dvModelPageData function

DVPageData dvModelPageData(DVModelPageSpec spec, Map<String, Object?> row, { String? applicationFavicon, })

The page data a model row is: the title field, the longest content field as description and text, the image, and structured data naming the record; hidden when the published field says so.

Implementation

DVPageData dvModelPageData(
  DVModelPageSpec spec,
  Map<String, Object?> row, {
  String? applicationFavicon,
}) {
  // A person's row, or one that is not published, is answered exactly as a
  // row that is not there: the same data, so nothing about the response says
  // which of the three it was.
  if (spec.personal) return dvModelPageNotFound(spec);
  final Object? published = spec.publishedField == null ? true : row[spec.publishedField];
  final bool visible = published == true || published == 1 || '$published'.toLowerCase() == 'true';
  if (!visible) return dvModelPageNotFound(spec);

  // Read through this rather than the row, so a protected field cannot be
  // reached from any of the places below whatever the spec names.
  String? text(String? field) {
    if (field == null || spec.protectedFields.contains(field)) return null;
    final Object? value = row[field];
    if (value == null) return null;
    final String s = '$value'.trim();
    return s.isEmpty ? null : s;
  }

  final String title = text(spec.titleField) ?? text(spec.keyField) ?? spec.model;
  String? content;
  for (final String field in spec.contentFields) {
    final String? candidate = text(field);
    if (candidate != null && (content == null || candidate.length > content.length)) content = candidate;
  }
  final String? image = text(spec.imageField);
  return DVPageData(
    title: title,
    description: content,
    image: image,
    // Never the featured image. This field was declared, emitted by the head
    // writer, and set by nothing at all, so every model page wore the
    // shell's icon -- and filling it with the featured image would have been
    // worse than leaving it: a photograph at 32 pixels is the whole
    // photograph, downloaded on every page.
    favicon: spec.favicon ?? applicationFavicon,
    text: <String>[title, if (content != null && content != title) content],
    structuredData: <String, Object?>{
      '@context': 'https://schema.org',
      '@type': spec.schemaType ?? 'Thing',
      'name': title,
      if (content != null) 'description': content,
      if (image != null) 'image': image,
    },
    visibility: DVPageVisibility.public,
  );
}