Dec. 30, 2022

Mastodon is a real breeze to develop for. I was able to use nbb (Clojure scripting on Node.js) to post an image using the API in a few minutes. Here's how.

Step 1: Create a new Mastodon app.

Go to Preferences -> Development -> New Application, or visit /settings/applications/new on your Mastodon server.


Step 2: Store the access token

Once that is done copy the "Access token" and your server's URL. Put them in an env file:

export MASTO_SERVER=...

Get these into your current environment (or use direnv etc.):

. ./env

Step 3: Set up nbb & libraries

echo {} > package.json
npm i nbb masto

Step 4: Create the code

In a file called post-image.cljs put the following code:

(ns post-image
    [promesa.core :as p]
    [applied-science.js-interop :as j]
    ["fs" :refer [readFileSync]]
    ["process" :refer [env]]
    ["masto" :refer [login]]))

(p/let [masto (login #js {:url (j/get env :MASTO_SERVER) :accessToken (j/get env :MASTO_ACCESS_TOK)})
        attachment (j/call-in masto [:v2 :mediaAttachments :create] #js {:file (readFileSync (last argv))
                                                                         :description "Test image"})
        status (j/call-in masto [:v1 :statuses :create] #js {:status "Hello this is a test!"
                                                             :visibility "public"
                                                             :mediaIds #js [(j/get attachment :id)]})]
  (js/console.log status))

Step 5: Test it.

npx nbb post-image.cljs some-image.png

Congratulations, you now have an nbb script which can post images to Mastodon. Enjoy!

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