username, out var todos) 
                && request.TodoIdx >= 0 && request.TodoIdx < todos.Count)
            {
                todos.RemoveAt(request.TodoIdx);
            }
            return Ok();
        }
    }
    public class TodoRequest
    {
        public string Todo { get; set; }
    }
    public class TodoIndexRequest
    {
        public int TodoIdx { get; set; }
    }
}

Finally, add a folder named .well-known and a ai-plugin.json file with the following contents:

{
  "schema_version": "v1",
  "name_for_human": "Blazor TODO Plugin (no auth)",
  "name_for_model": "blazortodo",
  "description_for_human": "Plugin for managing a TODO list, you can add, remove and view your TODOs.",
  "description_for_model": "Plugin for managing a TODO list, you can add, remove and view your TODOs.",
  "auth": {
    "type": "none"
  },
  "api": {
    "type": "openapi",
    "url": http://localhost:5288/swagger/v1/swagger.yaml,
    "is_user_authenticated": false
  },
  "logo_url": http://localhost:5288/.well-known/favicon.png,
  "contact_email": "contact@email.com",
  "legal_info_url": "http://example.com/legal"
}