readme

README.md

@@ -1,2 +1,57 @@
 # VLCFileUrl
-Open vlc-file://foo with VLC as http://foo.
+
+Open `vlc-file://foo` with VLC as `http://foo`.
+
+![](.media/open.png)
+
+
+## Rationale
+
+So you're building a simple webapp to play video files (i.e. a minimal DIY plex-like media server).
+
+The HTML5 [`<video>`](https://en.wikipedia.org/wiki/HTML5_video) tag can natively stream `.mp4` files, `.webm` files, etc.
+
+But what about other types of video files, like `.mkv`?  Unfortunately, there's no good way to do this in the browser.
+
+[VLC](https://www.videolan.org/vlc/) can play `.mkv` files, but downloading the file first isn't convenient -- we want to _stream_ it.  VLC can also stream `.mkv` URLs, but how to we get the browser to hand off the URL to VLC (without downloading the file)?
+
+This is the problem.  There's no way to tell your browser that an `http://` URL to a specific type of file should be handled by an external application.
+
+But if we invent our own URL scheme, we can register an external application to handle it natively.  That's what this app is for.
+
+This app registers the URL scheme `vlc-file://`, rewrites those URLs as `http://` and hands them off to VLC for streaming.
+
+
+## Simple
+
+This is the simplest possible app which can do this.  No joke, here's the entirety of the source code:
+
+```swift
+import Cocoa
+
+@main
+class AppDelegate: NSObject, NSApplicationDelegate {
+
+    @IBOutlet var window: NSWindow!
+
+    func application(_ application: NSApplication, open urls: [URL]) {
+        for url in urls {
+            let httpUrlString = url.absoluteString.replacingOccurrences(
+                of: "vlc-file://",
+                with: "http://"
+            )
+            let job = Process()
+            job.executableURL = URL(fileURLWithPath: "/usr/bin/open")
+            job.arguments = ["-a", "VLC", httpUrlString]
+            try? job.run()
+            job.waitUntilExit()
+        }
+        NSApp.terminate(self)
+    }
+}
+```
+
+
+## License
+
+[MIT](https://opensource.org/license/mit/), baby 😎.