nettext/src/lib.rs

//! A text-based data format for cryptographic network protocols.
//!
//! ```
//! use nettext::enc::*;
//! use nettext::dec::*;
//! use nettext::crypto::*;
//!
//! let final_payload = {
//!     let keypair = SigningKeyPair::gen_with_defaults();
//!
//!     // Encode a fist object that represents a payload that will be hashed and signed
//!     let signed_payload = seq([
//!         string("CALL").unwrap(),
//!         string("myfunction").unwrap(),
//!         dict([
//!             ("a", string("hello").unwrap()),
//!             ("b", string("world").unwrap()),
//!             ("c", raw(b"{ a = 12; b = 42 }").unwrap()),
//!             ("d", bytes_split(&((0..128u8).collect::<Vec<_>>()))),
//!         ]).unwrap(),
//!         keypair.public_key.term().unwrap(),
//!     ]).unwrap().encode();
//!     eprintln!("{}", std::str::from_utf8(&signed_payload).unwrap());
//!
//!     let hash = compute_hash(&signed_payload, None);
//!     let sign = compute_signature(&signed_payload[..], &keypair.secret_key);
//!
//!     // Encode a second object that represents the signed and hashed payload
//!     dict([
//!         ("hash", hash.term().unwrap()),
//!         ("signature", sign.term().unwrap()),
//!         ("payload", raw(&signed_payload).unwrap()),
//!     ]).unwrap().encode()
//! };
//! eprintln!("{}", std::str::from_utf8(&final_payload).unwrap());
//!
//! // Decode and check everything is fine
//! let signed_object = decode(&final_payload).unwrap();
//! let [hash, signature, payload] = signed_object.dict_of(["hash", "signature", "payload"], false).unwrap();
//! let hash = hash.hash().unwrap();
//! let signature = signature.signature().unwrap();
//! let expected_hash = compute_hash(payload.raw(), None);
//! assert_eq!(hash, expected_hash);
//!
//! let object2 = decode(payload.raw()).unwrap();
//!
//! let [verb, arg1, arg2, pubkey] = object2.seq_of().unwrap();
//! let pubkey = pubkey.public_key().unwrap();
//! assert!(verify_signature(&signature, payload.raw(), &pubkey));
//!
//! assert_eq!(verb.string().unwrap(), "CALL");
//! assert_eq!(arg1.string().unwrap(), "myfunction");
//! ```
//!
//! The value of `signed_payload` would be as follows:
//!
//! ```raw
//! CALL myfunction {
//!     a = hello;
//!     b = world;
//!     c = { a = 12; b = 42 };
//!     d = AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4v
//!       MDEyMzQ1Njc4OTo7PD0-P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5f
//!       YGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn8;
//!   } ZCkE-mTMlK3355u_0UzabRbSNcNO3CWAur7dAhglYtI
//! ```
//!
//! And the value of `final_payload` would be as follows:
//! ```raw
//! {
//!   hash = fTTk8Hm0HLGwaskCIqFBzRVMrVTeXGetmNBK2X3pNyY;
//!   payload = CALL myfunction {
//!     a = hello;
//!     b = world;
//!     c = { a = 12; b = 42 };
//!     d = AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4v
//!       MDEyMzQ1Njc4OTo7PD0-P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5f
//!       YGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn8;
//!   } ZCkE-mTMlK3355u_0UzabRbSNcNO3CWAur7dAhglYtI;
//!   signature = XPMrlhAIMfZb6a5Fh5F_ZaEf61olJ1hK4I2kh7vEPT1n20S-943X5cH35bb0Bfwkvy_ENfOTbb3ep1zn2lSIBg;
//! }
//! ```
//!
//! Note that the value of `text1` is embedded as-is inside `text2`. This is what allows us
//! to check the hash and the signature: the raw representation of the term hasn't changed.

pub mod dec;
pub mod enc;
pub mod switch64;

#[cfg(feature = "dryoc")]
pub mod crypto;

#[cfg(feature = "serde")]
pub mod serde;

/// Possible encodings for byte strings in NetText
#[derive(Clone, Copy)]
pub enum BytesEncoding {
    /// Base64 encoding (default)
    Base64 { split: bool },
    /// Hexadecimal encoding
    Hex { split: bool },
    /// Switch64 encoding, a mix of plain text and base64
    Switch64 { allow_whitespace: bool },
}

impl Default for BytesEncoding {
    fn default() -> Self {
        BytesEncoding::Base64 { split: true }
    }
}

impl BytesEncoding {
    pub fn without_whitespace(&self) -> Self {
        match self {
            BytesEncoding::Base64 { .. } => BytesEncoding::Base64 { split: false },
            BytesEncoding::Hex { .. } => BytesEncoding::Hex { split: false },
            BytesEncoding::Switch64 { .. } => BytesEncoding::Switch64 {
                allow_whitespace: false,
            },
        }
    }
}

// ---- syntactic elements of the data format ----

pub(crate) const DICT_OPEN: u8 = b'{';
pub(crate) const DICT_CLOSE: u8 = b'}';
pub(crate) const DICT_ASSIGN: u8 = b'=';
pub(crate) const DICT_DELIM: u8 = b';';
pub(crate) const LIST_OPEN: u8 = b'[';
pub(crate) const LIST_CLOSE: u8 = b']';
pub(crate) const LIST_DELIM: u8 = b';';
const BASE_EXTRA_CHARS: &[u8] = b".,:?!@$^<>|&#'_-+*/%";
const STR_EXTRA_CHARS: &[u8] = b"\\";

pub(crate) const SWITCH64_SEPARATOR: u8 = b'\\';
pub(crate) const SWITCH64_EXTRA_CHARS: &[u8] = BASE_EXTRA_CHARS;

#[inline]
pub(crate) fn is_string_char(c: u8) -> bool {
    c.is_ascii_alphanumeric() || BASE_EXTRA_CHARS.contains(&c) || STR_EXTRA_CHARS.contains(&c)
}

#[inline]
pub(crate) fn is_whitespace(c: u8) -> bool {
    c.is_ascii_whitespace()
}

pub(crate) fn debug(x: &[u8]) -> &str {
    std::str::from_utf8(x).unwrap_or("<invalid ascii>")
}