feat: Add proxy pac generator

server.py

@@ -13,13 +13,101 @@ from flask import (
 import os
 import json
 import requests
-from datetime import datetime
+from datetime import datetime, timedelta
 import dotenv
 
 dotenv.load_dotenv()
 
 app = Flask(__name__)
 
+# Proxy PAC configuration
+PROXY_ADDRESS = os.getenv('PROXY_ADDRESS', '127.0.0.1:9590')
+# URL for IANA TLD list
+IANA_TLD_URL = "https://data.iana.org/TLD/tlds-alpha-by-domain.txt"
+# Default TLDs to always skip (in addition to IANA list)
+DEFAULT_SKIP_TLDS = [
+    'localhost', 'test', 'invalid', 'example', 'local',
+    'arpa', 'onion', 'internal', 'private', 'home'
+]
+# Additional TLDs to skip specified in environment
+ADDITIONAL_SKIP_TLDS = os.getenv('ADDITIONAL_SKIP_TLDS', '').split(',')
+if ADDITIONAL_SKIP_TLDS == ['']:
+    ADDITIONAL_SKIP_TLDS = []
+
+# IANA TLD list cache
+tld_list_cache = {
+    'tlds': [],
+    'last_updated': None,
+    'initialized': False
+}
+
+def get_iana_tlds():
+    """Download and parse the IANA TLD list."""
+    now = datetime.now()
+    
+    # Check if we need to refresh the cache (daily)
+    if (tld_list_cache['last_updated'] is None or 
+        now - tld_list_cache['last_updated'] > timedelta(days=1)):
+        try:
+            response = requests.get(IANA_TLD_URL)
+            if response.status_code == 200:
+                # Parse the TLD list (skip the header line, convert to lowercase)
+                tlds = [line.strip().lower() for line in response.text.splitlines() 
+                       if line.strip() and not line.startswith('#')]
+                tld_list_cache['tlds'] = tlds
+                tld_list_cache['last_updated'] = now
+                tld_list_cache['initialized'] = True
+                print(f"Downloaded {len(tlds)} TLDs from IANA")
+            else:
+                print(f"Failed to download IANA TLD list: {response.status_code}")
+                # If we failed but have a previous cache, keep using it
+                if not tld_list_cache['tlds']:
+                    # Otherwise use an empty list
+                    tld_list_cache['tlds'] = []
+        except Exception as e:
+            print(f"Error downloading IANA TLD list: {e}")
+            # If exception occurs but we have a previous cache, keep using it
+            if not tld_list_cache['tlds']:
+                # Otherwise use an empty list
+                tld_list_cache['tlds'] = []
+    
+    # Combine IANA TLDs with our default skip TLDs and additional skip TLDs
+    all_tlds = list(set(tld_list_cache['tlds'] + DEFAULT_SKIP_TLDS + ADDITIONAL_SKIP_TLDS))
+    return all_tlds
+
+def generate_pac_script(proxy_addr, skip_tlds):
+    """Generate a Proxy Auto-Configuration script."""
+    skipped_tlds = "', '".join(skip_tlds)
+    return f"""
+function FindProxyForURL(url, host) {{
+    var skipped = ['{skipped_tlds}'];
+
+    // skip any TLD in the list 
+    var tld = host;
+    var lastDot = tld.lastIndexOf('.');
+    if (lastDot != -1) {{
+      tld = tld.substr(lastDot+1);
+    }}
+    tld = tld.toLowerCase();
+
+    if (skipped.includes(tld)) {{
+      return 'DIRECT';
+    }}
+
+    // skip IP addresses
+    var isIpV4Addr = /^(\\d+.)(\\d+.)(\\d+.)(\\d+)$/;
+    if (isIpV4Addr.test(host)) {{
+       return "DIRECT";
+    }}
+
+    // loosely check if IPv6
+    if (lastDot == -1 && host.split(':').length > 2) {{
+      return "DIRECT";
+    }}
+
+    return "PROXY {proxy_addr}";
+}}
+"""
 
 def find(name, path):
     for root, dirs, files in os.walk(path):
@@ -59,6 +147,16 @@ def faviconPNG():
     return send_from_directory("templates/assets/img", "favicon.png")
 
 
+@app.route("/proxy.pac")
+def proxy_pac():
+    """Serve the Proxy Auto-Configuration file."""
+    proxy_addr = PROXY_ADDRESS
+    skip_tlds = get_iana_tlds()
+    
+    response = make_response(generate_pac_script(proxy_addr, skip_tlds))
+    response.headers["Content-Type"] = "application/x-ns-proxy-autoconfig"
+    return response
+
 @app.route("/.well-known/<path:path>")
 def wellknown(path):
     # Try to proxy to https://nathan.woodburn.au/.well-known/
@@ -110,5 +208,14 @@ def not_found(e):
 
 
 # endregion
+
+# Replace before_first_request with a startup initialization
+# This runs once at server startup
+with app.app_context():
+    get_iana_tlds()
+
 if __name__ == "__main__":
+    # Initialize TLD list at startup if running directly
+    if not tld_list_cache['initialized']:
+        get_iana_tlds()
     app.run(debug=True, port=5000, host="0.0.0.0")