xia_fields.fields_ext.OsEnvironField

class xia_fields.fields_ext.OsEnvironField(prefix='XIA_', **kwargs)

Bases: StringField

Environment Variable Field

Value Forms:

• Database form: Environment variable Name

• Internal form: Bytes (encode) => Variable Value

• Display form: String (decode) => Variable Value

Parameters

prefix – The variable value start with prefix will be considered as the name of environment variable. For the security reason, only the environment variable name start with prefix will be interpreted.

__init__(prefix='XIA_', **kwargs)

Parameters

• regex (str) – String pattern

• max_length (int) – A max length that will be applied during validation

• min_length (int) – A min length that will be applied during validation

• **kwargs – Keyword arguments passed into the parent class

Methods

__init__([prefix])	param regex String pattern
estimate_max_length()	Estimate Max length of the string
from_db(value, /[, decoder, engine])	Value transformation from database form
from_display(value[, runtime_display])	Value transformation from display form to internal form
from_runtime(runtime_value, /)	Value transformation from runtime value to internal form
get_sample()	Get a sample value of a field
get_value([value, runtime_value])	Get runtime value when it is necessary
guess_value([value])	Guess field value
to_db(value[, runtime_value, catalog, ...])	Value transformation to database form
to_display(value[, runtime_value])	Value transformation to display form
validate(value[, runtime_value])	Validate data

Attributes

SAMPLE_DICT

db_form

alias of str

detail_form

alias of str

display_form

alias of str

estimate_max_length() → int

Estimate Max length of the string

Returns

Max string length

from_db(value: Any, /, decoder: callable = None, engine=None)

Value transformation from database form

Parameters

• decoder (callable) – Encode the value

• value (any) – value to be transformed from database form to internal form

• engine (BaseEngine) – Engine to be passed

Returns

internal value and runtime value tuple

from_display(value: Any, runtime_display: Any = None, /)

Value transformation from display form to internal form

Parameters

• value (any) – display value to be transformed

• runtime_display (any) – display runtime value to be transformed

from_runtime(runtime_value: str, /)

Value transformation from runtime value to internal form

Parameters

runtime_value – runtime value

get_sample()

Get a sample value of a field

Returns

sample value

Return type

object

get_value(value: Any = None, runtime_value: Any = None, /, **kwargs)

Get runtime value when it is necessary

Parameters

• value (any) – value on internal form. could be None for no-stateful fields

• runtime_value (any) – value of runtime value. could be None when the data is not loaded

guess_value(value: Optional[str] = None)

Guess field value

Guess field value is normally called when parsing front. The general rules are:

• If the fields is type runtime

  • Check if the input is type of runtime or detail form

  • When true, the output guess will be a tuple contain internal form, runtime form

• Or the check will continue to see if it is display form or db_form

  • When found, it will return internal form

  • When field is runtime type, will return internal from, None (lazy load mode)

Parameters

value – value to be guessed

Notes

The default priority

internal_form

alias of bytes

runtime_form

alias of str

to_db(value: Any, runtime_value: Any = None, /, catalog: dict = None, encoder: callable = None, ignore_unknown: bool = False, engine=None)

Value transformation to database form

Parameters

• encoder (callable) – Encode the value

• runtime_value (any) – runtime value to be transformed

• value (any) – value to be transformed from internal form to database form

• catalog (dict) – Data catalog to decide if the field will be shown or not

• ignore_unknown (bool) – If the unknown field should be ignored

• engine (BaseEngine) – Engine to be passed

to_display(value: Any, runtime_value: Any = None, /, **kwargs)

Value transformation to display form

Parameters

• value (any) – value to be transformed from internal form to database form

• runtime_value (any) – value of runtime value. could be None when the data is not loaded

validate(value: Any, runtime_value: Any = None, /)

Validate data

Parameters

• value (any) – internal value to be validated

• runtime_value (any) – runtime data to be validated

Notes

• No exception raised = validation passed