compile javascript and encrypt into native module - blah

.gitignore

node_modules/
package-lock.json
plugin.c
plugin.node

build.js

#!/usr/bin/env node

const {
  readFileSync: readFile,
  writeFileSync: writeFile,
} = require('fs')

const crypto = require('ara-crypto')

function map(line) {
  return `"${line}\\n"`
}

function split(buf) {
  var list = []
  for (var i = 0; i < buf.length; i += 65535) {
    list.push(buf.slice(i, i + 65535))
  }
  return list
}

const secret = crypto.blake2b(Buffer.from(process.argv[2]), 64)
const source = String(readFile('plugin.c.in'))

const code = String(readFile('plugin/index.js'))
  .replace(RegExp("\\\\'", 'g'), '\\"')
  .replace(RegExp('\\\\"', 'g'), '\\\\"')
  .replace(RegExp('\\\\\\\\', 'g'), '\\\\\\\\')
  .replace(/"/g, '\\"')
  .split('\n')
  .map(map)
  .join('\n')

const lines = split(Buffer.from(code))
const boxes = lines.map((line) => crypto.box(Buffer.from(line), { secret }))

const plugin = boxes.map((box) => box.toString('hex')).join('|')
const wrapper = `(function(payload) {
  __dirname = 'not available'
  let sourceString = null
  try {
    const secret = Buffer.from('${secret.toString('hex')}', 'hex')
    const crypto = require('ara-crypto')
    const boxes = payload.split('|').map((hex) => Buffer.from(hex, 'hex'))
    const unboxes = boxes.map((box) => crypto.unbox(box, { secret }))
    const source = unboxes.reduce((buf, out) => Buffer.concat([buf, out]), Buffer.alloc(0))
    const lines = String(source).split('\\\\n')

    sourceString = lines.join('+ \\\\n')
  } catch (err) {
    console.error(err.stack || err)
    return
  }

  if (null !== sourceString) {
    eval('string =' + sourceString)
    eval(string)
  }
})('${plugin}')
`.split('\n').map(map).join('\n')

const output = Buffer.from(source.replace('{{SOURCE}}', `${wrapper}`))

writeFile('plugin.c', output)

index.js

const { init } = require('./init')
require('ara-crypto')

init()

module.exports = {
  init
}

init.js

const http = require('http')

function init() {
  const server = http.createServer(onrequest)
  server.listen(3000)
  console.log('hello world')
}

function onrequest(req, res) {
  res.end('hello world')
}

module.exports = {
  init
}

Makefile

CC ?= gcc

SECRET ?= secrets
PREFIX ?= /usr/local
CFLAGS += -I $(shell find $(PREFIX) -name node_api.h | head -n 1 | xargs dirname)
CFLAGS += -I node_modules/napi-macros
CFLAGS += -shared -fPIC

plugin.node: plugin.c
	$(CC) $(CFLAGS) -o $@ $^

plugin.c: plugin.c.in build.js
	./build.js $(SECRET)

plugin.c.in: plugin/index.js build.js

plugin/index.js: index.js init.js
	ncc build index.js -o plugin

package.json

{
  "name": "napi-embed-example",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "ara-crypto": "github:arablocks/ara-crypto",
    "napi-macros": "^1.8.2"
  }
}

plugin.c.in

#include <node_api.h>
#include <napi-macros.h>
#include <string.h>
#include <stdio.h>
#include <sodium.h>

const char *javascript = {{SOURCE}};

NAPI_METHOD(my_plugin_init) {
  const napi_extended_error_info *err = 0;
  napi_value result;
  napi_value string;
  napi_create_string_utf8(env, javascript, strlen(javascript), &string);
  napi_status rc = napi_run_script(env, string, &result);
  if (0 != rc) {
    napi_get_last_error_info(env, &err);
    printf("error: %s\n", err->error_message);
  }
  printf("my_plugin_init() = %d\n", rc);
  return NULL;
}

NAPI_MODULE_INIT() {
  printf("Init plugin\n");
  NAPI_EXPORT_FUNCTION(my_plugin_init)
}