Add support for relative image source paths with no prefix

Cargo.toml

@@ -26,6 +26,7 @@ log            = "0.4"
 notify         = "4.0.17"
 pathbuftools   = "0.1.2"
 pulldown-cmark = { version = "0.9.0", default-features = false, features = ["simd"] }
+regex          = "1.5.4"
 serde          = { version = "1.0", features = ["derive"] }
 serde_json     = "1.0.74"
 serde_yaml     = "0.8.23"

src/markdown.rs

@@ -7,6 +7,7 @@ use std::fs;
 use std::io;
 use std::path::{PathBuf, Path};
 use std::collections::HashSet;
+use regex::Regex;
 use pulldown_cmark::{Parser, Options, Event, html};
 
 /// Encapsulates a markdown file and provides an interface to turn its contents into HTML.
@@ -35,6 +36,9 @@ impl Renderer {
         let markdown = fs::read_to_string(&self.canonical_md_path)?;
         let root_dir = self.canonical_md_path.parent().unwrap_or_else(|| Path::new(""));
 
+        let re_absolute_url = Regex::new(r"^[a-z]+://").unwrap();
+        let re_path_prefix = Regex::new(r"^(/|\./)?").unwrap();
+
         let mut options = Options::empty();
         options.insert(Options::ENABLE_TABLES);
         options.insert(Options::ENABLE_FOOTNOTES);
@@ -52,8 +56,8 @@ impl Renderer {
                         languages.insert(content.to_string());
                     }
                 },
-                Event::Start(Tag::Image(_, url, _)) if url.starts_with("./") => {
-                    *url = format!("file://{}/{}", root_dir.display(), &url[2..]).into();
+                Event::Start(Tag::Image(_, url, _)) if !re_absolute_url.is_match(url) => {
+                    *url = format!("file://{}/{}", root_dir.display(), re_path_prefix.replace(url, "")).into();
                 },
                 _ => (),
             }

tests/test_markdown.rs

@@ -34,17 +34,22 @@ fn test_renders_local_images() {
     let mut file = NamedTempFile::new().unwrap();
     let tempdir = file.path().parent().unwrap().to_path_buf();
 
-    writeln!(file, "![demo image](./local-image.png)").unwrap();
-    writeln!(file, "![demo image](http://remote-image.png)").unwrap();
-    writeln!(file, "![demo image](unprefixed_image.png)").unwrap();
+    writeln!(file, "![demo image](local-image-01.png)").unwrap();
+    writeln!(file, "![demo image](.local-image-02.png)").unwrap();
+    writeln!(file, "![demo image](/local-image-03.png)").unwrap();
+    writeln!(file, "![demo image](./local-image-04.png)").unwrap();
+    writeln!(file, "![demo image](../local-image-05.png)").unwrap();
+    writeln!(file, "![demo image](http://remote-image-01.png)").unwrap();
+    writeln!(file, "![demo image](https://remote-image-02.png)").unwrap();
 
     let renderer = Renderer::new(file.path().to_path_buf());
     let content = renderer.run().unwrap();
 
-    let local_src = format!("src=\"file://{}/local-image.png\"", tempdir.display());
-    assert!(content.html.contains(&local_src));
-    assert!(content.html.contains("src=\"http://remote-image.png\""));
-
-    // Without a ./ prefix, it's left alone
-    assert!(content.html.contains("src=\"unprefixed_image.png\""));
+    assert!(content.html.contains(&format!("src=\"file://{}/local-image-01.png\"", tempdir.display())));
+    assert!(content.html.contains(&format!("src=\"file://{}/.local-image-02.png\"", tempdir.display())));
+    assert!(content.html.contains(&format!("src=\"file://{}/local-image-03.png\"", tempdir.display())));
+    assert!(content.html.contains(&format!("src=\"file://{}/local-image-04.png\"", tempdir.display())));
+    assert!(content.html.contains(&format!("src=\"file://{}/../local-image-05.png\"", tempdir.display())));
+    assert!(content.html.contains("src=\"http://remote-image-01.png\""));
+    assert!(content.html.contains("src=\"https://remote-image-02.png\""));
 }