nu_plugin_core/serializers/
msgpack.rs

1use std::io::ErrorKind;
2
3use nu_plugin_protocol::{PluginInput, PluginOutput};
4use nu_protocol::{shell_error::io::IoError, ShellError};
5use serde::Deserialize;
6
7use crate::{Encoder, PluginEncoder};
8
9/// A `PluginEncoder` that enables the plugin to communicate with Nushell with MsgPack
10/// serialized data.
11///
12/// Each message is written as a MessagePack object. There is no message envelope or separator.
13#[derive(Clone, Copy, Debug)]
14pub struct MsgPackSerializer;
15
16impl PluginEncoder for MsgPackSerializer {
17    fn name(&self) -> &str {
18        "msgpack"
19    }
20}
21
22impl Encoder<PluginInput> for MsgPackSerializer {
23    fn encode(
24        &self,
25        plugin_input: &PluginInput,
26        writer: &mut impl std::io::Write,
27    ) -> Result<(), nu_protocol::ShellError> {
28        rmp_serde::encode::write_named(writer, plugin_input).map_err(rmp_encode_err)
29    }
30
31    fn decode(
32        &self,
33        reader: &mut impl std::io::BufRead,
34    ) -> Result<Option<PluginInput>, ShellError> {
35        let mut de = rmp_serde::Deserializer::new(reader);
36        PluginInput::deserialize(&mut de)
37            .map(Some)
38            .or_else(rmp_decode_err)
39    }
40}
41
42impl Encoder<PluginOutput> for MsgPackSerializer {
43    fn encode(
44        &self,
45        plugin_output: &PluginOutput,
46        writer: &mut impl std::io::Write,
47    ) -> Result<(), ShellError> {
48        rmp_serde::encode::write_named(writer, plugin_output).map_err(rmp_encode_err)
49    }
50
51    fn decode(
52        &self,
53        reader: &mut impl std::io::BufRead,
54    ) -> Result<Option<PluginOutput>, ShellError> {
55        let mut de = rmp_serde::Deserializer::new(reader);
56        PluginOutput::deserialize(&mut de)
57            .map(Some)
58            .or_else(rmp_decode_err)
59    }
60}
61
62/// Handle a msgpack encode error
63fn rmp_encode_err(err: rmp_serde::encode::Error) -> ShellError {
64    match err {
65        rmp_serde::encode::Error::InvalidValueWrite(_) => {
66            // I/O error
67            ShellError::Io(IoError::new_internal(
68                // TODO: get a better kind here
69                std::io::ErrorKind::Other,
70                "Could not encode with rmp",
71                nu_protocol::location!(),
72            ))
73        }
74        _ => {
75            // Something else
76            ShellError::PluginFailedToEncode {
77                msg: err.to_string(),
78            }
79        }
80    }
81}
82
83/// Handle a msgpack decode error. Returns `Ok(None)` on eof
84fn rmp_decode_err<T>(err: rmp_serde::decode::Error) -> Result<Option<T>, ShellError> {
85    match err {
86        rmp_serde::decode::Error::InvalidMarkerRead(err)
87        | rmp_serde::decode::Error::InvalidDataRead(err) => {
88            if matches!(err.kind(), ErrorKind::UnexpectedEof) {
89                // EOF
90                Ok(None)
91            } else {
92                // I/O error
93                Err(ShellError::Io(IoError::new_internal(
94                    // TODO: get a better kind here
95                    std::io::ErrorKind::Other,
96                    "Could not decode with rmp",
97                    nu_protocol::location!(),
98                )))
99            }
100        }
101        _ => {
102            // Something else
103            Err(ShellError::PluginFailedToDecode {
104                msg: err.to_string(),
105            })
106        }
107    }
108}
109
110#[cfg(test)]
111mod tests {
112    use super::*;
113    crate::serializers::tests::generate_tests!(MsgPackSerializer {});
114}
nu_plugin_core/serializers/msgpack.rs

nu_plugin_core/serializers/
msgpack.rs
