2 unstable releases

Uses new Rust 2021

0.2.0 Sep 7, 2022
0.1.0 Aug 26, 2022

#389 in Cryptography

37 downloads per month

MIT/Apache

28KB
447 lines

clap-digest

Integration to choose digest with clap on a CLI.

Features

  1. A clap::ValueEnum implementation for the different digest algorithm types:

    use clap::builder::{Arg, EnumValueParser};
    use clap_digest::Digest;
    
    Arg::new("digest")
        .takes_value(true)
        .value_parser(EnumValueParser::<Digest>::new())
    
  2. Ready-to-use clap::Arg implementations:

    use clap::{Command, ValueEnum};
    use clap_digest::{Digest, DynDigest};
    
    let cli = Command::new("myapp")
        .arg(clap_digest::arg::digest().required_unless_present("list-digests"))
        .arg(clap_digest::arg::list_digests());
    
    let args = cli.get_matches_from(["myapp", "--list-digests"]);
    
    if args.contains_id("list-digests") {
        for digest in Digest::value_variants() {
            println!("{digest}");
        }
    } else {
        let digest = *args
            .get_one::<Digest>("digest")
            .expect("has default via clap");
    
        todo!()
    }
    

    See the clap_digest::arg module for more information.

  3. A conversion from clap_digest::Digest to digest::DynDigest:

    use clap_digest::{Digest, DynDigest};
    
    // fn doing some hashing, using any DynDigest implementation
    fn dyn_hash(hasher: &mut dyn DynDigest, data: &[u8]) -> String {
        hasher.update(data);
        let hash = hasher.finalize_reset();
        hash.iter().map(|byte| format!("{:02x}", byte)).collect()
    }
    
    // parse user-supplied CLI input to clap_digest::Digest with clap
    // suppose user runs this with: `command --digest MD5`
    // let args = cli.get_matches();
    let digest = *args.get_one::<Digest>("digest").unwrap();
    
    // convert to DynDigest
    let mut digest: Box<dyn DynDigest> = digest.into();
    
    // use with hashing function
    let hash = dyn_hash(&mut (*digest), b"foo");
    
    assert_eq!(hash, "acbd18db4cc2f85cedef654fccc4a4d8");
    
  4. Digest algorithm groups are feature-gated. Use cargo feature clap-digest for a complete listing. At least one digest algorithm group feature must be chosen. To limit the digest algorithm families you want to support in your crate, define your own features, e.g.:

    [features]
    default = ["sha2"]
    md5 = ["clap-digest/md5"]
    sha1 = ["clap-digest/sha1"]
    sha2 = ["clap-digest/sha2"]
    

Example

For a complete CLI example, see examples/cksum.rs.

$ cargo run --example cksum -- -d SHA1 Cargo.toml
7a96ee85606435fe1f39c3fa6bdf4cf9bbbc338c  Cargo.toml

$ sha1sum Cargo.toml
7a96ee85606435fe1f39c3fa6bdf4cf9bbbc338c  Cargo.toml

$ cargo run --example cksum -- -d MD5 Cargo.toml | md5sum -c
Cargo.toml: OK

List all supported algorithms:

$ cargo run --example cksum -- --list-digests
BLAKE2b512
BLAKE2s256
BLAKE3
...

All algorithm groups are feature-gated, so you can choose:

$ cargo run --example cksum --no-default-features --features md5,sha1,sha2 -- --list-digests
MD5
SHA1
SHA224
SHA256
SHA384
SHA512
SHA512/224
SHA512/256

Dependencies

~5.5MB
~91K SLoC