Support opening single markdown files

README.md

@@ -28,8 +28,9 @@ A native macOS Markdown viewer built with [Tauri v2](https://v2.tauri.app/). Bro
 - **Relative link navigation** — Click `.md` links to navigate between documents
 - **Dark mode** — Follows macOS system appearance, toggleable manually
 - **Session persistence** — Remembers your last opened folder across launches
+- **Open single files** — Open `.md` files directly via CLI, Finder "Open With", or drag & drop
 - **PDF export** — Export the current document as PDF with native rendering
-- **CLI support** — Open a folder directly: `mdv ~/docs`
+- **CLI support** — Open a folder or file directly: `mdv ~/docs` or `mdv ~/docs/README.md`
 - **Native menu** — Cmd+O to open a folder, standard macOS app menu
 
 ### Markdown Rendering
@@ -106,10 +107,10 @@ The built app will be at `src-tauri/target/release/bundle/macos/Markdown Viewer.
 
 ```bash
 # Open a specific folder
-./src-tauri/target/release/mdv ~/my-docs
+mdv ~/my-docs
 
-# Or after installing the .app
-/Applications/Markdown\ Viewer.app/Contents/MacOS/mdv ~/my-docs
+# Open a single file (loads its parent directory in the sidebar)
+mdv ~/my-docs/README.md
 ```
 
 ## Tech Stack

docs/guide/features.md

@@ -119,6 +119,15 @@ Click the PDF button in the sidebar header to export the current document as a P
 
 The app remembers the last opened folder and restores it on next launch.
 
+## Open Single Files
+
+You can open individual `.md` files directly:
+
+- **CLI**: `mdv ~/docs/README.md`
+- **Finder**: Right-click a `.md` file → "Open With" → Markdown Viewer
+
+The app loads the file and displays its parent directory in the sidebar for easy navigation to related documents. File associations are declared for `.md`, `.markdown`, and `.mdx` extensions.
+
 ## Relative Link Navigation
 
 Click any `.md` link in a document to navigate to that file. Anchor links (`#section`) scroll to the target heading. External links open in the default browser.

docs/guide/getting-started.md

@@ -44,10 +44,10 @@ The built app will be at `src-tauri/target/release/bundle/macos/Markdown Viewer.
 
 ```bash
 # Open a specific folder
-./src-tauri/target/release/mdv ~/my-docs
+mdv ~/my-docs
 
-# Or after installing the .app
-/Applications/Markdown\ Viewer.app/Contents/MacOS/mdv ~/my-docs
+# Open a single file (loads its parent directory in the sidebar)
+mdv ~/my-docs/README.md
 ```
 
 ## Examples

src-tauri/src/lib.rs

@@ -1,3 +1,4 @@
+use std::path::Path;
 use tauri::Emitter;
 use tauri::menu::{MenuBuilder, MenuItemBuilder, SubmenuBuilder};
 
@@ -57,8 +58,8 @@ async fn export_pdf(_output_path: String) -> Result<(), String> {
 }
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
-pub fn run(folder_arg: Option<String>) {
-    tauri::Builder::default()
+pub fn run(path_arg: Option<String>) {
+    let app = tauri::Builder::default()
         .invoke_handler(tauri::generate_handler![print_webview, export_pdf])
         .plugin(tauri_plugin_store::Builder::new().build())
         .plugin(tauri_plugin_dialog::init())
@@ -88,16 +89,24 @@ pub fn run(folder_arg: Option<String>) {
                 }
             });
 
-            // Pass CLI arg to frontend
-            if let Some(ref folder) = folder_arg {
-                let folder = folder.clone();
+            // Pass CLI arg to frontend — detect file vs folder
+            if let Some(ref path_str) = path_arg {
+                let path = Path::new(path_str);
                 let handle = app.handle().clone();
-                // Emit after the window is ready
-                tauri::async_runtime::spawn(async move {
-                    // Small delay to ensure frontend is loaded
-                    tokio::time::sleep(std::time::Duration::from_millis(500)).await;
-                    let _ = handle.emit("open-folder", folder);
-                });
+
+                if path.is_file() {
+                    let file_path = path_str.clone();
+                    tauri::async_runtime::spawn(async move {
+                        tokio::time::sleep(std::time::Duration::from_millis(500)).await;
+                        let _ = handle.emit("open-file", file_path);
+                    });
+                } else if path.is_dir() {
+                    let folder = path_str.clone();
+                    tauri::async_runtime::spawn(async move {
+                        tokio::time::sleep(std::time::Duration::from_millis(500)).await;
+                        let _ = handle.emit("open-folder", folder);
+                    });
+                }
             }
 
             if cfg!(debug_assertions) {
@@ -109,6 +118,20 @@ pub fn run(folder_arg: Option<String>) {
             }
             Ok(())
         })
-        .run(tauri::generate_context!())
-        .expect("error while running tauri application");
+        .build(tauri::generate_context!())
+        .expect("error while building tauri application");
+
+    app.run(|app_handle, event| {
+        #[cfg(target_os = "macos")]
+        if let tauri::RunEvent::Opened { ref urls } = event {
+            for url in urls {
+                if let Ok(path) = url.to_file_path() {
+                    if path.is_file() {
+                        let _ = app_handle.emit("open-file", path.to_string_lossy().to_string());
+                    }
+                }
+            }
+        }
+        let _ = (app_handle, event);
+    });
 }

src-tauri/src/main.rs

@@ -3,6 +3,6 @@
 
 fn main() {
     let args: Vec<String> = std::env::args().collect();
-    let folder_arg = args.get(1).cloned();
-    app_lib::run(folder_arg);
+    let path_arg = args.get(1).cloned();
+    app_lib::run(path_arg);
 }

src-tauri/tauri.conf.json

@@ -42,6 +42,13 @@
     "macOS": {
       "signingIdentity": "Developer ID Application: NICOLAS PATRICK PRUD'HOMME (44DTA694H9)",
       "entitlements": "entitlements.plist"
-    }
+    },
+    "fileAssociations": [
+      {
+        "ext": ["md", "markdown", "mdx"],
+        "name": "Markdown Document",
+        "role": "Viewer"
+      }
+    ]
   }
 }

src/main.ts

@@ -287,6 +287,15 @@ async function init(): Promise<void> {
     setRootPath(event.payload);
   });
 
+  // Listen for file open (via "Open With" or CLI with a file path)
+  appWindow.listen<string>("open-file", (event) => {
+    const filePath = event.payload;
+    const lastSep = filePath.lastIndexOf("/");
+    const parentDir = filePath.substring(0, lastSep);
+    const fileName = filePath.substring(lastSep + 1);
+    setRootPath(parentDir, fileName);
+  });
+
   // Listen for menu "Open Folder" (Cmd+O)
   appWindow.listen("menu-open-folder", () => {
     openFolder();
@@ -299,14 +308,21 @@ async function init(): Promise<void> {
   }
 }
 
-async function setRootPath(path: string): Promise<void> {
+async function setRootPath(
+  path: string,
+  fileToOpen?: string
+): Promise<void> {
   rootPath = path;
   rootName = extractRootName(path);
   currentPath = [];
   activeFile = null;
   await saveRootPath(path);
   await renderSidebar();
-  await autoSelectReadme();
+  if (fileToOpen) {
+    await loadFile(fileToOpen);
+  } else {
+    await autoSelectReadme();
+  }
 }
 
 async function openFolder(): Promise<void> {