A node script that abuses child_process to run cfx and post the resulting xpi to Firefox. Requires: *nix, a working installation of the Add-on SDK ( with cfx on your PATH ) and a recent version of Firefox with the 'Extension Auto-installer' extension installed.

install-addon

#!/usr/bin/env node

var util = require('util'),
  fs = require('fs'),
  path = require('path'),
  http = require('http'),
  _ = require('lodash'),
  url = require('url');

var DEBUG = false,
  host = 'http://127.0.0.1:8888/';



if (!module.parent) {
  /*
    1. get some info from package.json
    2. run cfx
    3. on completion, post the xpi file to Firefox
  */
  var xpi = false;
  var cwd = process.cwd();
  var spawn = require('child_process').spawn;
  var optimist = require('optimist');

  var argv = optimist
    .usage('addon-install -h http://localhost:888/')
    .default({h: host})
    .describe('h', 'The host and port that the extension auto-installer is listening on')
    .alias('p', 'port')
    .argv;

  fs.readFile(path.join(cwd, 'package.json'),
    {encoding: 'utf8'},
    function(err, buffer) {
      //
      if (err) throw err;
      // console.log(buffer);

      var package_data = JSON.parse(buffer),
        xpi_name = package_data.name + '.xpi';

      console.log("Building %s", xpi_name);

      var builder = spawn('cfx', ['xpi'], {cwd: cwd});

      builder.stdout.on('data', function(data) {
        console.log("cfx> %s", data);
      });

      builder.stderr.on('data', function(data) {
        console.log("cfx> %s", data);
      });

      builder.on('error', function(err) {
        console.log([].slice.call(arguments));
      });

      builder.on('close', function(err, result) {
        post_file = spawn('wget', ['--post-file='+xpi_name, host], {cwd: cwd});
        post_file.stderr.on('data', function(data) {
          console.log("wget> %s", data);
        });
        post_file.stdout.on('data', function(data) {
          console.log("wget> %s", data);
        });
        post_file.on('close', function(err, result) {
          console.log("done?");
        });
      });
  });
}

What if we use http module instead of wget?

Here is an example:

var req = http.request(host, function (res) {
    console.log('status:', res.statusCode, res.statusMessage);
    res.on('data', function (d) {
        process.stdout.write(d);
    });
});

var xpi = fs.createReadStream(path.resolve(cwd, xpi_name));
xpi.pipe(req);

req.on('error', function (err) {
    console.log(err);
});

https://gist.github.com/duzun/d1b90826e6fbbb7bd8b0