nu_command/network/
port.rs

1use nu_engine::command_prelude::*;
2use nu_protocol::shell_error::io::IoError;
3
4use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, TcpListener};
5
6#[derive(Clone)]
7pub struct Port;
8
9impl Command for Port {
10    fn name(&self) -> &str {
11        "port"
12    }
13
14    fn signature(&self) -> Signature {
15        Signature::build("port")
16            .input_output_types(vec![(Type::Nothing, Type::Int)])
17            .optional(
18                "start",
19                SyntaxShape::Int,
20                "The start port to scan (inclusive).",
21            )
22            .optional("end", SyntaxShape::Int, "The end port to scan (inclusive).")
23            .category(Category::Network)
24    }
25
26    fn description(&self) -> &str {
27        "Get a free port from system."
28    }
29
30    fn search_terms(&self) -> Vec<&str> {
31        vec!["network", "http"]
32    }
33
34    fn run(
35        &self,
36        engine_state: &EngineState,
37        stack: &mut Stack,
38        call: &Call,
39        _input: PipelineData,
40    ) -> Result<PipelineData, ShellError> {
41        get_free_port(engine_state, stack, call)
42    }
43
44    fn examples(&self) -> Vec<Example> {
45        vec![
46            Example {
47                description: "get a free port between 3121 and 4000",
48                example: "port 3121 4000",
49                result: Some(Value::test_int(3121)),
50            },
51            Example {
52                description: "get a free port from system",
53                example: "port",
54                result: None,
55            },
56        ]
57    }
58}
59
60fn get_free_port(
61    engine_state: &EngineState,
62    stack: &mut Stack,
63    call: &Call,
64) -> Result<PipelineData, ShellError> {
65    let from_io_error = IoError::factory(call.head, None);
66
67    let start_port: Option<Spanned<usize>> = call.opt(engine_state, stack, 0)?;
68    let end_port: Option<Spanned<usize>> = call.opt(engine_state, stack, 1)?;
69
70    let listener = if start_port.is_none() && end_port.is_none() {
71        // get free port from system.
72        TcpListener::bind("127.0.0.1:0").map_err(&from_io_error)?
73    } else {
74        let (start_port, start_span) = match start_port {
75            Some(p) => (p.item, Some(p.span)),
76            None => (1024, None),
77        };
78
79        let start_port = match u16::try_from(start_port) {
80            Ok(p) => p,
81            Err(e) => {
82                return Err(ShellError::CantConvert {
83                    to_type: "u16".into(),
84                    from_type: "usize".into(),
85                    span: start_span.unwrap_or(call.head),
86                    help: Some(format!("{e} (min: {}, max: {})", u16::MIN, u16::MAX)),
87                });
88            }
89        };
90
91        let (end_port, end_span) = match end_port {
92            Some(p) => (p.item, Some(p.span)),
93            None => (65535, None),
94        };
95
96        let end_port = match u16::try_from(end_port) {
97            Ok(p) => p,
98            Err(e) => {
99                return Err(ShellError::CantConvert {
100                    to_type: "u16".into(),
101                    from_type: "usize".into(),
102                    span: end_span.unwrap_or(call.head),
103                    help: Some(format!("{e} (min: {}, max: {})", u16::MIN, u16::MAX)),
104                });
105            }
106        };
107
108        let range_span = match (start_span, end_span) {
109            (Some(start), Some(end)) => Span::new(start.start, end.end),
110            (Some(start), None) => start,
111            (None, Some(end)) => end,
112            (None, None) => call.head,
113        };
114
115        // check input range valid.
116        if start_port > end_port {
117            return Err(ShellError::InvalidRange {
118                left_flank: start_port.to_string(),
119                right_flank: end_port.to_string(),
120                span: range_span,
121            });
122        }
123
124        'search: {
125            let mut last_err = None;
126            for port in start_port..=end_port {
127                let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::LOCALHOST, port));
128                match TcpListener::bind(addr) {
129                    Ok(listener) => break 'search Ok(listener),
130                    Err(err) => last_err = Some(err),
131                }
132            }
133
134            Err(IoError::new_with_additional_context(
135                last_err.expect("range not empty, validated before"),
136                range_span,
137                None,
138                "Every port has been tried, but no valid one was found",
139            ))
140        }?
141    };
142
143    let free_port = listener.local_addr().map_err(&from_io_error)?.port();
144    Ok(Value::int(free_port as i64, call.head).into_pipeline_data())
145}
nu_command/network/port.rs

nu_command/network/
port.rs
