Nix and npm-shrinkwrap

builder.sh

source $stdenv/setup

# Place npm-shrinkwrap.json alongside package.json
ln -s $NPM_SHRINKWRAP ./npm-shrinkwrap.json

# Create fake package.json. This is not used by npm when npm-shrinkwrap.json is available, but npm does parse this as json
echo "{}" > package.json

# Create fake HOME directory for npm
export HOME=$PWD/home
mkdir -p $HOME

npm install

for package in node_modules/**/package.json
do
	node $clean_package_js $package
done

cp -r node_modules $out

fetchnpm.nix

{stdenv, writeScript, git, nodejs, cacert}:
{ name, shrinkwrap, sha256 }:
stdenv.mkDerivation {
  inherit name;
  builder = ./builder.sh;
  buildInputs = [ git nodejs ];

  outputHashAlgo = "sha256";
  outputHashMode = "recursive";
  outputHash = sha256;

  GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
  NPM_SHRINKWRAP = shrinkwrap;
  clean_package_js = writeScript "clean-package.js" ''
    var fs = require('fs');
    var filePath = process.argv[2];
    console.log("Cleaning up", filePath);
    var fileContents = fs.readFileSync(filePath);
    var packageContents = JSON.parse(fileContents);
    delete packageContents._shasum;
    delete packageContents._from;
    fileContents = JSON.stringify(packageContents);
    fs.writeFileSync(filePath, fileContents);
  '';


  preferLocalBuild = true;
}