worker-links/README.md

# Worker Links (URL Shortener)

A simple URL Shortener for Cloudflare Workers, using Workers KV. Redirect short URLs at the edge of the Cloudflare network to keep latency down and access fast!

I run this code in production on [erisa.link](https://erisa.link/example), though the root name redirects and without the secret it doesn't make a very good demo.

It was made for my personal use but is available publicly in the hopes that it may be useful to someone somewhere.

## Deploy (simple)

Wrangler 2 is required now, but should be handled automatically for `yarn` commands.  
To run manual wrangler commands, try `npx wrangler`.

Simple steps:

- `yarn install`
- `yarn addsecret`
- `yarn deploy`

## Deploy (More involved)

To deploy to your Cloudflare Workers account, edit the relevant entries in `wrangler.toml`, add a secret with `wrangler secret put WORKERLINKS_SECRET` and use `wrangler publish`.

## Debugging

For debuggging, you can use `yarn dev` (Which runs `wrangler dev --local`). To change the secret used in this mode, edit the `.dev.vars` file.

You can also debug on the edge with `wrangler dev`, though you will need to first configure a prepview namespace in `wrangler.toml` and add the `WORKERLINKS_SECRET` secret to the Worker.

## (Optional) User Interface

If `ENABLE_INDEX_FORM` is enabled in `wrangler.toml`, an optional UI form is available when visiting the Worker in a browser, allowing easy creation of links:

![](https://up.erisa.uk/firefox_qFWwv7NIqf.png)

## Usage

Once deployed, interacting with the API should be rather simple. It's based on headers, specifically with the `Authorization` and `URL` headers.

To create a short URL with a random URL, send a `POST` to `/` with `Authorization` and `URL` headers:

```json
erisa@Tuturu:~$ curl -X POST -H "Authorization: mysecret" -H "URL: https://erisa.uk" https://erisa.link/
{
  "message": "URL created succesfully.",
  "key": "q2w083eq",
  "shorturl": "https://erisa.link/q2w083eq",
  "longurl": "https://erisa.uk"
}
```

And you can test it worked if you wish:

```http
erisa@Tuturu:~$ curl https://erisa.link/q2w083eq -D-
HTTP/2 302
date: Fri, 11 Sep 2020 12:43:04 GMT
content-length: 0
location: https://erisa.uk
server: cloudflare
..other ephemeral headers..
```

To create or update a custom short URL, send a `PUT` to the intended target URL:

```json
erisa@Tuturu:~$ curl -X PUT -H "Authorization: mysecret" -H "URL: https://erisa.uk" https://erisa.link/mywebsite
{
  "message": "URL created succesfully.",
  "key": "mywebsite",
  "shorturl": "https://erisa.link/mywebsite",
  "longurl": "https://erisa.uk"
}
```

And to delete an existing shortlink, send a `DELETE` to it with only the `Authorization` header:

```json
erisa@Tuturu:~$ curl -X DELETE -H "Authorization: mysecret" https://erisa.link/keytodelete
{
  "message": "Short URL deleted succesfully.",
  "key": "keytodelete",
  "shorturl": "https://erisa.link/keytodelete",
  "longurl": "https://erisa.uk"
}
```

You can also bulk create multiple shortlinks at once by sending a `POST` to `/` with no `URL` header and with a JSON body instead:

```json
erisa@Tuturu:~$ curl -X POST -H "Authorization: mysecret" https://erisa.link/ \
    -H 'Content-Type: application/json' \
    -d '{ "/short1": "https://example.com", "/mywebsite": "https://erisa.uk" }'
{
  "message": "URLs created successfully",
  "entries": [
    {
      "key": "short1",
      "shorturl": "https://erisa.link/short1",
      "longurl": "https://example.com"
    },
    {
      "key": "mywebsite",
      "shorturl": "http://erisa.link/mywebsite",
      "longurl": "https://erisa.uk"
    }
  ]
}
```

You can list all URLs by sending a `GET` to `/` (with the `Authorization` header set to your secret, of course).

```json
kot@Starry:~$ curl -H "Authorization: mysecret" "https://erisa.link/?prefix=%2F&limit=1"
{
    "list_complete": false,
    "cursor": "AAAAAJhOXekucRAqut7Xs7Q2f09GCZyStWBfONvq6u5JP05Bg-z5FM5gf7krRaDrsvyxqfDuvFWUHIZp2n9OZ7Au92h-x68xwg8-bwerIoPd7fesG5w-ZB6f6oXopZHNXDCscmVUQ0OIaDEOx_6pruyEcCKfD3WpOstj6lO_sYJG_zQKdBgmYvLoMFQpK-cK7t8mCLWQA2t351xc9sJ08SM0JniY73t7bOdSxF3ADVTV6ihMSti0Z6svhpknfCn9VHjT",
    "links": [
        {
            "key": "/0031qr7q7"
        },
        {
            "key": "/00ybqita"
        },
        {
            "key": "/02ji9wlg"
        }
    ]
}
```

The endpoint is paginated by default (1000/page). Just send `cursor` in the query string to access the next page.

You can set `limit` in the query string to `0` to retrieve all URLs.

You can also view URLs from your Cloudflare Dashboard:
`Cloudflare Dashboard -> Workers -> KV -> View` on the namespace.

## Plausible Analytics

To get statistics for your short URLs with Plausible Analytics, define a `PLAUSIBLE_HOST` secret set to the URL of your Plausible instance. For example, `https://plausible.io/`.

## Security

This code is relatively simple but still, if you find any security issues that can be exploited publicly, please reach out to me via email: `erisa (at) erisa.uk` with any relevant details.

If you don't have access to Workers KV you're welcome to test these issues on my live `erisa.link`, provided you don't send excessive (constant) requests or delete/modify any keys except ones created by you or the `/sample` key.

If I don't respond to your email for whatever reason please feel free to publicly open an issue.