Deno nuggets: Get path and query params in Oak

This article is a part of the Deno nuggets series, where each article attempts to suggest a pointed solution to a specific question that can be read in less than a minute. There is no ordering of nuggets.

Problem

How to access path & query params in Oak?

P-indicates path param

Q-indicates query param

http://localhost:8080/products/101/review/201?sort=recent&limit=100
                                P          P          Q          Q 

Solution

Oak middleware framework automatically parses the path and query params. No explicit parsing is required. Both type of params are accessed from different places and in different ways.

Query params

Query params are accessed through the searchParams (of type URLSearchParams) attribute in context’s request’s url object. The URLSearchParams is a web standard object with APIs like has, get, entries, etc.

ctx.request.url.searchParams
ctx.request.url.searchParams.get('someParam');

Path params

The path params are available at context level in params attribute. It’s a simple JS object.

ctx.params.someParam
ctx.params.someOtherParam

Here is the code of an application that prints both the query and path params:

import { Application, Router } from "https://deno.land/x/oak/mod.ts";
const app = new Application();
const router = new Router();
router.get("/products/:prdId/images/:imgId", (ctx) => {
  console.log("QUERY PARAMS:");
  ctx.request.url.searchParams.forEach((v, k) => console.log(`${k}:${v}`));
  console.log("PATH PARAMS:");
  console.log(ctx.params);
});
app.use(router.routes());
app.use(router.allowedMethods());
app.listen({ port: 8080 });

Here is a quick run:

> curl "http://localhost:8080/products/101/images/201?a=b&c=d"
> > deno run --allow-net app.ts 
QUERY PARAMS:
a:b
c:d
PATH PARAMS:
{ prdId: "101", imgId: "201" }