fix(api): fix init servers; gracefully handle port already in use

webui.lua

@@ -864,23 +864,43 @@ local function get_ip(udp_method, check_ip)
   return ip
 end
 
+local function get_server(ipv)
+  local address = "0.0.0.0"
+  local udp_method = socket.udp
+  local check_ip = "91.198.174.192"
+  local listen_format = "%s:%s"
+  if ipv == 6 then
+    address = "::0"
+    udp_method = socket.udp6
+    check_ip = "2620:0:862:ed1a::1"
+    listen_format = "[%s]:%s"
+  end
+
+  local server = {}
+  local s = socket.bind(address, options.port)
+  if s == nil then
+    return {}
+  end
+
+  server.server = s
+  local ip = get_ip(udp_method, check_ip)
+
+  server.listen = listen_format:format(ip, options.port)
+
+  return {[address] = server}
+end
+
 local function init_servers()
   local servers = {}
   if not options.ipv4 and not options.ipv6 then
     mp.msg.error("Error: ipv4 and ipv6 is disabled!")
     return servers
   end
   if options.ipv6 then
-    local address = '::0'
-    servers[address] = {server = socket.bind(address, options.port)}
-    local ip = get_ip(socket.udp6, "2620:0:862:ed1a::1")
-    servers[address].listen = "[" .. ip .. "]:" .. options.port
+    for k,v in pairs(get_server(6)) do servers[k] = v end
   end
   if options.ipv4 then
-    local address = '0.0.0.0'
-    servers[address] = {server = socket.bind(address, options.port)}
-    local ip = get_ip(socket.udp, "91.198.174.192")
-    servers[address].listen = ip .. ":" .. options.port
+    for k,v in pairs(get_server(4)) do servers[k] = v end
   end
 
   return servers