ADD unit tests, split and refactor source code

src/actions/install.js

@@ -0,0 +1,52 @@
+const mkdirp = require('mkdirp');
+const request = require('request');
+const { parsePackageJson } = require('../common');
+const verifyAndPlaceBinary = require('../assets/binary');
+
+/**
+ * Select a resource handling strategy based on given options.
+ */
+function getStrategy({ url }) {
+
+  if (url.endsWith('.tar.gz')) {
+      return require('../assets/untar');
+  } else {
+      return require('../assets/move');
+  }
+}
+
+/**
+ * Reads the configuration from application's package.json,
+ * validates properties, downloads the binary, untars, and stores at
+ * ./bin in the package's root. NPM already has support to install binary files
+ * specific locations when invoked with "npm install -g"
+ *
+ *  See: https://docs.npmjs.com/files/package.json#bin
+ */
+function install(callback) {
+
+  const opts = parsePackageJson();
+  if (!opts) return callback('Invalid inputs');
+
+  mkdirp.sync(opts.binPath);
+
+  console.log('Downloading from URL: ' + opts.url);
+
+  const req = request({ uri: opts.url });
+
+  req.on('error', () => callback('Error downloading from URL: ' + opts.url));
+  req.on('response', (res) => {
+      if (res.statusCode !== 200) return callback('Error downloading binary. HTTP Status Code: ' + res.statusCode);
+
+      const strategy = getStrategy(opts);
+
+      strategy({
+          opts,
+          req,
+          onSuccess: () => verifyAndPlaceBinary(opts.binName, opts.binPath, callback),
+          onError: callback
+      });
+  });
+}
+
+module.exports = install;