add backlinks

src/main.rs

@@ -6,8 +6,8 @@ use chrono::{DateTime, Local};
 use clap::{App as ClapApp, Arg};
 use linkify::LinkFinder;
 use log::{info, trace};
-use percent_encoding::utf8_percent_encode;
-use pulldown_cmark::{html, Options, Parser};
+use percent_encoding::{percent_decode_str, utf8_percent_encode};
+use pulldown_cmark::{html, Event, Options, Parser, Tag};
 use regex::{Captures, Regex};
 use std::collections::HashMap;
 use std::fs::File;
@@ -33,7 +33,7 @@ struct MutableState {
 
 #[derive(Clone, Debug)]
 struct GardenCache {
-    pages: HashMap<PathBuf, ParsedPage>,
+    pages: HashMap<String, ParsedPage>,
     files: Vec<PathBuf>,
 }
 
@@ -167,20 +167,41 @@ async fn render(
     let full_path = data.garden_dir.join(path.as_str());
 
     // Redirect to ".md" version if requested path matches a .md file without the extension
-    if !full_path.exists() && full_path.extension().is_none() {
-        let md_path = format!("{}.md", path.to_string());
-        if Path::new(&md_path).exists() {
+    if !full_path.exists()
+        && full_path.extension().is_none()
+        && Path::new(&format!("{}.md", full_path.to_str().unwrap())).exists()
+    {
         return Ok(HttpResponse::Found()
-                .header(http::header::LOCATION, md_path)
+            .header(http::header::LOCATION, format!("{}.md", path.to_string()))
             .finish());
     }
-    }
 
     if full_path.exists() && !path.ends_with(".md") {
         return Ok(NamedFile::open(full_path)?.into_response(&request)?);
     }
 
-    let page = cache.pages.get(&full_path);
+    let filename = full_path
+        .components()
+        .last()
+        .unwrap()
+        .as_os_str()
+        .to_str()
+        .unwrap();
+
+    let normalized_name = normalize_name(filename);
+
+    let mut backlinks: Vec<String> = vec![];
+    for (path, page) in cache.pages.iter() {
+        if page
+            .links
+            .iter()
+            .any(|link| normalize_name(link.as_str()) == normalized_name)
+        {
+            backlinks.push(normalize_name(path));
+        }
+    }
+
+    let page = cache.pages.get(path.as_ref());
 
     let mut context = Context::new();
     context.insert("version", VERSION);
@@ -193,14 +214,7 @@ async fn render(
         "page_title",
         &match page {
             Some(page) => page.title.clone(),
-            None => full_path
-                .components()
-                .last()
-                .unwrap()
-                .as_os_str()
-                .to_str()
-                .unwrap()
-                .to_string(),
+            None => filename.to_string(),
         },
     );
     context.insert(
@@ -213,6 +227,7 @@ async fn render(
                 .map_err(ErrorInternalServerError)?,
         },
     );
+    context.insert("backlinks", &backlinks);
     context.insert(
         "mtime",
         &match page {
@@ -265,12 +280,12 @@ fn update_garden<P: AsRef<Path>>(
 
     let markdown_paths = files
         .iter()
-        .filter(|p| p.to_str().unwrap_or("").ends_with(".md"))
-        .map(|p| garden_path.join(p));
+        .filter(|p| p.to_str().unwrap_or("").ends_with(".md"));
     for path in markdown_paths {
         trace!("Loading {} into cache...", path.display());
-        let mtime = path.metadata().unwrap().modified().ok();
-        if let Some(page) = pages.get(&path) {
+        let full_path = garden_path.join(path);
+        let mtime = full_path.metadata().unwrap().modified().ok();
+        if let Some(page) = pages.get(path.to_str().unwrap()) {
             if let (Some(fs_time), Some(last_time)) = (mtime, page.timestamp) {
                 if fs_time == last_time {
                     continue;
@@ -278,34 +293,29 @@ fn update_garden<P: AsRef<Path>>(
             }
         }
 
-        let mut file = File::open(&path)?;
+        let mut file = File::open(&full_path)?;
         let mut file_string = String::new();
         file.read_to_string(&mut file_string)?;
         let markdown_source = preprocess_markdown(file_string);
-        let parser = Parser::new_ext(markdown_source.as_str(), Options::all());
-        let mut html_output = String::new();
-        html::push_html(&mut html_output, parser);
+        let result = GardenParser::parse(&markdown_source);
 
-        // TODO!
-        let h1_regex = Regex::new(r"<h1>([^>]+)</h1>").unwrap();
-        let title = match h1_regex.captures(&html_output) {
-            Some(h1_match) => h1_match.get(1).unwrap().as_str(),
-            _ => &path
-                .components()
+        pages.insert(
+            String::from(path.to_str().unwrap()),
+            ParsedPage {
+                timestamp: mtime,
+                html: result.html,
+                links: result.links,
+                title: match result.title {
+                    Some(title) => title,
+                    _ => String::from(
+                        path.components()
                             .last()
                             .unwrap()
                             .as_os_str()
                             .to_str()
                             .unwrap_or("???"),
-        };
-
-        pages.insert(
-            path.clone(),
-            ParsedPage {
-                timestamp: mtime,
-                html: html_output.clone(),
-                title: String::from(title),
-                links: vec![], // todo!,
+                    ),
+                },
             },
         );
     }
@@ -315,6 +325,67 @@ fn update_garden<P: AsRef<Path>>(
     Ok(result)
 }
 
+struct GardenParser<'a> {
+    parser: Parser<'a>,
+    last_nontext_event: Option<Event<'a>>,
+    current_top_heading: u32,
+    top_heading_text: &'a mut Option<String>,
+    links: &'a mut Vec<String>,
+}
+
+struct ParseResult {
+    html: String,
+    title: Option<String>,
+    links: Vec<String>,
+}
+
+impl<'a> GardenParser<'a> {
+    fn parse<S: AsRef<str>>(text: &'a S) -> ParseResult {
+        let mut title: Option<String> = None;
+        let mut links: Vec<String> = vec![];
+
+        let parser = GardenParser {
+            parser: Parser::new_ext(text.as_ref(), Options::all()),
+            last_nontext_event: None,
+            current_top_heading: 999,
+            top_heading_text: &mut title,
+            links: &mut links,
+        };
+
+        let mut html = String::new();
+        html::push_html(&mut html, parser);
+
+        ParseResult { html, title, links }
+    }
+}
+
+impl<'a> Iterator for GardenParser<'a> {
+    type Item = Event<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let event = self.parser.next();
+
+        if let Some(event) = &event {
+            if let Event::Start(Tag::Link(_, str, _)) = &event {
+                self.links.push(str.to_string());
+            }
+
+            if let Some(Event::Start(Tag::Heading(hl))) = self.last_nontext_event {
+                if hl < self.current_top_heading {
+                    self.current_top_heading = hl;
+                    if let Event::Text(str) = &event {
+                        *self.top_heading_text = Some(str.clone().into_string());
+                    }
+                }
+            }
+
+            self.last_nontext_event = Some(event.clone());
+        }
+
+        event
+    }
+}
+
 fn preprocess_markdown(string: String) -> String {
     let double_brackets = Regex::new(r"\[\[(?P<inner>[\w .]+)\]\]").unwrap();
     let finder = LinkFinder::new();
@@ -351,3 +422,9 @@ fn preprocess_markdown(string: String) -> String {
 
     result_string
 }
+
+fn normalize_name(filename: &str) -> String {
+    let decoded = percent_decode_str(filename).decode_utf8_lossy();
+    let result = decoded.strip_suffix(".md");
+    String::from(result.unwrap_or(filename))
+}

templates/main.html

@@ -28,6 +28,17 @@
     <main>
         {{content | safe}}
 
+        <hr>
+
+        {% if backlinks %}
+        <h1>Linked from:</h1>
+        <ul>
+            {% for link in backlinks %}
+            <li><a href="/{{ link }}">{{link}}</a></li>
+            {% endfor %}
+        </ul>
+        {% endif %}
+
         {% if mtime %}
             <footer>
                 Last modified at {{mtime}}