don't store when a client did anything but disconnect

src/ports.rs

@@ -112,17 +112,32 @@ impl<T: Display> Debug for DisplayAsDebug<T> {
 
 #[derive(Default, Serialize, Deserialize)]
 pub struct PortState {
+    #[serde(deserialize_with = "deserialize_last_change")]
     last_change: UnixTimestamp,
     #[serde(skip_deserializing)]
     status: PortStatus,
 }
 
+fn deserialize_last_change<'de, D>(deserializer: D) -> Result<UnixTimestamp, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    Ok(match Option::<UnixTimestamp>::deserialize(deserializer)? {
+        Some(timestamp) => timestamp,
+        None => now(),
+    })
+}
+
+fn now() -> UnixTimestamp {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("timestamp overflow")
+        .as_secs()
+}
+
 impl PortState {
     pub fn new_state(&mut self, status: PortStatus) {
-        self.last_change = SystemTime::now()
+        self.last_change = now();
-            .duration_since(UNIX_EPOCH)
-            .expect("timestamp overflow")
-            .as_secs();
 
         self.status = status;
     }
@@ -187,7 +202,15 @@ impl PortHandler {
             .unwrap()
             .values_mut()
             .for_each(|value| {
-                value.as_object_mut().unwrap().remove("status").unwrap();
+                let value_object = value.as_object_mut().unwrap();
+
+                // it does not make sense to store when the did anything else other than disconnect
+                // because when we restart the server it will no longer be connected
+                if value_object.get("status").unwrap().as_str().unwrap() != "disconnected" {
+                    *value_object.get_mut("last_change").unwrap() = serde_json::Value::Null;
+                }
+
+                value_object.remove("status").unwrap();
             });
 
         serde_json::to_writer(BufWriter::new(File::create(&temp_file)?), &value)?;