add absolute links support

src/config.rs

@@ -522,6 +522,8 @@ pub struct HtmlConfig {
     pub input_404: Option<String>,
     /// Absolute url to site, used to emit correct paths for the 404 page, which might be accessed in a deeply nested directory
     pub site_url: Option<String>,
+    /// Prepend the `site_url` in links with absolute path.
+    pub use_site_url_as_root: bool,
     /// The DNS subdomain or apex domain at which your book will be hosted. This
     /// string will be written to a file named CNAME in the root of your site,
     /// as required by GitHub Pages (see [*Managing a custom domain for your
@@ -568,6 +570,7 @@ impl Default for HtmlConfig {
             edit_url_template: None,
             input_404: None,
             site_url: None,
+            use_site_url_as_root: false,
             cname: None,
             live_reload_endpoint: None,
             redirect: HashMap::new(),

src/renderer/html_handlebars/hbs_renderer.rs

@@ -52,10 +52,23 @@ impl HtmlHandlebars {
         }
 
         let content = ch.content.clone();
-        let content = utils::render_markdown(&content, ctx.html_config.curly_quotes);
+        let content = if ctx.html_config.use_site_url_as_root {
+            utils::render_markdown_with_path(
+                &content,
+                ctx.html_config.curly_quotes,
+                None,
+                ctx.html_config.site_url.as_ref(),
+            )
+        } else {
+            utils::render_markdown(&content, ctx.html_config.curly_quotes)
+        };
 
-        let fixed_content =
-            utils::render_markdown_with_path(&ch.content, ctx.html_config.curly_quotes, Some(path));
+        let fixed_content = utils::render_markdown_with_path(
+            &ch.content,
+            ctx.html_config.curly_quotes,
+            Some(path),
+            None,
+        );
         if !ctx.is_index && ctx.html_config.print.page_break {
             // Add page break between chapters
             // See https://developer.mozilla.org/en-US/docs/Web/CSS/break-before and https://developer.mozilla.org/en-US/docs/Web/CSS/page-break-before

src/utils/mod.rs

@@ -95,13 +95,13 @@ pub fn unique_id_from_content(content: &str, id_counter: &mut HashMap<String, us
 /// page go to the original location. Normal page rendering sets `path` to
 /// None. Ideally, print page links would link to anchors on the print page,
 /// but that is very difficult.
-fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
+fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>, abs_url: Option<&String>) -> Event<'a> {
     lazy_static! {
         static ref SCHEME_LINK: Regex = Regex::new(r"^[a-z][a-z0-9+.-]*:").unwrap();
         static ref MD_LINK: Regex = Regex::new(r"(?P<link>.*)\.md(?P<anchor>#.*)?").unwrap();
     }
 
-    fn fix<'a>(dest: CowStr<'a>, path: Option<&Path>) -> CowStr<'a> {
+    fn fix<'a>(dest: CowStr<'a>, path: Option<&Path>, abs_url: Option<&String>) -> CowStr<'a> {
         if dest.starts_with('#') {
             // Fragment-only link.
             if let Some(path) = path {
@@ -138,12 +138,19 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
             } else {
                 fixed_link.push_str(&dest);
             };
-            return CowStr::from(fixed_link);
+            if fixed_link.starts_with('/') {
+                fixed_link = match abs_url {
+                    Some(abs_url) => format!("{}{}", abs_url.trim_end_matches('/'), &fixed_link),
+                    None => fixed_link,
+                }
+                .into();
+            }
+            return CowStr::from(format!("{}", fixed_link));
         }
         dest
     }
 
-    fn fix_html<'a>(html: CowStr<'a>, path: Option<&Path>) -> CowStr<'a> {
+    fn fix_html<'a>(html: CowStr<'a>, path: Option<&Path>, abs_url: Option<&String>) -> CowStr<'a> {
         // This is a terrible hack, but should be reasonably reliable. Nobody
         // should ever parse a tag with a regex. However, there isn't anything
         // in Rust that I know of that is suitable for handling partial html
@@ -159,7 +166,7 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
 
         HTML_LINK
             .replace_all(&html, |caps: &regex::Captures<'_>| {
-                let fixed = fix(caps[2].into(), path);
+                let fixed = fix(caps[2].into(), path, abs_url);
                 format!("{}{}\"", &caps[1], fixed)
             })
             .into_owned()
@@ -168,19 +175,19 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
 
     match event {
         Event::Start(Tag::Link(link_type, dest, title)) => {
-            Event::Start(Tag::Link(link_type, fix(dest, path), title))
+            Event::Start(Tag::Link(link_type, fix(dest, path, abs_url), title))
         }
         Event::Start(Tag::Image(link_type, dest, title)) => {
-            Event::Start(Tag::Image(link_type, fix(dest, path), title))
+            Event::Start(Tag::Image(link_type, fix(dest, path, abs_url), title))
         }
-        Event::Html(html) => Event::Html(fix_html(html, path)),
+        Event::Html(html) => Event::Html(fix_html(html, path, abs_url)),
         _ => event,
     }
 }
 
 /// Wrapper around the pulldown-cmark parser for rendering markdown to HTML.
 pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
-    render_markdown_with_path(text, curly_quotes, None)
+    render_markdown_with_path(text, curly_quotes, None, None)
 }
 
 pub fn new_cmark_parser(text: &str, curly_quotes: bool) -> Parser<'_, '_> {
@@ -195,12 +202,17 @@ pub fn new_cmark_parser(text: &str, curly_quotes: bool) -> Parser<'_, '_> {
     Parser::new_ext(text, opts)
 }
 
-pub fn render_markdown_with_path(text: &str, curly_quotes: bool, path: Option<&Path>) -> String {
+pub fn render_markdown_with_path(
+    text: &str,
+    curly_quotes: bool,
+    path: Option<&Path>,
+    abs_url: Option<&String>,
+) -> String {
     let mut s = String::with_capacity(text.len() * 3 / 2);
     let p = new_cmark_parser(text, curly_quotes);
     let events = p
         .map(clean_codeblock_headers)
-        .map(|event| adjust_links(event, path));
+        .map(|event| adjust_links(event, path, abs_url));
 
     html::push_html(&mut s, events);
     s