Add ApplicationTicket and fix naming/typehint

py/client/pydeephaven/_arrow_flight_service.py

@@ -21,7 +21,7 @@ def import_table(self, data: pa.Table) -> Table:
         try:
             if not isinstance(data, (pa.Table, pa.RecordBatch)):
                 raise DHError("source data must be either a pa table or RecordBatch.")
-            ticket = self.session.next_export_ticket_no()
+            ticket = self.session.next_export_ticket_number()
             dh_fields = []
             for f in data.schema:
                 dh_fields.append(pa.field(name=f.name, type=f.type, metadata=map_arrow_type(f.type)))

py/client/pydeephaven/_session_service.py

@@ -39,8 +39,8 @@ def close(self):
         except Exception as e:
             raise DHError("failed to close the session.") from e
 
-    def release(self, ticket: Ticket):
-        """Releases an exported ticket."""
+    def release(self, ticket: ExportTicket) -> None:
+        """Releases an export ticket."""
         try:
             self.session.wrap_rpc(
                 self._grpc_session_stub.Release,

py/client/pydeephaven/experimental/plugin_client.py

@@ -53,7 +53,8 @@ class Fetchable(ServerObject):
     """
 
     def __init__(self, session, typed_ticket: ticket_pb2.TypedTicket):
-        super().__init__(type=typed_ticket.type, ticket=_ticket_from_proto(typed_ticket.ticket))
+        export_ticket = ExportTicket(typed_ticket.ticket.ticket)
+        super().__init__(type=typed_ticket.type, ticket=export_ticket)
         self.session = session
 
     def fetch(self) -> Union[Table, PluginClient]:

py/client/pydeephaven/session.py

@@ -335,11 +335,11 @@ def plugin_object_service(self) -> PluginObjService:
 
     def make_export_ticket(self, ticket_no=None) -> ExportTicket:
         if not ticket_no:
-            ticket_no = self.next_export_ticket_no()
+            ticket_no = self.next_export_ticket_number()
         ticket_bytes = ticket_no.to_bytes(4, byteorder='little', signed=True)
         return ExportTicket(ticket_bytes=b'e' + ticket_bytes)
 
-    def next_export_ticket_no(self) -> int:
+    def next_export_ticket_number(self) -> int:
         with self._r_lock:
             self._last_ticket += 1
             if self._last_ticket == 2 ** 31 - 1:
@@ -487,8 +487,8 @@ def close(self) -> None:
             self._last_ticket = 0
             self._flight_client.close()
 
-    def release(self, ticket: Ticket) -> None:
-        """Releases a ticket.
+    def release(self, ticket: ExportTicket) -> None:
+        """Releases an export ticket.
 
         Args:
             ticket (Ticket): the ticket to release

py/client/pydeephaven/ticket.py

@@ -114,6 +114,41 @@ def scope_ticket(cls, name: str) -> ScopeTicket:
         return cls(ticket_bytes=f's/{name}'.encode(encoding='ascii'))
 
 
+class ApplicationTicket(Ticket):
+    """An ApplicationTicket is a ticket that references a field of an application on the server. """
+
+    def __init__(self, ticket_bytes: bytes):
+        """Initializes an ApplicationTicket object
+
+        Args:
+            ticket_bytes (bytes): the raw bytes for the ticket
+        """
+        if not ticket_bytes:
+            raise DHError('ApplicationTicket: ticket is None')
+        elif not ticket_bytes.startswith(b'a/'):
+            raise DHError(f'ApplicationTicket: ticket {ticket_bytes} is not an application ticket')
+        elif len(ticket_bytes.split(b'/')) != 3:
+            raise DHError(f'ApplicationTicket: ticket {ticket_bytes} is not in the correct format')
+
+        self.app_id = ticket_bytes.split(b'/')[1].decode(encoding='ascii')
+        self.field = ticket_bytes.split(b'/')[2].decode(encoding='ascii')
+
+        super().__init__(ticket_bytes)
+
+    @classmethod
+    def app_ticket(cls, app_id: str, field: str) -> ApplicationTicket:
+        """Creates an application ticket that references a field of an application.
+
+        Args:
+            app_id (str): the application id
+            field (str): the name of the application field
+
+        Returns:
+            an ApplicationTicket object
+        """
+        return cls(ticket_bytes=f'a/{app_id}/{field}'.encode(encoding='ascii'))
+
+
 def _ticket_from_proto(ticket: ticket_pb2.Ticket) -> Ticket:
     """Creates a Ticket object from a gRPC protobuf ticket object.
 
@@ -133,6 +168,8 @@ def _ticket_from_proto(ticket: ticket_pb2.Ticket) -> Ticket:
         return ExportTicket(ticket_bytes)
     elif ticket_bytes.startswith(b's/'):
         return ScopeTicket(ticket_bytes)
+    elif ticket_bytes.startswith(b'a/'):
+        return ApplicationTicket(ticket_bytes)
     else:
         raise DHError(f'Unknown ticket type: {ticket_bytes}')