#1916: Created FTP superclass + working retrieve file method for FTP

src/primaite/simulator/system/services/ftp/ftp_service.py

@@ -0,0 +1,132 @@
+from abc import ABC
+from ipaddress import IPv4Address
+from typing import Optional
+
+from primaite.simulator.file_system.file_system import File
+from primaite.simulator.network.protocols.ftp import FTPCommand, FTPPacket, FTPStatusCode
+from primaite.simulator.network.transmission.transport_layer import Port
+from primaite.simulator.system.core.software_manager import SoftwareManager
+from primaite.simulator.system.services.service import Service
+
+
+class FTPServiceABC(Service, ABC):
+    """
+    Abstract Base Class for FTP Client and Service.
+
+    Contains shared methods between both classes.
+    """
+
+    def _process_ftp_command(self, payload: FTPPacket, session_id: Optional[str] = None, **kwargs) -> FTPPacket:
+        # handle PORT request
+        if payload.ftp_command == FTPCommand.PORT:
+            # check that the port is valid
+            if isinstance(payload.ftp_command_args, Port) and payload.ftp_command_args.value in range(0, 65535):
+                # return successful connection
+                payload.status_code = FTPStatusCode.OK
+
+        # handle STOR request
+        if payload.ftp_command == FTPCommand.STOR:
+            # check that the file is created in the computed hosting the FTP server
+            if self._store_data(payload=payload):
+                payload.status_code = FTPStatusCode.OK
+
+        if payload.ftp_command == FTPCommand.RETR:
+            # check that the file exists in the FTP Server
+            file: File = self.file_system.get_file(
+                folder_name=payload.ftp_command_args["src_folder_name"],
+                file_name=payload.ftp_command_args["src_file_name"],
+            )
+            if file:
+                payload.status_code = FTPStatusCode.OK
+                self._send_data(
+                    file=file,
+                    dest_folder_name=payload.ftp_command_args["dest_folder_name"],
+                    dest_file_name=payload.ftp_command_args["dest_file_name"],
+                    session_id=session_id,
+                )
+
+        return payload
+
+    def _store_data(self, payload: FTPPacket) -> bool:
+        """
+        Handle the transfer of data.
+
+        :param: payload: The FTP Packet that contains the file data
+        :type: FTPPacket
+        """
+        try:
+            file_name = payload.ftp_command_args["dest_file_name"]
+            folder_name = payload.ftp_command_args["dest_folder_name"]
+            file_size = payload.ftp_command_args["file_size"]
+            self.file_system.create_file(
+                file_name=file_name,
+                folder_name=folder_name,
+                size=file_size,
+            )
+            self.sys_log.info(
+                f"Created item in {self.sys_log.hostname}: {payload.ftp_command_args['dest_folder_name']}/"
+                f"{payload.ftp_command_args['dest_file_name']}"
+            )
+            # file should exist
+            return self.file_system.get_file(file_name=file_name, folder_name=folder_name) is not None
+        except Exception as e:
+            self.sys_log.error(f"Unable to create file in {self.sys_log.hostname}: {e}")
+            return False
+
+    def _send_data(
+        self,
+        file: File,
+        dest_folder_name: str,
+        dest_file_name: str,
+        dest_ip_address: Optional[IPv4Address] = None,
+        dest_port: Optional[Port] = None,
+        session_id: Optional[str] = None,
+    ) -> bool:
+        # send STOR request
+        payload: FTPPacket = FTPPacket(
+            ftp_command=FTPCommand.STOR,
+            ftp_command_args={
+                "dest_folder_name": dest_folder_name,
+                "dest_file_name": dest_file_name,
+                "file_size": file.sim_size,
+            },
+            packet_payload_size=file.sim_size,
+        )
+        software_manager: SoftwareManager = self.software_manager
+        software_manager.send_payload_to_session_manager(
+            payload=payload, dest_ip_address=dest_ip_address, dest_port=dest_port, session_id=session_id
+        )
+
+        if payload.status_code == FTPStatusCode.OK:
+            return True
+
+        return False
+
+    def _retrieve_data(self, payload: FTPPacket, session_id: Optional[str] = None) -> bool:
+        """
+        Handle the transfer of data from Server to Client.
+
+        :param: payload: The FTP Packet that contains the file data
+        :type: FTPPacket
+        """
+        try:
+            # find the file
+            file_name = payload.ftp_command_args["src_file_name"]
+            folder_name = payload.ftp_command_args["src_folder_name"]
+            retrieved_file: File = self.file_system.get_file(folder_name=folder_name, file_name=file_name)
+
+            # if file does not exist, return an error
+            if not retrieved_file:
+                self.sys_log.error(
+                    f"File  {payload.ftp_command_args['dest_folder_name']}/"
+                    f"{payload.ftp_command_args['dest_file_name']} does not exist in {self.sys_log.hostname}"
+                )
+                return False
+            else:
+                # send requested data
+                return self._send_data(
+                    file=retrieved_file, dest_file_name=file_name, dest_folder_name=folder_name, session_id=session_id
+                )
+        except Exception as e:
+            self.sys_log.error(f"Unable to retrieve file from {self.sys_log.hostname}: {e}")
+            return False