Python UI Website Blocker

website_blocker.py

#!/usr/bin/env python3

from PySide6.QtWidgets import (
    QApplication,
    QMessageBox,
    QWidget,
    QLabel,
    QPushButton,
    QVBoxLayout,
    QPlainTextEdit
)


app = QApplication([])
app.setStyle('macos')
window = QWidget()
v_layout = QVBoxLayout()

cancelBtn = QPushButton('Cancel')
saveBtn = QPushButton('Save')
textBox = QPlainTextEdit()

f = open("/etc/hosts")
etc_contents = f.read()
f.close()

backup = open('/etc/.hosts_backup', 'a')
backup.truncate(0)
backup.write(etc_contents)
backup.close()

do_not_delete = etc_contents.split("# BLOCK_SITES\n")[0]
block_sites_segment = etc_contents.split("# BLOCK_SITES\n")[1]
blocked_sites_lines = block_sites_segment.split('\n')

def parse_urls(blocked_site_lines):
    result = []
    for line in blocked_sites_lines:
        if(line.startswith('127.0.0.1')):
           result.append(line.split(' ')[1])
    return result

urls = parse_urls(blocked_sites_lines)
print(urls)

textBox.setPlainText('\n'.join(urls))

v_layout.addWidget(QLabel('Block Sites'))
v_layout.addWidget(textBox)
v_layout.addWidget(cancelBtn)
v_layout.addWidget(saveBtn)

def on_cancel():
    QApplication.closeAllWindows()

def format_urls(urls):
    result = []
    for url in urls:
        result.append('127.0.0.1 ' + url + '\n')
        result.append(url + ' 127.0.0.1 \n')
    return result

def on_save():
    new_urls = textBox.toPlainText().split('\n')
    new_contents = ''.join([do_not_delete, '# BLOCK_SITES\n', *format_urls(new_urls)])
    f = open('/etc/hosts', 'a')
    f.truncate(0)
    f.write(new_contents)
    f.close()
    alert = QMessageBox()
    alert.setText('Saved Blocked Sites')
    alert.exec()

cancelBtn.clicked.connect(on_cancel)
saveBtn.clicked.connect(on_save)

window.setLayout(v_layout)
window.show()
app.exec()