Add validators to your template

Add validators to your template#

Validators run when a user submits a field value during the interactive prompt. If the validator returns False, the prompt stays open and asks the user to enter a valid value.

Use a built-in validator#

Cookieplone automatically wires built-in validators to fields whose names match the DEFAULT_VALIDATORS table. The following field names are autowired without any configuration:

Field name

Validator applied

plone_version

cookieplone.validators.plone_version

volto_version

cookieplone.validators.volto_version

python_package_name

cookieplone.validators.python_package_name

hostname

cookieplone.validators.hostname

language_code

cookieplone.validators.language_code

Name your field python_package_name and the validator applies automatically.

Assign a validator explicitly in cookieplone.json#

Add a validator key to a field property in your cookieplone.json:

{
  "version": "2.0",
  "properties": {
    "python_package_name": {
      "type": "string",
      "title": "Python package name",
      "default": "my_package",
      "validator": "cookieplone.validators.python_package_name"
    }
  }
}

The validator value is an import path to a callable that accepts the field value as a string and returns a boolean.

Assign a validator in cookiecutter.json (v1 format)#

In the v1 schema, add a __validators__ key at the top level of cookiecutter.json:

{
  "python_package_name": "my_package",
  "__validators__": {
    "python_package_name": "cookieplone.validators.python_package_name"
  }
}

Write a custom validator#

Place a Python module in your template's hook directory or in a package that is importable when Cookieplone runs. A validator is any callable that takes a single string and returns True when valid and False when invalid.

def no_spaces(value: str) -> bool:
    """Reject values that contain spaces."""
    return " " not in value

Reference it by its import path in your schema:

{
  "validator": "myhooks.validators.no_spaces"
}
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