NAME
Validate::Tiny - Minimalistic data validation
VERSION
Version 0.981
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. As of version
0.981 you can use an empty array for "fields", which will work on all
input fields.
my @field_names = qw/username email password password2/;
or
my @field_names = (); # Use all input fields
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_required_if
is_required_if( $condition, $err_msg );
Require a field conditionally. The condition can be either a scalar or a
code reference that returns true/false value. If the condition is a code
reference, it will be passed the $params hash with all filtered fields.
Example:
my $rules = {
fields => [qw/country state/],
checks => [
country => is_required(),
state => is_required_if(
sub {
my $params = shift;
return $params->{country} eq 'USA';
},
"Must select a state if you're in the USA"
)
]
};
Second example:
our $month = 'October';
my $rules = {
fields => ['mustache'],
checks => [
mustache => is_required_if(
$month eq 'October',
"You must grow a mustache this month!"
)
]
};
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
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
AUTHOR
minimalist (cpan: MINIMAL) - minimalist@lavabit.com
CONTRIBUTORS
Viktor Tuskyi (cpan: KOORCHIK) - koorchik@cpan.org
LICENCE
This program is free software; you can redistribute it and/or modify it
under the terms as perl itself.