asimov_patterns/programs/
fetcher.rs

1// This is free and unencumbered software released into the public domain.
2
3//! URL-to-RDF retrieval: the fetcher marker trait and options.
4
5#![allow(unused)]
6
7use crate::Execute;
8use alloc::{string::String, vec::Vec};
9use bon::Builder;
10
11const HELP_OUTPUT: &str = r#"The output format."#;
12
13/// A URL protocol client that retrieves one resource and represents it as RDF.
14///
15/// The program defines supported URL schemes and the mapping from retrieved
16/// content to RDF. A single resource may produce many RDF statements. Returning
17/// arbitrary response bytes alone does not fulfill the RDF output contract.
18///
19/// # Command-line contract
20///
21/// `PROGRAM [OPTIONS] INPUT-URL`
22///
23/// One absolute URL is required as a single argument; it is not a stdin
24/// payload or an implicitly converted local pathname. RDF is written to stdout
25/// using [`FetcherOptions::output`] (`jsonl` by default). The program validates
26/// the URL and rejects unsupported schemes.
27///
28/// `T` is the implementation's result representation. Retrieval, redirects,
29/// authentication, caching, and resource-to-RDF mapping belong to the program.
30/// See [`crate::programs`] for links to concrete execution behavior and the
31/// [fetcher specification][spec].
32///
33/// [spec]: https://asimov-specs.github.io/program-patterns/#fetcher
34pub trait Fetcher<T>: Execute<T> {}
35
36/// Output-format selection and additional arguments for a [`Fetcher`].
37///
38/// The URL is supplied separately by the implementation's invocation API.
39/// `Default` leaves optional fields unset and `other` empty; format support and
40/// URL validity are not checked by this configuration type. A host can flatten
41/// [`crate::CachingOptions`], [`crate::FilteringOptions`], and
42/// [`crate::TimingOptions`] alongside this type for shared caching, output
43/// filtering, and execution timing arguments.
44///
45/// # Examples
46///
47/// ```rust
48/// use asimov_patterns::FetcherOptions;
49///
50/// let options = FetcherOptions::builder()
51///     .output("jsonl")
52///     .build();
53/// ```
54#[derive(Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Builder)]
55#[builder(derive(Debug), on(String, into))]
56#[cfg_attr(feature = "clap", derive(clap::Args))]
57#[cfg_attr(feature = "clap", command(about = None, long_about = None))]
58pub struct FetcherOptions {
59    /// Additional arguments placed after generated options and before the URL.
60    ///
61    /// Each string is one literal argument, without shell expansion. The runner
62    /// supplies the URL separately; do not duplicate it here. See [`crate::programs`].
63    #[builder(field)]
64    #[cfg_attr(feature = "clap", clap(skip))]
65    pub other: Vec<String>,
66
67    /// The output format.
68    ///
69    /// RDF serialization passed as `--output=FORMAT` (`-o` in the CLI).
70    ///
71    /// `None` omits the option; the specified program default is `jsonl`.
72    /// This names a serialization, not a file or a raw-response retrieval mode.
73    #[cfg_attr(
74        feature = "clap",
75        clap(
76            value_name = "FORMAT",
77            short = 'o',
78            long,
79            help = HELP_OUTPUT,
80            long_help = HELP_OUTPUT
81        )
82    )]
83    pub output: Option<String>,
84}
85
86impl<S: fetcher_options_builder::State> FetcherOptionsBuilder<S> {
87    /// Appends one literal argument to [`FetcherOptions::other`], preserving order.
88    pub fn other(mut self, flag: impl Into<String>) -> Self {
89        self.other.push(flag.into());
90        self
91    }
92
93    /// Appends a present argument to [`FetcherOptions::other`]; `None` adds nothing.
94    pub fn maybe_other(mut self, flag: Option<impl Into<String>>) -> Self {
95        if let Some(flag) = flag {
96            self.other.push(flag.into());
97        }
98        self
99    }
100}
asimov_patterns/programs/fetcher.rs

asimov_patterns/programs/
fetcher.rs
