def _delete_rule(rule_json):
"""
Deletes a rule from a table, if it exists.
"""
rule_instance = _get_existing_rule(rule_json)
if rule_instance != None:
try:
_session.delete(rule_instance)
except Exception as e:
raise RuleException(status=500,
name='Rule Delete Error',
error=str(e))
else:
error_description = 'Attempt to delete rule with invalid id'
raise RuleException(status=400,
name='Rule Does Not Exist',
error=error_description)
def _update_existing_rule(rule_json):
"""
Modifies the 'name' and 'trusted' fields of a rule stored in the database.
"""
rule_instance = _get_existing_rule(rule_json)
if rule_instance != None:
try:
rule_instance.name = rule_json[Keyword.NAME]
rule_instance.trusted = rule_json[Keyword.TRUSTED]
except (IntegrityError, Exception) as e:
raise RuleException(status=500,
name='Rule Update Error',
error=str(e))
else:
error_description = 'Attempt to update rule with invalid id.'
raise RuleException(status=400,
name='Rule Does Not Exist',
error=error_description)
def _create_new_rule(rule_json):
"""
Writes a new rule to the corresponding table based on the '__tablename__' property of rule_class.
"""
rule_instance = _get_rule_instance(rule_json)
try:
_session.add(rule_instance)
return rule_instance
except (IntegrityError, Exception) as e:
raise RuleException(status=500, name='Rule Create Error', error=str(e))
def _read_existing_rules(rule_type):
"""
Queries the database for all rows in a table based on the '__tablename__' property of the rule_class.
"""
rule_class = _get_rule_class(rule_type)
try:
query = _session.query(rule_class)
rules_list = query.all()
return [rule.serialize() for rule in rules_list]
except Exception as e:
raise RuleException(status=500, name='Rule Query Error', error=str(e))
def _get_existing_rule(rule_json):
"""
Queries the database for a rule based on provided 'id' property in the rule JSON.
"""
rule_type = rule_json[Keyword.TYPE]
rule_id = rule_json[Keyword.ID]
rule_class = _get_rule_class(rule_type)
try:
query = _session.query(rule_class)
return query.get(rule_id)
except Exception as e:
raise RuleException(status=500, name='Rule Query Error', error=str(e))
def _get_rule_class(rule_type):
"""
Returns a class based on rule type
"""
if rule_type == Keyword.IP:
return RuleIP
elif rule_type == Keyword.DNS:
return RuleDNS
else:
error_description = f"\'{rule_type}\' is not valid."
raise RuleException(status=400,
name='Unhandled Rule Type',
error=error_description)
def _process_rule_json(action, rule_json):
"""
Routes actions to corresponding methods for existing rules.
"""
if action == Action.CREATE:
if not _check_rule_exists(rule_json):
rule_instance = _create_new_rule(rule_json)
rule_json[Keyword.ID] = rule_instance.id
elif action == Action.UPDATE:
_update_existing_rule(rule_json)
elif action == Action.DELETE:
_delete_rule(rule_json)
else:
error_description = f"\'{action}\' is not valid."
raise RuleException(status=400,
name='Unhandled Action',
error=error_description)
def _check_rule_exists(rule_json):
"""
Checks for the existence of a rule basd on the value of the rule.
"""
rule_type = rule_json[Keyword.TYPE]
rule_value = rule_json[rule_type]
rule_class = _get_rule_class(rule_type)
if rule_type == Keyword.IP:
query = _session.query(rule_class).filter(rule_class.ip == rule_value)
elif rule_type == Keyword.DNS:
query = _session.query(rule_class).filter(rule_class.dns == rule_value)
if _session.query(query.exists()).scalar():
error_description = "One or more rules in request already already exists."
raise RuleException(status=400,
name='Rule Already Exists',
error=error_description)
return False
def _get_request_json():
try:
return flask.request.get_json()
except JSONBadRequest as e:
raise RuleException(status=400, name='JSON Error', error=e.get_body())