Crate acme_micro[−][src]

Expand description

acme-lib is a library for accessing ACME (Automatic Certificate Management Environment) services such as Let’s Encrypt.

Uses ACME v2 to issue/renew certificates.

Example

use acme_micro::{Error, Certificate, Directory, DirectoryUrl};
use acme_micro::create_p384_key;
use std::time::Duration;

fn request_cert() -> Result<Certificate, Error> {

// Use DirectoryUrl::LetsEncrypStaging for dev/testing.
let url = DirectoryUrl::LetsEncrypt;

// Create a directory entrypoint.
let dir = Directory::from_url(url)?;

// Your contact addresses, note the `mailto:`
let contact = vec!["mailto:foo@bar.com".to_string()];

// Generate a private key and register an account with your ACME provider.
// You should write it to disk any use `load_account` afterwards.
let acc = dir.register_account(contact.clone())?;

// Example of how to load an account from string:
let privkey = acc.acme_private_key_pem()?;
let acc = dir.load_account(&privkey, contact)?;

// Order a new TLS certificate for a domain.
let mut ord_new = acc.new_order("mydomain.io", &[])?;

// If the ownership of the domain(s) have already been
// authorized in a previous order, you might be able to
// skip validation. The ACME API provider decides.
let ord_csr = loop {
    // are we done?
    if let Some(ord_csr) = ord_new.confirm_validations() {
        break ord_csr;
    }

    // Get the possible authorizations (for a single domain
    // this will only be one element).
    let auths = ord_new.authorizations()?;

    // For HTTP, the challenge is a text file that needs to
    // be placed in your web server's root:
    //
    // /var/www/.well-known/acme-challenge/<token>
    //
    // The important thing is that it's accessible over the
    // web for the domain(s) you are trying to get a
    // certificate for:
    //
    // http://mydomain.io/.well-known/acme-challenge/<token>
    let chall = auths[0].http_challenge().unwrap();

    // The token is the filename.
    let token = chall.http_token();
    let path = format!(".well-known/acme-challenge/{}", token);

    // The proof is the contents of the file
    let proof = chall.http_proof()?;

    // Here you must do "something" to place
    // the file/contents in the correct place.
    // update_my_web_server(&path, &proof);

    // After the file is accessible from the web, the calls
    // this to tell the ACME API to start checking the
    // existence of the proof.
    //
    // The order at ACME will change status to either
    // confirm ownership of the domain, or fail due to the
    // not finding the proof. To see the change, we poll
    // the API with 5000 milliseconds wait between.
    chall.validate(Duration::from_millis(5000))?;

    // Update the state against the ACME API.
    ord_new.refresh()?;
};

// Ownership is proven. Create a private key for
// the certificate. These are provided for convenience, you
// can provide your own keypair instead if you want.
let pkey_pri = create_p384_key()?;

// Submit the CSR. This causes the ACME provider to enter a
// state of "processing" that must be polled until the
// certificate is either issued or rejected. Again we poll
// for the status change.
let ord_cert =
    ord_csr.finalize_pkey(pkey_pri, Duration::from_millis(5000))?;

// Now download the certificate. Also stores the cert in
// the persistence.
let cert = ord_cert.download_cert()?;
println!("{:?}", cert);

Ok(cert)
}

Domain ownership

Most website TLS certificates tries to prove ownership/control over the domain they are issued for. For ACME, this means proving you control either a web server answering HTTP requests to the domain, or the DNS server answering name lookups against the domain.

To use this library, there are points in the flow where you would need to modify either the web server or DNS server before progressing to get the certificate.

See http_challenge and dns_challenge.