Files
deb-python-colander/colander/__init__.py
Chris McDonough cb8b9d0c91 - Raise a `colander.Invalid error if a colander.SequenceSchema`
is created with more than one member.
2010-04-04 23:32:56 +00:00

1041 lines
37 KiB
Python

import datetime
import itertools
import iso8601
import pprint
class _missing(object):
pass
class Invalid(Exception):
"""
An exception raised by data types and validators indicating that
the value for a particular node was not valid.
The constructor receives a mandatory ``node`` argument. This must
be an instance of the :class:`colander.SchemaNode` class, or at
least something with the same interface.
The constructor also receives an optional ``msg`` keyword
argument, defaulting to ``None``. The ``msg`` argument is a
freeform field indicating the error circumstance.
"""
pos = None
parent = None
def __init__(self, node, msg=None):
Exception.__init__(self, node, msg)
self.node = node
self.msg = msg
self.children = []
def add(self, exc, pos=None):
""" Add a child exception; ``exc`` must be an instance of
:class:`colander.Invalid` or a subclass.
``pos`` is a value important for accurate error reporting. If
it is provided, it must be an integer representing the
position of ``exc`` relative to all other subexceptions of
this exception node. For example, if the exception being
added is about the third child of the exception which is
``self``, ``pos`` might be passed as ``3``.
If ``pos`` is provided, it will be assigned to the ``pos``
attribute of the provided ``exc`` object.
The ``parent`` attribute of the provided ``exc`` will be set
as a reference to ``self``.
"""
exc.parent = self
if pos is not None:
exc.pos = pos
self.children.append(exc)
def __setitem__(self, name, msg):
""" Add a subexception related to a child node with the
message ``msg``. ``name`` must be present in the names of the
set of child nodes of this exception's node; if this is not
so, a :exc:`KeyError` is raised.
For example, if the exception upon which ``__setitem__`` is
called has a node attribute, and that node attribute has
children that have the names ``name`` and ``title``, you may
successfully call ``__setitem__('name', 'Bad name')`` or
``__setitem__('title', 'Bad title')``. But calling
``__setitem__('wrong', 'whoops')`` will result in a
:exc:`KeyError`.
This method is typically only useful if the ``node`` attribute
of the exception upon which it is called is a schema node
representing a mapping.
"""
for num, child in enumerate(self.node.children):
if child.name == name:
exc = Invalid(child, msg)
self.add(exc, num)
return
raise KeyError(name)
def paths(self):
""" Return all paths through the exception graph """
def traverse(node, stack):
stack.append(node)
if not node.children:
yield tuple(stack)
for child in node.children:
for path in traverse(child, stack):
yield path
stack.pop()
return traverse(self, [])
def _keyname(self):
if self.parent and isinstance(self.parent.node.typ, Positional):
return str(self.pos)
return str(self.node.name)
def asdict(self):
""" Return a dictionary containing an error report for this
exception"""
paths = self.paths()
errors = {}
for path in paths:
keyparts = []
msgs = []
for exc in path:
exc.msg and msgs.append(exc.msg)
keyname = exc._keyname()
keyname and keyparts.append(keyname)
errors['.'.join(keyparts)] = '; '.join(msgs)
return errors
def __str__(self):
""" Return a pretty-formatted string representation of the
result of an execution of this exception's ``asdict`` method"""
return pprint.pformat(self.asdict())
class All(object):
""" Composite validator which succeeds if none of its
subvalidators raises an :class:`colander.Invalid` exception"""
def __init__(self, *validators):
self.validators = validators
def __call__(self, node, value):
msgs = []
for validator in self.validators:
try:
validator(node, value)
except Invalid, e:
msgs.append(e.msg)
if msgs:
raise Invalid(node, msgs)
class Function(object):
""" Validator which accepts a function and an optional message;
the function is called with the ``value`` during validation.
If the function returns anything falsy (``None``, ``False``, the
empty string, ``0``, an object with a ``__nonzero__`` that returns
``False``, etc) when called during validation, an
:exc:`colander.Invalid` exception is raised (validation fails);
its msg will be the value of the ``message`` argument passed to
this class' constructor.
If the function returns a stringlike object (a ``str`` or
``unicode`` object) that is *not* the empty string , a
:exc:`colander.Invalid` exception is raised using the stringlike
value returned from the function as the exeption message
(validation fails).
If the function returns anything *except* a stringlike object
object which is truthy (e.g. ``True``, the integer ``1``, an
object with a ```__nonzero__`` that returns ``True``, etc), an
:exc:`colander.Invalid` exception is *not* raised (validation
succeeds).
The default value for the ``message`` when not provided via the
constructor is ``Invalid value``.
"""
def __init__(self, function, message='Invalid value'):
self.function = function
self.message = message
def __call__(self, node, value):
result = self.function(value)
if not result:
raise Invalid(node, self.message)
if isinstance(result, basestring):
raise Invalid(node, result)
class Range(object):
""" Validator which succeeds if the value it is passed is greater
or equal to ``min`` and less than or equal to ``max``. If ``min``
is not specified, or is specified as ``None``, no lower bound
exists. If ``max`` is not specified, or is specified as ``None``,
no upper bound exists."""
def __init__(self, min=None, max=None):
self.min = min
self.max = max
def __call__(self, node, value):
if self.min is not None:
if value < self.min:
raise Invalid(
node,
'%s is less than minimum value %s' % (value, self.min))
if self.max is not None:
if value > self.max:
raise Invalid(
node,
'%s is greater than maximum value %s' % (value, self.max))
class Length(object):
""" Validator which succeeds if the value passed to it has a
length between a minimum and maximum. The value is most often a
string."""
def __init__(self, min=None, max=None):
self.min = min
self.max = max
def __call__(self, node, value):
if self.min is not None:
if len(value) < self.min:
raise Invalid(
node,
'Shorter than minimum length %s' % self.min)
if self.max is not None:
if len(value) > self.max:
raise Invalid(
node,
'Longer than maximum length %s' % self.max)
class OneOf(object):
""" Validator which succeeds if the value passed to it is one of
a fixed set of values """
def __init__(self, values):
self.values = values
def __call__(self, node, value):
if not value in self.values:
raise Invalid(node, '"%s" is not one of %s' % (
value, ', '.join(['%s' % x for x in self.values])))
class Mapping(object):
""" A type which represents a mapping of names to nodes.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type imply the named keys and values in the mapping.
The constructor of this type accepts two extra optional keyword
arguments that other types do not: ``unknown`` and ``partial``.
Attributes of the same name can be set on a type instance to
control the behavior after construction.
unknown
``unknown`` controls the behavior of this type when an
unknown key is encountered in the value passed to the
``deserialize`` method of this instance. The potential
values of ``unknown`` are:
- ``ignore`` means that keys that are not present in the schema
associated with this type will be ignored during
deserialization.
- ``raise`` will cause a :exc:`colander.Invalid` exception to be
raised when unknown keys are present during deserialization.
- ``preserve`` will preserve the 'raw' unknown keys and values
in the returned data structure during deserialization.
Default: ``ignore``.
partial
``partial`` controls the behavior of this type when a
schema-expected key is missing from the value passed to the
``deserialize`` method of this instance.
During deserialization, when ``partial`` is ``False``, a
:exc:`colander.Invalid` exception will be raised if the
mapping value does not contain a key specified by the schema
node related to this mapping type. When ``partial`` is
``True``, no exception is raised and a partial mapping will be
deserialized.
Default: ``False``.
"""
def __init__(self, unknown='ignore', partial=False):
self.unknown = unknown
self.partial = partial
def _set_unknown(self, value):
if not value in ('ignore', 'raise', 'preserve'):
raise ValueError(
'unknown attribute must be one of "ignore", "raise", '
'or "preserve"')
self._unknown = value
def _get_unknown(self):
return self._unknown
unknown = property(_get_unknown, _set_unknown)
def _validate(self, node, value):
try:
return dict(value)
except Exception, e:
raise Invalid(node, '%r is not a mapping type: %s' % (value, e))
def _impl(self, node, value, callback, default_callback, unknown=None,
partial=None):
if partial is None:
partial = self.partial
if unknown is None:
unknown = self.unknown
value = self._validate(node, value)
error = None
result = {}
for num, subnode in enumerate(node.children):
name = subnode.name
subval = value.pop(name, _missing)
try:
if subval is _missing:
if subnode.required:
if not partial:
raise Invalid(
subnode,
'"%s" is required but missing' % subnode.name)
else:
continue
result[name] = default_callback(subnode)
else:
result[name] = callback(subnode, subval)
except Invalid, e:
if error is None:
error = Invalid(node)
error.add(e, num)
if unknown == 'raise':
if value:
raise Invalid(node,
'Unrecognized keys in mapping: %r' % value)
elif unknown == 'preserve':
result.update(value)
if error is not None:
raise error
return result
def serialize(self, node, value):
def callback(subnode, subval):
return subnode.serialize(subval)
def default_callback(subnode):
return subnode.serialize(subnode.default)
return self._impl(node, value, callback, default_callback,
unknown='ignore', partial=True)
def deserialize(self, node, value):
def callback(subnode, subval):
return subnode.deserialize(subval)
def default_callback(subnode):
return subnode.default
return self._impl(node, value, callback, default_callback)
class Positional(object):
"""
Marker abstract base class meaning 'this type has children which
should be addressed by position instead of name' (e.g. via seq[0],
but never seq['name']). This is consulted by Invalid.asdict when
creating a dictionary representation of an error tree.
"""
class Tuple(Positional):
""" A type which represents a fixed-length sequence of nodes.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type imply the positional elements of the tuple in the order
they are added.
This type is willing to serialize and deserialized iterables that,
when converted to a tuple, have the same number of elements as the
number of the associated node's subnodes.
"""
def _validate(self, node, value):
if not hasattr(value, '__iter__'):
raise Invalid(node, '%r is not iterable' % value)
valuelen, nodelen = len(value), len(node.children)
if valuelen != nodelen:
raise Invalid(
node,
('%s has an incorrect number of elements '
'(expected %s, was %s)' % (value, nodelen, valuelen)))
return list(value)
def _impl(self, node, value, callback):
value = self._validate(node, value)
error = None
result = []
for num, subnode in enumerate(node.children):
subval = value[num]
try:
result.append(callback(subnode, subval))
except Invalid, e:
if error is None:
error = Invalid(node)
error.add(e, num)
if error is not None:
raise error
return tuple(result)
def deserialize(self, node, value):
def callback(subnode, subval):
return subnode.deserialize(subval)
return self._impl(node, value, callback)
def serialize(self, node, value):
def callback(subnode, subval):
return subnode.serialize(subval)
return self._impl(node, value, callback)
class Sequence(Positional):
"""
A type which represents a variable-length sequence of nodes,
all of which must be of the same type.
The type of the first subnode of the
:class:`colander.SchemaNode` that wraps this type is considered the
sequence type.
The optional ``accept_scalar`` argument to this type's constructor
indicates what should happen if the value found during serialization or
deserialization does not have an ``__iter__`` method or is a
mapping type.
If ``accept_scalar`` is ``True`` and the value does not have an
``__iter__`` method or is a mapping type, the value will be turned
into a single element list.
If ``accept_scalar`` is ``False`` and the value does not have an
``__iter__`` method or is a mapping type, an
:exc:`colander.Invalid` error will be raised during serialization
and deserialization.
The default value of ``accept_scalar`` is ``False``.
"""
def __init__(self, accept_scalar=False):
self.accept_scalar = accept_scalar
def _validate(self, node, value, accept_scalar):
if hasattr(value, '__iter__') and not hasattr(value, 'get'):
return list(value)
if accept_scalar:
return [value]
else:
raise Invalid(node, '%r is not iterable' % value)
def _impl(self, node, value, callback, accept_scalar):
if accept_scalar is None:
accept_scalar = self.accept_scalar
value = self._validate(node, value, accept_scalar)
error = None
result = []
for num, subval in enumerate(value):
try:
result.append(callback(node.children[0], subval))
except Invalid, e:
if error is None:
error = Invalid(node)
error.add(e, num)
if error is not None:
raise error
return result
def deserialize(self, node, value, accept_scalar=None):
"""
Along with the normal ``node`` and ``value`` arguments, this
method accepts an additional optional keyword argument:
``accept_scalar``. This keyword argument can be used to
override the constructor value of the same name.
If ``accept_scalar`` is ``True`` and the ``value`` does not
have an ``__iter__`` method or is a mapping type, the value
will be turned into a single element list.
If ``accept_scalar`` is ``False`` and the value does not have an
``__iter__`` method or is a mapping type, an
:exc:`colander.Invalid` error will be raised during serialization
and deserialization.
The default of ``accept_scalar`` is ``None``, which means
respect the default ``accept_scalar`` value attached to this
instance via its constructor.
"""
def callback(subnode, subval):
return subnode.deserialize(subval)
return self._impl(node, value, callback, accept_scalar)
def serialize(self, node, value, accept_scalar=None):
"""
Along with the normal ``node`` and ``value`` arguments, this
method accepts an additional optional keyword argument:
``accept_scalar``. This keyword argument can be used to
override the constructor value of the same name.
If ``accept_scalar`` is ``True`` and the ``value`` does not
have an ``__iter__`` method or is a mapping type, the value
will be turned into a single element list.
If ``accept_scalar`` is ``False`` and the value does not have an
``__iter__`` method or is a mapping type, an
:exc:`colander.Invalid` error will be raised during serialization
and deserialization.
The default of ``accept_scalar`` is ``None``, which means
respect the default ``accept_scalar`` value attached to this
instance via its constructor.
"""
def callback(subnode, subval):
return subnode.serialize(subval)
return self._impl(node, value, callback, accept_scalar)
Seq = Sequence
default_encoding = 'utf-8'
class String(object):
""" A type representing a Unicode string.
This type constructor accepts a single argument ``encoding``,
representing the encoding which should be applied to object
serialization. It defaults to ``utf-8`` if not provided.
Input to ``serialize`` is serialized to a Python ``str`` object,
which is encoded in the encoding provided.
If a string (as opposed to a unicode object) is provided as a
value to either the serialize or deserialize method of this type,
it must be encoded with the type's encoding; an
:exc:`colander.Invalid` error will result if not.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
def __init__(self, encoding=None):
if encoding is None:
encoding = default_encoding
self.encoding = encoding
def deserialize(self, node, value):
try:
if not isinstance(value, unicode):
value = unicode(str(value), self.encoding)
except Exception, e:
raise Invalid(node, '%r is not a string: %s' % (value, e))
if not value:
if node.required:
raise Invalid(node, 'Required')
value = node.default
return value
def serialize(self, node, value):
try:
if isinstance(value, unicode):
result = value.encode(self.encoding)
else:
# do validation here
result = unicode(value, self.encoding).encode(self.encoding)
return result
except Exception, e:
raise Invalid(node,
'%r cannot be serialized to str: %s' % (value, e))
Str = String
class Integer(object):
""" A type representing an integer.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
def deserialize(self, node, value):
try:
return int(value)
except Exception:
if value == '':
if node.required:
raise Invalid(node, 'Required')
return node.default
raise Invalid(node, '"%s" is not a number' % value)
def serialize(self, node, value):
try:
return str(int(value))
except Exception:
raise Invalid(node, '"%s" is not a number' % value)
Int = Integer
class Float(object):
""" A type representing a float.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
def deserialize(self, node, value):
try:
return float(value)
except Exception:
if value == '':
if node.required:
raise Invalid(node, 'Required')
return node.default
raise Invalid(node, '"%s" is not a number' % value)
def serialize(self, node, value):
try:
return str(float(value))
except Exception:
raise Invalid(node, '"%s" is not a number' % value)
Int = Integer
class Boolean(object):
""" A type representing a boolean object.
During deserialization, a value in the set (``false``, ``0``) will
be considered ``False``. Anything else is considered
``True``. Case is ignored.
Serialization will produce ``true`` or ``false`` based on the
value.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
def deserialize(self, node, value):
try:
value = str(value)
except:
raise Invalid(node, '%r is not a string' % value)
if not value:
if node.required:
raise Invalid(node, 'Required')
value = node.default
value = value.lower()
if value in ('false', '0'):
return False
return True
def serialize(self, node, value):
return value and 'true' or 'false'
Bool = Boolean
class GlobalObject(object):
""" A type representing an importable Python object. This type
serializes 'global' Python objects (objects which can be imported)
to dotted Python names.
Two dotted name styles are supported during deserialization:
- ``pkg_resources``-style dotted names where non-module attributes
of a module are separated from the rest of the path using a ':'
e.g. ``package.module:attr``.
- ``zope.dottedname``-style dotted names where non-module
attributes of a module are separated from the rest of the path
using a '.' e.g. ``package.module.attr``.
These styles can be used interchangeably. If the serialization
contains a ``:`` (colon), the ``pkg_resources`` resolution
mechanism will be chosen, otherwise the ``zope.dottedname``
resolution mechanism will be chosen.
The constructor accepts a single argument named ``package`` which
should be a Python module or package object; it is used when
*relative* dotted names are supplied to the ``deserialize``
method. A serialization which has a ``.`` (dot) or ``:`` (colon)
as its first character is treated as relative. E.g. if
``.minidom`` is supplied to ``deserialize``, and the ``package``
argument to this type was passed the ``xml`` module object, the
resulting import would be for ``xml.minidom``. If a relative
package name is supplied to ``deserialize``, and no ``package``
was supplied to the constructor, an :exc:`colander.Invalid` error
will be raised.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
def __init__(self, package):
self.package = package
def _pkg_resources_style(self, node, value):
""" package.module:attr style """
import pkg_resources
if value.startswith('.') or value.startswith(':'):
if not self.package:
raise Invalid(
node,
'relative name "%s" irresolveable without package' % value)
if value in ['.', ':']:
value = self.package.__name__
else:
value = self.package.__name__ + value
return pkg_resources.EntryPoint.parse(
'x=%s' % value).load(False)
def _zope_dottedname_style(self, node, value):
""" package.module.attr style """
module = self.package and self.package.__name__ or None
if value == '.':
if self.package is None:
raise Invalid(
node,
'relative name "%s" irresolveable without package' % value)
name = module.split('.')
else:
name = value.split('.')
if not name[0]:
if module is None:
raise Invalid(
node,
'relative name "%s" irresolveable without package' %
value)
module = module.split('.')
name.pop(0)
while not name[0]:
module.pop()
name.pop(0)
name = module + name
used = name.pop(0)
found = __import__(used)
for n in name:
used += '.' + n
try:
found = getattr(found, n)
except AttributeError:
__import__(used)
found = getattr(found, n)
return found
def deserialize(self, node, value):
if not isinstance(value, basestring):
raise Invalid(node, '"%s" is not a string' % value)
try:
if ':' in value:
return self._pkg_resources_style(node, value)
else:
return self._zope_dottedname_style(node, value)
except ImportError:
raise Invalid(node,
'The dotted name "%s" cannot be imported' % value)
def serialize(self, node, value):
try:
return value.__name__
except AttributeError:
raise Invalid(node, '%r has no __name__' % value)
class DateTime(object):
""" A type representing a Python ``datetime.datetime`` object.
This type serializes python ``datetime.datetime`` objects to a
`ISO8601 <http://en.wikipedia.org/wiki/ISO_8601>`_ string format.
The format includes the date, the time, and the timezone of the
datetime.
The constructor accepts an argument named ``default_tzinfo`` which
should be a Python ``tzinfo`` object; by default it is None,
meaning that the default tzinfo will be equivalent to UTC (Zulu
time). The ``default_tzinfo`` tzinfo object is used to convert
'naive' datetimes to a timezone-aware representation during
serialization.
You can adjust the error message reported by this class by
changing its ``err_template`` attribute in a subclass on an
instance of this class. By default, the ``err_tempalte``
attribute is the string ``%(value)s cannot be parsed as an iso8601
date: %(exc)s``. This string is used as the interpolation subject
of a dictionary composed of ``value`` and ``exc``. ``value`` and
``exc`` are the unvalidatable value and the exception caused
trying to convert the value, respectively.
For convenience, this type is also willing to coerce
``datetime.date`` objects to a DateTime ISO string representation
during serialization. It does so by using midnight of the day as
the time, and uses the ``default_tzinfo`` to give the
serialization a timezone.
Likewise, for convenience, during deserialization, this type will
convert ``YYYY-MM-DD`` ISO8601 values to a datetime object. It
does so by using midnight of the day as the time, and uses the
``default_tzinfo`` to give the serialization a timezone.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
err_template = '%(value)s cannot be parsed as an iso8601 date: %(exc)s'
def __init__(self, default_tzinfo=None):
if default_tzinfo is None:
default_tzinfo = iso8601.iso8601.Utc()
self.default_tzinfo = default_tzinfo
def serialize(self, node, value):
if type(value) is datetime.date: # cant use isinstance; dt subs date
value = datetime.datetime.combine(value, datetime.time())
if not isinstance(value, datetime.datetime):
raise Invalid(node, '%r is not a datetime object' % value)
if value.tzinfo is None:
value = value.replace(tzinfo=self.default_tzinfo)
return value.isoformat()
def deserialize(self, node, value):
try:
result = iso8601.parse_date(value)
except (iso8601.ParseError, TypeError), e:
try:
year, month, day = map(int, value.split('-', 2))
result = datetime.datetime(year, month, day,
tzinfo=self.default_tzinfo)
except Exception, e:
raise Invalid(node, self.err_template % {'value':value,
'exc':e})
return result
class Date(object):
""" A type representing a Python ``datetime.date`` object.
This type serializes python ``datetime.date`` objects to a
`ISO8601 <http://en.wikipedia.org/wiki/ISO_8601>`_ string format.
The format includes the date only.
The constructor accepts no arguments.
You can adjust the error message reported by this class by
changing its ``err_template`` attribute in a subclass on an
instance of this class. By default, the ``err_template``
attribute is the string ``%(value)s cannot be parsed as an iso8601
date: %(exc)s``. This string is used as the interpolation subject
of a dictionary composed of ``value`` and ``exc``. ``value`` and
``exc`` are the unvalidatable value and the exception caused
trying to convert the value, respectively.
For convenience, this type is also willing to coerce
``datetime.datetime`` objects to a date-only ISO string
representation during serialization. It does so by stripping off
any time information, converting the ``datetime.datetime`` into a
date before serializing.
Likewise, for convenience, this type is also willing to coerce ISO
representations that contain time info into a ``datetime.date``
object during deserialization. It does so by throwing away any
time information related to the serialized value during
deserialization.
The subnodes of the :class:`colander.SchemaNode` that wraps
this type are ignored.
"""
err_template = '%(value)s cannot be parsed as an iso8601 date: %(exc)s'
def serialize(self, node, value):
if isinstance(value, datetime.datetime):
value = value.date()
if not isinstance(value, datetime.date):
raise Invalid(node, '%r is not a date object' % value)
return value.isoformat()
def deserialize(self, node, value):
try:
result = iso8601.parse_date(value)
result = result.date()
except (iso8601.ParseError, TypeError):
try:
year, month, day = map(int, value.split('-', 2))
result = datetime.date(year, month, day)
except Exception, e:
raise Invalid(node, self.err_template % {'value':value,
'exc':e})
return result
class SchemaNode(object):
"""
Fundamental building block of schemas.
The constructor accepts these arguments:
- ``typ`` (required): The 'type' for this node. It should be an
instance of a class that implements the
:class:`colander.interfaces.Type` interface.
- ``children``: a sequence of subnodes. If the subnodes of this
node are not known at construction time, they can later be added
via the ``add`` method.
- ``name``: The name of this node.
- ``default``: The default value for this node; if it is not
provided, this node has no default value and it will be
considered 'required' (the ``required`` attribute will be True).
- ``validator``: Optional validator for this node. It should be
an object that implements the
:class:`colander.interfaces.Validator` interface.
- ``title``: The title of this node. Defaults to a captialization
of the ``name``. The title is used by higher-level systems (not
by Colander itself).
- ``description``: The description for this node. Defaults to
``''`` (the emtpty string). The description is used by
higher-level systems (not by Colander itself).
"""
_counter = itertools.count()
def __new__(cls, *arg, **kw):
inst = object.__new__(cls)
inst._order = cls._counter.next()
return inst
def __init__(self, typ, *children, **kw):
self.typ = typ
self.validator = kw.get('validator', None)
self.default = kw.get('default', _missing)
self.name = kw.get('name', '')
self.title = kw.get('title', self.name.capitalize())
self.description = kw.get('description', '')
self.children = list(children)
def __repr__(self):
return '<%s object at %x named %r>' % (self.__class__.__name__,
id(self),
self.name)
@property
def required(self):
""" Property which returns true if this node is required in the
schema """
return self.default is _missing
@property
def sdefault(self):
""" Return the *serialized* default of the node default or
``None`` if there is no default."""
if self.default is _missing:
return None
return self.typ.serialize(self, self.default)
def deserialize(self, value):
""" Deserialize the value based on the schema represented by
this node. """
value = self.typ.deserialize(self, value)
if self.validator is not None:
self.validator(self, value)
return value
def serialize(self, value):
""" Serialize the value based on the schema represented by
this node."""
return self.typ.serialize(self, value)
def add(self, node):
""" Add a subnode to this node. """
self.children.append(node)
def __getitem__(self, name):
for node in self.children:
if node.name == name:
return node
raise KeyError(name)
def clone(self):
""" Clone the schema node and return the clone. All subnodes
are also cloned recursively. Attributes present in node
dictionaries are preserved."""
cloned = self.__class__(self.typ)
cloned.__dict__.update(self.__dict__)
cloned.children = [ node.clone() for node in self.children ]
return cloned
class _SchemaMeta(type):
def __init__(cls, name, bases, clsattrs):
nodes = []
for name, value in clsattrs.items():
if isinstance(value, SchemaNode):
value.name = name
if not value.title:
value.title = name.capitalize()
nodes.append((value._order, value))
cls.__schema_nodes__ = nodes
# Combine all attrs from this class and its subclasses.
extended = []
for c in cls.__mro__:
extended.extend(getattr(c, '__schema_nodes__', []))
# Sort the attrs to maintain the order as defined, and assign to the
# class.
extended.sort()
cls.nodes = [x[1] for x in extended]
class Schema(object):
schema_type = Mapping
node_type = SchemaNode
__metaclass__ = _SchemaMeta
def __new__(cls, *args, **kw):
node = object.__new__(cls.node_type)
node.name = None
node._order = SchemaNode._counter.next()
typ = cls.schema_type()
node.__init__(typ, *args, **kw)
for n in cls.nodes:
node.add(n)
return node
MappingSchema = Schema
class SequenceSchema(object):
schema_type = Sequence
node_type = SchemaNode
__metaclass__ = _SchemaMeta
def __new__(cls, *args, **kw):
node = object.__new__(cls.node_type)
node.name = None
node._order = SchemaNode._counter.next()
typ = cls.schema_type()
node.__init__(typ, *args, **kw)
if not len(cls.nodes) == 1:
raise Invalid(node,
'Sequence schemas must have exactly one child node')
for n in cls.nodes:
node.add(n)
return node
class TupleSchema(Schema):
schema_type = Tuple