xs/nu/commands/
cat_command.rs

1use nu_engine::CallExt;
2use nu_protocol::engine::{Call, Command, EngineState, Stack};
3use nu_protocol::shell_error::generic::GenericError;
4use nu_protocol::{Category, PipelineData, ShellError, Signature, SyntaxShape, Type};
5
6use crate::store::{ReadOptions, Store};
7
8#[derive(Clone)]
9pub struct CatCommand {
10    store: Store,
11}
12
13impl CatCommand {
14    pub fn new(store: Store) -> Self {
15        Self { store }
16    }
17}
18
19impl Command for CatCommand {
20    fn name(&self) -> &str {
21        ".cat"
22    }
23
24    fn signature(&self) -> Signature {
25        Signature::build(".cat")
26            .input_output_types(vec![(Type::Nothing, Type::Any)])
27            .named(
28                "limit",
29                SyntaxShape::Int,
30                "limit the number of frames to retrieve",
31                None,
32            )
33            .named(
34                "after",
35                SyntaxShape::String,
36                "start after a specific frame ID (exclusive)",
37                Some('a'),
38            )
39            .named(
40                "from",
41                SyntaxShape::String,
42                "start from a specific frame ID (inclusive)",
43                None,
44            )
45            .named(
46                "last",
47                SyntaxShape::Int,
48                "return the N most recent frames",
49                None,
50            )
51            .named("topic", SyntaxShape::String, "filter by topic", Some('T'))
52            .switch(
53                "with-timestamp",
54                "include timestamp extracted from frame ID",
55                None,
56            )
57            .category(Category::Experimental)
58    }
59
60    fn description(&self) -> &str {
61        "Reads the event stream and returns frames"
62    }
63
64    fn run(
65        &self,
66        engine_state: &EngineState,
67        stack: &mut Stack,
68        call: &Call,
69        _input: PipelineData,
70    ) -> Result<PipelineData, ShellError> {
71        let limit: Option<usize> = call.get_flag(engine_state, stack, "limit")?;
72        let last: Option<usize> = call.get_flag(engine_state, stack, "last")?;
73        let after: Option<String> = call.get_flag(engine_state, stack, "after")?;
74        let from: Option<String> = call.get_flag(engine_state, stack, "from")?;
75        let topic: Option<String> = call.get_flag(engine_state, stack, "topic")?;
76        let with_timestamp = call.has_flag(engine_state, stack, "with-timestamp")?;
77
78        // Helper to parse Scru128Id
79        let parse_id = |s: &str, name: &str| -> Result<scru128::Scru128Id, ShellError> {
80            s.parse().map_err(|e| {
81                ShellError::Generic(GenericError::new(
82                    format!("Invalid {name}"),
83                    format!("Failed to parse Scru128Id: {e}"),
84                    call.head,
85                ))
86            })
87        };
88
89        let after: Option<scru128::Scru128Id> =
90            after.as_deref().map(|s| parse_id(s, "after")).transpose()?;
91        let from: Option<scru128::Scru128Id> =
92            from.as_deref().map(|s| parse_id(s, "from")).transpose()?;
93
94        let options = ReadOptions::builder()
95            .maybe_after(after)
96            .maybe_from(from)
97            .maybe_limit(limit)
98            .maybe_last(last)
99            .maybe_topic(topic)
100            .build();
101
102        let frames: Vec<_> = self.store.read_sync(options).collect();
103
104        use nu_protocol::Value;
105
106        let output = Value::list(
107            frames
108                .into_iter()
109                .map(|frame| crate::nu::util::frame_to_value(&frame, call.head, with_timestamp))
110                .collect(),
111            call.head,
112        );
113
114        Ok(PipelineData::Value(output, None))
115    }
116}
xs/nu/commands/cat_command.rs

xs/nu/commands/
cat_command.rs
