worker-links/index.js

let secret

addEventListener('fetch', (event) => {
    event.respondWith(handleRequest(event))
})

/**
 * Respond to the request
 * @param {Event} event
 */
async function handleRequest(event) {
    const { request } = event
    // Set this in your worker's environment. wrangler.toml or cloudflare dashboard
    if (WORKERLINKS_SECRET === undefined) {
        return new Response('Secret is not defined. Please add WORKERLINKS_SECRET.')
    } else {
        secret = WORKERLINKS_SECRET
    }

    var key = new URL(request.url).pathname
    var shorturl = new URL(request.url).origin + key

    if (request.method == 'PUT') {
        return await putLink(
            request.headers.get('Authorization'),
            shorturl,
            key,
            request.headers.get('URL'),
        )
    } else if (request.method == 'POST') {
        if (key != '/') {
            return Response.json(
                {
                    code: '405 Method Not Allowed',
                    message: 'POST not valid for individual keys. Did you mean PUT?',
                },
                {
                    status: 405,
                },
            )
        }
        key = '/' + Math.random().toString(36).slice(5)
        shorturl = new URL(request.url).origin + key
        return await putLink(
            request.headers.get('Authorization'),
            shorturl,
            key,
            request.headers.get('URL'),
        )
    } else if (request.method == 'GET' || request.method == 'HEAD') {
        let url = await kv.get(key)
        if (url == null) {
            return Response.json(
                {
                    code: '404 Not Found',
                    message: 'Key does not exist or has not propagated.',
                },
                {
                    status: 404,
                },
            )
        } else {
            // PLAUSIBLE_HOST should be the full URL to your Plausible Analytics instance
            // e.g. https://plausible.io/
            if (typeof PLAUSIBLE_HOST !== 'undefined') {
                const url = PLAUSIBLE_HOST + 'api/event'
                const headers = new Headers()
                headers.append('User-Agent', request.headers.get('User-Agent'))
                headers.append(
                    'X-Forwarded-For',
                    request.headers.get('X-Forwarded-For'),
                )
                headers.append('Content-Type', 'application/json')

                const data = {
                    name: 'pageview',
                    url: request.url,
                    domain: new URL(request.url).hostname,
                    referrer: request.referrer,
                }
                event.waitUntil(
                    fetch(url, { method: 'POST', headers, body: JSON.stringify(data) }),
                )
            }
            return new Response(null, { status: 302, headers: { Location: url } })
        }
    } else if (request.method == 'DELETE') {
        if (request.headers.get('Authorization') != secret) {
            return Response.json(
                {
                    code: '401 Unauthorized',
                    message: 'Unauthorized.',
                },
                {
                    status: 401,
                },
            )
        }

        shorturl = new URL(request.url).origin + key
        let url = await kv.get(key)
        if (url == null) {
            return Response.json(
                {
                    code: '404 Not Found',
                    message: 'Key does not exist or has not propagated.',
                },
                {
                    status: 404,
                },
            )
        } else {
            await kv.delete(key)
            return Response.json(
                {
                    message: 'Short URL deleted succesfully.',
                    key: key.substr(1),
                    shorturl: shorturl,
                    longurl: url,
                },
                {
                    status: 200,
                },
            )
        }
    }

    return Response.json(
        {
            code: '405 Method Not Allowed',
            message:
                'Unsupported method. Please use one of GET, PUT, POST, DELETE, HEAD.',
        },
        {
            status: 405,
        },
    )
}

function validateUrl(url) {
    // quick and dirty validation
    if (url == '') {
        return false
    }
    try {
        new URL(url)
    } catch (TypeError) {
        return false
    }
    return true
}

async function putLink(givenSecret, shorturl, key, url) {
    if (givenSecret != secret) {
        return Response.json(
            {
                code: '401 Unauthorized',
                message: 'Unauthorized.',
            },
            {
                status: 401,
            },
        )
    }

    if (url == null || !validateUrl(url)) {
        return Response.json(
            {
                code: '400 Bad Request',
                message: "No valid URL given. Please set a 'URL' header.",
            },
            {
                status: 400,
            },
        )
    }

    await kv.put(key, url)
    return Response.json(
        {
            message: 'URL created succesfully.',
            key: key.substr(1),
            shorturl: shorturl,
            longurl: url,
        },
        {
            status: 200,
        },
    )
}