Among quite a few ways to implement a go-link server (i.e. url-forwarder, short-url server etc.), here I’m going to show you how to use free-tier Cloudflare Worker (& KV) to create an in-house, on-edge, no-webserver go-link server.
For example, the short-link for this article is
/latest(by which I mean
go.yourdomain.co/latest) may point to
https://www.yourcompany.com/about/newswhich is a public page
/hr-helpmay point to
https://www.company-internal.com/long-link/hr/contact.htmlwhich is company’s internal human-resources help portal
/cnypromomay point to
https://shop.yourcompany.com/sales/promotions/?marketing-promo=2021-cnywhich is a temporary sales promotions page targeting the shoppers during the Chinese new year of 2021.
Please note that using the setup and the code below, it’ll be possible resolve shortlinks via a single sub-domain, e.g.
go.your-domain.co. However, it’s totally possible (with some modification of the code) to resolve/re-direct via any number of domains (your own, of course) towards any other public or private URL, and all sorts of novelties. However, for brevity’s sake, I’m going to discuss the first one, single sub-domain usecase.
To setup a go-link server or short-URL resolver via a proper KV+Worker combination, we’ll go through these steps:
- The DNS resolver for the root domain (in the example below,
kmonsoor.com) needs to be Cloudflare. Because the core of the solution, the “worker”, runs on the nearest (from the user) edge of Cloudflare using a common KV (“key, value”) list.
- Write permission to the DNS configuration as you’d need to add a new AAAA DNS record.
Create the short-link map as a KV¶
We’ll start the setup by creating the short-link map, the list between the short-link segments that you (or, someone in your org) define and the actual URLs they needed to point to.
Find the KV stuff in the
Workers section. From the screenshot, please ignore the “Route” section for now.
- you’d need to create a Worker KV “Namespace”. Name the namespace as you seem fit. I named it
REDIRECTS(in all caps just as convention, not required).
- List the short-links & their respective target URLs. From the examples in the intro, the keys
cnypromoetc. would be in as the “key”, and the target full links as the respective “value”.
- Remember NOT to start the short part with ‘/’. In the code, it’ll be taken care of.
Once you’ve listed all your desired (short-link, target-link) combinations, now we have a KV on CLoudflare. However, it’s not referencable from your Worker code, not yet. Hence the next step.
Mapping a KV to a Worker variable¶
Now, we gonna map the previously created KV to a variable that can be referenced from our Workeer code. Please note that though I used diffrent names, but it can be same as well. Also note that a single KV can be accessed by multiple workers, and vice versa, a single Worker can reference multiple KVs.
Handling a route with webworker¶
Create the Worker¶
Now, we going to write Workercode that runs on V8-runtime on an nearest(from the requesting user) edge location of Cloudflare to complete its functionality and deliver it to the user. Tn this case, that would be to redirect user’s requested address to the mapped one by you, in the KV namespace above.
The code editor looks like this:
If you rather prefer to copy-paste, please feel free to do it from the below GitHub Gist.
Once done, it should look like …
Pointing a DNS record to the Worker¶
Finally, we need to point a DNS record that’ll redirect all requests to your re-soutign sub-domain (e.g.
go.your-domain.com) to the Cloudflare Worker that we just created.
According to the Cloudflare docs, the DNNS record must be an AAAA record, pointing to the IPv6 address
100:. The “Name” here is the “sub-domain” part of your choice which is better be short to serve our goal here.
Voila ! Now, test some of the short-urls that you’ve mapped via the KV. Enjoy ! Watch out for the target usage though against the limit.
I think you’ll be fine, unnless you’re some kind of celebrity ;)
As the next next step, I’m thinking to create a generic
Go/Link resolver browser extension. Then, someone can set their own default domain or company domain of choice as short-domain host. In that case, entering just
go/hr-help on the browser will take to
https://www.company-internal.com/.../hr/contact.html that we have discussed at the beginning (remember the example case of an internal human resources help portal?).
- If you want to do this url-direction on your own webserver, but only using webserver, try this: Personal short-link server using only Caddyserver