LudumDare web build download and extract

package.json

{
  "name": "ld-pull",
  "version": "1.0.0",
  "description": "Pull LudumDare web builds and unpack them",
  "main": "pull.js",
  "dependencies": {
    "request": "^2.72.0"
  },
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Colin Kennedy <moshen.colin@gmail.com>",
  "license": "MIT"
}

pull.js

const request = require('request'),
  spawn = require('child_process').spawn,
  buildRegex = /build-([0-9]+)-web/;

const ludumDareNum = process.argv[process.argv.length - 1];

if (ludumDareNum !== Number(ludumDareNum).toString()) {
  console.error('Pass a valid number');
  process.exit(1);
}

const downloadUrlBase = 'https://dl.bintray.com/bploeckelman/LudumDare/',
  apiUrl = 'https://api.bintray.com/packages/bploeckelman/LudumDare/LudumDare' + ludumDareNum + '/files';

function getBuildNumber(name) {
  const matches = name.match(buildRegex);
  if(matches && matches.length > 1) {
    return +matches[1];
  }

  return 0;
}

async function getFromApi() {
  return new Promise((resolve, reject) => {
    request({
      method: 'GET',
      url: apiUrl,
      json: true
    }, function(err, res, body) {
      if (err) {
        return reject(err);
      }

      if (res.statusCode > 299) {
        return reject(body);
      }

      resolve(body);
    });
  });
}

async function doPull() {
  const body = await getFromApi();

  if (!body instanceof Array) {
    return Promise.reject('Didn\'t get a result back');
  }

  const latest = body.reduce((memo, file) => {
    file.buildNumber = getBuildNumber(file.name);

    if (!memo) {
      return file;
    }

    if (file.buildNumber > memo.buildNumber) {
      return file;
    }

    return memo;
  }, false);

  console.log('Downloading', latest.name);

  return new Promise((resolve, reject) => {
    // The directory needs to exist for this to work, look at `run`
    const tar = spawn('bsdtar', ['-xf', '-', '-C', ludumDareNum]);
    tar.on('error', reject)
    .on('close', code => {
      if (code !== 0) {
        return reject('Unzip failed');
      }

      resolve();
    });

    request({
      method: 'GET',
      url: downloadUrlBase + latest.name,
    })
    .pipe(tar.stdin)
    .on('error', reject);
  });
};

doPull()
.catch(err => {
  console.log(err);
  process.exit(1);
});

run

#!/bin/bash

# Which Ludum Dare number to get
LUDUM_DARE_NUM=39

# Stash the current build in case fetching fails
if [[ -d $LUDUM_DARE_NUM ]]; then
  mv $LUDUM_DARE_NUM "${LUDUM_DARE_NUM}-old"
fi
mkdir $LUDUM_DARE_NUM

# Fetch and unpack the new build
[[ -s $HOME/.nvm/nvm.sh ]] && . $HOME/.nvm/nvm.sh # This loads NVM
nvm use 8
node pull.js $LUDUM_DARE_NUM

# If we failed to fetch the new build, put the old one back
# If we don't have an "old" one, do nothing
if [[ $? -gt 0 ]] && [[ -d "${LUDUM_DARE_NUM}-old" ]]; then
  rm -rf $LUDUM_DARE_NUM
  mv "${LUDUM_DARE_NUM}-old" $LUDUM_DARE_NUM
elif [[ -d "${LUDUM_DARE_NUM}-old" ]]; then
  rm -rf "${LUDUM_DARE_NUM}-old"
fi

Requires nvm with node 8 installed