helpers4 0.0.3

General-purpose Rust helpers, one crate, one feature per module (string, array, ...)
Documentation

Pre-1.0 (0.x). While the crate is at version 0, how the helpers are split into modules — and therefore into Cargo features — may change between releases, and the code-quality and security checks will keep improving. Do not use it in production for critical or sensitive applications until 1.0, which waits for independent security audits. Pin the exact version and read the changelog before upgrading.

Overview

helpers4 is a collection of small, typed helpers for the everyday code every project ends up rewriting: string casing, slice operations, expiring caches, hex, network checks, and more. Each helper does one thing, returns a typed error instead of panicking, and ships with tests and a runnable example.

Modules

One module per category, each behind a Cargo feature of the same name (all enabled by default):

Module What it covers
string case conversion, slugs, truncation, indentation, whitespace, HTML escaping
array unique, difference, intersection, grouping, counting, duplicates, interleaving
number interpolation, rounding, mean, median, percentages, gcd and lcm
cache maps and sets whose entries expire, with the clock passed in
env reading and editing .env files as text
hex hexadecimal encoding and decoding with typed errors
net is this IP address public (an SSRF guard), is this a valid hostname
http extracting a bearer token from an Authorization header
time the system clock as unix time, without a silent 0

More are planned (random values and identifiers, validation, iterators, maps and sets, durations, …): see the roadmap.

Quick start

cargo add helpers4                                              # every module
cargo add helpers4 --no-default-features --features string,hex  # only what you use

use helpers4::hex;
use helpers4::net::is_public_ip;
use helpers4::string::slugify;

assert_eq!(slugify("Hello, World!"), "hello-world");
assert_eq!(hex::encode(&[0xde, 0xad, 0xbe, 0xef]), "deadbeef");
assert!(!is_public_ip("169.254.169.254".parse().unwrap())); // the cloud metadata address

Names can repeat across modules, so always go through the module path (helpers4::string::capitalize) and never glob-import a module.

Key features

  • Zero dependencies by default: a module that needs one gets its own optional feature
  • Take only what you use: one Cargo feature per module, so unused modules are not compiled
  • Typed errors instead of panics: unsafe is forbidden, and unwrap, expect and panic! are denied outside tests
  • Explicit inputs: the clock and the process environment are parameters, never ambient
  • Standard library first: nothing here duplicates what std already offers
  • Fully tested: 100% coverage of lines, functions and regions, unit tests, property-based tests, doc tests, mutation testing and benchmarks, all enforced or tracked in CI
  • AI-ready: llms.txt describes every module, and every example is a doc test

Documentation

Every helper, with its signature, parameters, errors and examples, is on helpers4.dev/rust and on docs.rs.

Development

cargo test --all-features                       # unit, property and doc tests
cargo clippy --all-targets --all-features -- -D warnings
cargo llvm-cov --all-features --ignore-filename-regex '\.(test|spec|bench)\.rs$'
cargo bench --all-features

See AGENTS.md for the layout and rules, and CONTRIBUTING.md for how to add a helper or a module.

Contributing

Contributions are welcome! Please read CONTRIBUTING.md and the organization's Contributing Guide.

  1. Fork the repository
  2. Create a feature branch (git checkout -b feat/amazing-feature)
  3. Commit your changes following Conventional Commits
  4. Push to the branch and open a Pull Request

To report a vulnerability, see SECURITY.md.

License

Licensed under the GNU Lesser General Public License v3.0 or later: you can freely use it in proprietary or open-source projects.