# Link

A Link field type is provided to offer a way to store and retrieve well-formed URI (URL) while optionally restricting the allowable schemes, or protocols. Internally these values are stored as strings after normalization through the `URI` datatype, and on access provide that URI instance.

### Import

`from marrow.mongo.field import Link`

### Inherits

`marrow.mongo.field:`**`String`**

## Attributes

This field type inherits all [`Field` attributes](https://github.com/marrow/mongo/tree/128b1ec81ec6a48e05a95c32b636deede377854b/reference/field/field.md#attributes) and represents a singular, scalar text value.

## Usage

Instantiate and assign an instance of this class during construction of a new `Document` subclass. Accessing as a class attribute will return a Queryable allowing filtering operations, and access as an instance attribute will return a `URI` cast value.

Assignment of any value matched by the `truthy` iterable (via `in` comparison) will store `True`, and likewise with the `falsy` iterable storing `False`. Additionally, if an attempt is made to assign a non-boolean, non-string value, the value will be passed through `bool()` conversion prior to storage, allowing use of objects which define their own `__nonzero__`/`__bool__` methods.