Validator

Create a Validator object that validates/transforms R objects using a Schema.

Usage

Validator(data, schema, error = FALSE)

is.Validator(x)

Arguments

data: An R object. If using a nested schema, the object must have a [[ method.
schema: Schema object or a non-empty list defining the schema. See the Schema constructor for details on the schema structure and rules.
error: Single logical value. If TRUE, the constructor throws an error when validation fails.
x: Object to be tested.

Value

A Validator S7 object.

Details

The Validator class validates/transforms data using a Schema. The process checks each field in the schema against the data, applying the rules specified. Any data element not present in the schema is ignored. Validation is done in four passes, according to rule categories in the Registry: control, transform, validate, and finalize.

Validation results are stored in the @errors property, and the overall validity is indicated by the @valid property. If the @error property/argument is set to TRUE, any validation failure will result in an error being thrown. To customise the truncation of error messages, see the Schema @error_print_opts property. The (possibly) transformed data is stored in the @data property.

The Validator is re-evaluated upon any change to the object properties. If an invalid schema is provided, the validation will fail immediately with the validation error indicating that the schema is invalid. To see the errors in the schema validation, see the Validator@Schema@errors property.

For full details see the vignettes on builtin rules, data validation, and adding custom rules.

Additional properties

@data: The validated input data, with any changes that were made during validation.
@Schema: An object of class Schema containing the schema used for validation, as well as the Registry.
@errors: (Read-only) A list mirroring the schema structure, with NULL for rules that pass and character error messages for rules that fail.
@.validator_cache: (Read-only) An environment for caching validation results. Used to avoid redundant validation.
@error: Boolean; whether to error upon failure (invalid data or schema).
@valid: (Read-only) Boolean; TRUE if the schema is valid and all data validation rules pass, FALSEotherwise.

Examples

v <- Validator(
  data = list(name = "Alice", age = 30),
  schema = list(
    name = list(type = "character", required = TRUE),
    age = list(type = "numeric", min_val = 0, max_val = 150)
  )
)
v@valid # TRUE
#> [1] TRUE

# Schema object can be given directly
s <- Schema(list(a = list(type = "numeric"), b = list(type = "character")))
v <- Validator(list(a = "Hello", b = 42), s)
v@valid # FALSE
#> [1] FALSE
v@errors
#> $a
#> $a$type
#> [1] "Is not type `numeric`."
#> 
#> 
#> $b
#> $b$type
#> [1] "Is not type `character`."
#> 
#> 

# To error on invalid schema or data
try(Validator(list(a = "Hello", b = 42), s, error = TRUE))
#> Error : <fluffy::Validator> object is invalid:
#> - Data validation failed with the following errors:
#> ├─ a
#> │ └─ type: Is not type `numeric`.
#> └─ b
#>   └─ type: Is not type `character`.

# Invalid schemas show their errors
try(Validator(list(42), list(type = 123), error = TRUE))
#> Error : <fluffy::Validator> object is invalid:
#> - Schema validation failed with the following errors:
#> └─ type: Must be a function or a string.

# Transforms data according to rules
v <- Validator(1, list(coerce = "character"))
v@data # "1"
#> [1] "1"