buildPresentationDefinitionForCredential function

PresentationDefinition buildPresentationDefinitionForCredential(dynamic credential)

Build a Presentation definition to e.g. propose the given credential for presentation.

Implementation

PresentationDefinition buildPresentationDefinitionForCredential(
    dynamic credential) {
  VerifiableCredential cred;
  if (credential is VerifiableCredential) {
    cred = credential;
  } else {
    cred = VerifiableCredential.fromJson(credential);
  }

  List<InputDescriptorField> fields = [];

  var type = cred.type.firstWhere(
      (element) => element != 'VerifiableCredential',
      orElse: () => '');
  if (type.isNotEmpty) {
    var typeField = InputDescriptorField(
        path: [JsonPath(r'$.type')],
        filter: JsonSchema.create({
          'type': 'array',
          'contains': {'type': 'string', 'pattern': type}
        }));
    fields.add(typeField);
  }

  var vcAsJson = cred.toJson();

  var paths = getAllJsonPathsOfCredential(vcAsJson);

  for (var path in paths) {
    var asJsonPath = JsonPath('\$.credentialSubject.$path');
    var value = asJsonPath.read(vcAsJson).first.value;
    var field = InputDescriptorField(path: [JsonPath('\$..$path')]);
    if (value is String) {
      field.filter = JsonSchema.create({'type': 'string', 'pattern': value});
    } else if (value is num) {
      field.filter = JsonSchema.create({'type': 'number'});
    } else if (value is bool) {
      field.filter = JsonSchema.create({'type': 'boolean'});
    }
    fields.add(field);
  }

  return PresentationDefinition(inputDescriptors: [
    InputDescriptor(constraints: InputDescriptorConstraints(fields: fields))
  ]);
}