// 在Startup.cs中配置
public void Configure(IApplicationBuilder app)
{
    app.UsePathBase("/api");
    
    var format = new RequestDelegate(async context =>
    {
        var path = context.Request.Path.Value;
        if (path.EndsWith(".json"))
        {
            context.Response.ContentType = "application/json";
            await context.Response.WriteAsync(JsonConvert.SerializeObject(new { Message = "JSON Response" }));
        }
        else if (path.EndsWith(".xml"))
        {
            context.Response.ContentType = "application/xml";
            await context.Response.WriteAsync("<Message>XML Response</Message>");
        }
    });
    
    app.Map("/products", format);
}

const express = require('express');
const app = express();

app.get('/api/products.:format', (req, res) => {
    const format = req.params.format;
    const data = { id: 1, name: "Product" };
    
    switch(format) {
        case 'json':
            res.json(data);
            break;
        case 'xml':
            res.type('application/xml');
            res.send(`
                <product>
                    <id>${data.id}</id>
                    <name>${data.name}</name>
                </product>
            `);
            break;
        default:
            res.status(400).send('Unsupported format');
    }
});

app.listen(3000);