feat: add a SessionTimeout error (#251)

core/src/client.rs

@@ -242,6 +242,10 @@ impl APIClient {
         };
         let resp = Retry::spawn(retry_strategy, req).await?;
         if resp.status() != StatusCode::OK {
+            // TODO(liyz): currently it's not possible to distinguish between session timeout and server crashed
+            if resp.status() == StatusCode::NOT_FOUND {
+                return Err(Error::SessionTimeout(resp.text().await?));
+            }
             let resp_err = QueryError {
                 code: resp.status().as_u16(),
                 message: resp.text().await?,

core/src/error.rs

@@ -20,6 +20,9 @@ pub enum Error {
     BadArgument(String),
     Request(String),
     IO(String),
+    // if you have not polled the next_page_uri for too long, the session will be expired, you'll get a 404
+    // on accessing this next page uri.
+    SessionTimeout(String),
     InvalidResponse(response::QueryError),
     InvalidPage(response::QueryError),
 }
@@ -31,6 +34,7 @@ impl std::fmt::Display for Error {
             Error::BadArgument(msg) => write!(f, "BadArgument: {msg}"),
             Error::Request(msg) => write!(f, "RequestError: {msg}"),
             Error::IO(msg) => write!(f, "IOError: {msg}"),
+            Error::SessionTimeout(msg) => write!(f, "SessionExpired: {msg}"),
             Error::InvalidResponse(e) => {
                 write!(f, "ResponseError with {}: {}", e.code, e.message)
             }