[pbs-devel] [PATCH proxmox v5 1/2] router: cli: added `ask_for_confirmation` helper
Thomas Lamprecht
t.lamprecht at proxmox.com
Wed Apr 24 21:03:42 CEST 2024
Am 18/04/2024 um 13:49 schrieb Gabriel Goller:
> Added `ask_for_confirmation` helper that outputs a prompt and
> lets the user confirm or deny it.
> Implemented to close #4763.
>
> Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
> ---
> proxmox-router/Cargo.toml | 1 +
> proxmox-router/src/cli/mod.rs | 46 ++++++++++++++++++++++++++++++++++-
> 2 files changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/proxmox-router/Cargo.toml b/proxmox-router/Cargo.toml
> index dcd71a4..0b9d361 100644
> --- a/proxmox-router/Cargo.toml
> +++ b/proxmox-router/Cargo.toml
> @@ -19,6 +19,7 @@ percent-encoding.workspace = true
> serde_json.workspace = true
> serde.workspace = true
> unicode-width ="0.1.8"
> +regex.workspace = true
>
> # cli:
> tokio = { workspace = true, features = [], optional = true }
> diff --git a/proxmox-router/src/cli/mod.rs b/proxmox-router/src/cli/mod.rs
> index 7df94ad..7f87284 100644
> --- a/proxmox-router/src/cli/mod.rs
> +++ b/proxmox-router/src/cli/mod.rs
> @@ -12,7 +12,10 @@
> //! - Ability to create interactive commands (using ``rustyline``)
> //! - Supports complex/nested commands
>
> -use std::collections::HashMap;
> +use std::{
> + collections::HashMap,
> + io::{self, Write},
> +};
>
> use crate::ApiMethod;
>
> @@ -61,6 +64,47 @@ pub fn init_cli_logger(env_var_name: &str, default_log_level: &str) {
> .init();
> }
>
> +pub enum DefaultAnswer {
The enumeration is not really tied to being a _default_ answer, you just use
it that way now in this patch, I'd rather use just Answer and then also use that
as return value.
See for a replacement proposal at the end.
> + Yes,
> + No,
> +}
> +
> +/// Prints a prompt to ask for confirmation
> +pub fn ask_for_confirmation(query: String, default: DefaultAnswer) -> Result<bool, io::Error> {
> + let yesnoprompt: (char, char) = match default {
> + DefaultAnswer::Yes => ('Y', 'n'),
> + DefaultAnswer::No => ('y', 'N'),
> + };
> + print!("{query} [{}/{}]: ", yesnoprompt.0, yesnoprompt.1);
> +
> + io::stdout().flush()?;
> + let stdin = io::stdin();
> + let mut line = String::new();
> + stdin.read_line(&mut line)?;
> +
> + use regex::Regex;
> + match default {
> + DefaultAnswer::Yes => {
> + // unwrap is okay, because this regex is correct
> + let no_regex: Regex = Regex::new("^[nN]$").unwrap();
> + if no_regex.is_match(line.trim()) {
> + Ok(false)
> + } else {
> + Ok(true)
So, a caller passes DefaultAnswer::Yes, the user enter the full word "no", your logic
then makes it a Yes like it would for all other unrecognized input... I do not like
such dangerous interfaces, so NACK.
The default must only be taken if the user did not make any input, but just pressed
enter.
> + }
> + }
> + DefaultAnswer::No => {
> + // unwrap is okay, because this regex is coorrect
> + let yes_regex: Regex = Regex::new("^[yY]$").unwrap();
> + if yes_regex.is_match(line.trim()) {
> + Ok(true)
> + } else {
> + Ok(false)
same here
> + }
> + }
I'd rather prefer something like the following interface, it's mostly boilerplate
and docs, but it should allow some safer usage. Could also do s/Confirmation/Confirm/
but no hard feelings there.
The code from patch 2/2 could look the roughly like:
let destroy_group_answer = Confirmation:query_with_default(
format!("Delete group \"{backup_group}\" with {snapshots} snapshot(s)?"),
Confirmation:No,
)?;
if destroy_group_answer.is_yes() {
// ....
}
----8<----
>From 6287a4dd3f092e2413356798a41e3a7423536f98 Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht at proxmox.com>
Date: Wed, 24 Apr 2024 20:55:43 +0200
Subject: [PATCH] router: cli: add yes/no confirmation enum with prompt query
helper
Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
---
proxmox-router/src/cli/mod.rs | 115 +++++++++++++++++++++++++++++++++-
1 file changed, 114 insertions(+), 1 deletion(-)
diff --git a/proxmox-router/src/cli/mod.rs b/proxmox-router/src/cli/mod.rs
index 7df94ad9..7e561b33 100644
--- a/proxmox-router/src/cli/mod.rs
+++ b/proxmox-router/src/cli/mod.rs
@@ -12,7 +12,10 @@
//! - Ability to create interactive commands (using ``rustyline``)
//! - Supports complex/nested commands
-use std::collections::HashMap;
+use std::{
+ collections::HashMap,
+ io::{self, Write},
+};
use crate::ApiMethod;
@@ -61,6 +64,116 @@ pub fn init_cli_logger(env_var_name: &str, default_log_level: &str) {
.init();
}
+#[derive(PartialEq, Debug)]
+/// Use for simple yes or no questions, where booleans can be confusing, especially if there's a
+/// default response to consider. The implementation provides query helper for the CLI.
+pub enum Confirmation {
+ Yes,
+ No,
+}
+
+impl Confirmation {
+ /// get the formatted choice for the query prompt, with self being the highlighted (default)
+ /// one displayed as upper case.
+ pub fn default_choice_str(&self) -> &'static str {
+ match self {
+ Self::Yes => "Y/n",
+ Self::No => "y/N",
+ }
+ }
+
+ /// Returns true if the answer is Yes
+ pub fn is_yes(&self) -> bool {
+ *self == Self::Yes
+ }
+
+ /// Returns true if the answer is No
+ pub fn is_no(&self) -> bool {
+ *self == Self::No
+ }
+
+ /// Parse an input string reference as yes or no confirmation.
+ ///
+ /// The input string is checked verbatim if it is exactly one of the single chars 'y', 'Y',
+ /// 'n', or 'N'. You must trim the string before calling, if needed, or use one of the query
+ /// helper functions.
+ ///
+ /// ```
+ /// use proxmox_router::cli::Confirmation;
+ ///
+ /// let answer = Confirmation::from_str("y");
+ /// assert!(answer.expect("valid").is_yes());
+ ///
+ /// let answer = Confirmation::from_str("N");
+ /// assert!(answer.expect("valid").is_no());
+ ///
+ /// let answer = Confirmation::from_str("bogus");
+ /// assert!(answer.is_err());
+ /// ```
+ pub fn from_str(input: &str) -> Result<Self, io::Error> {
+ match input.trim() {
+ "y" | "Y" => Ok(Self::Yes),
+ "n" | "N" => Ok(Self::No),
+ _ => Err(io::Error::new(
+ io::ErrorKind::InvalidInput,
+ "invalid input, enter one of y, Y, n, or N",
+ )),
+ }
+ }
+
+ /// Parse a input string reference as yes or no confirmation, allowing a fallback default
+ /// answer if the user enters an empty choice.
+ ///
+ /// The input string is checked verbatim if it is exactly one of the single chars 'y', 'Y',
+ /// 'n', or 'N'. The empty string maps to the default. You must trim the string before calling,
+ /// if needed, or use one of the query helper functions.
+ ///
+ /// ```
+ /// use proxmox_router::cli::Confirmation;
+ ///
+ /// let answer = Confirmation::from_str_with_default("", Confirmation::No);
+ /// assert!(answer.expect("valid").is_no());
+ ///
+ /// let answer = Confirmation::from_str_with_default("n", Confirmation::Yes);
+ /// assert!(answer.expect("valid").is_no());
+ ///
+ /// let answer = Confirmation::from_str_with_default("yes", Confirmation::Yes);
+ /// assert!(answer.is_err()); // full-word answer not allowed for now.
+ /// ```
+ pub fn from_str_with_default(input: &str, default: Self) -> Result<Self, io::Error> {
+ match input.trim() {
+ "y" | "Y" => Ok(Self::Yes),
+ "n" | "N" => Ok(Self::No),
+ "" => Ok(default),
+ _ => Err(io::Error::from(io::ErrorKind::InvalidInput)),
+ }
+ }
+
+ /// Print a query prompt with available yes no choices and returns the String the user enters.
+ fn read_line(query: &str, choices: &str) -> Result<String, io::Error> {
+ print!("{query} [{choices}]: ");
+
+ io::stdout().flush()?;
+ let stdin = io::stdin();
+ let mut line = String::new();
+ stdin.read_line(&mut line)?;
+ Ok(line)
+ }
+
+ /// Print a query prompt and parse the white-space trimmed answer using from_str.
+ pub fn query(query: &str) -> Result<Self, io::Error> {
+ let line = Self::read_line(query, "y/n")?;
+ Confirmation::from_str(line.trim())
+ }
+
+ /// Print a query prompt and parse the answer using from_str_with_default, falling back to the
+ /// default_answer if the user provided an empty string.
+ pub fn query_with_default(query: &str, default_answer: Self) -> Result<Self, io::Error> {
+ let line = Self::read_line(query, default_answer.default_choice_str())?;
+ Confirmation::from_str_with_default(line.trim(), default_answer)
+ }
+}
+
/// Define a simple CLI command.
pub struct CliCommand {
/// The Schema definition.
--
2.39.2
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