class Fontist::Import::Google::MetadataAdapter

Adapts unibuf’s generic Message model to our domain Metadata model

This adapter bridges between the generic protocol buffer parser (unibuf) and our rich domain model (Models::Metadata), extracting and transforming all fields according to our business requirements.

@example Basic usage

unibuf_message = Unibuf.parse_textproto_file("METADATA.pb")
metadata = MetadataAdapter.adapt(unibuf_message)
puts metadata.name # => "Roboto"

Public Class Methods

adapt (unibuf_message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 24
def self.adapt(unibuf_message)
  hash = extract_metadata_hash(unibuf_message)
  Models::Metadata.new(hash)
end

Adapt unibuf message to Metadata model

@param unibuf_message [Unibuf::Models::Message] parsed message from unibuf @return [Models::Metadata] domain metadata model with rich behavior

create_message_from_hash (hash)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 183
                     def self.create_message_from_hash(hash)
  # Convert hash representation back to queryable object
  # hash has structure: {"fields" => [{"name" => "...", "value" => "..."}]}
  MessageWrapper.new(hash)
end

Create a Message-like object from hash for field queries

extract_axes (message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 102
                     def self.extract_axes(message)
  axis_fields = message.find_fields("axes")
  return nil if axis_fields.empty?

  axis_fields.map do |field|
    next unless field.message_field?

    axis_hash = field.value
    next unless axis_hash.is_a?(Hash) && axis_hash["fields"]

    axis_msg = create_message_from_hash(axis_hash)
    {
      "tag" => field_value(axis_msg, "tag"),
      "min_value" => field_float(axis_msg, "min_value"),
      "max_value" => field_float(axis_msg, "max_value"),
      "default_value" => field_float(axis_msg, "default_value"),
    }.compact
  end.compact
end

Extract axes array

extract_files (source_msg)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 142
                     def self.extract_files(source_msg)
  file_fields = source_msg.find_fields("files")
  return nil if file_fields.empty?

  file_fields.map do |field|
    next unless field.message_field?

    file_hash = field.value
    next unless file_hash.is_a?(Hash) && file_hash["fields"]

    file_msg = create_message_from_hash(file_hash)
    {
      "source_file" => field_value(file_msg, "source_file"),
      "dest_file" => field_value(file_msg, "dest_file"),
    }.compact
  end.compact
end

Extract source files array

extract_fonts (message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 77
                     def self.extract_fonts(message)
  font_fields = message.find_fields("fonts")
  return nil if font_fields.empty?

  font_fields.map do |field|
    next unless field.message_field?

    # field.value is a Hash for message fields in unibuf
    font_hash = field.value
    next unless font_hash.is_a?(Hash) && font_hash["fields"]

    font_msg = create_message_from_hash(font_hash)
    {
      "name" => field_value(font_msg, "name"),
      "style" => field_value(font_msg, "style"),
      "weight" => field_integer(font_msg, "weight"),
      "filename" => field_value(font_msg, "filename"),
      "post_script_name" => field_value(font_msg, "post_script_name"),
      "full_name" => field_value(font_msg, "full_name"),
      "copyright" => field_value(font_msg, "copyright"),
    }.compact
  end.compact
end

Extract fonts array

extract_metadata_hash (message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 33
                     def self.extract_metadata_hash(message)
  {
    "name" => field_value(message, "name"),
    "designer" => field_value(message, "designer"),
    "license" => field_value(message, "license"),
    "category" => field_value(message, "category"),
    "date_added" => field_value(message, "date_added"),
    "fonts" => extract_fonts(message),
    "subsets" => find_all_values(message, "subsets"),
    "axes" => extract_axes(message),
    "source" => extract_source(message),
    "registry_default_overrides" => extract_registry_overrides(message),
    "is_noto" => field_boolean(message, "is_noto"),
    "languages" => find_all_values(message, "languages"),
    "primary_script" => field_value(message, "primary_script"),
  }.compact
end

Extract metadata hash from unibuf message

@param message [Unibuf::Models::Message] parsed message @return [Hash] hash suitable for Models::Metadata.new

extract_registry_overrides (message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 161
                     def self.extract_registry_overrides(message)
  override_fields = message.find_fields("registry_default_overrides")
  return nil if override_fields.empty?

  overrides = {}
  override_fields.each do |field|
    next unless field.message_field?

    override_hash = field.value
    next unless override_hash.is_a?(Hash) && override_hash["fields"]

    # Each override is a message with key and value fields
    override_msg = create_message_from_hash(override_hash)
    key = field_value(override_msg, "key")
    value = field_float(override_msg, "value")
    overrides[key] = value if key && value
  end

  overrides.empty? ? nil : overrides
end

Extract registry default overrides as hash

extract_source (message)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 123
                     def self.extract_source(message)
  source_field = message.find_field("source")
  return nil unless source_field&.message_field?

  source_hash = source_field.value
  return nil unless source_hash.is_a?(Hash) && source_hash["fields"]

  source_msg = create_message_from_hash(source_hash)
  {
    "repository_url" => field_value(source_msg, "repository_url"),
    "commit" => field_value(source_msg, "commit"),
    "archive_url" => field_value(source_msg, "archive_url"),
    "branch" => field_value(source_msg, "branch"),
    "config_yaml" => field_value(source_msg, "config_yaml"),
    "files" => extract_files(source_msg),
  }.compact
end

Extract source information

field_boolean (message, name)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 60
                     def self.field_boolean(message, name)
  field = message.find_field(name)
  return nil unless field

  value = field.value.to_s
  value == "true"
end

Get field value as boolean

field_float (message, name)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 250
                     def self.field_float(message, name)
  field = message.find_field(name)
  return nil unless field

  field.value.to_s.to_f
end

Get field value as float

field_integer (message, name)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 242
                     def self.field_integer(message, name)
  field = message.find_field(name)
  return nil unless field

  field.value.to_s.to_i
end

Get field value as integer

field_value (message, name)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 52
                     def self.field_value(message, name)
  field = message.find_field(name)
  return nil unless field

  field.value.to_s
end

Get field value as string

find_all_values (message, name)

Source

# File lib/fontist/import/google/metadata_adapter.rb, line 69
                     def self.find_all_values(message, name)
  fields = message.find_fields(name)
  return nil if fields.empty?

  fields.map { |f| f.value.to_s }
end

Get all values for repeated field