# NAME Data::Validate::Domain - Domain and host name validation # VERSION version 0.15 # SYNOPSIS use Data::Validate::Domain qw(is_domain); # as a function my $test = is_domain($suspect); die "$test is not a domain" unless $test; # or die "$test is not a domain" unless is_domain($suspect, \%options); # or as an object my $v = Data::Validate::Domain->new(%options); die "$test is not a domain" unless $v->is_domain($suspect); # DESCRIPTION This module offers a few subroutines for validating domain and host names. # FUNCTIONS All of the functions below are exported by default. All of the functions return an untainted value on success and a false value (`undef` or an empty list) on failure. In scalar context, you should check that the return value is defined, because something like `is_domain_label('0')` will return a defined but false value. The value to test is always the first (and often only) argument. Note that none of these functions test whether a domain or hostname is actually resolvable or reachable. ## Data::Validate::Domain->new() This method constructs a validation object. It accepts the following arguments: - domain\_allow\_underscore According to RFC underscores are forbidden in hostnames but not domain names. By default `is_domain()`, `is_domain_label()`, and `is_hostname()` will fail if the value to be checked includes underscores. Setting this to a true value will allow the use of underscores in all functions. - domain\_allow\_single\_label By default `is_domain()` will fail if you ask it to verify a domain that only has a single label i.e. "neely.cx" is good, but "com" would fail. If you set this option to a true value then `is_domain()` will allow single label domains through. This is most likely to be useful in combination with the `domain_private_tld` argument. - domain\_disable\_tld\_validation Disables TLD validation for `is_domain()`. This may be useful if you need to check domains with new gTLDs that have not yet been added to [Net::Domain::TLD](https://metacpan.org/pod/Net%3A%3ADomain%3A%3ATLD). - domain\_private\_tld By default `is_domain()` requires all domains to have a valid public TLD (i.e. com, net, org, uk, etc). This is verified using the [Net::Domain::TLD](https://metacpan.org/pod/Net%3A%3ADomain%3A%3ATLD) module. This behavior can be extended in two different ways. You can provide either a hash reference where additional TLDs are keys or you can supply a regular expression. NOTE: The TLD is normalized to the lower case form prior to the check being done. This is done only for the TLD check, and does not alter the output in any way. Hashref example: domain_private_tld => { privatetld1 => 1, privatetld2 => 1, } Regular expression example: domain_private_tld => qr /^(?:privatetld1|privatetld2)$/, ## is\_domain($domain, \\%options) This can be called as either a subroutine or a method. If called as a sub, you can pass any of the arguments accepted by the constructor as options. If called as a method, any additional options are ignored. This returns the untainted domain name if the given `$domain` is a valid domain. A dotted quad (such as 127.0.0.1) is not considered a domain and will return false. See [Data::Validate::IP](https://metacpan.org/pod/Data%3A%3AValidate%3A%3AIP) for IP Validation. Per RFC 1035, this sub does accept a value ending in a single period (i.e. "domain.com.") to be a valid domain. This is called an absolute domain name, and should be properly resolved by any DNS tool (tested with `dig`, `ssh`, and [Net::DNS](https://metacpan.org/pod/Net%3A%3ADNS)). - _From RFC 952_ A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". No blank or space characters are permitted as part of a name. No distinction is made between upper and lower case. The first character must be an alpha character [Relaxed in RFC 1123] . The last character must not be a minus sign or period. - _From RFC 1035_ labels 63 octets or less names 255 octets or less [snip] limit the label to 63 octets or less. To simplify implementations, the total length of a domain name (i.e., label octets and label length octets) is restricted to 255 octets or less. - _From RFC 1123_ One aspect of host name syntax is hereby changed: the restriction on the first character is relaxed to allow either a letter or a digit. Host software MUST support this more liberal syntax. Host software MUST handle host names of up to 63 characters and SHOULD handle host names of up to 255 characters. ## is\_hostname($hostname, \\%options) This can be called as either a subroutine or a method. If called as a sub, you can pass any of the arguments accepted by the constructor as options. If called as a method, any additional options are ignored. This returns the untainted hostname if the given `$hostname` is a valid hostname. Hostnames are not required to end in a valid TLD. ## is\_domain\_label($label, \\%options) This can be called as either a subroutine or a method. If called as a sub, you can pass any of the arguments accepted by the constructor as options. If called as a method, any additional options are ignored. This returns the untainted label if the given `$label` is a valid label. A domain label is simply a single piece of a domain or hostname. For example, the "www.foo.com" hostname contains the labels "www", "foo", and "com". # SEE ALSO **\[RFC 1034\] \[RFC 1035\] \[RFC 2181\] \[RFC 1123\]** - [Data::Validate](https://metacpan.org/pod/Data%3A%3AValidate) - [Data::Validate::IP](https://metacpan.org/pod/Data%3A%3AValidate%3A%3AIP) # ACKNOWLEDGEMENTS Thanks to Richard Sonnen <`sonnen@richardsonnen.com`> for writing the Data::Validate module. Thanks to Len Reed <`lreed@levanta.com`> for helping develop the options mechanism for Data::Validate modules. # SUPPORT Bugs may be submitted at [https://github.com/houseabsolute/Data-Validate-Domain/issues](https://github.com/houseabsolute/Data-Validate-Domain/issues). I am also usually active on IRC as 'autarch' on `irc://irc.perl.org`. # SOURCE The source code repository for Data-Validate-Domain can be found at [https://github.com/houseabsolute/Data-Validate-Domain](https://github.com/houseabsolute/Data-Validate-Domain). # AUTHORS - Neil Neely - Dave Rolsky # CONTRIBUTORS - Anirvan Chatterjee - David Steinbrunner - Felipe Gasper - Gregory Oschwald # COPYRIGHT AND LICENSE This software is copyright (c) 2021 by Neil Neely. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. The full text of the license can be found in the `LICENSE` file included with this distribution.