add config option to allow binding to a specific address

original idea by @OH2LAK (see #367)

openwebrx.conf

@@ -6,6 +6,10 @@ log_level = INFO
 [web]
 port = 8073
 ipv6 = true
+# Uncomment bind_address to bind OpenWebRX to a specific IP-address.
+# By default, OpenWebRX will bind to all interfaces.
+# Use ::1 for localhost only, or any other configured address to bind to that address only.
+#bind_address = ::1
 
 [aprs]
 # path to the aprs symbols repository (get it here: https://github.com/hessu/aprs-symbols)

owrx/__main__.py

@@ -27,11 +27,11 @@ import socket
 
 
 class ThreadedHttpServer(ThreadingMixIn, HTTPServer):
-    def __init__(self, web_port, RequestHandlerClass, use_ipv6):
-        bind_address = "0.0.0.0"
+    def __init__(self, web_port, RequestHandlerClass, use_ipv6, bind_address=None):
+        if bind_address is None:
+            bind_address = "::" if use_ipv6 else "0.0.0.0"
         if use_ipv6:
             self.address_family = socket.AF_INET6
-            bind_address = "::"
         super().__init__((bind_address, web_port), RequestHandlerClass)
 
 
@@ -135,7 +135,9 @@ Support and info:       https://groups.io/g/openwebrx
     Services.start()
 
     try:
-        server = ThreadedHttpServer(coreConfig.get_web_port(), RequestHandler, coreConfig.get_web_ipv6())
+        server = ThreadedHttpServer(
+            coreConfig.get_web_port(), RequestHandler, coreConfig.get_web_ipv6(), coreConfig.get_web_bind_address()
+        )
         logger.info("Ready to serve requests.")
         server.serve_forever()
     except SignalException:

owrx/config/core.py

@@ -1,6 +1,7 @@
 from owrx.config import ConfigError
 from configparser import ConfigParser
 from pathlib import Path
+from typing import Optional
 import os
 
 
@@ -16,6 +17,8 @@ class CoreConfig(object):
         "web": {
             "port": 8073,
             "ipv6": True,
+            # won't work this way because values must be strings, but this is effectively the way it behaves.
+            #"bind_address": None,
         },
         "aprs": {
             "symbols_path": "/usr/share/aprs-symbols/png"
@@ -64,6 +67,7 @@ class CoreConfig(object):
         self.log_level = config.get("core", "log_level")
         self.web_port = config.getint("web", "port")
         self.web_ipv6 = config.getboolean("web", "ipv6")
+        self.web_bind_address = config.get("web", "bind_address", fallback=None)
         self.aprs_symbols_path = config.get("aprs", "symbols_path")
 
     @staticmethod
@@ -81,6 +85,9 @@ class CoreConfig(object):
     def get_web_ipv6(self) -> bool:
         return self.web_ipv6
 
+    def get_web_bind_address(self) -> Optional[str]:
+        return self.web_bind_address
+
     def get_data_directory(self) -> str:
         return self.data_directory