extractNamespaceAndLocalPart static method

(String, String) extractNamespaceAndLocalPart(
  1. String iri, {
  2. bool allowNumericLocalNames = true,
})

Extracts the namespace and local part from an IRI

A namespace is defined as the part of the IRI up to and including the last '#' character, or the part up to and including the last '/' character if there is no '#'. However, if the resulting namespace would be a protocol-only URI (like 'http://' or 'https://'), the entire IRI is treated as the namespace to avoid generating invalid or meaningless prefixes.

The iri is the IRI to split into namespace and local part. When allowNumericLocalNames is false, local parts that start with a digit will be considered invalid for prefixed notation (which is common in formats like Turtle), resulting in an empty local part and the full IRI as the namespace.

Parameters:

  • iri The IRI to split
  • allowNumericLocalNames Whether to allow local names that start with digits (default: true)

Returns a tuple containing (namespace, localPart).

Implementation

static (String namespace, String localPart) extractNamespaceAndLocalPart(
  String iri, {
  bool allowNumericLocalNames = true,
}) {
  final hashIndex = iri.lastIndexOf('#');
  final slashIndex = iri.lastIndexOf('/');

  String namespace;
  String localPart;

  if (hashIndex > slashIndex && hashIndex != -1) {
    namespace = iri.substring(0, hashIndex + 1);
    localPart = iri.substring(hashIndex + 1);
  } else if (slashIndex != -1) {
    // Check if the namespace would only be a protocol like 'http://' or 'https://'
    namespace = iri.substring(0, slashIndex + 1);
    if (namespace == 'http://' ||
        namespace == 'https://' ||
        namespace == 'ftp://' ||
        namespace == 'file://') {
      // If just a protocol, use the entire IRI as namespace and leave local part empty
      return (iri, '');
    }
    localPart = iri.substring(slashIndex + 1);
  } else {
    return (iri, '');
  }

  if (!isValidLocalPart(localPart,
      allowNumericLocalNames: allowNumericLocalNames)) {
    return (iri, '');
  }
  return (namespace, localPart);
}