keyfork-prompt: add choice mechanism

crates/daemon/keyforkd-client/src/lib.rs

@@ -1,8 +1,10 @@
 //! # The Keyforkd Client
 //!
 //! Keyfork allows securing the master key and highest-level derivation keys by having derivation
-//! requests performed against a server, "Keyforkd" or the "Keyfork Server". The server is operated
-//! on a UNIX socket with messages sent using the Keyfork Frame format.
+//! requests performed against a server, "Keyforkd" or the "Keyfork Server". This allows
+//! enforcement of policies, such as requiring at least two leves of a derivation path (for
+//! instance, `m/0'` would not be allowed, but `m/0'/0'` would). The server is operated on a UNIX
+//! socket with messages sent using the Keyfork Frame format.
 //!
 //! Programs using the Keyfork Client should ensure they are built against a compatible version of
 //! the Keyfork Server. For versions prior to `1.0.0`, all versions within a "minor" version (i.e.,
@@ -10,18 +12,23 @@
 //! after `1.0.0`, all versions within a "major" version (i.e., `1.0.0`) will be compatible, but
 //! `1.x.y` will not be compatible with `2.0.0`.
 //!
-//! Presently, the Keyfork server only supports the following requests:
+//! The Keyfork Client documentation makes extensive use of the `keyforkd::test_util` module.
+//! This provides testing infrastructure to set up a temporary Keyfork Daemon. In
+//! your code, you should assume the daemon has already been initialized, whether by another
+//! process, on another terminal, or some other instance. At no point should a program deriving an
+//! "endpoint" key have control over a mnemonic or a seed.
 //!
-//! * Derive Key
+//! ## Server Requests
 //!
-//! ## Extended Private Keys
+//! Keyfork is designed as a client-request/server-response model. The client sends a request, such
+//! as a derivation request, and the server sends its response.  Presently, the Keyfork server
+//! supports the following requests:
 //!
-//! Keyfork doesn't need to be continuously called once a key has been derived. Once an Extended
-//! Private Key (often shortened to "XPrv") has been created, further derivations can be performed.
-//! The tests for this library ensure that all levels of Keyfork derivation beyond the required two
-//! will be derived similarly between the server and the client.
+//! ### Request: Derive Key
+//!
+//! The client creates a derivation path of at least two indices and requests a derived XPrv
+//! (Extended Private Key) from the server.
 //!
-//! # Examples
 //! ```rust
 //! use std::str::FromStr;
 //!
@@ -31,17 +38,121 @@
 //! // use k256::SecretKey as PrivateKey;
 //! // use ed25519_dalek::SigningKey as PrivateKey;
 //!
-//! # let seed = b"funky accordion noises";
-//! # keyforkd::test_util::run_test(seed, |socket_path| {
-//! # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
-//! let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
-//! let mut client = Client::discover_socket().unwrap();
-//! let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
-//! # keyforkd::test_util::Infallible::Ok(())
-//! # }).unwrap();
+//! #[derive(Debug, thiserror::Error)]
+//! enum Error {
+//!     #[error(transparent)]
+//!     Path(#[from] keyfork_derive_util::PathError),
+//!
+//!     #[error(transparent)]
+//!     Keyforkd(#[from] keyforkd_client::Error),
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//! #   let seed = b"funky accordion noises";
+//! #   keyforkd::test_util::run_test(seed, |socket_path| {
+//!     let derivation_path = DerivationPath::from_str("m/44'/0'")?;
+//!     let mut client = Client::discover_socket()?;
+//!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//! #   Ok::<_, Error>(())
+//! #   })?;
+//!     Ok(())
+//! }
 //! ```
 //!
-//! In tests, the Keyforkd test_util module and TestPrivateKeys can be used.
+//! ---
+//!
+//! Request objects are typically handled by the Keyfork Client library (such as with
+//! [`Client::request_xprv`]). While unadvised, clients can also attempt to handle their own
+//! requests, using [`Client::request`].
+//!
+//! ## Extended Private Keys
+//!
+//! Keyfork doesn't need to be continuously called once a key has been derived. Once an Extended
+//! Private Key (often shortened to "XPrv") has been created, further derivations can be performed.
+//! The tests for this library ensure that all levels of Keyfork derivation beyond the required two
+//! will be derived similarly between the server and the client.
+//!
+//! ```rust
+//! use std::str::FromStr;
+//!
+//! use keyforkd_client::Client;
+//! use keyfork_derive_util::{DerivationIndex, DerivationPath};
+//! # use keyfork_derive_util::private_key::TestPrivateKey as PrivateKey;
+//! // use k256::SecretKey as PrivateKey;
+//! // use ed25519_dalek::SigningKey as PrivateKey;
+//! # fn check_wallet<T>(_: T) {}
+//!
+//! #[derive(Debug, thiserror::Error)]
+//! enum Error {
+//!     #[error(transparent)]
+//!     Index(#[from] keyfork_derive_util::IndexError),
+//!
+//!     #[error(transparent)]
+//!     Path(#[from] keyfork_derive_util::PathError),
+//!
+//!     #[error(transparent)]
+//!     PrivateKey(#[from] keyfork_derive_util::PrivateKeyError),
+//!
+//!     #[error(transparent)]
+//!     Keyforkd(#[from] keyforkd_client::Error),
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//!     # let seed = b"funky accordion noises";
+//!     # keyforkd::test_util::run_test(seed, |socket_path| {
+//!     let derivation_path = DerivationPath::from_str("m/44'/0'/0'/0")?;
+//!     let mut client = Client::discover_socket()?;
+//!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//!     // scan first 20 wallets
+//!     for index in 0..20 {
+//!         // use non-hardened derivation
+//!         let new_xprv = xprv.derive_child(&DerivationIndex::new(index, false)?);
+//!         check_wallet(new_xprv)
+//!     }
+//! #   Ok::<_, Error>(())
+//! #   })?;
+//!     Ok(())
+//! }
+//! ```
+//!
+//! ## Testing Infrastructure
+//!
+//! In tests, the `keyforkd::test_util` module and TestPrivateKeys can be used. These provide
+//! useful utilities for writing tests that interact with the Keyfork Server without needing to
+//! manually create the server for the purpose of the test. The `run_test` method can be used to
+//! run a test, which can handle both returning errors and correctly translating panics (though,
+//! the panics definitely won't look tidy).
+//!
+//! ```rust
+//! use std::str::FromStr;
+//!
+//! use keyforkd_client::Client;
+//! use keyfork_derive_util::DerivationPath;
+//! use keyfork_derive_util::private_key::TestPrivateKey as PrivateKey;
+//!
+//! #[derive(Debug, thiserror::Error)]
+//! enum Error {
+//!     #[error(transparent)]
+//!     Path(#[from] keyfork_derive_util::PathError),
+//!
+//!     #[error(transparent)]
+//!     Keyforkd(#[from] keyforkd_client::Error),
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//!     let seed = b"funky accordion noises";
+//!     keyforkd::test_util::run_test(seed, |socket_path| {
+//!         let derivation_path = DerivationPath::from_str("m/44'/0'")?;
+//!         let mut client = Client::discover_socket()?;
+//!         let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//!         Ok::<_, Error>(())
+//!     })?;
+//!     Ok(())
+//! }
+//! ```
+//!
+//! If you would rather write tests to panic rather than error, or would rather not deal with error
+//! types, the Panicable type should be used, which will handle the Error type for the closure.
 //!
 //! ```rust
 //! use std::str::FromStr;
@@ -52,11 +163,10 @@
 //!
 //! let seed = b"funky accordion noises";
 //! keyforkd::test_util::run_test(seed, |socket_path| {
-//!     std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
 //!     let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
 //!     let mut client = Client::discover_socket().unwrap();
 //!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
-//!     keyforkd::test_util::Infallible::Ok(())
+//!     keyforkd::test_util::Panicable::Ok(())
 //! }).unwrap();
 //! ```
 
@@ -165,10 +275,9 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
-    /// let mut socket = get_socket().unwrap();
+    /// let mut socket = get_socket()?;
     /// let mut client = Client::new(socket);
-    /// # keyforkd::test_util::Infallible::Ok(())
+    /// # Ok::<_, keyforkd_client::Error>(())
     /// # }).unwrap();
     /// ```
     pub fn new(socket: UnixStream) -> Self {
@@ -187,9 +296,8 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
-    /// let mut client = Client::discover_socket().unwrap();
-    /// # keyforkd::test_util::Infallible::Ok(())
+    /// let mut client = Client::discover_socket()?;
+    /// # Ok::<_, keyforkd_client::Error>(())
     /// # }).unwrap();
     /// ```
     pub fn discover_socket() -> Result<Self> {
@@ -217,11 +325,10 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
     /// let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
     /// let mut client = Client::discover_socket().unwrap();
     /// let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
-    /// # keyforkd::test_util::Infallible::Ok(())
+    /// # keyforkd::test_util::Panicable::Ok(())
     /// # }).unwrap();
     /// ```
     pub fn request_xprv<K>(&mut self, path: &DerivationPath) -> Result<ExtendedPrivateKey<K>>
@@ -244,15 +351,20 @@ impl Client {
             _ => Err(Error::InvalidResponse),
         }
     }
+}
 
+impl Client {
     /// Serialize and send a [`Request`] to the server, awaiting a [`Result<Response>`].
     ///
+    /// This function does not properly assert the association between a request type and a
+    /// response type, and does not perform any serialization of native objects into Request or
+    /// Response types, and should only be used when absolutely necessary.
+    ///
     /// # Errors
     /// An error may be returned if:
     /// * Reading or writing from or to the socket encountered an error.
     /// * Bincode could not serialize the request or deserialize the response.
     /// * An error occurred in Keyforkd.
-    #[doc(hidden)]
     pub fn request(&mut self, req: &Request) -> Result<Response> {
         try_encode_to(&bincode::serialize(&req)?, &mut self.socket)?;
         let resp = try_decode_from(&mut self.socket)?;

crates/daemon/keyforkd-client/src/tests.rs

@@ -1,7 +1,7 @@
 use crate::Client;
 use keyfork_derive_util::{request::*, DerivationPath};
 use keyfork_slip10_test_data::test_data;
-use keyforkd::test_util::{run_test, Infallible};
+use keyforkd::test_util::{run_test, Panicable};
 use std::{os::unix::net::UnixStream, str::FromStr};
 
 #[test]
@@ -109,7 +109,7 @@ fn ed25519_test_suite() {
                     DerivationResponse::try_from(client.request(&req.into()).unwrap()).unwrap();
                 assert_eq!(&response.data, test.private_key.as_slice());
             }
-            Infallible::Ok(())
+            Panicable::Ok(())
         })
         .unwrap();
     }

crates/daemon/keyforkd/src/test_util.rs

@@ -12,20 +12,21 @@ use keyfork_bug::bug;
 #[derive(Debug, thiserror::Error)]
 #[error("This error can never be instantiated")]
 #[doc(hidden)]
-pub struct InfallibleError {
-    protected: (),
-}
+pub enum UninstantiableError {}
 
-/// An infallible result. This type can be used to represent a function that should never error.
+/// A panicable result. This type can be used when a closure chooses to panic instead of
+/// returning an error.  This doesn't necessarily mean a closure _has_ to panic, and its absence
+/// doesn't imply a closure _can't_ panic, but this is a useful utility function for writing tests,
+/// to avoid the necessity of making custom error types.
 ///
 /// ```rust
-/// use keyforkd::test_util::Infallible;
+/// use keyforkd::test_util::Panicable;
 /// let closure = || {
-///     Infallible::Ok(())
+///     Panicable::Ok(())
 /// };
 /// assert!(closure().is_ok());
 /// ```
-pub type Infallible<T> = std::result::Result<T, InfallibleError>;
+pub type Panicable<T> = std::result::Result<T, UninstantiableError>;
 
 /// Run a test making use of a Keyforkd server. The test may use a seed (the first argument) from a
 /// test suite, or (as shown in the example below) a simple seed may be used solely to ensure
@@ -39,6 +40,8 @@ pub type Infallible<T> = std::result::Result<T, InfallibleError>;
 /// runtime.
 ///
 /// # Examples
+/// The test utility provides a socket that can be connected to for deriving keys.
+///
 /// ```rust
 /// use std::os::unix::net::UnixStream;
 /// let seed = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
@@ -46,6 +49,18 @@ pub type Infallible<T> = std::result::Result<T, InfallibleError>;
 ///     UnixStream::connect(&path).map(|_| ())
 /// }).unwrap();
 /// ```
+///
+/// The `keyforkd-client` crate uses the `KEYFORKD_SOCKET_PATH` variable to determine the default
+/// socket path. The test will export the environment variable so it may be used by default.
+///
+/// ```rust
+/// use std::os::unix::net::UnixStream;
+/// let seed = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
+/// keyforkd::test_util::run_test(seed.as_slice(), |path| {
+///     assert_eq!(std::env::var_os("KEYFORKD_SOCKET_PATH").unwrap(), path.as_os_str());
+///     UnixStream::connect(&path).map(|_| ())
+/// }).unwrap();
+/// ```
 #[allow(clippy::missing_errors_doc)]
 pub fn run_test<F, E>(seed: &[u8], closure: F) -> Result<(), E>
 where
@@ -82,6 +97,7 @@ where
         rx.recv()
             .await
             .expect(bug!("can't receive server start signal from channel"));
+        std::env::set_var("KEYFORKD_SOCKET_PATH", &socket_path);
         let test_handle = tokio::task::spawn_blocking(move || closure(&socket_path));
 
         let result = test_handle.await;
@@ -89,8 +105,8 @@ where
         result
     });
     if let Err(e) = result {
-        if e.is_panic() {
-            std::panic::resume_unwind(e.into_panic());
+        if let Ok(reason) = e.try_into_panic() {
+            std::panic::resume_unwind(reason);
         }
     }
     Ok(())
@@ -103,6 +119,6 @@ mod tests {
     #[test]
     fn test_run_test() {
         let seed = b"beefbeef";
-        run_test(seed, |_path| Infallible::Ok(())).expect("infallible");
+        run_test(seed, |_path| Panicable::Ok(())).expect("infallible");
     }
 }

crates/util/keyfork-prompt/examples/test-basic-prompt.rs

@@ -3,36 +3,34 @@
 use std::io::{stdin, stdout};
 
 use keyfork_prompt::{
-    validators::{mnemonic, Validator},
-    Terminal, PromptHandler,
+    MaybeIdentifier, PromptHandler, Terminal,
 };
 
-use keyfork_mnemonic_util::English;
+#[derive(PartialEq, Eq, Debug)]
+pub enum Example {
+    RetryQR,
+    UseMnemonic,
+}
+
+impl MaybeIdentifier for Example {}
+
+impl std::fmt::Display for Example {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Example::RetryQR => f.write_str("Retry QR Code"),
+            Example::UseMnemonic => f.write_str("Use Mnemonic"),
+        }
+    }
+}
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut mgr = Terminal::new(stdin(), stdout())?;
-    let transport_validator = mnemonic::MnemonicSetValidator {
-        word_lengths: [9, 24],
-    };
-    let combine_validator = mnemonic::MnemonicSetValidator {
-        word_lengths: [24, 48],
-    };
 
-    let mnemonics = mgr.prompt_validated_wordlist::<English, _>(
-        "Enter a 9-word and 24-word mnemonic: ",
-        3,
-        transport_validator.to_fn(),
+    let choice = mgr.prompt_choice(
+        "Unable to detect QR code.",
+        &[Example::RetryQR, Example::UseMnemonic],
     )?;
-    assert_eq!(mnemonics[0].as_bytes().len(), 12);
-    assert_eq!(mnemonics[1].as_bytes().len(), 32);
-
-    let mnemonics = mgr.prompt_validated_wordlist::<English, _>(
-        "Enter a 24 and 48-word mnemonic: ",
-        3,
-        combine_validator.to_fn(),
-    )?;
-    assert_eq!(mnemonics[0].as_bytes().len(), 32);
-    assert_eq!(mnemonics[1].as_bytes().len(), 64);
+    dbg!(choice);
 
     Ok(())
 }

crates/util/keyfork-prompt/src/lib.rs

@@ -8,7 +8,7 @@ use keyfork_mnemonic_util::Wordlist;
 ///
 pub mod terminal;
 pub mod validators;
-pub use terminal::{Terminal, DefaultTerminal, default_terminal};
+pub use terminal::{default_terminal, DefaultTerminal, Terminal};
 
 /// An error occurred while displaying a prompt.
 #[derive(thiserror::Error, Debug)]
@@ -42,6 +42,12 @@ pub enum Message {
     Data(String),
 }
 
+pub trait MaybeIdentifier {
+    fn identifier(&self) -> Option<char> {
+        None
+    }
+}
+
 /// A trait to allow displaying prompts and accepting input.
 pub trait PromptHandler {
     /// Prompt the user for input.
@@ -58,7 +64,9 @@ pub trait PromptHandler {
     /// The method may return an error if the message was not able to be displayed or if the input
     /// could not be read.
     #[cfg(feature = "mnemonic")]
-    fn prompt_wordlist<X>(&mut self, prompt: &str) -> Result<String> where X: Wordlist;
+    fn prompt_wordlist<X>(&mut self, prompt: &str) -> Result<String>
+    where
+        X: Wordlist;
 
     /// Prompt the user for input based on a wordlist, while validating the wordlist using a
     /// provided parser function, returning the type from the parser. A language must be specified
@@ -97,6 +105,19 @@ pub trait PromptHandler {
         validator_fn: impl Fn(String) -> Result<V, Box<dyn std::error::Error>>,
     ) -> Result<V, Error>;
 
+    /// Prompt the user to select a choice between multiple options.
+    ///
+    /// # Errors
+    /// The method may return an error if the message was not able to be displayed or if a choice
+    /// could not be received.
+    fn prompt_choice<'a, T>(
+        &mut self,
+        prompt: &str,
+        choices: &'a [T],
+    ) -> Result<&'a T, Error>
+    where
+        T: std::fmt::Display + PartialEq + MaybeIdentifier;
+
     /// Prompt the user with a [`Message`].
     ///
     /// # Errors

crates/util/keyfork-prompt/src/terminal.rs

@@ -15,7 +15,7 @@ use keyfork_crossterm::{
 
 use keyfork_bug::bug;
 
-use crate::{Error, Message, PromptHandler, Wordlist};
+use crate::{Error, MaybeIdentifier, Message, PromptHandler, Wordlist};
 
 #[allow(missing_docs)]
 pub type Result<T, E = Error> = std::result::Result<T, E>;
@@ -122,6 +122,9 @@ where
     W: Write + AsRawFd,
 {
     fn drop(&mut self) {
+        self.write
+            .execute(cursor::Show)
+            .expect(bug!("can't enable cursor blinking"));
         self.write
             .execute(DisableBracketedPaste)
             .expect(bug!("can't restore bracketed paste"));
@@ -455,6 +458,77 @@ where
         Ok(passphrase)
     }
 
+    fn prompt_choice<'a, T>(&mut self, prompt: &str, choices: &'a [T]) -> Result<&'a T, Error>
+    where
+        T: std::fmt::Display + PartialEq + MaybeIdentifier,
+    {
+        let mut terminal = self.lock().alternate_screen()?.raw_mode()?;
+
+        terminal
+            .queue(terminal::Clear(terminal::ClearType::All))?
+            .queue(cursor::MoveTo(0, 0))?
+            .queue(cursor::Hide)?;
+
+        for line in prompt.lines() {
+            terminal.queue(Print(line))?;
+            terminal
+                .queue(cursor::MoveDown(1))?
+                .queue(cursor::MoveToColumn(0))?;
+
+        }
+        terminal.flush()?;
+
+        let mut active_choice = 0;
+
+        let mut redraw = |active_choice| {
+            terminal.queue(cursor::MoveToColumn(0))?;
+
+            let mut iter = choices.iter().enumerate().peekable();
+            while let Some((i, choice)) = iter.next() {
+                // if active choice, flip foreground and background
+                // if active choice, wrap in []
+                // if not, wrap in spaces, to preserve spacing
+                if i == active_choice {
+                    terminal.queue(PrintStyledContent(format!("[{choice}]").to_string().reverse()))?;
+                } else {
+                    terminal.queue(Print(format!(" {choice} ").to_string()))?;
+                }
+                if iter.peek().is_some() {
+                    terminal.queue(Print(" "))?;
+                }
+            }
+            terminal.flush()?;
+            Ok::<_, Error>(())
+        };
+
+        redraw(active_choice)?;
+
+        loop {
+            if let Event::Key(k) = read()? {
+                match k.code {
+                    KeyCode::Char('c') if k.modifiers.contains(KeyModifiers::CONTROL) => {
+                        return Err(Error::CtrlC);
+                    }
+                    KeyCode::Left => {
+                        // prevent underflow
+                        // if 0, max is 1, -1 is 0, no underflow
+                        // if 1, max is 1, -1 is 0
+                        // if 2 or higher, max is 2 or higher, -1 is fine
+                        active_choice = std::cmp::max(1, active_choice) - 1;
+                    }
+                    KeyCode::Right => {
+                        active_choice = std::cmp::min(choices.len() - 1, active_choice + 1);
+                    }
+                    KeyCode::Enter => {
+                        return Ok(&choices[active_choice]);
+                    }
+                    _ => {}
+                }
+            }
+            redraw(active_choice)?;
+        }
+    }
+
     fn prompt_message(&mut self, prompt: impl Borrow<Message>) -> Result<()> {
         let mut terminal = self.lock().alternate_screen()?.raw_mode()?;