Add dynamic port assigning to Bun.serve (#2062)

2 files changed, 11 insertions, 5 deletions

diff --git a/src/bun.js/api/server.zig b/src/bun.js/api/server.zig
index 029ce6533..62d8f602a 100644
--- a/src/bun.js/api/server.zig
+++ b/src/bun.js/api/server.zig
@@ -408,10 +408,6 @@ pub const ServerConfig = struct {
             }
         }
 
-        if (args.port == 0) {
-            JSC.throwInvalidArguments("Invalid port: must be > 0", .{}, global, exception);
-        }
-
         if (args.base_uri.len > 0) {
             args.base_url = URL.parse(args.base_uri);
             if (args.base_url.hostname.len == 0) {
@@ -4308,7 +4304,8 @@ pub fn NewServer(comptime ssl_enabled_: bool, comptime debug_mode_: bool) type {
         }
 
         pub fn getPort(this: *ThisServer) JSC.JSValue {
-            return JSC.JSValue.jsNumber(this.config.port);
+            var listener = this.listener orelse return JSC.JSValue.jsNumber(this.config.port);
+            return JSC.JSValue.jsNumber(listener.getLocalPort());
         }
 
         pub fn getPendingRequests(this: *ThisServer) JSC.JSValue {
diff --git a/src/deps/uws.zig b/src/deps/uws.zig
index 6925fce19..73eb72649 100644
--- a/src/deps/uws.zig
+++ b/src/deps/uws.zig
@@ -987,6 +987,9 @@ pub const ListenSocket = opaque {
     pub fn close(this: *ListenSocket, ssl: bool) void {
         us_listen_socket_close(@boolToInt(ssl), this);
     }
+    pub fn getLocalPort(this: *ListenSocket, ssl: bool) i32 {
+        return us_socket_local_port(@boolToInt(ssl), this);
+    }
 };
 extern fn us_listen_socket_close(ssl: i32, ls: *ListenSocket) void;
 extern fn uws_app_close(ssl: i32, app: *uws_app_s) void;
@@ -1058,6 +1061,12 @@ pub fn NewApp(comptime ssl: bool) type {
                 }
                 return us_listen_socket_close(ssl_flag, @ptrCast(*uws.ListenSocket, this));
             }
+            pub inline fn getLocalPort(this: *ThisApp.ListenSocket) i32 {
+                if (comptime is_bindgen) {
+                    unreachable;
+                }
+                return us_socket_local_port(ssl_flag, @ptrCast(*uws.Socket, this));
+            }
         };
 
         pub fn get(