practicekea_backend/gateway/Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Tokens;
using Ocelot.DependencyInjection;
using Ocelot.Middleware;
using System.IO;

namespace OnlineAssessment.Gateway
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddOcelot();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public async void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGet("/", async context =>
                {
                    await context.Response.WriteAsync(GetIndexPage());
                });
            });

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
            await app.UseOcelot();
        }

        public string GetIndexPage()
        {
            string indexFileContent = File.ReadAllText("index.html");
            return indexFileContent;
            //string indexPage = @"
            //        <div style='width: 80%; display: block; margin: 100px auto; border: none; text-align:center;font-family: arial'>
            //                <img style='height: 80px;' src='https://www.odiware.com/wp-content/uploads/2020/04/color_logo_transparent-scaled.jpg' srcset='https://www.odiware.com/wp-content/uploads/2020/04/color_logo_transparent-scaled.jpg 1x, https://www.odiware.com/wp-content/uploads/2020/04/color_logo_transparent-scaled.jpg 2x' alt='Odiware Technologies' class='logo logoDefault' />                            

            //                <h3 style='color:green'>API Gateway (Online Assessment)</h3>
            //                <ul style='list-style-type:none;'>
            //                    <li>
            //                        User API &nbsp;&nbsp;<a href='http://api-user.odiprojects.com/swagger/index.html' target='_blank'>(api-user)</a>
            //                    </li>
            //                    <li style='height: 20px'>&nbsp;</li>
            //                    <li>
            //                        Admin API&nbsp;&nbsp; <a href='http://api-admin.odiprojects.com/swagger/index.html' target='_blank'>(api-admin)</a>
            //                    </li>
            //                    <li style='height: 20px'>&nbsp;</li>
            //                    <li>
            //                        Institute API&nbsp;&nbsp; <a href='http://api-institute.odiprojects.com/swagger/index.html' target='_blank'>(api-institute)</a>
            //                    </li>
            //                    <li style='height: 20px'>&nbsp;</li>
            //                    <li>
            //                        Student API&nbsp;&nbsp; <a href='http://api-student.odiprojects.com/swagger/index.html' target='_blank'>(api-institute)</a>
            //                    </li>
            //                    <li style='height: 20px'>&nbsp;</li>
            //                    <li>
            //                        Images API&nbsp;&nbsp; <a href='http://api-bucket.odiprojects.com/swagger/index.html' target='_blank'>(api-institute)</a>
            //                    </li>

            //                </ul>
            //            </div>
            //            ";
            //return indexPage;
        }
    }
}