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"""User input parameter validation.
This module handles user input parameter validation
against a provided input model.
Note that the objects in this module do *not* mutate any
arguments. No type version happens here. It is up to another
layer to properly convert arguments to any required types.
Validation Errors
-----------------
"""
from botocore.compat import six
import decimal
import json
from datetime import datetime
from botocore.utils import parse_to_aware_datetime
from botocore.utils import is_json_value_header
from botocore.exceptions import ParamValidationError
def validate_parameters(params, shape):
"""Validates input parameters against a schema.
This is a convenience function that validates parameters against a schema.
You can also instantiate and use the ParamValidator class directly if you
want more control.
If there are any validation errors then a ParamValidationError
will be raised. If there are no validation errors than no exception
is raised and a value of None is returned.
:param params: The user provided input parameters.
:type shape: botocore.model.Shape
:param shape: The schema which the input parameters should
adhere to.
:raise: ParamValidationError
"""
validator = ParamValidator()
report = validator.validate(params, shape)
if report.has_errors():
raise ParamValidationError(report=report.generate_report())
def type_check(valid_types):
def _create_type_check_guard(func):
def _on_passes_type_check(self, param, shape, errors, name):
if _type_check(param, errors, name):
return func(self, param, shape, errors, name)
def _type_check(param, errors, name):
if not isinstance(param, valid_types):
valid_type_names = [six.text_type(t) for t in valid_types]
errors.report(name, 'invalid type', param=param,
valid_types=valid_type_names)
return False
return True
return _on_passes_type_check
return _create_type_check_guard
def range_check(name, value, shape, error_type, errors):
failed = False
min_allowed = float('-inf')
if 'min' in shape.metadata:
min_allowed = shape.metadata['min']
if value < min_allowed:
failed = True
elif hasattr(shape, 'serialization'):
# Members that can be bound to the host have an implicit min of 1
if shape.serialization.get('hostLabel'):
min_allowed = 1
if value < min_allowed:
failed = True
if failed:
errors.report(name, error_type, param=value, min_allowed=min_allowed)
class ValidationErrors(object):
def __init__(self):
self._errors = []
def has_errors(self):
if self._errors:
return True
return False
def generate_report(self):
error_messages = []
for error in self._errors:
error_messages.append(self._format_error(error))
return '\n'.join(error_messages)
def _format_error(self, error):
error_type, name, additional = error
name = self._get_name(name)
if error_type == 'missing required field':
return 'Missing required parameter in %s: "%s"' % (
name, additional['required_name'])
elif error_type == 'unknown field':
return 'Unknown parameter in %s: "%s", must be one of: %s' % (
name, additional['unknown_param'],
', '.join(additional['valid_names']))
elif error_type == 'invalid type':
return 'Invalid type for parameter %s, value: %s, type: %s, ' \
'valid types: %s' % (name, additional['param'],
str(type(additional['param'])),
', '.join(additional['valid_types']))
elif error_type == 'invalid range':
min_allowed = additional['min_allowed']
return ('Invalid value for parameter %s, value: %s, '
'valid min value: %s' % (name, additional['param'],
min_allowed))
elif error_type == 'invalid length':
min_allowed = additional['min_allowed']
return ('Invalid length for parameter %s, value: %s, '
'valid min length: %s' % (name, additional['param'],
min_allowed))
elif error_type == 'unable to encode to json':
return 'Invalid parameter %s must be json serializable: %s' \
% (name, additional['type_error'])
def _get_name(self, name):
if not name:
return 'input'
elif name.startswith('.'):
return name[1:]
else:
return name
def report(self, name, reason, **kwargs):
self._errors.append((reason, name, kwargs))
class ParamValidator(object):
"""Validates parameters against a shape model."""
def validate(self, params, shape):
"""Validate parameters against a shape model.
This method will validate the parameters against a provided shape model.
All errors will be collected before returning to the caller. This means
that this method will not stop at the first error, it will return all
possible errors.
:param params: User provided dict of parameters
:param shape: A shape model describing the expected input.
:return: A list of errors.
"""
errors = ValidationErrors()
self._validate(params, shape, errors, name='')
return errors
def _check_special_validation_cases(self, shape):
if is_json_value_header(shape):
return self._validate_jsonvalue_string
def _validate(self, params, shape, errors, name):
special_validator = self._check_special_validation_cases(shape)
if special_validator:
special_validator(params, shape, errors, name)
else:
getattr(self, '_validate_%s' % shape.type_name)(
params, shape, errors, name)
def _validate_jsonvalue_string(self, params, shape, errors, name):
# Check to see if a value marked as a jsonvalue can be dumped to
# a json string.
try:
json.dumps(params)
except (ValueError, TypeError) as e:
errors.report(name, 'unable to encode to json', type_error=e)
@type_check(valid_types=(dict,))
def _validate_structure(self, params, shape, errors, name):
# Validate required fields.
for required_member in shape.metadata.get('required', []):
if required_member not in params:
errors.report(name, 'missing required field',
required_name=required_member, user_params=params)
members = shape.members
known_params = []
# Validate known params.
for param in params:
if param not in members:
errors.report(name, 'unknown field', unknown_param=param,
valid_names=list(members))
else:
known_params.append(param)
# Validate structure members.
for param in known_params:
self._validate(params[param], shape.members[param],
errors, '%s.%s' % (name, param))
@type_check(valid_types=six.string_types)
def _validate_string(self, param, shape, errors, name):
# Validate range. For a string, the min/max contraints
# are of the string length.
# Looks like:
# "WorkflowId":{
# "type":"string",
# "min":1,
# "max":256
# }
range_check(name, len(param), shape, 'invalid length', errors)
@type_check(valid_types=(list, tuple))
def _validate_list(self, param, shape, errors, name):
member_shape = shape.member
range_check(name, len(param), shape, 'invalid length', errors)
for i, item in enumerate(param):
self._validate(item, member_shape, errors, '%s[%s]' % (name, i))
@type_check(valid_types=(dict,))
def _validate_map(self, param, shape, errors, name):
key_shape = shape.key
value_shape = shape.value
for key, value in param.items():
self._validate(key, key_shape, errors, "%s (key: %s)"
% (name, key))
self._validate(value, value_shape, errors, '%s.%s' % (name, key))
@type_check(valid_types=six.integer_types)
def _validate_integer(self, param, shape, errors, name):
range_check(name, param, shape, 'invalid range', errors)
def _validate_blob(self, param, shape, errors, name):
if isinstance(param, (bytes, bytearray, six.text_type)):
return
elif hasattr(param, 'read'):
# File like objects are also allowed for blob types.
return
else:
errors.report(name, 'invalid type', param=param,
valid_types=[str(bytes), str(bytearray),
'file-like object'])
@type_check(valid_types=(bool,))
def _validate_boolean(self, param, shape, errors, name):
pass
@type_check(valid_types=(float, decimal.Decimal) + six.integer_types)
def _validate_double(self, param, shape, errors, name):
range_check(name, param, shape, 'invalid range', errors)
_validate_float = _validate_double
@type_check(valid_types=six.integer_types)
def _validate_long(self, param, shape, errors, name):
range_check(name, param, shape, 'invalid range', errors)
def _validate_timestamp(self, param, shape, errors, name):
# We don't use @type_check because datetimes are a bit
# more flexible. You can either provide a datetime
# object, or a string that parses to a datetime.
is_valid_type = self._type_check_datetime(param)
if not is_valid_type:
valid_type_names = [six.text_type(datetime), 'timestamp-string']
errors.report(name, 'invalid type', param=param,
valid_types=valid_type_names)
def _type_check_datetime(self, value):
try:
parse_to_aware_datetime(value)
return True
except (TypeError, ValueError, AttributeError):
# Yes, dateutil can sometimes raise an AttributeError
# when parsing timestamps.
return False
class ParamValidationDecorator(object):
def __init__(self, param_validator, serializer):
self._param_validator = param_validator
self._serializer = serializer
def serialize_to_request(self, parameters, operation_model):
input_shape = operation_model.input_shape
if input_shape is not None:
report = self._param_validator.validate(parameters,
operation_model.input_shape)
if report.has_errors():
raise ParamValidationError(report=report.generate_report())
return self._serializer.serialize_to_request(parameters,
operation_model)
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