Expose YAML frontmatter

CHANGELOG.md

@@ -1,9 +1,11 @@
 ## [Unreleased]
 
 - Added support for wikilinks that embed files. These are rendered as images or links in the HTML content.
-- Added method `#page.generate_html` to replace `#page.content.generate_html`, and removed the `MarkdownDocument` class. `#page.content` is now a callable that returns the markdown content.
-- Added `#mark_referenced` and `#referenced?` to page objects
-- Added `#prune!` method to page objects, to remove non-referenced pages
+- Added method `Page#generate_html` to replace `Page#content.generate_html`, and removed the `MarkdownDocument` class. `Page#content` is now a callable that returns the markdown content.
+- Added `Page#mark_referenced` and `Page#referenced?`
+- Added `Page#prune!` method to page objects, to remove non-referenced pages
+- Added `Page#parse` method to expose `ParsedMarkdownDocument` objects
+- Added `#frontmatter` to `ParsedMarkdownDocument`
 
 ## [0.7.0] - 2023-08-03
 

SMELLS.txt

@@ -0,0 +1,9 @@
+Bad naming
+
+- MarkdownParser does more than parse markdown - it takes a file from the vault and parses it into an object that can be inspected
+- The document argument of ParsedMarkdownDocument is very vague
+
+Huge classes
+
+- Page has lots of optional arguments that should not really be optional
+- Could perhaps extract out some graph behaviour to a mixin

lib/obsidian/parser/frontmatter_parser.rb

@@ -8,19 +8,27 @@ class Obsidian::MarkdownParser::FrontMatterParser
   def parse(content)
     enumerator = content.each_line
     first_line = enumerator.next
+    complete = false
 
     if first_line.chomp != "---"
+      puts "bye"
       return {}
     end
 
     lines = []
     loop do
       line = enumerator.next
-      break if line.chomp == "---"
+      if line.chomp == "---"
+        complete = true
+        break
+      end
       lines << line
     end
 
-    YAML.safe_load(lines.join)
+    puts lines
+    puts complete
+
+    complete ? YAML.safe_load(lines.join) : {}
   rescue YAML::SyntaxError, StopIteration
     {}
   end

lib/obsidian/parser/markdown_parser.rb

@@ -28,6 +28,11 @@ class MarkdownParser
       \]\]
     }x
 
+    def initialize(frontmatter_parser: FrontMatterParser.new, renderer: HtmlRenderer.new)
+      @frontmatter_parser = frontmatter_parser
+      @renderer = renderer
+    end
+
     # Convert Obsidian-flavored-markdown syntax to something parseable
     # (i.e. with Github-flavored-markdown syntax)
     def expand_wikilinks(markdown_text, root:)
@@ -79,11 +84,16 @@ def expand_attachments(markdown_text, root:, media_root:)
     end
 
     def parse(markdown_text, root: nil, media_root: nil)
-      renderer = HtmlRenderer.new
+      frontmatter = frontmatter_parser.parse(markdown_text)
       normalized1 = expand_attachments(markdown_text, root: root, media_root: media_root)
       normalized2 = expand_wikilinks(normalized1, root: root)
       document = Markly.parse(normalized2, flags: Markly::SMART | Markly::UNSAFE | Markly::HARD_BREAKS, extensions: [:table, :tasklist, :autolink])
-      Obsidian::ParsedMarkdownDocument.new(document, renderer: renderer)
+      Obsidian::ParsedMarkdownDocument.new(document, renderer: renderer, frontmatter: frontmatter)
     end
+
+    private
+
+    attr_reader :renderer
+    attr_reader :frontmatter_parser
   end
 end

lib/obsidian/parser/page.rb

@@ -161,10 +161,14 @@ def find_in_tree(query_slug)
       nil
     end
 
-    def generate_html(markdown_parser: MarkdownParser.new)
+    def parse(markdown_parser: MarkdownParser.new)
       return nil if content.nil?
 
-      markdown_parser.parse(content.call, root: root, media_root: media_root).to_html
+      markdown_parser.parse(content.call, root: root, media_root: media_root)
+    end
+
+    def generate_html(markdown_parser: MarkdownParser.new)
+      parse(markdown_parser: markdown_parser).to_html
     end
 
     def referenced?

lib/obsidian/parser/parsed_markdown_document.rb

@@ -2,9 +2,11 @@
 
 module Obsidian
   class ParsedMarkdownDocument
-    def initialize(document, renderer:)
+    def initialize(document, renderer:, frontmatter: {})
       @document = document
       @renderer = renderer
+      @links = extract_links
+      @frontmatter = frontmatter
     end
 
     def extract_links
@@ -25,6 +27,9 @@ def to_html
       renderer.render(document)
     end
 
+    attr_reader :frontmatter
+    attr_reader :links
+
     private
 
     attr_reader :document

spec/obsidian/parser/frontmatter_parser.rb → spec/obsidian/parser/frontmatter_parser_spec.rb

@@ -2,6 +2,7 @@
 
 RSpec.describe(Obsidian::MarkdownParser::FrontMatterParser) do
   subject(:parser) { described_class.new }
+
   it "parses valid yaml" do
     content = %(---
 foo: 1

spec/obsidian/parser/markdown_parser_spec.rb

@@ -1,9 +1,10 @@
 # frozen_string_literal: true
 
 RSpec.describe Obsidian::MarkdownParser do
-  describe ".expand_wikilinks" do
+  subject(:parser) { described_class.new }
+
+  describe "#expand_wikilinks" do
     let(:index) { Obsidian::Page.create_root }
-    subject(:parser) { described_class.new }
 
     before do
       index.add_page("foo/bar")
@@ -110,4 +111,23 @@
       end
     end
   end
+
+  describe "#parse" do
+    it "parses frontmatter if available" do
+      content = %(---
+        foo: 1
+        bar: banana
+---
+        some text
+      )
+      result = parser.parse(content)
+      expect(result.frontmatter).to eq("foo" => 1, "bar" => "banana")
+    end
+
+    it "returns empty frontmatter if not available" do
+      content = "some text"
+      result = parser.parse(content)
+      expect(result.frontmatter).to eq({})
+    end
+  end
 end