rebasematic.js

#!/usr/bin/env node

var assert = require('assert');
var childProcess = require('child_process');

var express = require('express');
var request = require('request');

var app = express();

app.get('/', function(req, res, next) {
  var uri = req.query.url;

  console.log(uri);

  function errorResponse(reason) {
    return '<h1><a href="' + uri + '">' + reason + '</a></h1>';
  }

  var repository;
  function start() {
    if (uri.match(/\?url=([^&=]+)/)) {
      return res.redirect(uri);
    }

    // https://github.com/dohse/test/pull/1
    var match = uri.match(/github\.com\/([^\/]+\/[^\/]+)\/pull\/(\d+)/);
    if (!match) {
      return res.send(errorResponse('Invalid Site'));
    }

    repository = match[1];
    var pullRequestNumber = match[2];

    // GET /repos/:owner/:repo/pulls/:number
    var pullRequestUrl = 'https://api.github.com/repos/' + repository +
                         '/pulls/' + pullRequestNumber;
    var options = {
      method: 'get',
      url: pullRequestUrl,
      qs: {
        access_token: process.env.GITHUB_TOKEN
      },
      headers: {
        'user-agent': 'Rebasematic'
      },
      json: true
    };
    request(options, handlePullRequest);
  }

  function handlePullRequest(err, githubRes) {
    if (err) {
      return next(err);
    }

    if (githubRes.statusCode !== 200) {
      return res.send(errorResponse('Github API access failed'));
    }

    var branch = githubRes.body.head.ref;

    var command = [
      'mkdir -p $1',
      'exec {LOCK}<$1',
      'flock -x $LOCK',
      '[[ -e $1/.git ]] || git clone github.com:$1 $1',
      'cd $1',
      'git fetch',
      'git checkout -B rebase origin/$2',
      'if ! git rebase origin/master',
      'then',
      '    git rebase --abort',
      '    false',
      'fi',
      'git push -f origin HEAD:$2'
    ].join('\n');
    var args = ['-euc', command, '-', repository, branch];
    var options = {
      cwd: process.env.REBASEMATIC_WORKDIR,
      stdio: 'inherit'
    };
    childProcess.spawn('/bin/bash', args, options).once('exit', handleDone);
  }

  function handleDone(code, signal) {
    if (code !== 0) {
      return res.send(errorResponse('Rebase failed'));
    }

    res.redirect(uri);
  }

  start();
});

app.listen(Number(process.env.REBASEMATIC_PORT || '19585'));