Support QR code for session links (#158)

crates/sshx-core/src/lib.rs

@@ -10,7 +10,11 @@ use serde::{Deserialize, Serialize};
 
 /// Protocol buffer and gRPC definitions, automatically generated by Tonic.
 #[allow(missing_docs, non_snake_case)]
-#[allow(clippy::derive_partial_eq_without_eq, clippy::result_large_err)]
+#[allow(
+    clippy::derive_partial_eq_without_eq,
+    clippy::result_large_err,
+    clippy::double_must_use
+)]
 pub mod proto {
     tonic::include_proto!("sshx");
 

crates/sshx/Cargo.toml

@@ -19,6 +19,7 @@ clap.workspace = true
 ctr = "0.9.2"
 encoding_rs = "0.8.31"
 pin-project = "1.1.3"
+qrcode = { version = "0.14.1", default-features = false }
 sshx-core.workspace = true
 tokio.workspace = true
 tokio-stream.workspace = true

crates/sshx/src/lib.rs

@@ -8,5 +8,6 @@
 
 pub mod controller;
 pub mod encrypt;
+pub mod qr;
 pub mod runner;
 pub mod terminal;

crates/sshx/src/main.rs

@@ -3,7 +3,7 @@ use std::process::ExitCode;
 use ansi_term::Color::{Cyan, Fixed, Green};
 use anyhow::Result;
 use clap::Parser;
-use sshx::{controller::Controller, runner::Runner, terminal::get_default_shell};
+use sshx::{controller::Controller, qr::render_qr, runner::Runner, terminal::get_default_shell};
 use tokio::signal;
 use tracing::error;
 
@@ -31,9 +31,17 @@ struct Args {
     /// editors.
     #[clap(long)]
     enable_readers: bool,
+
+    /// Print a QR code for the session link in the terminal.
+    #[clap(long)]
+    qr: bool,
+
+    /// Print a QR code for the writable link when --enable-readers is active.
+    #[clap(long)]
+    qr_write: bool,
 }
 
-fn print_greeting(shell: &str, controller: &Controller) {
+fn print_greeting(shell: &str, controller: &Controller, qr: bool, qr_write: bool) {
     let version_str = match option_env!("CARGO_PKG_VERSION") {
         Some(version) => format!("v{version}"),
         None => String::from("[dev]"),
@@ -54,6 +62,21 @@ fn print_greeting(shell: &str, controller: &Controller) {
             link_e = Cyan.underline().paint(write_url),
             shell_v = Fixed(8).paint(shell),
         );
+        if qr {
+            println!(
+                "  {arr}  Scan for read-only link:\n",
+                arr = Green.paint("➜")
+            );
+            if let Some(code) = render_qr(controller.url()) {
+                println!("{code}\n");
+            }
+        }
+        if qr_write {
+            println!("  {arr}  Scan for writable link:\n", arr = Green.paint("➜"));
+            if let Some(code) = render_qr(write_url) {
+                println!("{code}\n");
+            }
+        }
     } else {
         println!(
             r#"
@@ -68,6 +91,12 @@ fn print_greeting(shell: &str, controller: &Controller) {
             link_v = Cyan.underline().paint(controller.url()),
             shell_v = Fixed(8).paint(shell),
         );
+        if qr || qr_write {
+            println!("  {arr}  Scan for link:\n", arr = Green.paint("➜"));
+            if let Some(code) = render_qr(controller.url()) {
+                println!("{code}\n");
+            }
+        }
     }
 }
 
@@ -98,7 +127,7 @@ async fn start(args: Args) -> Result<()> {
             println!("{}", controller.url());
         }
     } else {
-        print_greeting(&shell, &controller);
+        print_greeting(&shell, &controller, args.qr, args.qr_write);
     }
 
     let exit_signal = signal::ctrl_c();

crates/sshx/src/qr.rs

@@ -0,0 +1,91 @@
+//! QR code generation for terminal output.
+
+use ansi_term::Color;
+use qrcode::render::unicode::Dense1x2;
+use qrcode::QrCode;
+
+/// Render an ANSI-styled QR code for a URL, with optional line prefix indentation.
+///
+/// Uses Unicode half-block characters (`Dense1x2`) with explicit black-on-white
+/// coloring so the QR code remains readable and scannable across both dark and
+/// light terminal color schemes.
+///
+/// Returns `None` if the input cannot be encoded into a QR code.
+pub fn render_qr_with_prefix(url: &str, prefix: &str) -> Option<String> {
+    let code = QrCode::new(url.as_bytes()).ok()?;
+    let image = code
+        .render::<Dense1x2>()
+        .dark_color(Dense1x2::Light)
+        .light_color(Dense1x2::Dark)
+        .quiet_zone(true)
+        .build();
+
+    let styled = image
+        .lines()
+        .map(|line| format!("{prefix}{}", Color::White.on(Color::Black).paint(line)))
+        .collect::<Vec<_>>()
+        .join("\n");
+
+    Some(styled)
+}
+
+/// Render an ASCII/ANSI QR code for a given URL string indented by 2 spaces.
+pub fn render_qr(url: &str) -> Option<String> {
+    render_qr_with_prefix(url, "  ")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_render_qr_standard_url() {
+        let url = "https://sshx.io/s/abc1234567#key1234567890";
+        let rendered = render_qr(url);
+        assert!(rendered.is_some());
+        let output = rendered.unwrap();
+        assert!(!output.is_empty());
+        // Check that lines have indentation and ANSI codes.
+        for line in output.lines() {
+            assert!(line.starts_with("  "));
+            assert!(line.contains("\x1b[40;37m"));
+        }
+    }
+
+    #[test]
+    fn test_render_qr_with_prefix() {
+        let url = "https://sshx.io/s/test#123";
+        let prefix = ">>> ";
+        let rendered = render_qr_with_prefix(url, prefix);
+        assert!(rendered.is_some());
+        let output = rendered.unwrap();
+        for line in output.lines() {
+            assert!(line.starts_with(prefix));
+        }
+    }
+
+    #[test]
+    fn test_render_qr_empty() {
+        // Empty string can still be encoded as a valid minimal QR code.
+        let rendered = render_qr("");
+        assert!(rendered.is_some());
+    }
+
+    #[test]
+    fn test_render_qr_read_write_urls() {
+        let read_url = "https://sshx.io/s/abcdefghij#0123456789abcd";
+        let write_url = "https://sshx.io/s/abcdefghij#0123456789abcd,9876543210zyxw";
+
+        let qr_read = render_qr(read_url).expect("failed to render read-only qr");
+        let qr_write = render_qr(write_url).expect("failed to render writable qr");
+
+        assert!(!qr_read.is_empty());
+        assert!(!qr_write.is_empty());
+
+        // Check line counts: should be around 17-21 lines (compact for standard 80x24 terminal)
+        let lines_read = qr_read.lines().count();
+        let lines_write = qr_write.lines().count();
+        assert!(lines_read <= 22, "QR code height too large: {lines_read}");
+        assert!(lines_write <= 22, "QR code height too large: {lines_write}");
+    }
+}