The Perl Toolchain Summit needs more sponsors. If your company depends on Perl, please support this very important event.
 / 
Net-ACME-0.093
River stage zero No dependents
2 ++
/ Net::ACME

NAME

Net::ACME - Client for the ACME protocol (e.g., Let’s Encrypt)

SYNOPSIS

    package MyACME::SomeService;

    sub _HOST { }   #return the name of the ACME host

    #See below for full examples.

DESCRIPTION

This module implements client logic for the ACME protocol, the system for automated issuance of SSL certificates used by Let’s Encrypt.

The methods of this class return objects that correspond to the respective ACME resource:

  • register(): Net::ACME::Registration

  • start_domain_authz(): Net::ACME::Authorization::Pending

  • get_certificate(): Net::ACME::Certificate or Net::ACME::Certificate::Pending

WHY USE THIS MODULE?

  • Closely based on cPanel’s widely used Let’s Encrypt plugin.

  • Thorough error-checking: any deviation from what the ACME protocol expects is reported immediately via an exception.

  • Well-defined object system, including typed, queryable exceptions.

  • Extensive test coverage.

  • Light memory footprint - no Moose/Moo/etc.

  • No careless overwriting of globals like $@, $!, and $?. (Hopefully your code isn’t susceptible to this anyway, but it’s just a good precaution.)

  • All dependencies are either core or pure Perl. For RSA crypto we use Crypt::OpenSSL::RSA if it’s available, or the system’s openssl binary. Net::ACME will run almost anywhere!

STATUS

This module is now well-tested and should be safe for use in your application.

CUSTOMIZATION

OpenSSL: This module will attempt to use Crypt::OpenSSL::RSA if it is available; if not, it falls back to the openssl binary. On most systems this should already be in the process’s search path, but if not, specify the binary’s location by setting $Net::ACME::Crypt::OPENSSL_BIN_PATH.

HTTPS options: This module uses HTTP::Tiny for its network operations. In some instances it is desirable to specify custom SSL_options in that module’s constructor; to do this, populate @Net::ACME::HTTP_Tiny::SSL_OPTIONS.

URI vs. URL

This module uses “uri” for ACME-related objects and “url” for HTTP-related ones. This apparent conflict is a result of maintaining consistency with both the ACME specification (“uri”) and HTTP::Tiny (“url”).

EXAMPLES

See the examples directory in the distribution for complete, interactive example scripts that also illustrate a bit of how ACME works.

See below for cut-paste-y examples.

EXAMPLE: REGISTRATION

    my $tos_url = Net::ACME::LetsEncrypt->get_terms_of_service();

    my $acme = Net::ACME::LetsEncrypt->new( key => $reg_rsa_pem );

    #Use this method any time you want to update contact information,
    #not just when you set up a new account.
    my $reg = $acme->register('mailto:who.am@i.tld', 'mailto:who@else.tld');

    $acme->accept_tos( $reg->uri(), $tos_url );

EXAMPLE: DOMAIN AUTHORIZATION & CERTIFICATE PROCUREMENT

    for my $domain (@domains) {
        my $authz_p = $acme->start_domain_authz($domain);

        for my $cmb_ar ( $authz_p->combinations() ) {

            #$cmb_ar is a set of challenges that the ACME server will
            #accept as proof of domain control. As of November 2016, these
            #sets all contain exactly one challenge each: “http-01”, etc.

            #Each member of @$cmb_ar is an instance of
            #Net::ACME::Challenge::Pending--maybe a subclass thereof such as
            #Net::ACME::Challenge::Pending::http_01.

            #At this point, you examine $cmb_ar and determine if this
            #combination is one that you’re interested in. You might try
            #something like:
            #
            #   next if @$cmb_ar > 1;
            #   next if $cmb_ar->[0]->type() ne 'http-01';

            #Once you’ve examined $cmb_ar and set up the appropriate response(s),
            #it’s time to tell the ACME server to send its challenge query.
            $acme->do_challenge($_) for @$cmb_ar;

            while (1) {
                if ( $authz_p->is_time_to_poll() ) {
                    my $poll = $authz_p->poll();

                    last if $poll->status() eq 'valid';

                    if ( $poll->status() eq 'invalid' ) {
                        my @failed = grep { $_->error() } $poll->challenges();

                        warn $_->to_string() . $/ for @failed;

                        die "Failed authorization for “$domain”!";
                    }

                }

                sleep 1;
            }
        }
    }

    #Make a key and CSR.
    #Creation of CSRs is well-documented so won’t be discussed here.

    my $cert = $acme->get_certificate($csr_pem);

    #This shouldn’t actually be necessary for Let’s Encrypt,
    #but the ACME protocol describes it.
    while ( !$cert->pem() ) {
        sleep 1;
        next if !$cert->is_time_to_poll();
        $cert = $cert->poll() || $cert;
    }

TODO

  • Find a way to sign with RSA in pure Perl. (NB: Crypt::RSA has XS dependencies.)

  • Support EC keys.

  • Test and support more ACME v2 features (pending server support).

THANKS

  • cPanel, Inc. for permission to adapt their ACME framework for public consumption.

  • Stephen Ludin for developing and maintaining Protocol::ACME, from which this module took its inspiration.

SEE ALSO

I am aware of the following additional CPAN modules that implement this protocol:

REPOSITORY (FEEDBACK/BUGS)

https://github.com/FGasper/p5-Net-ACME

AUTHOR

Felipe Gasper (FELIPE)

LICENSE

This module is licensed under the same terms as Perl.