The beginnings of a link shortening service in Deno, using Deno KV and Oak. Live coded on 6/14 here - https://www.youtube.com/watch?v=XaZTGGnP6EU

db.ts

const kv = await Deno.openKv();

export interface Link {
  slug: string;
  destination: string;
}

export async function getLink(
  slug: string,
): Promise<Link | null> {
  if (!slug) {
    throw new Error("A slug is required!");
  }

  const res = await kv.get(["links", slug]);

  if (res.value) {
    const l: Link = res.value as Link;
    return l;
  } else {
    return null;
  }
}

export async function createLink(
  slug: string,
  destination: string,
): Promise<Link> {
  if (!slug || !destination) {
    throw new Error("A slug and destination are required!");
  }

  const key = ["links", slug];
  const value: Link = {
    slug,
    destination,
  };

  const res = await kv.atomic()
    .check({ key, versionstamp: null })
    .set(key, value)
    .commit();

  if (res.ok) {
    return value;
  } else {
    throw new Error("Could not create link!");
  }
}

server.ts

import { Application, Router } from "https://deno.land/x/oak@v12.5.0/mod.ts";
import { createLink, getLink, Link } from "./db.ts";

const app = new Application();
const api = new Router();

api.get("/:slug", async (ctx) => {
  const l: Link = await getLink(ctx.params.slug);
  console.log(ctx.params.slug);
  ctx.response.body = JSON.stringify(l);
});

api.post("/create", async (ctx) => {
  const input = await ctx.request.body({
    type: "json",
  });

  const jsonInput: any = await input.value;

  const newLink: Link = await createLink(jsonInput.slug, jsonInput.destination);

  ctx.response.body = newLink;
});

app.use(api.routes());
app.use(api.allowedMethods());

await app.listen({ port: 8000 });