Utility for loading the Advent of Code 2020 input into the Clojure REPL on demand

aoc2020util.clj

(ns pez.aoc2020.util
  (:require [clj-http.client :as client]))

(defn fetch-input [day]
  (try
    (let [cookie (slurp ".aoc-session")]
      (:body (client/get
              (str "https://adventofcode.com/2020/day/" day "/input")
              {:cookies {"session" {:value cookie}}})))
    (catch Exception e
      (println "Ho, ho, ho! Did you forget to populate `.aoc-session` with your AOC session cookie?")
      (throw e))))

This is a utility for fetching Advent of Code 2020 input data.

How to use:

In preparation. (The cookie lives for only 10 years, so you need to redo this in a decade):

1. Be logged in at adventofcode.com/2020 and open the problem page
2. From Developer tools of the browser (Network tab), Copy the session cookie from the page resource (named just 2020 for index page).
3. Store this in the file .aoc-session at the root of your project.

When trying to collect a star or two:

1. Evaluate (util/fetch-input <day>) (probably into a def)

It looked like this in my Rich comment block for Day 2 (don't worry, no spoilers).

(comment
  (def input
    "1-3 a: abcde
1-3 b: cdefg
2-9 c: ccccccccc")
  (def input (util/fetch-input 2))
  (->> input
       (parse)
       (filter checks2?)
       (map :pwd)
       (count)))

I made do with the sample input until I thought my solution worked, then redefined input by fetching the problem input.