Convert an image url to a data URI without canvas

image-url-to-data-uri.js

// hard won knowledge from http://stackoverflow.com/questions/20035615/using-raw-image-data-from-ajax-request-for-data-uri
var xmlHTTP = xhr.XMLHttpRequest();
xmlHTTP.open('GET', url, true);
xmlHTTP.responseType = 'arraybuffer';
xmlHTTP.onload = function(e) {
  var arr = new Uint8Array(this.response);
  var raw = String.fromCharCode.apply(null,arr);
  var b64 = base64.encode(raw);
  var dataURL="data:image/png;base64," + b64;
};
xmlHTTP.send();

function toDataURL(url, callback) {
  var xhr = new XMLHttpRequest();
  xhr.onload = function() {
    var reader = new FileReader();
    reader.onloadend = function() {
      callback(reader.result);
    }
    reader.readAsDataURL(xhr.response);
  };
  xhr.open('GET', url);
  xhr.responseType = 'blob';
  xhr.send();
}

toDataURL('https://www.gravatar.com/avatar/d50c83cc0c6523b4d3f6085295c953e0', function(dataUrl) {
  console.log('RESULT:', dataUrl)
})

@CalebMacdonaldBlack seems to be having CORS error in XHR.
Any comments on this ??

@CalebMacdonaldBlack seems to be having CORS error in XHR.
Any comments on this ??

same problem

@CalebMacdonaldBlack
thanks a lot for this solution

Rewrote this into re-frame / ajax-cljs

(require '[ajax.protocols :as pr])

;; effecting with re-frame-http-fx
{:http-xhrio {,,,
              :response-format {:content-type "image/png"
                                :description "PNG image"
                                :read pr/-body
                                :type :arraybuffer}
              :on-success [::my-handler]}

(rf/reg-event-db
 ::my-handler
  (fn [db [_ response]]
    (assoc db :thing (->> response
                          (js/Uint8Array.)
                          (js/String.fromCharCode.apply nil)
                          (js/btoa)
                          (str "data:image/png;base64,")))))