The rust library hcaptcha is used with your backend service to verify the hcaptcha response provided from the client.

Contributions are welcome — please see the Contributing Guide and our Governance.

• Reproducible builds: see docs/REPRODUCIBLE_BUILDS.md

To use hcaptcha, add the following to your Cargo.toml:

[dependencies]
hcaptcha = "3.2.4"

Minimal example verifying a client token on your backend:

use hcaptcha::{Client, Request};

#[tokio::main]
async fn main() -> Result<(), hcaptcha::Error> {
    // Get the secret from your config/secret manager
    let secret = "0x123456789abcde0f123456789abcdef012345678".to_string();
    // Token comes from the client
    let token = "client-response-token".to_string();

let request = Request::new_from_response(&secret, &token)?;
    let client = Client::new();

    // This will call the hCaptcha API
    // In tests/examples, prefer mocking the network
    let _response = client.verify(request).await?;
    Ok(())
}

• The Hcaptcha prefix has been removed from all types.
• The default feature now uses rustls-backend and not the nativetls-backend.
• The verify_client_response method has been deprecated in favour or the verify method.

Derive a validation method on the data structure representing your data, marking the captcha components in the data structure.

# use hcaptcha::Hcaptcha;

#[derive(Debug, Deserialize, Hcaptcha)]
pub struct ContactForm {
    name: String,
    phone: String,
    email: String,
    message: String,
    #[captcha]
    token: String,
}

Validate the captcha data.

    # #[tokio::main]
    # async main() -> Result<(), Box<dyn std::error::Error>> {
    let contact_form: ContactForm = serde_json::from_str(e.body_string())?;
    contact_form.valid_response(&secret, None).await?;
    # }
    # fn get_your_secret() -> String {
    #   "0x123456789abcde0f123456789abcdef012345678".to_string()
    # }

See the examples folder for an AWS Lambda contact form example.

Hcaptcha has been tested in a web assembly project using wasm-bindgen and node.

See the hcaptcha-wasm example for a sample project which can be run using wasm-pack test --node.

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Initial version based on recaptcha-rs by panicbit.