HTML::FormValidator - Validates user input (usually from an HTML form) based on input profile.


In an HTML::Empberl page:

    use HTML::FormValidator;

    my $validator = new HTML::FormValidator( "/home/user/" );
    my ( $valid, $missing, $invalid, $unknown ) = $validator->validate(  \%fdat, "customer_infos" );


HTML::FormValidator's main aim is to make the tedious coding of input validation expressible in a simple format and to let the programmer focus on more interesting task.

When you are coding web application one of the most tedious though crucial task is to validate user's input (usually submitted by way of an HTML form). You have to check that each required fields is present and that some feed have valid data. (Does the phone input looks like a phone number ? Is that a plausible email address ? Is the YY state valid ? etc.) For simple form, this is not really a problem but as forms get more complex and you code more of them this task became really boring and tedious.

HTML::FormValidator lets you defines profiles which defines the required fields and their format. When you are ready to validate the user's input, you tell HTML::FormValidator the profile to apply to the user data and you get the valid fields, the name of the fields which are missing, the name of the fields that contains invalid input and the name of the fields that are unknown to this profile.

You are then free to use this information to build a nice display to the user telling which fields that he forgot to fill.


To create a HTML::FormValidator, use the following :

    my $validator = new HTML::FormValidator( $input_profile );

Where $input_profile may either be an hash reference to an input profiles specification or a file that will be evaluated at runtime to get a hash reference to an input profiles specification.

The input profiles specification is an hash reference where each key is the name of the input profile and each value is another hash reference which contains the actual profile elements. If the input profile is specified as a file name, the profiles will be reread each time that the disk copy is modified.

Here is an example of a valid input profiles specification :

        customer_infos => {
            optional     =>
                [ qw( company fax country ) ],
            required     =>
                [ qw( fullname phone email address city state zipcode ) ],
            constraints  =>
                    email       => "email",
                    fax         => "american_phone",
                    phone       => "american_phone",
                    zipcode     => '/^\s*\d{5}(?:[-]\d{4})?\s*$/',
                    state       => "state",
            defaults => {
                country => "USA",
        customer_billing_infos => {
             optional       => [ "cc_no" ],
             dependencies   => {
                "cc_no" => [ qw( cc_type cc_exp ) ],
             constraints => {
                cc_no      => {  constraint  => "cc_number",
                                 params      => [ qw( cc_no cc_type ) ],
                cc_type => "cc_type",
                cc_exp  => "cc_exp",
            filters       => [ "trim" ],
            field_filters => { cc_no => "digit" },

The following are the valid fields for an input specification :


This is an array reference which contains the name of the fields which are required. Any fields in this list which are not present in the user input will be reported as missing.


This is an array reference which contains the name of optional fields. These are fields which MAY be present and if they are, they will be check for valid input. Any fields not in optional or required list will be reported as unknown.


This is an hash reference which contains dependencies information. This is for the case where one optional fields has other requirements. For example, if you enter your credit card number, the field cc_exp and cc_type should also be present. Any fields in the dependencies list that is missing when the target is present will be reported as missing.


This is an hash reference which contains conflicts information. The key is the name of the field, which if present, the fields in the array reference value shouldn't be present. The fields which conflicts with another will be reported as conflicting.


This is an hash reference which contains defaults which should be substituted if the user hasn't filled the fields. Key is field name and value is default value which will be returned in the list of valid fields.


This is a reference to an array of filters that will be applied to ALL optional or required fields. This can be the name of a builting filter (trim,digit,etc) or an anonymous subroutine which should take one parameter, the field value and return the (possibly) modified value.


This is a reference to an hash which contains reference to array of filters which will be apply to specific input fields. The key of the hash is the name of the input field and the valud is a reference to an array of filters like for the filters parameter.


This is a reference to an hash which contains the constraints that will be used to check wheter or not the field contains valid data. Constraint can be either the name of a builtin constraint function (see below), a perl regexp or an anonymous subroutine which will check the input and return 1 or 0 depending on the input's validity. The constraint function may also -1 to express data that is valid but not recommended.

The constraint function takes one parameter, the input to be validated and returns 1, 0 or -1. It is possible to specify the parameters that will be passed to the subroutine. For that use an hash reference which contains in the constraint element, the anonymous subroutine or the name of the builtin and in the params element the name of the fields to pass a parameter to the function. (Don't forget to include the name of the field to check in that list!) For an example, look at the cc_no constraint example.


    my $results = $validator->check( \%fdat, "customer_infos" );

    my %fdat = $results->valid();
    if ( $results->has_missing) ) {
        foreach my $f ( $results->missing ) {
            print "Field ", $f , " is missing\n";

To validate input you use the check() method. This method takes two parameters :


Contains an hash which should correspond to the form input as submitted by the user. This hash is not modified by the call to validate.


Can be either a name which will be used to lookup the corresponding profile in the input profiles specification, or it can be an hash reference to the input profile which should be used.

This method returns an HTML::FormValidator::Results(3) object. This object can then be queried for valid, invalid, unknown, missing fields or fields which cause conflicts or have warnings. Consult the HTML::FormValidator::Results(3) for more information.

There is also a deprecated method which takes the same parameter but returns its as result in a 4 elements array.


This is an hash reference to the valid fields which were submitted in the data. The data may have been modified by the various filters specified.


This is a reference to an array which contains the name of the missing fields. Those are the fields that the user forget to fill or filled with space. These fields may comes from the required list or the dependencies list.


This is a reference to an hash which contains the the fields and their value which failed their constraint check.


This is a reference to an hash which contains the fields which are unknown to the profile. Whether or not this indicates an error in the user input is application dependant.


HTML::FormValidator::Constraints(3) HTML::FormValidator::Filters(3) HTML::FormValidator::ConstraintsFactory(3) HTML::FormValidator::Results(3)


Francis J. Lacoste <francis.lacoste@Contre.COM>


Copyright (c) 1999,2000 iNsu Innovations Inc. Copyright (c) 2001 Francis J. Lacoste All rights reserved.

This program is free software; you can redistribute it and/or modify it under the terms as perl itself.