P5-data-domain

Data description and validation

A data domain is a description of a set of values, either scalar or structured arrays or hashes. The description can include many constraints, like minimal or maximal values, regular expressions, required fields, forbidden fields, and also contextual dependencies. From that description, one can then invoke the domain’s inspect method to check if a given value belongs to it or not. In case of mismatch, a structured set of error messages is returned.

The motivation for writing this package was to be able to express in a compact way some possibly complex constraints about structured data. Typically the data is a Perl tree nested hashrefs or arrayrefs that may come from XML, JSON, from a database through DBIxDataModel, or from postprocessing an HTML form through CGIExpand. DataDomain is a kind of tree parser on that structure, with some facilities for dealing with dependencies within the structure, and with several options to finely tune the error messages returned to the user.