https://www.davidebarranca.com/2014/08/html-panels-tips-13-automate-zxp-packaging-with-gulp-js/

gulpfile.js

var gulp = require('gulp'); 
var clean = require('gulp-clean');
var shell = require('gulp-shell');

// 0. Clean all ZXPs found everywhere
gulp.task('clean-all', function () {
	return gulp.src('./**/*.zxp', { read: false })
	.pipe(clean());
});

// 1. Build the HTML Panel ZXP in src/
gulp.task('pack-html',  
	shell.task('./ZXPSignCmd -sign src/com.example.myExtension src/com.example.myExtension.zxp myCertificate.p12 myPassword -tsa https://timestamp.geotrust.com/tsa')
);

// 2. Copy the ZXP in src/ to src/MXI/HTML/
gulp.task('move-html-zxp', ['pack-html'], function (){
	return gulp.src('./src/*.zxp', { base: './src/' })
	.pipe(gulp.dest('./src/MXI/HTML'));
});

// 3. Delete the HTML Panel ZXP in src/
gulp.task('clean-html-zxp', ['move-html-zxp'], function () {
	return gulp.src('./src/*.zxp', { read: false })
	.pipe(clean());
});

// 4. Build the hybrid ZXP in src/
gulp.task('pack-hybrid-zxp', ['clean-html-zxp'], 
	shell.task('java -jar ucf.jar -package -storetype PKCS12 -keystore ./myCertificate.p12 -storepass myPassword -tsa http://timestamp.entrust.net/TSS/JavaHttpTS com.example.myExtension.zxp -C "./src/MXI/" .')
);

// 5. Copy the hybrid ZXP to build/
gulp.task('move-zxp-to-build', ['pack-hybrid-zxp'], function () {
	return gulp.src('./*.zxp', { base: './' })
	.pipe(gulp.dest('build'));
});

// 6. Delete the hybrid ZXP in src/
gulp.task('clean-hybrid-zxp', ['move-zxp-to-build'], function () {
	return gulp.src('./*.zxp', { read: false })
	.pipe(clean());
});

// 7. Define the default task
gulp.task('default', ['clean-all'], function () {
	gulp.start('clean-hybrid-zxp');
});