NAME¶
Data::FormValidator::Constraints - Basic sets of constraints on input profile.
SYNOPSIS¶
use Data::FormValidator::Constraints qw(:closures);
In an Data::FormValidator profile:
constraint_methods => {
email => email(),
phone => american_phone(),
first_names => {
constraint_method => FV_max_length(3),
name => 'my_custom_name',
},
},
msgs => {
constraints => {
my_custom_name => 'My message',
},
},
DESCRIPTION¶
These are the builtin constraints that can be specified by name in the input
profiles.
Be sure to check out the SEE ALSO section for even more pre-packaged constraints
you can use.
FV_length_between(1,23)¶
FV_max_length(23)¶
FV_min_length(1)¶
use Data::FormValidator::Constraints qw(
FV_length_between
FV_min_length
FV_max_length
);
constraint_methods => {
# specify a min and max, inclusive
last_name => FV_length_between(1,23),
}
Specify a length constraint for a field.
These constraints have a different naming convention because they are
higher-order functions. They take input and return a code reference to a
standard constraint method. A constraint name of "length_between",
"min_length", or "max_length" will be set, corresponding
to the function name you choose.
The checks are all inclusive, so a max length of '100' will allow the length
100.
Length is measured in perl characters as opposed to bytes or anything else.
This constraint
will untaint your data if you have untainting turned on.
However, a length check alone may not be enough to insure the safety of the
data you are receiving. Using additional constraints to check the data is
encouraged.
FV_eq_with¶
use Data::FormValidator::Constraints qw( FV_eq_with );
constraint_methods => {
password => FV_eq_with('password_confirm'),
}
Compares the current field to another field. A constraint name of
"eq_with" will be set.
FV_num_values¶
use Data::FormValidator::Constraints qw ( FV_num_values );
constraint_methods => {
attachments => FV_num_values(4),
}
Checks the number of values in the array named by this param. Note that this is
useful for making sure that only one value was passed for a given param (by
supplying a size argument of 1). A constraint name of "num_values"
will be set.
FV_num_values_between¶
use Data::FormValidator::Constraints qw ( FV_num_values_between );
constraint_methods => {
attachments => FV_num_values_between(1,4),
}
Checks that the number of values in the array named by this param is between the
supplied bounds (inclusively). A constraint name of
"num_values_between" will be set.
email¶
Checks if the email LOOKS LIKE an email address. This should be sufficient 99%
of the time.
Look elsewhere if you want something super fancy that matches every possible
variation that is valid in the RFC, or runs out and checks some MX records.
state_or_province¶
This one checks if the input correspond to an american state or a canadian
province.
state¶
This one checks if the input is a valid two letter abbreviation of an American
state.
province¶
This checks if the input is a two letter Canadian province abbreviation.
zip_or_postcode¶
This constraints checks if the input is an American zipcode or a Canadian postal
code.
postcode¶
This constraints checks if the input is a valid Canadian postal code.
zip¶
This input validator checks if the input is a valid american zipcode : 5 digits
followed by an optional mailbox number.
phone¶
This one checks if the input looks like a phone number, (if it contains at least
6 digits.)
american_phone¶
This constraints checks if the number is a possible North American style of
phone number : (XXX) XXX-XXXX. It has to contains 7 or more digits.
cc_number¶
This constraint references the value of a credit card type field.
constraint_methods => {
cc_no => cc_number({fields => ['cc_type']}),
}
The number is checked only for plausibility, it checks if the number could be
valid for a type of card by checking the checksum and looking at the number of
digits and the number of digits of the number.
This functions is only good at catching typos. IT DOESN'T CHECK IF THERE IS AN
ACCOUNT ASSOCIATED WITH THE NUMBER.
cc_exp¶
This one checks if the input is in the format MM/YY or MM/YYYY and if the MM
part is a valid month (1-12) and if that date is not in the past.
cc_type¶
This one checks if the input field starts by M(asterCard), V(isa), A(merican
express) or D(iscovery).
ip_address¶
This checks if the input is formatted like a dotted decimal IP address (v4). For
other kinds of IP address method, See Regexp::Common::net which provides
several more options. "REGEXP::COMMON SUPPORT" explains how we
easily integrate with Regexp::Common.
RENAMING BUILT-IN CONSTAINTS¶
If you'd like, you can rename any of the built-in constraints. Just define the
constraint_method and name in a hashref, like this:
constraint_methods => {
first_names => {
constraint_method => FV_max_length(3),
name => 'custom_length',
}
},
REGEXP::COMMON SUPPORT¶
Data::FormValidator also includes built-in support for using any of regular
expressions in Regexp::Common as named constraints. Simply use the name of
regular expression you want. This works whether you want to untaint the data
or not. For example:
use Data::FormValidator::Constraints qw(:regexp_common);
constraint_methods => {
my_ip_address => FV_net_IPv4(),
# An example with parameters
other_ip => FV_net_IPv4(-sep=>' '),
}
Notice that the routines are named with the prefix "FV_" instead of
"RE_" now. This is simply a visual cue that these are slightly
modified versions. We've made a wrapper for each Regexp::Common routine so
that it can be used as a named constraint like this.
Be sure to check out the Regexp::Common syntax for how its syntax works. It will
make more sense to add future regular expressions to Regexp::Common rather
than to Data::FormValidator.
PROCEDURAL INTERFACE¶
You may also call these functions directly through the procedural interface by
either importing them directly or importing the whole
:validators
group. This is useful if you want to use the built-in validators out of the
usual profile specification interface.
For example, if you want to access the
email validator directly, you
could either do:
use Data::FormValidator::Constraints (qw/valid_email/);
or
use Data::FormValidator::Constraints (:validators);
if (valid_email($email)) {
# do something with the email address
}
Notice that when you call validators directly, you'll need to prefix the
validator name with "valid_"
Each validator also has a version that returns the untainted value if the
validation succeeded. You may call these functions directly through the
procedural interface by either importing them directly or importing the
:matchers group. For example if you want to untaint a value with the
email validator directly you may:
if ($email = match_email($email)) {
system("echo $email");
}
else {
die "Unable to validate email";
}
Notice that when you call validators directly and want them to return an
untainted value, you'll need to prefix the validator name with
"match_"
WRITING YOUR OWN CONSTRAINT ROUTINES¶
New School Constraints Overview¶
This is the current recommended way to write constraints. See also "Old
School Constraints".
The most flexible way to create constraints to use closures-- a normal seeming
outer subroutine which returns a customized DFV method subroutine as a result.
It's easy to do. These "constraint methods" can be named whatever
you like, and imported normally into the name space where the profile is
located.
Let's look at an example.
# Near your profile
# Of course, you don't have to export/import if your constraints are in the same
# package as the profile.
use My::Constraints 'coolness';
# In your profile
constraint_methods => {
email => email(),
prospective_date => coolness( 40, 60,
{fields => [qw/personality smarts good_looks/]}
),
}
Let's look at how this complex "coolness" constraint method works. The
interface asks for users to define minimum and maximum coolness values, as
well as declaring three data field names that we should peek into to look
their values.
Here's what the code might look like:
sub coolness {
my ($min_cool,$max_cool, $attrs) = @_;
my ($personality,$smarts,$looks) = @{ $attrs->{fields} } if $attrs->{fields};
return sub {
my $dfv = shift;
# Name it to refer to in the 'msgs' system.
$dfv->name_this('coolness');
# value of 'prospective_date' parameter
my $val = $dfv->get_current_constraint_value();
# get other data to refer to
my $data = $dfv->get_filtered_data;
my $has_all_three = ($data->{$personality} && $data->{$smarts} && $data->{$looks});
return ( ($val >= $min_cool) && ($val <= $max_cool) && $has_all_three );
}
}
Old School Constraints¶
Here is documentation on how old school constraints are created. These are
supported, but the new school style documented above is recommended.
See also the "validator_packages" option in the input profile, for
loading sets of old school constraints from other packages.
Old school constraint routines are named two ways. Some are named with the
prefix "match_" while others start with "valid_". The
difference is that the "match_" routines are built to untaint the
data and return a safe version of it if it validates, while "valid_"
routines simply return a true value if the validation succeeds and false
otherwise.
It is preferable to write "match_" routines that untaint data for the
extra security benefits. Plus, Data::FormValidator will AUTOLOAD a
"valid_" version if anyone tries to use it, so you only need to
write one routine to cover both cases.
Usually constraint routines only need one input, the value being specified.
However, sometimes more than one value is needed.
Example:
image_field => {
constraint_method => 'max_image_dimensions',
params => [\100,\200],
},
Using that syntax, the first parameter that will be passed to the routine is the
Data::FormValidator object. The remaining parameters will come from the
"params" array. Strings will be replaced by the values of fields
with the same names, and references will be passed directly.
In addition to "constraint_method", there is also an even older
technique using the name "constraint" instead. Routines that are
designed to work with "constraint"
don't have access to
Data::FormValidator object, which means users need to pass in the name of the
field being validated. Besides adding unnecessary syntax to the user
interface, it won't work in conjunction with
"constraint_regexp_map".
Methods available for use inside of constraints¶
A few useful methods to use on the Data::FormValidator::Results object are
available to you to use inside of your routine.
get_input_data()
Returns the raw input data. This may be a CGI object if that's what was used in
the constraint routine.
Examples:
# Raw and uncensored
my $data = $self->get_input_data;
# tamed to be a hashref, if it wasn't already
my $data = $self->get_input_data( as_hashref => 1 );
get_filtered_data()
my $data = $self->get_filtered_data;
Returns the valid filtered data as a hashref, regardless of whether it started
out as a CGI.pm compatible object. Multiple values are expressed as array
references.
get_current_constraint_field()
Returns the name of the current field being tested in the constraint.
Example:
my $field = $self->get_current_constraint_field;
This reduces the number of parameters that need to be passed into the routine
and allows multi-valued constraints to be used with
"constraint_regexp_map".
For complete examples of multi-valued constraints, see
Data::FormValidator::Constraints::Upload
get_current_constraint_value()
Returns the name of the current value being tested in the constraint.
Example:
my $value = $self->get_current_constraint_value;
This reduces the number of parameters that need to be passed into the routine
and allows multi-valued constraints to be used with
"constraint_regexp_map".
get_current_constraint_name()
Returns the name of the current constraint being applied
Example:
my $value = $self->get_current_constraint_name;
This is useful for building a constraint on the fly based on its name. It's used
internally as part of the interface to the Regexp::Commmon regular
expressions.
untainted_constraint_value()
return $dfv->untainted_constraint_value($match);
If you have written a constraint which untaints, use this method to return the
untainted result. It will prepare the right result whether the user has
requested untainting or not.
name_this()
set_current_constraint_name()
Sets the name of the current constraint being applied.
Example:
sub my_constraint {
my @outer_params = @_;
return sub {
my $dfv = shift;
$dfv->set_current_constraint_name('my_constraint');
my @params = @outer_params;
# do something constraining here...
}
}
By returning a closure which uses this method, you can build an advanced named
constraint in your profile, before you actually have access to the DFV object
that will be used later. See Data::FormValidator::Constraints::Upload for an
example.
"name_this" is a provided as a shorter synonym.
The "meta()" method may also be useful to communicate meta data that
may have been found. See Data::FormValidator::Results for documentation of
that method.
BACKWARDS COMPATIBILITY¶
Prior to Data::FormValidator 4.00, constraints were specified a bit differently.
This older style is still supported.
It was not necessary to explicitly load some constraints into your name space,
and the names were given as strings, like this:
constraints => {
email => 'email',
fax => 'american_phone',
phone => 'american_phone',
state => 'state',
my_ip_address => 'RE_net_IPv4',
other_ip => {
constraint => 'RE_net_IPv4',
params => [ \'-sep'=> \' ' ],
},
my_cc_no => {
constraint => 'cc_number',
params => [qw/cc_no cc_type/],
}
},
SEE ALSO¶
Constraints available in other modules¶
- Data::FormValidator::Constraints::Upload - validate the bytes, format and
dimensions of file uploads
- Data::FormValidator::Constraints::DateTime - A newer DateTime constraint
module. May save you a step of transforming the date into a more useful
format after it's validated.
- Data::FormValidator::Constraints::Dates - the original DFV date constraint
module. Try the newer one first!
- Data::FormValidator::Constraints::Japanese - Japan-specific
constraints
- Data::FormValidator::Constraints::MethodsFactory - a useful collection of
tools generate more complex constraints. Recommended!
- Data::FormValidator::Filters - transform data before constraints are
applied
- Data::FormValidator::ConstraintsFactory - This is a historical collection
of constraints that suffer from cumbersome names. They are worth reviewing
though-- "make_and_constraint" will allow to validate against a
list of constraints and shortcircuit if the first one fails. That's perfect
if the second constraint depends on the first one having passed. For a
modern version of this toolkit, see
Data::FormValidator::Constraints::MethodsFactory.
- Data::FormValidator
CREDITS¶
Some of those input validation functions have been taken from MiniVend by
Michael J. Heins
The credit card checksum validation was taken from contribution by Bruce
Albrecht to the MiniVend program.
AUTHORS¶
Francis J. Lacoste
Michael J. Heins
Bruce Albrecht
Mark Stosberg
COPYRIGHT¶
Copyright (c) 1999 iNsu Innovations Inc. All rights reserved.
Parts Copyright 1996-1999 by Michael J. Heins Parts Copyright 1996-1999 by Bruce
Albrecht Parts Copyright 2005-2009 by Mark Stosberg
This program is free software; you can redistribute it and/or modify it under
the terms as perl itself.