faker_rand

faker_rand is a Rust crate that lets you easily generate fake data using the rand crate. It also provides macros so you can easily build your own data generators on top of those provided out of the box.

Installation

You can use faker_rand in your Rust project by adding the following to your Cargo.toml:

faker_rand = "0.1"

Usage

See the docs on docs.rs for more details, but at a high level here's how you can use this crate:

use rand::Rng;
use faker_rand::en_us::names::FirstName;

// you can display generators using "{}"
println!("random first name: {}", rand::random::<FirstName>());
println!("random first name: {}", rand::thread_rng().gen::<FirstName>());

// or, you can use to_string as well
let name = rand::random::<FirstName>().to_string();
println!("random first name: {}", name);

You can also build your own generators on top of those provided by this crate, for example if you already have a file of fake data you'd like to generate:

use faker_rand::faker_impl_from_file;

// First, declare your newtype wrapper around String.
struct Demo(String);

// Then, use the macro. data/lorem_words is a path to a file containing
// example words; you will need to change this path to suit your needs.
faker_impl_from_file!(Demo, "data/lorem_words");

use rand::{Rng, SeedableRng};
let mut rng = rand_chacha::ChaCha8Rng::seed_from_u64(0);

assert_eq!("impedit", rng.gen::<Demo>().to_string());

Or, if you want to compose upon sub-generators:

use faker_rand::faker_impl_from_templates;

// First, declare your newtype wrapper around String.
struct Demo(String);

// Then, invoke the macro.
//
// Note well: all commas and semicolons in this example, even trailing
// semicolons, are strictly required.
faker_impl_from_templates! {
    // The type we're creating a generator implementation for.
    Demo;

    // The template patterns.
    "{}.{}", faker_rand::util::AsciiDigit, faker_rand::lorem::Word;
    "{} ~~~ {}", faker_rand::lorem::Word, faker_rand::util::AsciiDigit;
}

use rand::{Rng, SeedableRng};
let mut rng = rand_chacha::ChaCha8Rng::seed_from_u64(0);

assert_eq!("qui ~~~ 5", rng.gen::<Demo>().to_string());
assert_eq!("debitis ~~~ 5", rng.gen::<Demo>().to_string());
assert_eq!("5.aliquid", rng.gen::<Demo>().to_string());
assert_eq!("0.doloribus", rng.gen::<Demo>().to_string());

Most of the documentation for this crate lives in the Rust docs, not this README. Check out https://docs.rs/faker_rand for copy-pastable examples you can use.

Prior Art

If you're considering using this crate, please be aware of prior art in this space. The most widely-used alternative to this crate is fake.

faker_rand was created because the author needed:

1. Types that specifically implemented rand's Distribution trait (to take advantage of blanket Distribution implementations). fake instead uses a custom Faker trait, and drives its own calls to rand, whereas faker_rand has rand call into it.

2. Macros for creating custom data fakers, making it easier to create one-off data generators without having to write much code.

3. Something with few moving parts (faker_rand exposes no new traits or functions, only types that implement existing traits), so that generators are consistent to use and document.

The biggest shortcoming to this crate as opposed to fake is that fake has more data generators than faker_rand. If there is a data generator you'd like in faker_rand that is not currently available, please open an issue on GitHub!