From 750db15e00b9bbdadb5c34280f5de74215259b63 Mon Sep 17 00:00:00 2001
From: Hanno Rein <hanno@hanno-rein.de>
Date: Tue, 7 Nov 2023 09:06:13 -0500
Subject: [PATCH] widget logic

---
 rebound/simulation.py | 21 ++++++++++++++-------
 src/server.c          |  4 ++--
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/rebound/simulation.py b/rebound/simulation.py
index 0d406cb48..837c2a93f 100644
--- a/rebound/simulation.py
+++ b/rebound/simulation.py
@@ -196,13 +196,20 @@ def start_server(self, port=1234):
         self.process_messages()
 
 
-    def widget(self, port=1234, host="localhost", size=(500,500)):
-        port = int(port)
-        if self._server_data:
-            if self._server_data.contents.port != port:
-                raise RuntimeError("Server is running already on port %d but port %d was requested."%(self._server_data.contents.port, port))
-        else:
-            self.start_server(port=port)
+    def widget(self, port=None, host="localhost", size=(500,500)):
+        if port is not None:
+            port = int(port)
+            if self._server_data:
+                if self._server_data.contents.port != port:
+                    raise RuntimeError("Server is running already on port %d but port %d was requested."%(self._server_data.contents.port, port))
+        if not self._server_data:
+            if port is not None:
+                self.start_server(port=port)
+            else:
+                self.start_server()
+        if not self._server_data:
+            raise RuntimeError("Server did not start up immediately. Try again in a few seconds.")
+        port = int(self._server_data.contents.port)
         from IPython.display import IFrame
         width, height = size
         display(IFrame("http://"+host+":"+"%d"%port, width, height))
diff --git a/src/server.c b/src/server.c
index 41fb7c195..908f51f47 100644
--- a/src/server.c
+++ b/src/server.c
@@ -175,7 +175,7 @@ void* reb_server_start(void* args){
     memset((char *) &serveraddr, 0, sizeof(serveraddr));
     serveraddr.sin_family = AF_INET;
     serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
-    serveraddr.sin_port = htons((unsigned short)data->port);
+    serveraddr.sin_port = htons(data->port);
     if (bind(data->socket, (struct sockaddr *) &serveraddr, sizeof(serveraddr)) < 0){
         char error_msg[BUFSIZE];
         snprintf(error_msg, BUFSIZE, "Error binding to port %d. Port might be in use.\n", data->port);
@@ -199,7 +199,7 @@ void* reb_server_start(void* args){
         data->ready = 1;
         childfd = accept(data->socket, (struct sockaddr *) &clientaddr, &clientlen);
         if (childfd < 0) { // Accept will fail if main thread is closing socket.
-            return 1;
+            return PTHREAD_CANCELED;
         }
 
         /* determine who sent the message */