NAME Validate::Tiny - Minimalistic data validation VERSION Version 0.35 SYNOPSIS Filter and validate user input from forms, etc. use Validate::Tiny ':all'; my $rules = { # List of fields to look for fields => [qw/name email pass pass2 gender/], # Filters to run on all fields filters => [ # Remove spaces from all qr/.+/ => filter(qw/trim strip/), # Lowercase email email => filter('lc'), # Remove non-alphanumeric symbols from # both passwords qr/pass?/ => sub { $_[0] =~ s/\W/./g; $_[0]; }, ], # Checks to perform on all fields checks => [ # All of these are required [qw/name email pass pass2/] => is_required(), # pass2 must be equal to pass pass2 => is_equal('pass'), # custom sub validates an email address email => sub { my ( $value, $params ) = @_; Email::Valid->address($value) ? undef : 'Invalid email'; }, # custom sub to validate gender gender => sub { my ( $value, $params ) = @_; return $value eq 'M' || $value eq 'F' ? undef : 'Invalid gender'; } ] }; # Validate the input agains the rules my $result = validate( $input, $rules ); if ( $result->{success} ) { my $values_hash = $result->{data}; ... } else { my $errors_hash = $result->{error}; ... } Or if you prefer an OOP approach: use Validate::Tiny; my $result = Validate::Tiny->new( $input, $rules ); if ( $result->success ) { my $values_hash = $result->data; my $name = $result->data('name'); my $email = $result->data('email'); ...; } else { my $errors_hash = $result->error; my $name_error = $result->error('name'); my $email_error = $result->error('email'); } DESCRIPTION This module provides a simple, light and minimalistic way of validating user input. Except perl core modules and some test modules it has no other dependencies, which is why it does not implement any complicated checks and filters such as email and credit card matching. The basic idea of this module is to provide the validation functionality, and leave it up to the user to write their own data filters and checks. If you need a complete data validation solution that comes with many ready features, I recommend you to take a look at Data::FormValidator. If your validation logic is not too complicated or your form is relatively short, this module is a decent candidate for your project. LOGIC The basic principle of data/form validation is that any user input must be sanitized and checked for errors before used in the logic of the program. Validate::Tiny breaks this process in three steps: 1 Specify the fields you want to work with via "fields". All others will be disregarded. 2 Filter the fields' values using "filters". A filter can be as simple as changing to lower case or removing excess white space, or very complicated such as parsing and removing HTML tags. 3 Perform a series of "checks" on the filtered values, to make sure they match the requirements. Again, the checks can be very simple as in checking if the value was defined, or very complicated as in checking if the value is a valid credit card number. The validation returns a hash ref which contains "success" => 1|0, "data" and "error" hashes. If success is 1, "data" will contain the filtered values, otherwise "error" will contain the error messages for each field. EXPORT This module does not automatically export anything. You can optionally request any of the below subroutines or use ':all' to export all. PROCEDURAL INTERFACE validate use Validate::Tiny qw/validate/; my $result = validate( \%input, \%rules ); Validates user input against a set of rules. The input is expected to be a reference to a hash. %rules my %rules = ( fields => \@field_names, filters => \@filters_array, checks => \@checks_array ); "rules" is a hash containing references to the following three arrays: "fields", "filters" and "checks". fields An array containing the names of the fields that must be filtered, checked and returned. All others will be disregarded. my @field_names = qw/username email password password2/; filters An array containing name matches and filter subs. The array must have an even number of elements. Each *odd* element is a field name match and each *even* element is a reference to a filter subroutine or a chain of filter subroutines. A filter subroutine takes one parameter - the value to be filtered, and returns the modified value. my @filters_array = ( email => sub { return lc $_[0] }, # Lowercase the email password => sub { $_[0] =~ s/\s//g; $_[0] } # Remove spaces from password ); The field name is matched with the perl smart match operator, so you could have a regular expression or a reference to an array to match several fields: my @filters_array = ( qr/.+/ => sub { lc $_[0] }, # Lowercase ALL [qw/password password2/] => sub { # Remove spaces from both $_[0] =~ s/\s//g; # password and password2 $_[0]; } ); Instead of a single filter subroutine, you can pass an array of subroutines to provide a chain of filters: my @filters_array = ( qr/.+/ => [ sub { lc $_[0] }, sub { ucfirst $_[0] } ] ); The above example will first lowercase the value then uppercase its first letter. Some simple text filters are provided by the "filter()" subroutine. use Validate::Tiny qw/validate :util/; my @filters_array = ( name => filter(qw/strip trim lc/) ); checks An array ref containing name matches and check subs. The array must have an even number of elements. Each *odd* element is a field name match and each *even* element is a reference to a check subroutine or a chain of check subroutines. A check subroutine takes two parameters - the value to be checked and a reference to the filtered input hash. A check subroutine must return undef if the check passes or a string with an error message if the check fails. Example: # Make sure the password is good sub is_good_password { my ( $value, $params ) = @_; if ( !defined $value or $value eq '' ) { return undef; } if ( length($value) < 6 ) { return "The password is too short"; } if ( length($value) > 40 ) { return "The password is too long"; } if ( $value eq $params->{username} ) { return "Your password can not be the same as your username"; } # At this point we're happy with the password return undef; } my $rules = { fields => [qw/username password/], checks => [ password => \&is_good_password ] }; It may be a bit counter-intuitive for some people to return undef when the check passes and a string when it fails. If you have a huge problem with this concept, then this module may not be right for you. Important! Notice that in the beginning of "is_good_password" we check if $value is defined and return undef if it is not. This is because it is not the job of "is_good_password" to check if "password" is required. Its job is to determine if the password is good. Consider the following example: # Password is required and it must pass the check for good password # my $rules = { fields => [qw/username password/], checks => [ password => [ is_required(), \&is_good_password ] ] }; and this one too: # Password is not required, but if it's provided then # it must pass the is_good_password constraint. # my $rules = { fields => [qw/username password/], checks => [ username => is_required(), password => \&is_good_password ] }; The above examples show how we make sure that "password" is defined and not empty before we check if it is a good password. Of course we can check if "password" is defined inside "is_good_password", but it would be redundant. Also, this approach will fail if "password" is not required, but must pass the rules for a good password if provided. Chaining The above example also shows that chaining check subroutines is available in the same fashion as chaining filter subroutines. The difference between chaining filters and chaining checks is that a chain of filters will always run all filters, and a chain of checks will exit after the first failed check and return its error message. This way the "$result->{error}" hash always has a single error message per field. Using closures When writing reusable check subroutines, sometimes you will want to be able to pass arguments. Returning closures (anonymous subs) is the recommended approach: sub is_long_between { my ( $min, $max ) = @_; return sub { my $value = shift; return length($value) >= $min && length($value) <= $max ? undef : "Must be between $min and $max symbols"; }; } my $rules = { fields => qw/password/, checks => [ password => is_long_between( 6, 40 ) ] }; Return value "validate" returns a hash ref with three elements: my $result = validate(\%input, \%rules); # Now $result looks like this $result = { success => 1, # or 0 if checks didn't pass data => \%data, error => \%error }; If "success" is 1 all of the filtered input will be in %data, otherwise the error messages will be stored in %error. If "success" is 0, %data may or may not contain values, but its use is not recommended. filter filter( $name1, $name2, ... ); Provides a shortcut to some basic text filters. In reality, it returns a list of anonymous subs, so the following: my $rules = { filters => [ email => filter('lc', 'ucfirst') ] }; is equivalent to this: my $rules = { filters => [ email => [ sub{ lc $_[0] }, sub{ ucfirst $_[0] } ] ] }; It provides a shortcut for the following filters: trim Removes leading and trailing white space. strip Shrinks two or more white spaces to one. lc Lower case. uc Upper case. ucfirst Upper case first letter is_required is_required( $opt_error_msg ); "is_required" provides a shortcut to an anonymous subroutine that checks if the matched field is defined and it is not an empty string. Optionally, you can provide a custom error message to be returned. is_equal is_equal( $other_field_name, $opt_error_msg ) "is_equal" checks if the value of the matched field is the same as the value of another field within the input hash. Example: my $rules = { checks => [ password2 => is_equal("password", "Passwords don't match") ] }; is_long_between my $rules = { checks => [ username => is_long_between( 6, 25, 'Bad username' ) ] }; Checks if the length of the value is >= $min and <= $max. Optionally you can provide a custom error message. The default is *Invalid value*. is_long_at_least my $rules = { checks => [ zip_code => is_long_at_least( 5, 'Bad zip code' ) ] }; Checks if the length of the value is >= $length. Optionally you can provide a custom error message. The default is *Must be at least %i symbols*. is_long_at_most my $rules = { checks => [ city_name => is_long_at_most( 40, 'City name is too long' ) ] }; Checks if the length of the value is <= $length. Optionally you can provide a custom error message. The default is *Must be at the most %i symbols*. is_a use DateTime::Format::Natural; use Try::Tiny; my $parser = DateTime::Format::Natural->new; my $rules = { fields => ['date'], filters => [ date => sub { try { $parser->parse_datetime( $_[0] ); } catch { $_[0] } } ], checks => [ date => is_a("DateTime", "Ivalid date") ] }; Checks if the value is an instance of a class. This can be particularly useful, when you need to parse dates or other user input that needs to get converted to an object. Since the filters get executed before checks, you can use them to instantiate the data, then use "is_a" to check if you got a successful object. is_like my $rules = { checks => [ username => is_like( qr/^[a-z0-9_]{6,20}$/, "Bad username" ) ] }; Checks if the value matches a regular expression. Optionally you can provide a custom error message. is_in my @cities = qw/Alchevsk Kiev Odessa/; my $rules = { checks => [ city => is_in( \@cities, "We only deliver to " . join(',', @cities)) ] }; Checks if the value matches a set of values. Optionally you can provide a custom error message. OBJECT INTERFACE new Validates the input against the rules and returns a class instance. use Validate::Tiny; my $result = Validate::Tiny->new( $input, $rules ); if ( $result->success ) { # Do something with the data $result->data->{name}; $result->data('name'); } else { # Do something with the errors $result->error->{name}; $result->error('name'); } success Returns a true value if the input passed all the rules. data Returns a hash reference to all filtered fields. If called with a parameter, it will return the value of that field or croak if there is no such field defined in the fields array. my $all_fields = $result->data; my $email = $result->data('email'); error Returns a hash reference to all error messages. If called with a parameter, it will return the error message of that field, or croak if there is no such field. my $errors = $result->error; my $email = $result->error('email'); error_string Returns a string with all errors. Sometimes you may want to display all errors together in a string. This function makes that easy. my $str = $result->error_string; # return a string with all errors my $str = $result->error_string( template => '%s is %s', separator => '
', names => { f_name => 'First name', l_name => 'Last name' } ); # An example output for the above would be: # "First name is required
Last name is required" "error_string" takes the following optional parameters: template A string for the "sprintf" function. It has to have two %s's in it: one for the field name and one for the error message. my $str = $result->error_string( template => '(%s)%s' ); # Result: "(field_name):Error message" The default value is "[%s] %s". separator A character or a string which will be used to join all error messages. The default value is ";". names A HASH reference, which contains field_name => "Field description" values, so instead of "field_name" your users will see a meaningful description for the field. my $str = $result->error_string( template => '%s %s', names => { pass => 'Chosen password', pass2 => 'Password verification' } ); # Result: "Password verification does not match." If a field description is not defined then the field name will be used. The default value for "names" is an empty hash. single If this is non-zero, the result will contain the error message only for one of the fields. This can be useful when you want to display a single error at a time. The value of "separator" in this case is disregarded. Default value 0. to_hash Return a result hash, much like using the procedural interface. See the output of "validate" for more information. SEE ALSO Data::FormValidator, Validation::Class AUTHOR minimalist, "" BUGS Bug reports and patches are welcome. Reports which include a failing Test::More style test are helpful and will receive priority. You may also fork the module on Github: https://github.com/naturalist/Validate--Tiny LICENSE AND COPYRIGHT Copyright 2011 minimalist. This program is free software; you can redistribute it and/or modify it under the terms as perl itself.