kittens.clj

(ns kittens.core
  (:require [environ.core :refer (env)]
            [clj-http.client :as http]
            [clojure.java.io :as io]
            [clojure.core.async :as async :refer (go go-loop <!)]))

(def api-key (-> env :dev :flickr :api-key))
(def rest-api-url "https://api.flickr.com/services/rest/")
(def folder "photos")

(defn photo-map->url [m]
  "https://farm{farm-id}.staticflickr.com/{server-id}/{id}_{secret}_[mstzb].jpg
b - large, 1024 on longest side
k - large 2048, 2048 on longest side
"
  (str "https://farm" (:farm m) ".staticflickr.com/"
       (:server m) "/" (:id m) "_" (:secret m) "_b.jpg"))

(defn search
  ([query] (search query 1 500))
  ([query page per-page]
   (-> (http/get rest-api-url
                 {:as :json
                  :query-params
                  {:method "flickr.photos.search"
                   :api_key api-key
                   :text query
                   :format "json"
                   :sort "interestingness-desc"
                   :nojsoncallback 1
                   :content_type 1
                   :page page
                   :extras "original_format"
                   :per_page per-page
                   :license "1,2,3"}})
       :body :photos :photo)))

;; https://api.flickr.com/services/rest/?method=flickr.photos.search&api_key=86d&text=kittens&license=&format=json&nojsoncallback=1

(defn store
  "Store photo unless already exists"
  [m]
  (let [fn (str folder "/" (:id m) ".jpg")]
    (when-not (.exists (io/as-file fn))
      (let [url (photo-map->url m)
            response (http/get url {:as :byte-array
                                    :follow-redirects false})]
        (when (= (:status response) 200)
          (with-open [o (io/output-stream fn)]
            (.write o
                    (:body response))))))))

(defonce kittens (search "kittens"))

(defn writer
  [c]
  (go-loop []
    (when-let [p (<! c)]
      (store p)
      (recur))))

(defn run []
  (let [n 100
        c (async/chan n)
        ws (dotimes [_ n]
             (writer c))
        c2 (async/onto-chan c kittens)]
    (time
     (async/<!! c2))))