NextJS Dynamic Sitemap

sitemap.xml.ts

import { NextApiRequest, NextApiResponse } from 'next';
import { SitemapStream, streamToPromise, EnumChangefreq } from 'sitemap';
import { createGzip } from 'zlib';
import { readdir } from 'fs';
import { promisify } from 'util';

const asyncReaddir = promisify(readdir);


export default async (req: NextApiRequest, res: NextApiResponse) => {
    req;
	if (!res) return {};
	try {
	    // Set response header 
		res.setHeader('content-type', 'application/xml');
		res.setHeader('Content-Encoding', 'gzip');
		
		// A Transform for turning a Readable stream of either SitemapItemOptions or url strings into a Sitemap.
		// The readable stream it transforms must be in object mode.
		const smStream = new SitemapStream({
			hostname: `https://${process.env.HOST_NAME}`,
		});
		
        const pipeline = smStream.pipe(createGzip());
        
        const files = await asyncReaddir('./pages');

        const filteredFiles = files
        .filter((name: string) => {
            return (
                // Make sure we leave out any folders until were ready to read slug based links
                name.indexOf('.tsx') > -1 &&
                // remove any template based files aka _app and _document
                name.indexOf('_') !== 0 &&
                // remove root as it's not at index in theory
                name.indexOf('index') !== 0
            )
        })
        .map((fileName: string) => {
            const pageName = fileName.split('.');
            return pageName[0];
        })

        //This part is a hack as we'll make the sitemap say the content has expired a couple hours prior to the request
        var lastmod = new Date();
        lastmod.setHours(lastmod.getHours() - 2);

        // We removed index as it's root so let's be sure to add it to the sitemap
        smStream.write({ url: '/', lastmod: lastmod, changefreq: EnumChangefreq.WEEKLY });

        // next we'll go through all of the files that are in the pages directory and add each one
        for(const fileName of filteredFiles) {
            smStream.write({ url: `/${fileName}`, lastmod: lastmod, changefreq: EnumChangefreq.WEEKLY });
        }
        
        // Here is an example of where we create a sitemap.xml for some query in our graphql
        
        // Create the client from with-apollo
        // const client = createApolloClient()

        // Do the query
		// const stuff = await client.query(gqlQuery, {});
        
        // Loop through everything and add it to the sitemap
        // stuff.map(responseItem => {
		// 	smStream.write({
		// 		url: `/products/${responseItem.slug}`,
		// 		lastmod: responseItem.updatedAt,
		// 		changefreq: EnumChangefreq.WEEKLY,
		// 	});
		// });
        
        // Important: Close the stream we are feeding and send it on it's way
        smStream.end();

		// cache the response
        streamToPromise(pipeline);
        
		// stream the response
		pipeline.pipe(res).on('error', e => {
			throw e;
        });
        
	} catch (e) {
		res.status(500).end();
	}
};