From 3aa2b894512ecea3a5791d452c0d3f2c1ea0bb8b Mon Sep 17 00:00:00 2001
From: Vincent Prouillet <vincent@wearewizards.io>
Date: Thu, 30 Mar 2017 14:48:07 +0900
Subject: [PATCH] Allow links to .md pages in pages contents

---
 CHANGELOG.md    |  1 +
 README.md       |  8 ++++++++
 src/markdown.rs | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2fd926be..cd33217d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,3 +6,4 @@
 - Add sections to the index page context
 - Fix page rendering not working when containing `+++`
 - Add shortcodes (see README for details)
+- Allow relative links to other content in markdown links
diff --git a/README.md b/README.md
index 791226df..2d5b9b61 100644
--- a/README.md
+++ b/README.md
@@ -150,6 +150,14 @@ built-in:
 A gallery containing lots of themes at https://tmtheme-editor.herokuapp.com/#!/editor/theme/Agola%20Dark.
 More themes can be easily added to gutenberg, just make a PR with the wanted theme.
 
+### Internal links
+You can have internal links in your markdown that will be replaced with the full URL when rendering.
+To do so, use the normal markdown link syntax, start the link with `./` and point to the `.md` file you want
+to link to. The path to the file starts from the `content` directory.
+
+For example, linking to a file located at `content/pages/about.md` would be `[my link](./pages/about.md).
+
+
 ### Shortcodes
 Gutenberg uses markdown for content but sometimes you want to insert some HTML, for example for a YouTube video.
 Rather than copy/pasting the HTML around, Gutenberg supports shortcodes, allowing you to define templates using Tera and call those templates inside markdown.
diff --git a/src/markdown.rs b/src/markdown.rs
index c11e4703..0f756942 100644
--- a/src/markdown.rs
+++ b/src/markdown.rs
@@ -204,6 +204,22 @@ pub fn markdown_to_html(content: &str, permalinks: &HashMap<String, String>, ter
                 highlighter = None;
                 Event::Html(Owned("</pre>".to_owned()))
             },
+            // Need to handle relative links
+            Event::Start(Tag::Link(ref link, ref title)) => {
+                if link.starts_with("./") {
+                    let permalink = match permalinks.get(&link.replacen("./", "", 1)) {
+                        Some(p) => p,
+                        None => {
+                            error = Some(format!("Relative link {} not found.", link).into());
+                            return Event::Html(Owned("".to_string()));
+                        }
+                    };
+                    return Event::Start(Tag::Link(Owned(permalink.clone()), title.clone()));
+                }
+
+                return Event::Start(Tag::Link(link.clone(), title.clone()));
+            },
+            // need to know when we are in a code block to disable shortcodes in them
             Event::Start(Tag::Code) => {
                 in_code_block = true;
                 event
@@ -212,6 +228,7 @@ pub fn markdown_to_html(content: &str, permalinks: &HashMap<String, String>, ter
                 in_code_block = false;
                 event
             },
+            // If we added shortcodes, don't close a paragraph since there's none
             Event::End(Tag::Paragraph) => {
                 if added_shortcode {
                     added_shortcode = false;
@@ -219,6 +236,7 @@ pub fn markdown_to_html(content: &str, permalinks: &HashMap<String, String>, ter
                 }
                 event
             },
+            // Ignore softbreaks inside shortcodes
             Event::SoftBreak => {
                 if shortcode_block.is_some() {
                     return Event::Html(Owned("".to_owned()));
@@ -369,4 +387,33 @@ A quote
         "#, &HashMap::new(), &tera, &Config::default()).unwrap();
         assert_eq!(res, "<p>Hello\n</p><blockquote>A quote - Keats</blockquote>");
     }
+
+    #[test]
+    fn test_markdown_to_html_unknown_shortcode() {
+        let res = markdown_to_html("{{ hello(flash=true) }}", &HashMap::new(), &Tera::default(), &Config::default());
+        assert!(res.is_err());
+    }
+
+    #[test]
+    fn test_markdown_to_html_relative_link_exists() {
+        let mut permalinks = HashMap::new();
+        permalinks.insert("pages/about.md".to_string(), "https://vincent.is/about".to_string());
+        let res = markdown_to_html(
+            r#"[rel link](./pages/about.md), [abs link](https://vincent.is/about)"#,
+            &permalinks,
+            &GUTENBERG_TERA,
+            &Config::default()
+        ).unwrap();
+
+        assert!(
+            res.contains(r#"<p><a href="https://vincent.is/about">rel link</a>, <a href="https://vincent.is/about">abs link</a></p>"#)
+        );
+    }
+
+    #[test]
+    fn test_markdown_to_html_relative_link_inexistant() {
+        let res = markdown_to_html("[rel link](./pages/about.md)", &HashMap::new(), &Tera::default(), &Config::default());
+        assert!(res.is_err());
+    }
+
 }