nu_command/platform/input/
input_.rs

1use crossterm::{
2    cursor,
3    event::{Event, KeyCode, KeyEventKind, KeyModifiers},
4    execute,
5    style::Print,
6    terminal::{self, ClearType},
7};
8use itertools::Itertools;
9use nu_engine::command_prelude::*;
10use nu_protocol::shell_error::io::IoError;
11
12use std::{io::Write, time::Duration};
13
14#[derive(Clone)]
15pub struct Input;
16
17impl Command for Input {
18    fn name(&self) -> &str {
19        "input"
20    }
21
22    fn description(&self) -> &str {
23        "Get input from the user."
24    }
25
26    fn search_terms(&self) -> Vec<&str> {
27        vec!["prompt", "interactive"]
28    }
29
30    fn signature(&self) -> Signature {
31        Signature::build("input")
32            .input_output_types(vec![(Type::Nothing, Type::Any)])
33            .allow_variants_without_examples(true)
34            .optional("prompt", SyntaxShape::String, "Prompt to show the user.")
35            .named(
36                "bytes-until-any",
37                SyntaxShape::String,
38                "read bytes (not text) until any of the given stop bytes is seen",
39                Some('u'),
40            )
41            .named(
42                "numchar",
43                SyntaxShape::Int,
44                "number of characters to read; suppresses output",
45                Some('n'),
46            )
47            .named(
48                "default",
49                SyntaxShape::String,
50                "default value if no input is provided",
51                Some('d'),
52            )
53            .switch("suppress-output", "don't print keystroke values", Some('s'))
54            .category(Category::Platform)
55    }
56
57    fn run(
58        &self,
59        engine_state: &EngineState,
60        stack: &mut Stack,
61        call: &Call,
62        _input: PipelineData,
63    ) -> Result<PipelineData, ShellError> {
64        let prompt: Option<String> = call.opt(engine_state, stack, 0)?;
65        let bytes_until: Option<String> = call.get_flag(engine_state, stack, "bytes-until-any")?;
66        let suppress_output = call.has_flag(engine_state, stack, "suppress-output")?;
67        let numchar: Option<Spanned<i64>> = call.get_flag(engine_state, stack, "numchar")?;
68        let numchar: Spanned<i64> = numchar.unwrap_or(Spanned {
69            item: i64::MAX,
70            span: call.head,
71        });
72
73        let from_io_error = IoError::factory(call.head, None);
74
75        if numchar.item < 1 {
76            return Err(ShellError::UnsupportedInput {
77                msg: "Number of characters to read has to be positive".to_string(),
78                input: "value originated from here".to_string(),
79                msg_span: call.head,
80                input_span: numchar.span,
81            });
82        }
83
84        let default_val: Option<String> = call.get_flag(engine_state, stack, "default")?;
85        if let Some(prompt) = &prompt {
86            match &default_val {
87                None => print!("{prompt}"),
88                Some(val) => print!("{prompt} (default: {val})"),
89            }
90            let _ = std::io::stdout().flush();
91        }
92
93        let mut buf = String::new();
94
95        crossterm::terminal::enable_raw_mode().map_err(&from_io_error)?;
96        // clear terminal events
97        while crossterm::event::poll(Duration::from_secs(0)).map_err(&from_io_error)? {
98            // If there's an event, read it to remove it from the queue
99            let _ = crossterm::event::read().map_err(&from_io_error)?;
100        }
101
102        loop {
103            if i64::try_from(buf.len()).unwrap_or(0) >= numchar.item {
104                break;
105            }
106            match crossterm::event::read() {
107                Ok(Event::Key(k)) => match k.kind {
108                    KeyEventKind::Press | KeyEventKind::Repeat => {
109                        match k.code {
110                            // TODO: maintain keycode parity with existing command
111                            KeyCode::Char(c) => {
112                                if k.modifiers == KeyModifiers::ALT
113                                    || k.modifiers == KeyModifiers::CONTROL
114                                {
115                                    if k.modifiers == KeyModifiers::CONTROL && c == 'c' {
116                                        crossterm::terminal::disable_raw_mode()
117                                            .map_err(&from_io_error)?;
118                                        return Err(IoError::new(
119                                            std::io::ErrorKind::Interrupted,
120                                            call.head,
121                                            None,
122                                        )
123                                        .into());
124                                    }
125                                    continue;
126                                }
127
128                                if let Some(bytes_until) = bytes_until.as_ref() {
129                                    if bytes_until.bytes().contains(&(c as u8)) {
130                                        break;
131                                    }
132                                }
133                                buf.push(c);
134                            }
135                            KeyCode::Backspace => {
136                                let _ = buf.pop();
137                            }
138                            KeyCode::Enter => {
139                                break;
140                            }
141                            _ => continue,
142                        }
143                    }
144                    _ => continue,
145                },
146                Ok(_) => continue,
147                Err(event_error) => {
148                    crossterm::terminal::disable_raw_mode().map_err(&from_io_error)?;
149                    return Err(from_io_error(event_error).into());
150                }
151            }
152            if !suppress_output {
153                // clear the current line and print the current buffer
154                execute!(
155                    std::io::stdout(),
156                    terminal::Clear(ClearType::CurrentLine),
157                    cursor::MoveToColumn(0),
158                )
159                .map_err(|err| IoError::new(err.kind(), call.head, None))?;
160                if let Some(prompt) = &prompt {
161                    execute!(std::io::stdout(), Print(prompt.to_string()))
162                        .map_err(&from_io_error)?;
163                }
164                execute!(std::io::stdout(), Print(buf.to_string())).map_err(&from_io_error)?;
165            }
166        }
167        crossterm::terminal::disable_raw_mode().map_err(&from_io_error)?;
168        if !suppress_output {
169            std::io::stdout().write_all(b"\n").map_err(&from_io_error)?;
170        }
171        match default_val {
172            Some(val) if buf.is_empty() => Ok(Value::string(val, call.head).into_pipeline_data()),
173            _ => Ok(Value::string(buf, call.head).into_pipeline_data()),
174        }
175    }
176
177    fn examples(&self) -> Vec<Example> {
178        vec![
179            Example {
180                description: "Get input from the user, and assign to a variable",
181                example: "let user_input = (input)",
182                result: None,
183            },
184            Example {
185                description: "Get two characters from the user, and assign to a variable",
186                example: "let user_input = (input --numchar 2)",
187                result: None,
188            },
189            Example {
190                description: "Get input from the user with default value, and assign to a variable",
191                example: "let user_input = (input --default 10)",
192                result: None,
193            },
194        ]
195    }
196}
197
198#[cfg(test)]
199mod tests {
200    use super::Input;
201
202    #[test]
203    fn examples_work_as_expected() {
204        use crate::test_examples;
205        test_examples(Input {})
206    }
207}
nu_command/platform/input/input_.rs

nu_command/platform/input/
input_.rs
