Function1.cs

using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading.Tasks;
using System.Web;
using System.Xml.Linq;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Extensions.Logging;
using Microsoft.OpenApi;
using Microsoft.OpenApi.CSharpAnnotations.DocumentGeneration;
using Microsoft.OpenApi.CSharpAnnotations.DocumentGeneration.Models;
using Microsoft.OpenApi.Extensions;
using Newtonsoft.Json;

namespace AzureFunctionsOpenAPIDemo
{
    public class Function1
    {
        [Function("Function1")]
        public async Task<HttpResponseData> Run([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequestData req,
            FunctionContext executionContext)
        {
            var log = executionContext.GetLogger<Function1>();

            log.LogInformation("C# HTTP trigger function processed a request.");

            var query = HttpUtility.ParseQueryString(req.Url.Query);
            string name = query["name"];

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;

            string responseMessage = string.IsNullOrEmpty(name)
                ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                : $"Hello, {name}. This HTTP triggered function executed successfully.";

            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content", "Content-Type: text/html; charset=utf-8");
            response.WriteString(responseMessage);

            return response;
        }


        [Function("SwaggerUI")]
        public async Task<HttpResponseData> SwaggerUi([HttpTrigger(AuthorizationLevel.Function, "get")] HttpRequestData req,
            FunctionContext executionContext)
        {
            var log = executionContext.GetLogger<Function1>();

            var page = System.IO.File.ReadAllText(@"Pages\swagger-ui.html");

            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content", "Content-Type: text/html; charset=utf-8");
            response.WriteString(page);

            return response;
        }

        [Function("Swagger")]
        public async Task<HttpResponseData> RunSwagger([HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = null)] HttpRequestData req, FunctionContext executionContext)
        {
            var input = new OpenApiGeneratorConfig(
                annotationXmlDocuments: new List<XDocument>()
                {
                    XDocument.Load(@"AzureFunctionsOpenAPIDemo.xml"),
                },
                assemblyPaths: new List<string>()
                {
                    @"AzureFunctionsOpenAPIDemo.dll"
                },
                openApiDocumentVersion: "V1",
                filterSetVersion: FilterSetVersion.V1
            );
            input.OpenApiInfoDescription = "This is a sample description...";

            var generator = new OpenApiGenerator();
            var openApiDocuments = generator.GenerateDocuments(
                openApiGeneratorConfig: input,
                generationDiagnostic: out GenerationDiagnostic result
            );

            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content", "Content-Type: application/json; charset=utf-8");
            response.WriteString(openApiDocuments.First().Value.SerializeAsJson(OpenApiSpecVersion.OpenApi3_0));

            return response;
        }

        [Function("SwaggerV2")]
        public async Task<HttpResponseData> RunSwagger2([HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = null)] HttpRequestData req, FunctionContext executionContext)
        {
            var input = new OpenApiGeneratorConfig(
                annotationXmlDocuments: new List<XDocument>()
                {
                    XDocument.Load(@"AzureFunctionsOpenAPIDemo.xml"),
                },
                assemblyPaths: new List<string>()
                {
                    @"AzureFunctionsOpenAPIDemo.dll"
                },
                openApiDocumentVersion: "V1",
                filterSetVersion: FilterSetVersion.V1
            );
            input.OpenApiInfoDescription = "This is a sample description...";

            var generator = new OpenApiGenerator();
            var openApiDocuments = generator.GenerateDocuments(
                openApiGeneratorConfig: input,
                generationDiagnostic: out GenerationDiagnostic result
            );

            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content", "Content-Type: application/json; charset=utf-8");
            response.WriteString(openApiDocuments.First().Value.SerializeAsJson(OpenApiSpecVersion.OpenApi2_0));

            return response;
        }
    }
}