google.appengine.api.appinfo.HttpHeadersDict.ValueValidator

Ensures that values in HttpHeadersDict are valid.

Inherits From: Validator, expected_type

google.appengine.api.appinfo.HttpHeadersDict.ValueValidator(
    default=None
)

An instance is used as HttpHeadersDict's VALUE_VALIDATOR.

default Default assignment is made during initialization and will not pass through validation.

Child Classes

class expected_type

Methods

AssertHeaderNotTooLong

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@staticmethod
AssertHeaderNotTooLong(
    name, value
)

CheckFieldInitialized

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CheckFieldInitialized(
    value, key, obj
)

Check for missing fields or conflicts between fields.

Default behavior performs a simple None-check, but this can be overridden. If the intent is to allow optional fields, then use the Optional validator instead.

Args
value Value to validate.
key Name of the field being validated.
obj The object to validate against.

Raises
ValidationError When there are missing or conflicting fields.

GetWarnings

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GetWarnings(
    value, key, obj
)

Return any warnings on this attribute.

Validates the value with an eye towards things that aren't fatal problems.

Args
value Value to validate.
key Name of the field being validated.
obj The object to validate against.

Returns
A list of tuples (context, warning) where

  • Context is the field (or dotted field path, if a sub-field)
  • Warning is the string warning text

ToValue

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ToValue(
    value
)

Convert value to a simplified collection or basic type.

Subclasses of Validator should override this method when the dumped representation of value is not a simple <type>(value) (e.g., a regex).

Args
value An object of the same type that was returned from Validate().

Returns
An instance of a builtin type (e.g., int, str, dict, etc). By default it returns value unmodified.

Validate

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Validate(
    value, key=None
)

Returns a value, or raises an exception if the value is invalid.

According to RFC 2616 section 4.2_ header field values must consist "of either *TEXT or combinations of token, separators, and quoted-string"::

TEXT = <any OCTET except CTLs, but including LWS>

Args
value HTTP header field value.
key HTTP header field name.

Returns
A value argument.

Raises
appinfo_errors.InvalidHttpHeaderValue An argument cannot be used as an HTTP header value.

.. _RFC 2616, section 4.2: https://www.ietf.org/rfc/rfc2616.txt

__call__

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__call__(
    value, key='???'
)

Main interface to validator is call mechanism.