Source code for flask_restx.fields

import re
import fnmatch
import inspect

from calendar import timegm
from datetime import date, datetime
from decimal import Decimal, ROUND_HALF_EVEN
from email.utils import formatdate

from urllib.parse import urlparse, urlunparse

from flask import url_for, request
from werkzeug.utils import cached_property

from .inputs import (
from .errors import RestError
from .marshalling import marshal
from .utils import camel_to_dash, not_none

__all__ = (

[docs]class MarshallingError(RestError): """ This is an encapsulating Exception in case of marshalling error. """ def __init__(self, underlying_exception): # just put the contextual representation of the error to hint on what # went wrong without exposing internals super(MarshallingError, self).__init__(str(underlying_exception))
def is_indexable_but_not_string(obj): return not hasattr(obj, "strip") and hasattr(obj, "__iter__") def is_integer_indexable(obj): return isinstance(obj, list) or isinstance(obj, tuple) def get_value(key, obj, default=None): """Helper for pulling a keyed value off various types of objects""" if isinstance(key, int): return _get_value_for_key(key, obj, default) elif callable(key): return key(obj) else: return _get_value_for_keys(key.split("."), obj, default) def _get_value_for_keys(keys, obj, default): if len(keys) == 1: return _get_value_for_key(keys[0], obj, default) else: return _get_value_for_keys( keys[1:], _get_value_for_key(keys[0], obj, default), default ) def _get_value_for_key(key, obj, default): if is_indexable_but_not_string(obj): try: return obj[key] except (IndexError, TypeError, KeyError): pass if is_integer_indexable(obj): try: return obj[int(key)] except (IndexError, TypeError, ValueError): pass return getattr(obj, key, default) def to_marshallable_type(obj): """ Helper for converting an object to a dictionary only if it is not dictionary already or an indexable object nor a simple type """ if obj is None: return None # make it idempotent for None if hasattr(obj, "__marshallable__"): return obj.__marshallable__() if hasattr(obj, "__getitem__"): return obj # it is indexable it is ok return dict(obj.__dict__)
[docs]class Raw(object): """ Raw provides a base field class from which others should extend. It applies no formatting by default, and should only be used in cases where data does not need to be formatted before being serialized. Fields should throw a :class:`MarshallingError` in case of parsing problem. :param default: The default value for the field, if no value is specified. :param attribute: If the public facing value differs from the internal value, use this to retrieve a different attribute from the response than the publicly named value. :param str title: The field title (for documentation purpose) :param str description: The field description (for documentation purpose) :param bool required: Is the field required ? :param bool readonly: Is the field read only ? (for documentation purpose) :param example: An optional data example (for documentation purpose) :param callable mask: An optional mask function to be applied to output """ #: The JSON/Swagger schema type __schema_type__ = "object" #: The JSON/Swagger schema format __schema_format__ = None #: An optional JSON/Swagger schema example __schema_example__ = None def __init__( self, default=None, attribute=None, title=None, description=None, required=None, readonly=None, example=None, mask=None, **kwargs ): self.attribute = attribute self.default = default self.title = title self.description = description self.required = required self.readonly = readonly self.example = example if example is not None else self.__schema_example__ self.mask = mask
[docs] def format(self, value): """ Formats a field's value. No-op by default - field classes that modify how the value of existing object keys should be presented should override this and apply the appropriate formatting. :param value: The value to format :raises MarshallingError: In case of formatting problem Ex:: class TitleCase(Raw): def format(self, value): return unicode(value).title() """ return value
[docs] def output(self, key, obj, **kwargs): """ Pulls the value for the given key from the object, applies the field's formatting and returns the result. If the key is not found in the object, returns the default value. Field classes that create values which do not require the existence of the key in the object should override this and return the desired value. :raises MarshallingError: In case of formatting problem """ value = get_value(key if self.attribute is None else self.attribute, obj) if value is None: default = self._v("default") return self.format(default) if default else default try: data = self.format(value) except MarshallingError as e: msg = 'Unable to marshal field "{0}" value "{1}": {2}'.format( key, value, str(e) ) raise MarshallingError(msg) return self.mask.apply(data) if self.mask else data
def _v(self, key): """Helper for getting a value from attribute allowing callable""" value = getattr(self, key) return value() if callable(value) else value @cached_property def __schema__(self): return not_none(self.schema()) def schema(self): return { "type": self.__schema_type__, "format": self.__schema_format__, "title": self.title, "description": self.description, "readOnly": self.readonly, "default": self._v("default"), "example": self.example, }
[docs]class Nested(Raw): """ Allows you to nest one set of fields inside another. See :ref:`nested-field` for more information :param dict model: The model dictionary to nest :param bool allow_null: Whether to return None instead of a dictionary with null keys, if a nested dictionary has all-null keys :param bool skip_none: Optional key will be used to eliminate inner fields which value is None or the inner field's key not exist in data :param kwargs: If ``default`` keyword argument is present, a nested dictionary will be marshaled as its value if nested dictionary is all-null keys (e.g. lets you return an empty JSON object instead of null) """ __schema_type__ = None def __init__( self, model, allow_null=False, skip_none=False, as_list=False, **kwargs ): self.model = model self.as_list = as_list self.allow_null = allow_null self.skip_none = skip_none super(Nested, self).__init__(**kwargs) @property def nested(self): return getattr(self.model, "resolved", self.model)
[docs] def output(self, key, obj, ordered=False, **kwargs): value = get_value(key if self.attribute is None else self.attribute, obj) if value is None: if self.allow_null: return None elif self.default is not None: return self.default return marshal(value, self.nested, skip_none=self.skip_none, ordered=ordered)
def schema(self): schema = super(Nested, self).schema() ref = "#/definitions/{0}".format( if self.as_list: schema["type"] = "array" schema["items"] = {"$ref": ref} elif any(schema.values()): # There is already some properties in the schema allOf = schema.get("allOf", []) allOf.append({"$ref": ref}) schema["allOf"] = allOf else: schema["$ref"] = ref return schema def clone(self, mask=None): kwargs = self.__dict__.copy() model = kwargs.pop("model") if mask: model = mask.apply(model.resolved if hasattr(model, "resolved") else model) return self.__class__(model, **kwargs)
[docs]class List(Raw): """ Field for marshalling lists of other fields. See :ref:`list-field` for more information. :param cls_or_instance: The field type the list will contain. """ def __init__(self, cls_or_instance, **kwargs): self.min_items = kwargs.pop("min_items", None) self.max_items = kwargs.pop("max_items", None) self.unique = kwargs.pop("unique", None) super(List, self).__init__(**kwargs) error_msg = "The type of the list elements must be a subclass of fields.Raw" if isinstance(cls_or_instance, type): if not issubclass(cls_or_instance, Raw): raise MarshallingError(error_msg) self.container = cls_or_instance() else: if not isinstance(cls_or_instance, Raw): raise MarshallingError(error_msg) self.container = cls_or_instance
[docs] def format(self, value): # Convert all instances in typed list to container type if isinstance(value, set): value = list(value) is_nested = isinstance(self.container, Nested) or type(self.container) is Raw def is_attr(val): return self.container.attribute and hasattr(val, self.container.attribute) if value is None: return [] return [ self.container.output( idx, val if (isinstance(val, dict) or is_attr(val)) and not is_nested else value, ) for idx, val in enumerate(value) ]
[docs] def output(self, key, data, ordered=False, **kwargs): value = get_value(key if self.attribute is None else self.attribute, data) # we cannot really test for external dict behavior if is_indexable_but_not_string(value) and not isinstance(value, dict): return self.format(value) if value is None: return self._v("default") return [marshal(value, self.container.nested)]
def schema(self): schema = super(List, self).schema() schema.update( minItems=self._v("min_items"), maxItems=self._v("max_items"), uniqueItems=self._v("unique"), ) schema["type"] = "array" schema["items"] = self.container.__schema__ return schema def clone(self, mask=None): kwargs = self.__dict__.copy() model = kwargs.pop("container") if mask: model = mask.apply(model) return self.__class__(model, **kwargs)
class StringMixin(object): __schema_type__ = "string" def __init__(self, *args, **kwargs): self.min_length = kwargs.pop("min_length", None) self.max_length = kwargs.pop("max_length", None) self.pattern = kwargs.pop("pattern", None) super(StringMixin, self).__init__(*args, **kwargs) def schema(self): schema = super(StringMixin, self).schema() schema.update( minLength=self._v("min_length"), maxLength=self._v("max_length"), pattern=self._v("pattern"), ) return schema class MinMaxMixin(object): def __init__(self, *args, **kwargs): self.minimum = kwargs.pop("min", None) self.exclusiveMinimum = kwargs.pop("exclusiveMin", None) self.maximum = kwargs.pop("max", None) self.exclusiveMaximum = kwargs.pop("exclusiveMax", None) super(MinMaxMixin, self).__init__(*args, **kwargs) def schema(self): schema = super(MinMaxMixin, self).schema() schema.update( minimum=self._v("minimum"), exclusiveMinimum=self._v("exclusiveMinimum"), maximum=self._v("maximum"), exclusiveMaximum=self._v("exclusiveMaximum"), ) return schema class NumberMixin(MinMaxMixin): __schema_type__ = "number" def __init__(self, *args, **kwargs): self.multiple = kwargs.pop("multiple", None) super(NumberMixin, self).__init__(*args, **kwargs) def schema(self): schema = super(NumberMixin, self).schema() schema.update(multipleOf=self._v("multiple")) return schema
[docs]class String(StringMixin, Raw): """ Marshal a value as a string. """ def __init__(self, *args, **kwargs): self.enum = kwargs.pop("enum", None) self.discriminator = kwargs.pop("discriminator", None) super(String, self).__init__(*args, **kwargs) self.required = self.discriminator or self.required
[docs] def format(self, value): try: return str(value) except ValueError as ve: raise MarshallingError(ve)
def schema(self): enum = self._v("enum") schema = super(String, self).schema() if enum: schema.update(enum=enum) if enum and schema["example"] is None: schema["example"] = enum[0] return schema
[docs]class Integer(NumberMixin, Raw): """ Field for outputting an integer value. :param int default: The default value for the field, if no value is specified. """ __schema_type__ = "integer"
[docs] def format(self, value): try: if value is None: return self.default return int(value) except (ValueError, TypeError) as ve: raise MarshallingError(ve)
[docs]class Float(NumberMixin, Raw): """ A double as IEEE-754 double precision. ex : 3.141592653589793 3.1415926535897933e-06 3.141592653589793e+24 nan inf -inf """
[docs] def format(self, value): try: if value is None: return self.default return float(value) except (ValueError, TypeError) as ve: raise MarshallingError(ve)
[docs]class Arbitrary(NumberMixin, Raw): """ A floating point number with an arbitrary precision. ex: 634271127864378216478362784632784678324.23432 """
[docs] def format(self, value): return str(Decimal(value))
ZERO = Decimal()
[docs]class Fixed(NumberMixin, Raw): """ A decimal number with a fixed precision. """ def __init__(self, decimals=5, **kwargs): super(Fixed, self).__init__(**kwargs) self.precision = Decimal("0." + "0" * (decimals - 1) + "1")
[docs] def format(self, value): dvalue = Decimal(value) if not dvalue.is_normal() and dvalue != ZERO: raise MarshallingError("Invalid Fixed precision number.") return str(dvalue.quantize(self.precision, rounding=ROUND_HALF_EVEN))
[docs]class Boolean(Raw): """ Field for outputting a boolean value. Empty collections such as ``""``, ``{}``, ``[]``, etc. will be converted to ``False``. """ __schema_type__ = "boolean"
[docs] def format(self, value): return boolean(value)
[docs]class DateTime(MinMaxMixin, Raw): """ Return a formatted datetime string in UTC. Supported formats are RFC 822 and ISO 8601. See :func:`email.utils.formatdate` for more info on the RFC 822 format. See :meth:`datetime.datetime.isoformat` for more info on the ISO 8601 format. :param str dt_format: ``rfc822`` or ``iso8601`` """ __schema_type__ = "string" __schema_format__ = "date-time" def __init__(self, dt_format="iso8601", **kwargs): super(DateTime, self).__init__(**kwargs) self.dt_format = dt_format def parse(self, value): if value is None: return None elif isinstance(value, str): parser = ( datetime_from_iso8601 if self.dt_format == "iso8601" else datetime_from_rfc822 ) return parser(value) elif isinstance(value, datetime): return value elif isinstance(value, date): return datetime(value.year, value.month, else: raise ValueError("Unsupported DateTime format")
[docs] def format(self, value): try: value = self.parse(value) if self.dt_format == "iso8601": return self.format_iso8601(value) elif self.dt_format == "rfc822": return self.format_rfc822(value) else: raise MarshallingError("Unsupported date format %s" % self.dt_format) except (AttributeError, ValueError) as e: raise MarshallingError(e)
[docs] def format_rfc822(self, dt): """ Turn a datetime object into a formatted date. :param datetime dt: The datetime to transform :return: A RFC 822 formatted date string """ return formatdate(timegm(dt.utctimetuple()))
[docs] def format_iso8601(self, dt): """ Turn a datetime object into an ISO8601 formatted date. :param datetime dt: The datetime to transform :return: A ISO 8601 formatted date string """ return dt.isoformat()
def _for_schema(self, name): value = self.parse(self._v(name)) return self.format(value) if value else None def schema(self): schema = super(DateTime, self).schema() schema["default"] = self._for_schema("default") schema["minimum"] = self._for_schema("minimum") schema["maximum"] = self._for_schema("maximum") return schema
[docs]class Date(DateTime): """ Return a formatted date string in UTC in ISO 8601. See :meth:`` for more info on the ISO 8601 format. """ __schema_format__ = "date" def __init__(self, **kwargs): kwargs.pop("dt_format", None) super(Date, self).__init__(dt_format="iso8601", **kwargs) def parse(self, value): if value is None: return None elif isinstance(value, str): return date_from_iso8601(value) elif isinstance(value, datetime): return elif isinstance(value, date): return value else: raise ValueError("Unsupported Date format")
[docs]class Url(StringMixin, Raw): """ A string representation of a Url :param str endpoint: Endpoint name. If endpoint is ``None``, ``request.endpoint`` is used instead :param bool absolute: If ``True``, ensures that the generated urls will have the hostname included :param str scheme: URL scheme specifier (e.g. ``http``, ``https``) """ def __init__(self, endpoint=None, absolute=False, scheme=None, **kwargs): super(Url, self).__init__(**kwargs) self.endpoint = endpoint self.absolute = absolute self.scheme = scheme
[docs] def output(self, key, obj, **kwargs): try: data = to_marshallable_type(obj) endpoint = self.endpoint if self.endpoint is not None else request.endpoint o = urlparse(url_for(endpoint, _external=self.absolute, **data)) if self.absolute: scheme = self.scheme if self.scheme is not None else o.scheme return urlunparse((scheme, o.netloc, o.path, "", "", "")) return urlunparse(("", "", o.path, "", "", "")) except TypeError as te: raise MarshallingError(te)
[docs]class FormattedString(StringMixin, Raw): """ FormattedString is used to interpolate other values from the response into this field. The syntax for the source string is the same as the string :meth:`~str.format` method from the python stdlib. Ex:: fields = { 'name': fields.String, 'greeting': fields.FormattedString("Hello {name}") } data = { 'name': 'Doug', } marshal(data, fields) :param str src_str: the string to format with the other values from the response. """ def __init__(self, src_str, **kwargs): super(FormattedString, self).__init__(**kwargs) self.src_str = str(src_str)
[docs] def output(self, key, obj, **kwargs): try: data = to_marshallable_type(obj) return self.src_str.format(**data) except (TypeError, IndexError) as error: raise MarshallingError(error)
[docs]class ClassName(String): """ Return the serialized object class name as string. :param bool dash: If `True`, transform CamelCase to kebab_case. """ def __init__(self, dash=False, **kwargs): super(ClassName, self).__init__(**kwargs) self.dash = dash
[docs] def output(self, key, obj, **kwargs): classname = obj.__class__.__name__ if classname == "dict": return "object" return camel_to_dash(classname) if self.dash else classname
[docs]class Polymorph(Nested): """ A Nested field handling inheritance. Allows you to specify a mapping between Python classes and fields specifications. .. code-block:: python mapping = { Child1: child1_fields, Child2: child2_fields, } fields = api.model('Thing', { owner: fields.Polymorph(mapping) }) :param dict mapping: Maps classes to their model/fields representation """ def __init__(self, mapping, required=False, **kwargs): self.mapping = mapping parent = self.resolve_ancestor(list(mapping.values())) super(Polymorph, self).__init__(parent, allow_null=not required, **kwargs)
[docs] def output(self, key, obj, ordered=False, **kwargs): # Copied from upstream NestedField value = get_value(key if self.attribute is None else self.attribute, obj) if value is None: if self.allow_null: return None elif self.default is not None: return self.default # Handle mappings if not hasattr(value, "__class__"): raise ValueError("Polymorph field only accept class instances") candidates = [ fields for cls, fields in self.mapping.items() if type(value) == cls ] if len(candidates) <= 0: raise ValueError("Unknown class: " + value.__class__.__name__) elif len(candidates) > 1: raise ValueError( "Unable to determine a candidate for: " + value.__class__.__name__ ) else: return marshal( value, candidates[0].resolved, mask=self.mask, ordered=ordered )
[docs] def resolve_ancestor(self, models): """ Resolve the common ancestor for all models. Assume there is only one common ancestor. """ ancestors = [m.ancestors for m in models] candidates = set.intersection(*ancestors) if len(candidates) != 1: field_names = [ for f in models] raise ValueError( "Unable to determine the common ancestor for: " + ", ".join(field_names) ) parent_name = candidates.pop() return models[0].get_parent(parent_name)
def clone(self, mask=None): data = self.__dict__.copy() mapping = data.pop("mapping") for field in ("allow_null", "model"): data.pop(field, None) data["mask"] = mask return Polymorph(mapping, **data)
[docs]class Wildcard(Raw): """ Field for marshalling list of "unkown" fields. :param cls_or_instance: The field type the list will contain. """ exclude = set() # cache the flat object _flat = None _obj = None _cache = set() _last = None def __init__(self, cls_or_instance, **kwargs): super(Wildcard, self).__init__(**kwargs) error_msg = "The type of the wildcard elements must be a subclass of fields.Raw" if isinstance(cls_or_instance, type): if not issubclass(cls_or_instance, Raw): raise MarshallingError(error_msg) self.container = cls_or_instance() else: if not isinstance(cls_or_instance, Raw): raise MarshallingError(error_msg) self.container = cls_or_instance def _flatten(self, obj): if obj is None: return None if obj == self._obj and self._flat is not None: return self._flat if isinstance(obj, dict): self._flat = [x for x in obj.items()] else: def __match_attributes(attribute): attr_name, attr_obj = attribute if inspect.isroutine(attr_obj) or ( attr_name.startswith("__") and attr_name.endswith("__") ): return False return True attributes = inspect.getmembers(obj) self._flat = [x for x in attributes if __match_attributes(x)] self._cache = set() self._obj = obj return self._flat @property def key(self): return self._last def reset(self): self.exclude = set() self._flat = None self._obj = None self._cache = set() self._last = None
[docs] def output(self, key, obj, ordered=False): value = None reg = fnmatch.translate(key) if self._flatten(obj): while True: try: # we are using pop() so that we don't # loop over the whole object every time dropping the # complexity to O(n) if ordered: # Get first element if respecting order (objkey, val) = self._flat.pop(0) else: # Previous default retained (objkey, val) = self._flat.pop() if ( objkey not in self._cache and objkey not in self.exclude and re.match(reg, objkey, re.IGNORECASE) ): value = val self._cache.add(objkey) self._last = objkey break except IndexError: break if value is None: if self.default is not None: return self.container.format(self.default) return None if isinstance(self.container, Nested): return marshal( value, self.container.nested, skip_none=self.container.skip_none, ordered=ordered, ) return self.container.format(value)
def schema(self): schema = super(Wildcard, self).schema() schema["type"] = "object" schema["additionalProperties"] = self.container.__schema__ return schema def clone(self): kwargs = self.__dict__.copy() model = kwargs.pop("container") return self.__class__(model, **kwargs)