deps-try recipe to step through examples of https://www.juxt.pro/blog/uri-templates/

juxt_blog_uri_template.clj

;; Use this file with [deps-try](https://github.com/eval/deps-try)
;; $ deps-try --recipe https://gist.github.com/eval/5af8064aa31bb981f573c3b4a9bb6684/raw
(ns recipes.juxt-blog-uri-template
  "Recipe to step through the examples from https://www.juxt.pro/blog/uri-templates/"
  {:deps-try.recipe/deps ["https://github.com/juxt/reap"]}
  (:require [juxt.reap.rfc6570 :refer [compile-uri-template make-uri match-uri]]))

;; helper-fns
(defn render [tpl variables]
  (make-uri (compile-uri-template tpl) variables))

(defn extract [tpl variable-types uri]
  (match-uri
   (compile-uri-template tpl)
   variable-types
   uri))


;; TIP to eval single expression place cursor behind it and press Ctrl-c Ctrl-e
;; TIP submit step with Ctrl-x Ctrl-m
;;
;; simple URI template
(def tpl1 "http://example.com/~{username}/")

;; render
(make-uri (compile-uri-template tpl1) {:username "malcolm"})

;; same but using the recipe helper
(render tpl1 {:username "malcolm"})


;; More complex template
(def tpl2 "https://{env}bank.com{/ctx*}/accounts/{accno}/transactions{.format}{?from,to}{#frag}")

;; env - An optional string so we can generate, say, https://uat.bank.com for testing.
;; /ctx* - The forward-slash indicates this is a path segment. The asterisk modifies this to mean it can have multiple segments.
;; accno - This will be the account number of our bank account.
;; .format - This might be .csv or .json.
;; from - The start of the date range.
;; to - The end of the date range.
;; #frag - An optional fragment, the #-prefix indicates ‘fragment expansion’.

;; render
(render tpl2 {:ctx    ["europe" "uk"]
              :accno  "12345678"
              :format "csv"
              :from   "20201010"
              :to     "20201110"})


;; The reverse: extract data from a uri.
(match-uri
 (compile-uri-template tpl2)

  ;; Specify the types of the variables we want to extract
 {:env    :string
  :frag   :string
  :accno  :string
  :ctx    :list
  :format :string
  :from   :string
  :to     :string}

 "https://bank.com/europe/uk/accounts/12345678/transactions.csv?from=20201010&to=20201110")

;; same but using the recipe helper-fn
(extract tpl2
         {:env    :string
          :frag   :string
          :accno  :string
          :ctx    :list
          :format :string
          :from   :string
          :to     :string}
         "https://bank.com/europe/uk/accounts/12345678/transactions.csv?from=20201010&to=20201110")