fix(udp_server): Add selection for bind IP

Author: lucasssvaz

libraries/WiFi/examples/WiFiUDPClient/udp_server.py

@@ -2,6 +2,92 @@
 # for messages from the ESP32 board and prints them
 import socket
 import sys
+import subprocess
+import platform
+
+def get_interface_ips():
+    """Get all available interface IP addresses"""
+    interface_ips = []
+
+    # Try using system commands to get interface IPs
+    system = platform.system().lower()
+
+    try:
+        if system == "darwin" or system == "linux":
+            # Use 'ifconfig' on macOS/Linux
+            result = subprocess.run(['ifconfig'], capture_output=True, text=True, timeout=5)
+            if result.returncode == 0:
+                lines = result.stdout.split('\n')
+                for line in lines:
+                    if 'inet ' in line and '127.0.0.1' not in line:
+                        # Extract IP address from ifconfig output
+                        parts = line.strip().split()
+                        for i, part in enumerate(parts):
+                            if part == 'inet':
+                                if i + 1 < len(parts):
+                                    ip = parts[i + 1]
+                                    if ip not in interface_ips and ip != '127.0.0.1':
+                                        interface_ips.append(ip)
+                                break
+        elif system == "windows":
+            # Use 'ipconfig' on Windows
+            result = subprocess.run(['ipconfig'], capture_output=True, text=True, timeout=5)
+            if result.returncode == 0:
+                lines = result.stdout.split('\n')
+                for line in lines:
+                    if 'IPv4 Address' in line and '127.0.0.1' not in line:
+                        # Extract IP address from ipconfig output
+                        if ':' in line:
+                            ip = line.split(':')[1].strip()
+                            if ip not in interface_ips and ip != '127.0.0.1':
+                                interface_ips.append(ip)
+    except (subprocess.TimeoutExpired, subprocess.SubprocessError, FileNotFoundError):
+        pass
+
+    # Fallback: try to get IPs using socket methods
+    if not interface_ips:
+        try:
+            # Get all IP addresses associated with the hostname
+            hostname = socket.gethostname()
+            ip_list = socket.gethostbyname_ex(hostname)[2]
+            for ip in ip_list:
+                if ip not in interface_ips and ip != '127.0.0.1':
+                    interface_ips.append(ip)
+        except socket.gaierror:
+            pass
+
+    # Fail if no interfaces found
+    if not interface_ips:
+        print("Error: No network interfaces found. Please check your network configuration.")
+        sys.exit(1)
+
+    return interface_ips
+
+def select_interface(interface_ips):
+    """Ask user to select which interface to bind to"""
+    if len(interface_ips) == 1:
+        print(f"Using interface: {interface_ips[0]}")
+        return interface_ips[0]
+
+    print("Multiple network interfaces detected:")
+    for i, ip in enumerate(interface_ips, 1):
+        print(f"  {i}. {ip}")
+
+    while True:
+        try:
+            choice = input(f"Select interface (1-{len(interface_ips)}): ").strip()
+            choice_idx = int(choice) - 1
+            if 0 <= choice_idx < len(interface_ips):
+                selected_ip = interface_ips[choice_idx]
+                print(f"Selected interface: {selected_ip}")
+                return selected_ip
+            else:
+                print(f"Please enter a number between 1 and {len(interface_ips)}")
+        except ValueError:
+            print("Please enter a valid number")
+        except KeyboardInterrupt:
+            print("\nExiting...")
+            sys.exit(1)
 
 try:
     s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
@@ -10,15 +96,17 @@
     print("Failed to create socket. Error Code : " + str(msg[0]) + " Message " + msg[1])
     sys.exit()
 
+# Get available interfaces and let user choose
+interface_ips = get_interface_ips()
+selected_ip = select_interface(interface_ips)
+
 try:
-    s.bind(("", 3333))
+    s.bind((selected_ip, 3333))
 except socket.error as msg:
     print("Bind failed. Error: " + str(msg[0]) + ": " + msg[1])
     sys.exit()
 
-print("Server listening")
-
-print("Server listening")
+print(f"Server listening on {selected_ip}:3333")
 
 while 1:
     d = s.recvfrom(1024)