Getting fastboot POSTs working for ember serve:

gistfile1.txt

// lib/post-middleware/package.json
{
  "name": "post-middlware",
  "keywords": [
    "ember-addon"
  ],
  "ember-addon": {
    "before": "broccoli-watcher"
  }
}


// lib/post-middleware/index.js
/*eslint-env node */

const HistorySupport = require('./history-support-addon'); (change to real history support lib path in ember-cli if >= 2.16)
const cleanBaseURL = require('clean-base-url');

class PostFriendlyHistorySupport extends HistorySupport {
  constructor(project) {
    super(project);
  }

  shouldAddMiddleware(environment) {
    let config = this.project.config(environment);
    let locationType = config.locationType;
    return ['auto', 'history'].indexOf(locationType) !== -1;
  }

  shouldHandleRequest(req, options) {
    //code here to allow POSTs
}

module.exports = PostFriendlyHistorySupport;

// package.json
 ...
   "ember-addon": {
    "paths": [
      "lib/post-middleware"
    ],
    
 ...
 
// config/environment.js
    ...
    historySupportMiddleware: false,
    ...