webpack-generate-widget-hash.js

const fs = require('fs')
const crypto = require('crypto')
const execSync = require('child_process').execSync

function GenerateWidgetHash(options) {
	const apply = function(compiler) {
		compiler.plugin('emit', function(compilation, callback) {

			// if widget isnt in options or it isnt in the output, just warn and exit
			if (typeof options.widget == 'undefined' || typeof compilation.assets[options.widget] == 'undefined') {
				console.warn('Widget Hash generator couldnt locate ' + options.widget)
				callback()
				return
			}


			const wigtData = compilation.assets[options.widget].source()

			// calculate hashes based on the wigt file
			var hashmd5 = crypto.createHash('md5').update(wigtData).digest('hex')
			var hashSha1 = crypto.createHash('sha1').update(wigtData).digest('hex')
			var hashsha256 = crypto.createHash('sha256').update(wigtData).digest('hex')

			// get some build environment information
			var date = new Date()
			var gitCommit = 'unkown'
			var email = 'unkown'
			var user = 'unkown'
			var gitRemote = 'unkown'

			try {
				gitCommit = execSync('git rev-parse HEAD').toString()
				gitRemote = execSync('git remote get-url origin').toString()
				email = execSync('git config user.email').toString()
				user = execSync('git config user.name').toString()
			} catch (error) {
				console.log('Error getting build data')
				console.warn(error)
			}

			// build checksum content
			var checksumYAML =
				`build_date: ${date.toISOString()}` +
				'\r\n' +
				`git: ${gitRemote.trim()}` +
				'\r\n' +
				`git_version: ${gitCommit.trim()}` +
				'\r\n' +
				`git_user: ${user.trim()}` +
				'\r\n' +
				`git_user_email: ${email.trim()}` +
				'\r\n' +
				`sha1: ${hashSha1.trim()}` +
				'\r\n' +
				`sha256: ${hashsha256.trim()}` +
				'\r\n' +
				`md5: ${hashmd5.trim()}` +
				'\r\n'

			// add checksum to the output (this is how webpack gets assets)
			compilation.assets[options.output] = {
				source: function() {
					return checksumYAML
				},
				size: function() {
					return checksumYAML.length
				}
			}

			callback()
		})
	}

	return {
		apply: apply
	}
}

module.exports = GenerateWidgetHash