Common rules

These rules check that a value is present, or that it is an object. Only required, not_empty and not_empty_list check empty values, all other rules skip them.

requiredChecks that the value is present: not missing, not null and not an empty string. Note that 0 and false are valid values.'required'REQUIREDnot_emptyChecks that the value is not an empty string, if the field is passed at all. Unlike required, a missing field is valid.'not_empty'CANNOT_BE_EMPTYnot_empty_listChecks that the value is a list with at least one element.'not_empty_list'CANNOT_BE_EMPTYany_objectChecks that the value is a plain object (a hash, a dictionary). The content of the object is not validated, use nested_object for that.'any_object'FORMAT_ERROR