initially draft the idea

mastodon_bot/infra.cljs

@@ -0,0 +1,41 @@
+(ns mastodon-bot.infra
+  (:require
+   [cljs.reader :as edn]
+   [clojure.set :refer [rename-keys]]
+   [clojure.string :as string]))
+
+(defn exit-with-error [error]
+  (js/console.error error)
+  (js/process.exit 1))
+
+(defn find-config []
+  (let [config (or (first *command-line-args*)
+                   (-> js/process .-env .-MASTODON_BOT_CONFIG)
+                   "config.edn")]
+    (if (fs/existsSync config)
+      config
+      (exit-with-error (str "failed to read config: " config)))))
+
+(def config (-> (find-config) (fs/readFileSync #js {:encoding "UTF-8"}) edn/read-string))
+
+(def mastodon-config (:mastodon config))
+
+(defn js->edn [data]
+  (js->clj data :keywordize-keys true))
+
+(defn trim-text [text]
+  (cond
+
+    (nil? max-post-length)
+    text
+
+    (> (count text) max-post-length)
+    (reduce
+     (fn [text word]
+       (if (> (+ (count text) (count word)) (- max-post-length 3))
+         (reduced (str text "..."))
+         (str text " " word)))
+     ""
+     (string/split text #" "))
+
+    :else text))

mastodon_bot/mastodon_api.cljs

@@ -0,0 +1,96 @@
+(ns mastodon-bot.mastodon-api
+  (:require
+   [clojure.spec.alpha :as s]
+   [clojure.spec.test.alpha :as st]
+   [orchestra.core :refer-macros [defn-spec]]
+   [cljs.reader :as edn]
+   [clojure.set :refer [rename-keys]]
+   [clojure.string :as string]
+   [mastodon-bot.infra :as infra]
+   ["mastodon-api" :as mastodon]))
+
+; Todo: think about how namespaced keywords & clj->js can play nicely together
+(s/def :access_token string?)
+(s/def :account-id string?)
+(s/def :api_url string?)
+
+(s/def ::mastodon-config (s/keys :req [:access_token :account-id :access_token]))
+
+(defn-spec mastodon-config ::mastodon-config
+  [config any?] 
+  (:mastodon config))
+
+(defn-spec mastodon-client any?
+  [mastodon-config ::mastodon-config]
+  (or (some-> mastodon-config clj->js mastodon.)
+      (infra/exit-with-error "missing Mastodon client configuration!")))
+
+(def content-filter-regexes (mapv re-pattern (:content-filters mastodon-config)))
+
+(def keyword-filter-regexes (mapv re-pattern (:keyword-filters mastodon-config)))
+
+(def append-screen-name? (boolean (:append-screen-name? mastodon-config)))
+
+(def max-post-length (:max-post-length mastodon-config))
+
+(defn blocked-content? [text]
+ (boolean
+   (or (some #(re-find % text) content-filter-regexes)
+       (when (not-empty keyword-filter-regexes)
+             (empty? (some #(re-find % text) keyword-filter-regexes))))))
+
+(defn delete-status [status]
+  (.delete mastodon-client (str "statuses/" status) #js {}))
+
+(defn set-signature [text]
+  (if-let [signature (:signature mastodon-config )]
+    (str text "\n" signature)
+    text))
+
+(defn post-status
+  ([status-text]
+   (post-status status-text nil))
+  ([status-text media-ids]
+   (let [{:keys [sensitive? signature visibility]} mastodon-config]
+     (.post mastodon-client "statuses"
+          (clj->js (merge {:status (-> status-text resolve-urls set-signature)}
+                          (when media-ids {:media_ids media-ids})
+                          (when sensitive? {:sensitive sensitive?})
+                          (when visibility {:visibility visibility})))))))
+
+(defn post-image [image-stream description callback]
+  (-> (.post mastodon-client "media" #js {:file image-stream :description description})
+      (.then #(-> % .-data .-id callback))))
+
+(defn post-status-with-images
+  ([status-text urls]
+   (post-status-with-images status-text urls []))
+  ([status-text [url & urls] ids]
+   (if url
+     (-> request
+         (.get url)
+         (.on "response"
+           (fn [image-stream]
+             (post-image image-stream status-text #(post-status-with-images status-text urls (conj ids %))))))
+     (post-status status-text (not-empty ids)))))
+
+(defn get-mastodon-timeline [callback]
+  (.then (.get mastodon-client (str "accounts/" (:account-id mastodon-config)"/statuses") #js {})
+         #(let [response (-> % .-data js->edn)]
+            (if-let [error (:error response)]
+              (exit-with-error error)
+              (callback response)))))
+
+(defn perform-replacements [post]
+  (assoc post :text (reduce-kv string/replace (:text post) (:replacements mastodon-config)))
+  )
+
+(defn post-items [last-post-time items]
+  (doseq [{:keys [text media-links]} (->> items
+                                          (remove #(blocked-content? (:text %)))
+                                          (filter #(> (:created-at %) last-post-time))
+                                          (map perform-replacements))]
+    (if media-links
+      (post-status-with-images text media-links)
+      (when-not (:media-only? mastodon-config)
+        (post-status text)))))

mastodon_bot/twitter_api.cljs

@@ -0,0 +1,58 @@
+(ns mastodon-bot.twitter-api
+  (:require
+   [clojure.set :refer [rename-keys]]
+   [clojure.string :as string]
+   ["deasync" :as deasync]
+   ["request" :as request]
+   ["twitter" :as twitter]))
+
+
+(defn resolve-url [[uri]]
+  (try
+    (or
+      (some-> ((deasync request)
+               #js {:method "GET"
+                    :uri (if (string/starts-with? uri "https://") uri (str "https://" uri))
+                    :followRedirect false})
+              (.-headers)
+              (.-location)
+              (string/replace "?mbid=social_twitter" ""))
+      uri)
+    (catch js/Error _ uri)))
+
+(def shortened-url-pattern #"(https?://)?(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?")
+
+(defn resolve-urls [text]
+  (cond-> text
+    (:resolve-urls? mastodon-config)
+    (string/replace shortened-url-pattern resolve-url)
+    (:nitter-urls? mastodon-config)
+    (string/replace #"https://twitter.com" "https://nitter.net")))
+
+; If the text ends in a link to the media (which is uploaded anyway),
+; chop it off instead of including the link in the toot
+(defn chop-tail-media-url [text media]
+  (string/replace text #" (\S+)$" #(if (in (%1 1) (map :url media)) "" (%1 0))))
+
+(defn parse-tweet [{created-at            :created_at
+                    text                  :full_text
+                    {:keys [media]}       :extended_entities
+                    {:keys [screen_name]} :user :as tweet}]
+  {:created-at (js/Date. created-at)
+   :text (trim-text (str (chop-tail-media-url text media) (if append-screen-name? ("\n - " screen_name) "")))
+   :media-links (keep #(when (= (:type %) "photo") (:media_url_https %)) media)})
+
+(defn post-tweets [last-post-time]
+  (fn [error tweets response]
+    (if error
+      (exit-with-error error)
+      (->> (js->edn tweets)
+           (map parse-tweet)
+           (post-items last-post-time)))))
+
+(defn twitter-client [access-keys]
+  (try
+    (twitter. (clj->js access-keys))
+    (catch js/Error e
+      (exit-with-error
+       (str "failed to connect to Twitter: " (.-message e))))))

shadow-cljs.edn

@@ -1,5 +1,5 @@
 {:source-paths ["mastodon_bot"]
- :dependencies []
+ :dependencies [[orchestra "2018.12.06-2"]]
  :builds       {:app {:target    :node-script
                       :output-to "target/mastodon-bot.js"
                       :main      mastodon-bot.core/main