Code for How to Build a Website Blocker in Python Tutorial

website_blocker.py

#!/usr/bin/env python3 """ Website Blocker — Block distracting websites by modifying the hosts file. This script adds entries to your system's hosts file to redirect specified websites to 127.0.0.1 (localhost), effectively blocking them. Usage: sudo python website_blocker.py block # Block all sites sudo python website_blocker.py unblock # Unblock all sites python website_blocker.py status # Show blocked sites """ import sys import platform # ============================================================ # CONFIGURATION — edit this list to block different sites # ============================================================ SITES_TO_BLOCK = [ # Social media "www.facebook.com", "facebook.com", "www.twitter.com", "twitter.com", "www.instagram.com", "instagram.com", "www.reddit.com", "reddit.com", # Video / entertainment "www.youtube.com", "youtube.com", "www.tiktok.com", "tiktok.com", "www.twitch.tv", "twitch.tv", ] REDIRECT_IP = "127.0.0.1" # Markers keep our entries isolated so we never touch # other entries in the hosts file. START_MARKER = "# >>> WEBSITE BLOCKER START >>>" END_MARKER = "# <<< WEBSITE BLOCKER END <<<" # ============================================================ # Cross‑platform hosts path # ============================================================ def get_hosts_path(): """Return the absolute path to the hosts file for this OS.""" system = platform.system() if system == "Windows": return r"C:\Windows\System32\drivers\etc\hosts" # macOS and Linux both use /etc/hosts return "/etc/hosts" HOSTS_PATH = get_hosts_path() # ============================================================ # Core operations # ============================================================ def block_websites(): """Write (or refresh) the blocker block into the hosts file.""" # Read the current file with open(HOSTS_PATH, "r") as fh: content = fh.read() # Strip any previous block so we start fresh if START_MARKER in content: content = content.split(START_MARKER)[0].rstrip("\n") + "\n" # Build the block block_lines = [START_MARKER + "\n"] for site in SITES_TO_BLOCK: block_lines.append(f"{REDIRECT_IP}\t{site}\n") block_lines.append(END_MARKER + "\n") # Write everything back with open(HOSTS_PATH, "w") as fh: fh.write(content) fh.writelines(block_lines) unique_sites = len(SITES_TO_BLOCK) // 2 print(f"[+] Blocked {unique_sites} websites " f"({len(SITES_TO_BLOCK)} URLs) → {REDIRECT_IP}") def unblock_websites(): """Remove the blocker block from the hosts file.""" with open(HOSTS_PATH, "r") as fh: content = fh.read() if START_MARKER not in content: print("[*] No websites are currently blocked.") return # Cut out the marked section before = content.split(START_MARKER)[0].rstrip("\n") after = content.split(END_MARKER)[-1] new_content = before + "\n" + after.lstrip("\n") with open(HOSTS_PATH, "w") as fh: fh.write(new_content) print("[+] All websites unblocked. Focus mode off.") def show_status(): """Print which websites are currently blocked.""" with open(HOSTS_PATH, "r") as fh: content = fh.read() if START_MARKER not in content: print("[*] No websites are currently blocked.") return block = content.split(START_MARKER)[1].split(END_MARKER)[0] sites = [line.strip() for line in block.split("\n") if line.strip() and not line.strip().startswith("#")] print(f"[*] {len(sites)} URLs currently blocked → {REDIRECT_IP}:") for site in sites: print(f" {site.split()[-1]}") # ============================================================ # CLI entry point # ============================================================ if __name__ == "__main__": if len(sys.argv) < 2: print("Website Blocker — block distracting sites via /etc/hosts\n") print("Usage:") print(" sudo python website_blocker.py block") print(" sudo python website_blocker.py unblock") print(" python website_blocker.py status") sys.exit(1) command = sys.argv[1].lower() if command == "block": block_websites() elif command == "unblock": unblock_websites() elif command == "status": show_status() else: print(f"[!] Unknown command: {command}") print("Valid commands: block, unblock, status") sys.exit(1)