const Koa = require('koa');
const app = new Koa();
const mime = require('mime-types')
const fs = require('fs');

app.use(ctx => {
    if (ctx.request.url === '/file') {
        var path = "/Users/apple/Downloads/test.zip";
        var mimeType = mime.lookup(path);
        const src = fs.createReadStream(path);
        ctx.response.set("content-type", mimeType);
        ctx.response.set("content-disposition", "attachment; filename=test.zip");
        ctx.body = src;
    } else if (ctx.request.url === '/image') {
        var path = "/Users/apple/Downloads/201228bli.bmp";
        var mimeType = mime.lookup(path);
        const src = fs.createReadStream(path);
        ctx.response.set("content-type", mimeType);
        ctx.body = src;
    } else if (ctx.request.url === '/json') {
        var jsonType = mime.lookup('json');
        ctx.response.set("content-type", jsonType);
        var json = {text: "Hello, World!"};
        ctx.body =  JSON.stringify(json);
    } else if (ctx.request.url === '/xml') {
        var jsonType = mime.lookup('xml');
        ctx.response.set("content-type", jsonType);
        var html = `
            
                
                    hello
                
            
        `;
        ctx.body = html;
    } else {
        ctx.body = "Hello World";
    }
});

app.listen(8000);