Validators reference

Validators reference#

Validators check user input at prompt time. A validator function accepts a single string value and either returns True (value accepted) or raises ValidationError with a message describing what is wrong.

All validators are defined in cookieplone/validators/__init__.py.

DEFAULT_VALIDATORS#

Cookieplone automatically applies a validator to any field whose name matches a key in DEFAULT_VALIDATORS. No configuration is needed in the template schema.

Field name

Validator

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

A template can override any of these by providing an explicit validator key in cookieplone.json.

Built-in validators#

not_empty#

Signature: not_empty(value: str) -> bool

Returns True when the value is non-empty after stripping whitespace.

Input

Result

"hello"

True

"  "

False

""

False

Not in DEFAULT_VALIDATORS. Reference it explicitly:

{
  "project_title": {
    "type": "string",
    "title": "Project title",
    "validator": "cookieplone.validators.not_empty"
  }
}

language_code#

Signature: language_code(value: str) -> bool

Returns True when the value is a valid IETF language tag (for example en, pt-BR, zh-CN).

Automatically applied to fields named language_code.

python_package_name#

Signature: python_package_name(value: str) -> bool

Returns True when the value is a valid Python identifier or dotted name (for example myaddon, collective.myaddon, plone.app.content).

Automatically applied to fields named python_package_name.

hostname#

Signature: hostname(value: str) -> bool

Returns True when the value is a syntactically valid hostname (for example example.com, my-server).

Automatically applied to fields named hostname.

volto_addon_name#

Signature: volto_addon_name(value: str) -> bool

Returns True when the value is a valid Volto add-on name (a scoped or unscoped npm package name that also satisfies Volto naming conventions).

Not in DEFAULT_VALIDATORS. Reference it explicitly as cookieplone.validators.volto_addon_name.

npm_package_name#

Signature: npm_package_name(value: str) -> bool

Returns True when the value is a valid npm package name.

Not in DEFAULT_VALIDATORS. Reference it explicitly as cookieplone.validators.npm_package_name.

plone_version#

Signature: plone_version(value: str) -> bool

Returns True when the value is a Plone version number of at least 6.0.

Automatically applied to fields named plone_version.

volto_version#

Signature: volto_version(value: str) -> bool

Returns True when the value is a Volto version number of at least 18.0.0-alpha.43.

Automatically applied to fields named volto_version.

Validation errors#

When a validator rejects user input, it raises a ValidationError with a human-readable message. The renderer displays the message inline so the user knows what to fix.

from tui_forms.form.question import ValidationError

def my_validator(value: str) -> bool:
    if not value.startswith("plone"):
        raise ValidationError("Value must start with 'plone'.")
    return True

Using a validator in a template#

In cookieplone.json (v2)#

Set the validator key to the dotted import path:

{
  "author_email": {
    "type": "string",
    "title": "Author email",
    "default": "",
    "validator": "cookieplone.validators.not_empty"
  }
}

In cookiecutter.json (v1)#

Add the field to __validators__:

{
  "author_email": "",
  "__validators__": {
    "author_email": "cookieplone.validators.not_empty"
  }
}
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