index.js

import RSVP from 'rsvp';
import Response from 'ember-cli-mirage/response';
import {
  extractFormData,
  extractFileMetadata
} from './utils';

const NETWORK = {
  'wired': 50000, // 500 Mb/s
  'wifi': 15000, // 15 Mb/s
  'dsl': 1000,  // 1 Mb/s
  '4g': 3000,  // 4 Mb/s
  '3g': 250,   // 250 kb/s
  '2g': 50,    // 50 kb/s
  'gprs': 20,    // 20 kb/s
  'offline': 0
};

export function upload(fn, options={ network: null, timeout: null }) {
  return function (db, request) {
    let speed = Infinity;

    if (NETWORK[options.network]) {
      speed = NETWORK[options.network] * 1024;
    }

    let { file, data } = extractFormData(request.requestBody);
    let loaded = 0;
    let total = file.value.size;

    return new RSVP.Promise((resolve) => {
      let start = new Date().getTime();
      let metadata = extractFileMetadata(file.value);

      let upload = () => {
        let timedOut = options.timeout && new Date().getTime() - start > options.timeout;
        if (timedOut || loaded >= total) {
          request.upload.onprogress({
            lengthComputable: true,
            total,
            loaded: Math.min(loaded, total)
          });

          metadata.then((metadata) => {
            request.requestBody = Object.assign({
              [file.key]: metadata
            }, data);
            if (timedOut) {
              resolve(new Response(408));
              return;
            }

            resolve(fn.call(this, db, request));
          }).catch((error) => {
            resolve(new Response(500, {}, { error: error.message }));
          });
        } else {
          request.upload.onprogress({
            lengthComputable: true,
            total,
            loaded
          });

          loaded += speed / 20;
          setTimeout(upload, 50);
        }
      };
      upload();
    });
  };
}