adding frontmatter parser

Cargo.lock

@@ -584,6 +584,18 @@ dependencies = [
  "regex-syntax",
 ]
 
+[[package]]
+name = "gray_matter"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1cf2fb99fac0b821a4e61c61abff076324bb0e5c3b4a83815bbc3518a38971ad"
+dependencies = [
+ "serde",
+ "serde_json",
+ "toml",
+ "yaml-rust",
+]
+
 [[package]]
 name = "h2"
 version = "0.3.24"
@@ -851,6 +863,12 @@ version = "0.2.153"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
 
+[[package]]
+name = "linked-hash-map"
+version = "0.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.13"
@@ -924,6 +942,7 @@ dependencies = [
  "elasticlunr-rs",
  "env_logger",
  "futures-util",
+ "gray_matter",
  "handlebars",
  "ignore",
  "log",
@@ -941,6 +960,7 @@ dependencies = [
  "semver",
  "serde",
  "serde_json",
+ "serde_yaml",
  "shlex",
  "tempfile",
  "tokio",
@@ -1510,6 +1530,19 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_yaml"
+version = "0.9.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fd075d994154d4a774f95b51fb96bdc2832b0ea48425c92546073816cda1f2f"
+dependencies = [
+ "indexmap",
+ "itoa",
+ "ryu",
+ "serde",
+ "unsafe-libyaml",
+]
+
 [[package]]
 name = "sha1"
 version = "0.10.6"
@@ -1870,6 +1903,12 @@ dependencies = [
  "tinyvec",
 ]
 
+[[package]]
+name = "unsafe-libyaml"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab4c90930b95a82d00dc9e9ac071b4991924390d46cbd0dfe566148667605e4b"
+
 [[package]]
 name = "url"
 version = "2.5.0"
@@ -2200,6 +2239,15 @@ dependencies = [
  "markup5ever",
 ]
 
+[[package]]
+name = "yaml-rust"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
+dependencies = [
+ "linked-hash-map",
+]
+
 [[package]]
 name = "yansi"
 version = "0.5.1"

Cargo.toml

@@ -35,6 +35,9 @@ shlex = "1.3.0"
 tempfile = "3.4.0"
 toml = "0.5.11" # Do not update, see https://github.com/rust-lang/mdBook/issues/2037
 topological-sort = "0.2.2"
+gray_matter = "0.2" #Fronmatter
+serde_yaml = "0.9"
+
 
 # Watch feature
 notify = { version = "6.1.1", optional = true }

src/renderer/html_handlebars/hbs_renderer.rs

@@ -19,6 +19,23 @@ use once_cell::sync::Lazy;
 use regex::{Captures, Regex};
 use serde_json::json;
 
+use gray_matter::Matter;
+use gray_matter::engine::YAML;
+use serde::Deserialize; 
+
+fn extract_frontmatter(content: &str) -> Option<&str> {
+    let start = content.find("---")? + 3; // Find the end of the first `---` + 3 to move past it
+    let end = content[start..].find("---")? + start; // Find the start of the closing `---`
+    Some(&content[start..end].trim())
+}
+
+#[derive(Deserialize, Debug)] 
+struct FrontMatter {
+    title: String,
+    description: String,
+    featured_image_url: String,
+}
+
 #[derive(Default)]
 pub struct HtmlHandlebars;
 
@@ -54,7 +71,34 @@ impl HtmlHandlebars {
                 .insert("git_repository_edit_url".to_owned(), json!(edit_url));
         }
 
-        let content = utils::render_markdown(&ch.content, ctx.html_config.curly_quotes);
+        // Parse frontmatter and prepare content
+        let matter = Matter::<YAML>::new();
+        let parsed = matter.parse(&ch.content);
+        let (content, new_content) = if let Some(data) = parsed.data {
+
+            eprintln!("DEBUG11: Parsed frontmatter: {:?}", &data);
+            let yaml_str = extract_frontmatter(&ch.content).unwrap_or_default();
+            let front_matter_result: Result<FrontMatter, serde_yaml::Error> = serde_yaml::from_str(yaml_str); 
+            // let front_matter_result: Result<FrontMatter, serde_yaml::Error> = serde_yaml::from_str(&ch.content);
+            match front_matter_result {
+                Ok(front_matter) => {
+                            ctx.data.insert("is_frontmatter".to_owned(), json!("true"));
+                            ctx.data.insert("og_title".to_owned(), json!(front_matter.title));
+                            ctx.data.insert("og_description".to_owned(), json!(front_matter.description));
+                            ctx.data.insert("og_image_url".to_owned(), json!(front_matter.featured_image_url));
+                },
+                Err(e) => {
+                    eprintln!("Deserialization error: {:?}", e);
+                },
+            }
+
+            // Prepare new content without frontmatter for rendering
+            let new_content = parsed.content.trim_start();
+            (utils::render_markdown(&new_content, ctx.html_config.curly_quotes), Some(new_content))
+        } else {
+            // No frontmatter, use original content
+            (utils::render_markdown(&ch.content, ctx.html_config.curly_quotes), None)
+        };
 
         let fixed_content =
             utils::render_markdown_with_path(&ch.content, ctx.html_config.curly_quotes, Some(path));
@@ -135,6 +179,8 @@ impl HtmlHandlebars {
             utils::fs::write_file(&ctx.destination, "index.html", rendered_index.as_bytes())?;
         }
 
+
+
         Ok(())
     }
 

src/theme/index.hbs

@@ -43,6 +43,29 @@
         <link rel="stylesheet" href="{{ path_to_root }}tomorrow-night.css">
         <link rel="stylesheet" href="{{ path_to_root }}ayu-highlight.css">
 
+        <!-- Open Graph Meta Tags for Social Media Exposure -->
+        {{#if is_frontmatter}}
+        <meta property="og:title" content="{{ og_title }}">
+        <meta property="og:description" content="{{ og_description }}">
+        <meta property="og:image" content="{{this.frontmatter.featured_image_url}}">
+        <meta property="og:url" content="{{ og_image_url}}">
+        <meta name="twitter:title" content="{{ og_title }}"/>
+        <meta name="twitter:description" content="{{ og_description }}"/>
+        <meta name="twitter:image" content="{{ og_image_url }}"/>
+        {{else}}
+        <meta property="og:title" content="mdBook Documentation">
+        <meta property="og:description" content="Create book from markdown files. Like Gitbook but implemented in Rust">
+        <meta property="og:image" content="https://rust-lang.github.io/mdBook/favicon.png">
+        <meta property="og:url" content="https://rust-lang.github.io/mdBook/">
+        <meta name="twitter:title" content="mdBook Documentation"/>
+        <meta name="twitter:image" content="https://rust-lang.github.io/mdBook/favicon.png"/>
+        <meta name="twitter:description" content="Create book from markdown files. Like Gitbook but implemented in Rust"/>
+        {{/if}}
+        <meta name="author" content="dBook">
+        <meta property="og:type" content="book">
+        <meta name="twitter:card" content="summary_large_image"/>
+        <meta name="twitter:creator" content="@rustlang"/>
+
         <!-- Custom theme stylesheets -->
         {{#each additional_css}}
         <link rel="stylesheet" href="{{ ../path_to_root }}{{ this }}">