Split offline-related functionality from cli.run into FlaskClient

- prepare for #53
- simplify return values of safely_run()
- introduce Client.latest_exception attribute

financeager/cli.py

@@ -85,9 +85,7 @@ def _info(message):
  formatting_options[option] = params.pop(option)
 
  client = comm.client(configuration=configuration, sinks=sinks)
- success, _ = client.safely_run(command, **params)
-
- if success:
+ if client.safely_run(command, **params):
  exit_code = SUCCESS
 
  client.shutdown()

financeager/communication.py

@@ -35,33 +35,35 @@ def __init__(self, *, sinks):
  """
  self.proxy = None
  self.sinks = sinks
+ self.latest_exception = None
 
  def safely_run(self, command, **params):
- """Execute self.proxy.run() while handling any errors. Return indicators
- about whether execution was successful, and whether to store the
- requested command offline, if execution failed due to a service-sided
- error.
+ """Execute self.proxy.run() while handling any errors.
+ A caught exception is stored in the 'latest_exception' attribute.
+ Return whether execution was successful.
 
- :return: tuple(bool, bool)
+ :return: bool
  """
- store_offline = False
  success = False
 
  try:
  self.sinks.info(self.proxy.run(command, **params))
+ self.latest_exception = None
  success = True
  except InvalidRequest as e:
- # Command is erroneous and hence not stored offline
  self.sinks.error(e)
+ self.latest_exception = e
+
  except CommunicationError as e:
  self.sinks.error(e)
- store_offline = True
- except Exception:
+ self.latest_exception = e
+
+ except Exception as e:
  self.sinks.error("Unexpected error: {}".format(
  traceback.format_exc()))
- store_offline = True
+ self.latest_exception = e
 
- return success, store_offline
+ return success
 
  def shutdown(self):
  """Routine to run at the end of the Client lifecycle."""
@@ -82,24 +84,30 @@ def safely_run(self, command, **params):
  """Execute base functionality.
  If successful, attempt to recover offline backup. Otherwise store
  request in offline backup.
+ Return whether execution was successful.
 
- :return: tuple(bool, bool)
+ :return: bool
  """
- success, store_offline = super().safely_run(command, **params)
+ success = super().safely_run(command, **params)
 
  if success:
  try:
+ # Avoid recursion by passing base class for invoking safely_run
  if offline.recover(super()):
  self.sinks.info("Recovered offline backup.")
+
  except OfflineRecoveryError:
  self.sinks.error("Offline backup recovery failed!")
  success = False
 
- if store_offline and offline.add(command, **params):
+ # If request was erroneous, it's not supposed to be stored offline
+ if not isinstance(self.latest_exception, InvalidRequest) and\
+ self.latest_exception is not None and\
+ offline.add(command, **params):
  self.sinks.info(
  "Stored '{}' request in offline backup.".format(command))
 
- return success, store_offline
+ return success
 
 
 class LocalServerClient(Client):

financeager/offline.py

@@ -36,9 +36,7 @@ def _recover_data(client, content):
  """
  while len(content):
  data = content.pop()
- success, _ = client.safely_run(**data)
-
- if not success:
+ if not client.safely_run(**data):
  return data