Class: Ace::Support::Markdown::Atoms::FrontmatterExtractor

Inherits:
Object
  • Object
show all
Defined in:
lib/ace/support/markdown/atoms/frontmatter_extractor.rb

Overview

Pure function to extract YAML frontmatter from markdown content Separates frontmatter and body content for safe editing

Class Method Summary collapse

Class Method Details

.body_only(content) ⇒ String

Extract only the body content without frontmatter

Parameters:

  • content (String) —

    The markdown content

Returns:

  • (String) —

    The body content



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# File 'lib/ace/support/markdown/atoms/frontmatter_extractor.rb', line 90

def self.body_only(content)
  result = extract(content)
  result[:body]
end

.empty_result ⇒ Object 



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# File 'lib/ace/support/markdown/atoms/frontmatter_extractor.rb', line 105

def self.empty_result
  {
    frontmatter: {},
    body: "",
    valid: false,
    errors: ["Empty content"]
  }
end

.extract(content) ⇒ Hash

Extract frontmatter from markdown content

Parameters:

  • content (String) —

    The markdown content with optional frontmatter

Returns:

  • (Hash) —

    Result with :frontmatter (Hash), :body (String), :valid (Boolean), :errors (Array)



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# File 'lib/ace/support/markdown/atoms/frontmatter_extractor.rb', line 15

def self.extract(content)
  return empty_result if content.nil? || content.empty?

  # Check if content starts with YAML frontmatter delimiter
  unless content.start_with?("---\n")
    return {
      frontmatter: {},
      body: content,
      valid: false,
      errors: ["No frontmatter found"]
    }
  end

  # Find the ending delimiter (searching from position 4 to skip the opening ---)
  end_index = content.index("\n---\n", 4)

  unless end_index
    return {
      frontmatter: {},
      body: content[4..-1] || "",
      valid: false,
      errors: ["Missing closing '---' delimiter for frontmatter"]
    }
  end

  # Extract YAML content (between delimiters) and body content (after delimiters)
  yaml_content = content[4...end_index]
  body_content = content[(end_index + 5)..-1] || ""

  # Parse YAML with safe_load
  begin
    frontmatter = YAML.safe_load(
      yaml_content,
      permitted_classes: [Date, Time, Symbol],
      permitted_symbols: [],
      aliases: true
    ) || {}

    # Ensure frontmatter is a hash
    unless frontmatter.is_a?(Hash)
      return {
        frontmatter: {},
        body: body_content,
        valid: false,
        errors: ["Frontmatter must be a hash/object, got #{frontmatter.class}"]
      }
    end

    {
      frontmatter: frontmatter,
      body: body_content,
      valid: true,
      errors: []
    }
  rescue Psych::SyntaxError => e
    {
      frontmatter: {},
      body: body_content,
      valid: false,
      errors: ["YAML syntax error: #{e.message}"]
    }
  end
end

.frontmatter_only(content) ⇒ Hash

Extract only the frontmatter hash

Parameters:

  • content (String) —

    The markdown content

Returns:

  • (Hash) —

    The frontmatter data or empty hash



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# File 'lib/ace/support/markdown/atoms/frontmatter_extractor.rb', line 82

def self.frontmatter_only(content)
  result = extract(content)
  result[:frontmatter]
end

.has_frontmatter?(content) ⇒ Boolean

Check if content has valid frontmatter

Parameters:

  • content (String) —

    The markdown content

Returns:

  • (Boolean) —

    true if valid frontmatter exists



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# File 'lib/ace/support/markdown/atoms/frontmatter_extractor.rb', line 98

def self.has_frontmatter?(content)
  result = extract(content)
  result[:valid]
end