NAME

CGI::FormBuilder - Easily generate and process stateful forms

SYNOPSIS

use CGI::FormBuilder;

# Assume we did a DBI query to get existing values
my $dbval = $sth->fetchrow_hashref;

# First create our form
my $form = CGI::FormBuilder->new(
                fields   => [qw(name email phone gender)],
                header   => 1,
                method   => 'POST',
                values   => $dbval,
                validate => {
                   email => 'EMAIL',
                   phone => '/^1?-?\d{3}-?\d{3}-?\d{4}$/',
                },
                required => 'ALL',
                stylesheet => '/path/to/style.css',
           );

# Change gender field to have options
$form->field(name => 'gender', options => [qw(Male Female)] );

if ($form->submitted && $form->validate) {
    # Get form fields as hashref
    my $field = $form->fields;

    # Do something to update your data (you would write this)
    do_data_update($field->{name},  $field->{email},
                   $field->{phone}, $field->{gender});

    # Show confirmation screen
    print $form->confirm;
} else {
    # Print out the form
    print $form->render;
}

DESCRIPTION

If this is your first time using FormBuilder, you should check out the website for tutorials and examples:

www.formbuilder.org

You should also consider joining the mailing list by sending an email to:

fbusers-subscribe@formbuilder.org

There are some pretty smart people on the list that can help you out.

Overview

I hate generating and processing forms. Hate it, hate it, hate it, hate it. My forms almost always end up looking the same, and almost always end up doing the same thing. Unfortunately, there haven't really been any tools out there that streamline the process. Many modules simply substitute Perl for HTML code:

# The manual way
print qq(<input name="email" type="text" size="20">);

# The module way
print input(-name => 'email', -type => 'text', -size => '20');

The problem is, that doesn't really gain you anything - you still have just as much code. Modules like CGI.pm are great for decoding parameters, but not for generating and processing whole forms.

The goal of CGI::FormBuilder (FormBuilder) is to provide an easy way for you to generate and process entire CGI form-based applications. Its main features are:

- Viewing fields as entities (instead of just params), where the HTML representation, CGI values, validation, and so on are properties of each field.

- Lots of built-in "intelligence" (such as automatic field typing), giving you about a 4:1 ratio of the code it generates versus what you have to write.

- Full-blown regex validation for fields, even including JavaScript code generation.

- Pluggable support for external template engines, such as HTML::Template, Text::Template, Template Toolkit, and CGI::FastTemplate.

Quick Reference

For the incredibly impatient, here's the quickest reference you can get:

# Create form
my $form = CGI::FormBuilder->new(

   # Important options
   fields     => \@array | \%hash,   # define form fields
   header     => 0 | 1,              # send Content-type?
   method     => 'POST' | 'GET',     # default is GET
   name       => $string,            # namespace (recommended)
   reset      => 0 | $str,           # "Reset" button
   submit     => 0 | $str | \@array, # "Submit" button(s)
   text       => $text,              # printed above form
   title      => $title,             # printed up top
   required   => \@array | 'ALL' | 'NONE',  # required fields?
   values     => \%hash | \@array,   # from DBI, session, etc
   validate   => \%hash,             # automatic field validation

   # Lesser-used options
   action     => $script,            # not needed (loops back)
   cookies    => 0 | 1,              # use cookies for sessionid?
   debug      => 0 | 1 | 2 | 3,      # gunk into error_log?
   fieldsubs  => 0 | 1,              # allow $form->$field()
   javascript => 0 | 1,              # generate JS validate() code?
   keepextras => 0 | 1 | \@array,    # keep non-field params?
   params     => $object,            # instead of CGI.pm
   sticky     => 0 | 1,              # keep CGI values "sticky"?
   messages   => $filename | \%hash | $object,  # locale 
   template   => $filename | \%hash | $object,  # custom HTML

   # Formatting options
   body       => \%attr,             # {background => 'black'}
   disabled   => 0 | 1,              # display as grayed-out?
   font       => $font | \%attr,     # 'arial,helvetica'
   jsfunc     => $jscode,            # JS code into validate()
   jshead     => $jscode,            # JS code into <head>
   linebreaks => 0 | 1,              # put breaks in form?
   selectnum  => $threshold,         # for auto-type generation
   smartness  => 0 | 1 | 2,          # tweak "intelligence"
   static     => 0 | 1 | 2,          # show non-editable form?
   styleclass => $string,            # prefix for class= ("fb_")
   stylesheet => 0 | 1 | $path,      # turn on style class=
   table      => 0 | 1 | \%attr,     # wrap form in <table>?
   td         => \%attr,             # <td> options
   tr         => \%attr,             # <tr> options

   # These are deprecated and you should use field() instead
   fieldtype  => 'type',
   fieldattr  => \%attr,
   labels     => \%hash,
   options    => \%hash,
   sortopts   => 'NAME' | 'NUM' | 1 | \&sub,

   # external source file (see CGI::FormBuilder::Source::File)
   source     => $file,
);

# Tweak fields
$form->field(

   # Important options
   name       => $name,          # name of field (required)
   label      => $string,        # shown in front of <input>
   type       => $type,          # normally auto-determined
   multiple   => 0 | 1,          # allow multiple values?
   options    => \@options | \%options,   # radio/select/checkbox
   value      => $value | \@values,       # default value

   # Lesser-used options
   force      => 0 | 1,          # override CGI value?
   growable   => 0 | 1 | $limit, # expand text/file inputs?
   jsclick    => $jscode,        # instead of onclick
   jsmessage  => $string,        # on JS validation failure
   message    => $string,        # other validation failure
   other      => 0 | 1,          # create "Other:" input?
   required   => 0 | 1,          # must fill field in?
   validate   => '/regex/',      # validate user input

   # Formatting options
   cleanopts  => 0 | 1,          # HTML-escape options?
   columns    => 0 | $width,     # wrap field options at $width
   comment    => $string,        # printed after field
   disabled   => 0 | 1,          # display as grayed-out?
   labels     => \%hash,         # deprecated (use "options")
   linebreaks => 0 | 1,          # insert breaks in options?
   nameopts   => 0 | 1,          # auto-name options?
   sortopts   => 'NAME' | 'NUM' | 1 | \&sub,   # sort options?

   # Change size, maxlength, or any other HTML attr
   $htmlattr  => $htmlval,
);

# Check for submission
if ($form->submitted && $form->validate) {

    # Get single value
    my $value = $form->field('name');

    # Get list of fields
    my @field = $form->field;

    # Get hashref of key/value pairs
    my $field = $form->field;
    my $value = $field->{name};

}

# Print form
print $form->render(any_opt_from_new => $some_value);

That's it. Keep reading.

Walkthrough

Let's walk through a whole example to see how FormBuilder works. We'll start with this, which is actually a complete (albeit simple) form application:

use CGI::FormBuilder;

my @fields = qw(name email password confirm_password zipcode);

my $form = CGI::FormBuilder->new(
                fields => \@fields,
                header => 1
           );

print $form->render;

The above code will render an entire form, and take care of maintaining state across submissions. But it doesn't really do anything useful at this point.

So to start, let's add the validate option to make sure the data entered is valid:

my $form = CGI::FormBuilder->new(
                fields   => \@fields, 
                header   => 1,
                validate => {
                   name  => 'NAME',
                   email => 'EMAIL'
                }
           );

We now get a whole bunch of JavaScript validation code, and the appropriate hooks are added so that the form is validated by the browser onsubmit as well.

Now, we also want to validate our form on the server side, since the user may not be running JavaScript. All we do is add the statement:

$form->validate;

Which will go through the form, checking each field specified to the validate option to see if it's ok. If there's a problem, then that field is highlighted, so that when you print it out the errors will be apparent.

Of course, the above returns a truth value, which we should use to see if the form was valid. That way, we only update our database if everything looks good:

if ($form->validate) {
    # print confirmation screen
    print $form->confirm;
} else {
    # print the form for them to fill out
    print $form->render;
}

However, we really only want to do this after our form has been submitted, since otherwise this will result in our form showing errors even though the user hasn't gotten a chance to fill it out yet. As such, we want to check for whether the form has been submitted() yet:

if ($form->submitted && $form->validate) {
    # print confirmation screen
    print $form->confirm;
} else {
    # print the form for them to fill out
    print $form->render;
}

Now that know that our form has been submitted and is valid, we need to get our values. To do so, we use the field() method along with the name of the field we want:

my $email = $form->field(name => 'email');

Note we can just specify the name of the field if it's the only option:

my $email = $form->field('email');   # same thing

As a very useful shortcut, we can get all our fields back as a hashref of field/value pairs by calling field() with no arguments:

my $fields = $form->field;      # all fields as hashref

To make things easy, we'll use this form so that we can pass it easily into a sub of our choosing:

if ($form->submitted && $form->validate) {
    # form was good, let's update database
    my $fields = $form->field;

    # update database (you write this part)
    do_data_update($fields); 

    # print confirmation screen
    print $form->confirm;
}

Finally, let's say we decide that we like our form fields, but we need the HTML to be laid out very precisely. No problem! We simply create an HTML::Template compatible template and tell FormBuilder to use it. Then, in our template, we include a couple special tags which FormBuilder will automatically expand:

<html>
<head>
<title><tmpl_var form-title></title>
<tmpl_var js-head><!-- this holds the JavaScript code -->
</head>
<tmpl_var form-start><!-- this holds the initial form tag -->
<h3>User Information</h3>
Please fill out the following information:
<!-- each of these tmpl_var's corresponds to a field -->
<p>Your full name: <tmpl_var field-name>
<p>Your email address: <tmpl_var field-email>
<p>Choose a password: <tmpl_var field-password>
<p>Please confirm it: <tmpl_var field-confirm_password>
<p>Your home zipcode: <tmpl_var field-zipcode>
<p>
<tmpl_var form-submit><!-- this holds the form submit button -->
</form><!-- can also use "tmpl_var form-end", same thing -->

Then, all we need to do add the template option, and the rest of the code stays the same:

my $form = CGI::FormBuilder->new(
                fields   => \@fields, 
                header   => 1,
                validate => {
                   name  => 'NAME',
                   email => 'EMAIL'
                },
                template => 'userinfo.tmpl'
           );

So, our complete code thus far looks like this:

use CGI::FormBuilder;

my @fields = qw(name email password confirm_password zipcode);

my $form = CGI::FormBuilder->new(
                fields   => \@fields, 
                header   => 1,
                validate => {
                   name  => 'NAME',
                   email => 'EMAIL'
                },
                template => 'userinfo.tmpl',
           );

if ($form->submitted && $form->validate) {
    # form was good, let's update database
    my $fields = $form->field;

    # update database (you write this part)
    do_data_update($fields); 

    # print confirmation screen
    print $form->confirm;

} else {
    # print the form for them to fill out
    print $form->render;
}

You may be surprised to learn that for many applications, the above is probably all you'll need. Just fill in the parts that affect what you want to do (like the database code), and you're on your way.

Note: If you are confused at all by the backslashes you see in front of some data pieces above, such as \@fields, skip down to the brief section entitled "REFERENCES" at the bottom of this document (it's short).

METHODS

This documentation is very extensive, but can be a bit dizzying due to the enormous number of options that let you tweak just about anything. As such, I recommend that you stop and visit:

www.formbuilder.org

And click on "Tutorials" and "Examples". Then, use the following section as a reference later on.

new()

This method creates a new $form object, which you then use to generate and process your form. In the very shortest version, you can just specify a list of fields for your form:

my $form = CGI::FormBuilder->new(
                fields => [qw(first_name birthday favorite_car)]
           );

As of 3.02, you can also now initialize FormBuilder from an external file:

my $form = CGI::FormBuilder->new(
                source => 'myform.conf'   # form and field options
           );

For details on the external file format, see CGI::FormBuilder::Source::File.

Any of the options below, in addition to being specified to new(), can also be manipulated directly with a method of the same name. For example, to change the header and stylesheet options, either of these works:

# Way 1
my $form = CGI::FormBuilder->new(
                fields => \@fields,
                header => 1,
                stylesheet => '/path/to/style.css',
           );

# Way 2
my $form = CGI::FormBuilder->new(
                fields => \@fields
           );
$form->header(1);
$form->stylesheet('/path/to/style.css');

The second form is useful if you want to wrap certain options in conditionals:

if ($have_template) {
    $form->header(0);
    $form->template('template.tmpl');
} else {
    $form->header(1);
    $form->stylesheet('/path/to/style.css');
}

The following is a description of each option, in alphabetical order:

action => $script

What script to point the form to. Defaults to itself, which is the recommended setting.

body => \%attr

This takes a hashref of attributes that will be stuck in the <body> tag verbatim (for example, bgcolor, alink, etc). See the fieldattr tag for more details, and also the template option.

debug => 0 | 1 | 2 | 3

If set to 1, the module spits copious debugging info to STDERR. If set to 2, it spits out even more gunk. 3 is too much. Defaults to 0.

fields => \@array | \%hash

As shown above, the fields option takes an arrayref of fields to use in the form. The fields will be printed out in the same order they are specified. This option is needed if you expect your form to have any fields, and is the central option to FormBuilder.

You can also specify a hashref of key/value pairs. The advantage is you can then bypass the values option. However, the big disadvantage is you cannot control the order of the fields. This is ok if you're using a template, but in real-life it turns out that passing a hashref to fields is not very useful.

fieldtype => 'type'

This can be used to set the default type for all fields in the form. You can then override it on a per-field basis using the field() method.

fieldattr => \%attr

This option allows you to specify any HTML attribute and have it be the default for all fields. This used to be good for stylesheets, but now that there is a stylesheet option, this is fairly useless.

fieldsubs => 0 | 1

This allows autoloading of field names so you can directly access them as:

$form->$fieldname(opt => 'val');

Instead of:

$form->field(name => $fieldname, opt => 'val');

Warning: If present, it will hide any attributes of the same name. For example, if you define "name" field, you won't be able to change your form's name dynamically. Also, you cannot use this format to create new fields. Use with caution.

font => $font | \%attr

The font face to use for the form. This is output as a series of <font> tags for best browser compatibility, and will even properly nest them in all of the table elements. If you specify a hashref instead of just a font name, then each key/value pair will be taken as part of the <font> tag:

font => {face => 'verdana', size => '-1', color => 'gray'}

That becomes:

<font face="verdana" size="-1" color="gray">

I use this option all the time.

header => 0 | 1

If set to 1, a valid Content-type header will be printed out, along with a whole bunch of HTML <body> code, a <title> tag, and so on. This defaults to 0, since often people end up using templates or embedding forms in other HTML.

javascript => 0 | 1

If set to 1, JavaScript is generated in addition to HTML, the default setting.

jsfunc => $jscode

This is verbatime JavaScript that will go into the validate JavaScript function. It is useful for adding your own verbatim code, while still getting all the automatic hooks. If something fails, you should do two things:

1. append to the JavaScript string "alertstr"
2. increment the JavaScript number "invalid"

For example:

my $jsfunc = <<'EOJS';   # note single quote (see Hint)
  if (form.password.value == 'password') {
    alertstr += "Moron, you can't use 'password' for your password!\\n";
    invalid++;
  }
EOJS

my $form = CGI::FormBuilder->new(... jsfunc => $jsfunc);

Then, this code will be automatically called when form validation is invoked. I find this option can be incredibly useful. Most often, I use it to bypass validation on certain submit modes. The submit button that was clicked is form._submit.value:

my $jsfunc = <<'EOJS';   # note single quotes (see Hint)
  if (form._submit.value == 'Delete') {
     if (confirm("Really DELETE this entry?")) return true;
     return false;
  } else if (form._submit.value == 'Cancel') {
     // skip validation since we're cancelling
     return true;
  }
EOJS

Hint: To prevent accidental expansion of embedding strings and escapes, you should put your HERE string in single quotes, as shown above.

jshead => $jscode

If using JavaScript, you can also specify some JavaScript code that will be included verbatim in the <head> section of the document. I'm not very fond of this one, what you probably want is the previous option.

keepextras => 0 | 1 | \@array

If set to 1, then extra parameters not set in your fields declaration will be kept as hidden fields in the form. However, you will need to use cgi_param(), NOT field(), to get to the values.

This is useful if you want to keep some extra parameters like mode or company available but not have them be valid form fields:

keepextras => 1

That will preserve any extra params. You can also specify an arrayref, in which case only params in that list will be preserved. For example:

keepextras => [qw(mode company)]

Will only preserve the params mode and company.

labels => \%hash

Like values, this is a list of key/value pairs where the keys are the names of fields specified above. By default, FormBuilder does some snazzy case and character conversion to create pretty labels for you. However, if you want to explicitly name your fields, use this option.

For example:

my $form = CGI::FormBuilder->new(
                fields => [qw(name email)],
                labels => {
                    name  => 'Your Full Name',
                    email => 'Primary Email Address'
                }
           );

Usually you'll find that if you're contemplating this option what you really want is a template.

linebreaks => 0 | 1

If set to 1, line breaks will be inserted after each input field. By default this is figured out for you, so usually not needed.

method => 'POST' | 'GET'

The type of CGI method to use, either POST or GET. Defaults to GET if nothing is specified. Note that for forms that cause changes on the server, such as database inserts, you should use the POST method.

messages => $filename | \%hash | $object

This option overrides the default FormBuilder messages in order to provide multilingual support (or just different text for the picky ones). For details on this option, please refer to CGI::FormBuilder::Messages.

name => $string

This names the form. It is optional, but when used, it renames several key variables and functions according to the name of the form. In addition, it also adds the following DOM id tags to each row of the table:

<tr id="${form}_${field}_row">
    <td id="${form}_${field}_label">Label</td>
    <td id="${form}_${field}_input"><input tag></td>
    <td id="${form}_${field}_error">Error</td><!-- if invalid -->
</tr>

These changes allow you to (a) use multiple forms in a sequential application and/or (b) display multiple forms inline in one document. If you're trying to build a complex multi-form app and are having problems, try naming your forms.

options => \%hash

This is one of several meta-options that allows you to specify stuff for multiple fields at once:

my $form = CGI::FormBuilder->new(
                fields => [qw(part_number department in_stock)],
                options => {
                    department => [qw(hardware software)],
                    in_stock   => [qw(yes no)],
                }
           );

This has the same effect as using field() for the department and in_stock fields to set options individually.

params => $object

This specifies an object from which the parameters should be derived. The object must have a param() method which will return values for each parameter by name. By default a CGI object will be automatically created and used.

However, you will want to specify this if you're using mod_perl:

use Apache::Request;
use CGI::FormBuilder;

sub handler {
    my $r = Apache::Request->new(shift);
    my $form = CGI::FormBuilder->new(... params => $r);
    print $form->render;
}

Or, if you need to initialize a CGI.pm object separately and are using a POST form method:

use CGI;
use CGI::FormBuilder;

my $q = new CGI;
my $form = CGI::FormBuilder->new(... params => $q);

Usually you don't need to do this, unless you need to access other parameters outside of FormBuilder's control.

required => \@array | 'ALL' | 'NONE'

This is a list of those values that are required to be filled in. Those fields named must be included by the user. If the required option is not specified, by default any fields named in validate will be required.

In addition, the required option also takes two other settings, the strings ALL and NONE. If you specify ALL, then all fields are required. If you specify NONE, then none of them are in spite of what may be set via the "validate" option.

This is useful if you have fields that are optional, but that you want to be validated if filled in:

my $form = CGI::FormBuilder->new(
                fields => qw[/name email/],
                validate => { email => 'EMAIL' },
                required => 'NONE'
           );

This would make the email field optional, but if filled in then it would have to match the EMAIL pattern.

In addition, it is very important to note that if the required and validate options are specified, then they are taken as an intersection. That is, only those fields specified as required must be filled in, and the rest are optional. For example:

my $form = CGI::FormBuilder->new(
                fields => qw[/name email/],
                validate => { email => 'EMAIL' },
                required => [qw(name)]
           );

This would make the name field mandatory, but the email field optional. However, if email is filled in, then it must match the builtin EMAIL pattern.

reset => 0 | $string

If set to 0, then the "Reset" button is not printed. If set to text, then that will be printed out as the reset button. Defaults to printing out a button that says "Reset".

selectnum => $threshold

This detects how FormBuilder's auto-type generation works. If a given field has options, then it will be a radio group by default. However, if more than selectnum options are present, then it will become a select list. The default is 5 or more options. For example:

# This will be a radio group
my @opt = qw(Yes No);
$form->field(name => 'answer', options => \@opt);

# However, this will be a select list
my @states = qw(AK CA FL NY TX);
$form->field(name => 'state', options => \@states);

# Single items are checkboxes (allows unselect)
$form->field(name => 'answer', options => ['Yes']);

There is no threshold for checkboxes since, if you think about it, they are really a multi-radio select group. As such, a radio group becomes a checkbox group if the multiple option is specified and the field has less than selectnum options. Got it?

smartness => 0 | 1 | 2

By default CGI::FormBuilder tries to be pretty smart for you, like figuring out the types of fields based on their names and number of options. If you don't want this behavior at all, set smartness to 0. If you want it to be really smart, like figuring out what type of validation routines to use for you, set it to 2. It defaults to 1.

sortopts => 'NAME' | 'NUM' | 1 | \&sub

If specified to new(), this has the same effect as the same-named option to field(), only it applies to all fields.

source => $filename

You can use this option to initialize FormBuilder from an external configuration file. This allows you to separate your field code from your form layout, which is pretty cool. See CGI::FormBuilder::Source::File for details on the format of the external file.

static => 0 | 1 | 2

If set to 1, then the form will be output with static hidden fields. If set to 2, then in addition fields without values will be omitted. Defaults to 0.

sticky => 0 | 1

Determines whether or not form values should be sticky across submissions. This defaults to 1, meaning values are sticky. However, you may want to set it to 0 if you have a form which does something like adding parts to a database. See the "EXAMPLES" section for a good example.

submit => 0 | $string | \@array

If set to 0, then the "Submit" button is not printed. It defaults to creating a button that says "Submit" verbatim. If given an argument, then that argument becomes the text to show. For example:

print $form->render(submit => 'Do Lookup');

Would make it so the submit button says "Do Lookup" on it.

If you pass an arrayref of multiple values, you get a key benefit. This will create multiple submit buttons, each with a different value. In addition, though, when submitted only the one that was clicked will be sent across CGI via some JavaScript tricks. So this:

print $form->render(submit => ['Add A Gift', 'No Thank You']);

Would create two submit buttons. Clicking on either would submit the form, but you would be able to see which one was submitted via the submitted() function:

my $clicked = $form->submitted;

So if the user clicked "Add A Gift" then that is what would end up in the variable $clicked above. This allows nice conditionality:

if ($form->submitted eq 'Add A Gift') {
    # show the gift selection screen
} elsif ($form->submitted eq 'No Thank You')
    # just process the form
}

See the "EXAMPLES" section for more details.

styleclass => $string

This string is prefixed to stylesheet class names. See below.

stylesheet => 0 | 1 | $path

This option turns on stylesheets in the HTML output by FormBuilder. Each element is prefixed by whatever styleclass is set to ("fb_" by default). It is up to you to provide the actual style definitions. If you provide a $path rather than just a 1/0 toggle, then that $path will be included in a <link> tag as well.

table => 0 | 1 | \%tabletags

By default FormBuilder decides how to layout the form based on the number of fields, values, etc. You can force it into a table by specifying 1, or force it out of one with 0.

If you specify a hashref instead, then these will be used to create the <table> tag. For example, to create a table with no cellpadding or cellspacing, use:

table => {cellpadding => 0, cellspacing => 0}

Also, you can specify options to the <td> and <tr> elements as well in the same fashion.

template => $filename | \%hash | \&sub | $object

This points to a filename that contains an HTML::Template compatible template to use to layout the HTML. You can also specify the template option as a reference to a hash, allowing you to further customize the template processing options, or use other template engines.

If template points to a sub reference, that routine is called and its return value directly returned. If it is an object, then that object's render() routine is called and its value returned.

For lots more information, please see CGI::FormBuilder::Template.

text => $text

This is text that is included below the title but above the actual form. Useful if you want to say something simple like "Contact $adm for more help", but if you want lots of text check out the template option above.

title => $title

This takes a string to use as the title of the form.

values => \%hash | \@array

The values option takes a hashref of key/value pairs specifying the default values for the fields. These values will be overridden by the values entered by the user across the CGI. The values are used case-insensitively, making it easier to use DBI hashref records (which are in upper or lower case depending on your database).

This option is useful for selecting a record from a database or hardwiring some sensible defaults, and then including them in the form so that the user can change them if they wish. For example:

my $rec = $sth->fetchrow_hashref;
my $form = CGI::FormBuilder->new(fields => \@fields,
                                 values => $rec);

You can also pass an arrayref, in which case each value is used sequentially for each field as specified to the fields option.

validate => \%hash

This option takes a hashref of key/value pairs. Each key is the name of a field from the fields option, or the string ALL in which case it applies to all fields. Each value is one of the following:

- a regular expression in 'quotes' to match against
- an arrayref of values, of which the field must be one
- a string that corresponds to one of the builtin patterns
- a string containing a literal code comparison to do
- a reference to a sub to be used to validate the field
  (the sub will receive the value to check as the first arg)

In addition, each of these can also be grouped together as:

- a hashref containing pairings of comparisons to do for
  the two different languages, "javascript" and "perl"

By default, the validate option also toggles each field to make it required. However, you can use the required option to change this, see it for more details.

Let's look at a concrete example:

my $form = CGI::FormBuilder->new(
                fields => [
                    qw(username password confirm_password
                       first_name last_name email)
                ],
                validate => {
                    username   => [qw(nate jim bob)],
                    first_name => '/^\w+$/',    # note the 
                    last_name  => '/^\w+$/',    # single quotes!
                    email      => 'EMAIL',
                    password   => \&check_password,
                    confirm_password => {
                        javascript => '== form.password.value',
                        perl       => 'eq $form->field("password")'
                    },
                },
           );

# simple sub example to check the password
sub check_password ($) {
    my $v = shift;                   # first arg is value
    return unless $v =~ /^.{6,8}/;   # 6-8 chars
    return if $v eq "password";      # dummy check
    return unless passes_crack($v);  # you write "passes_crack()"
    return 1;                        # success
}

This would create both JavaScript and Perl routines on the fly that would ensure:

- "username" was either "nate", "jim", or "bob"
- "first_name" and "last_name" both match the regex's specified
- "email" is a valid EMAIL format
- "password" passes the checks done by check_password(), meaning
   that the sub returns true
- "confirm_password" is equal to the "password" field

Any regular expressions you specify must be enclosed in single quotes because they need to be used in both JavaScript and Perl code. As such, specifying a qr// will NOT work.

Note that for both the javascript and perl hashref code options, the form will be present as the variable named form. For the Perl code, you actually get a complete $form object meaning that you have full access to all its methods (although the field() method is probably the only one you'll need for validation).

In addition to taking any regular expression you'd like, the validate option also has many builtin defaults that can prove helpful:

VALUE   -  is any type of non-null value
WORD    -  is a word (\w+)
NAME    -  matches [a-zA-Z] only
FNAME   -  person's first name, like "Jim" or "Joe-Bob"
LNAME   -  person's last name, like "Smith" or "King, Jr."
NUM     -  number, decimal or integer
INT     -  integer
FLOAT   -  floating-point number
PHONE   -  phone number in form "123-456-7890" or "(123) 456-7890"
INTPHONE-  international phone number in form "+prefix local-number"
EMAIL   -  email addr in form "name@host.domain"
CARD    -  credit card, including Amex, with or without -'s
DATE    -  date in format MM/DD/YYYY
EUDATE  -  date in format DD/MM/YYYY
MMYY    -  date in format MM/YY or MMYY
MMYYYY  -  date in format MM/YYYY or MMYYYY
CCMM    -  strict checking for valid credit card 2-digit month ([0-9]|1[012])
CCYY    -  valid credit card 2-digit year
ZIPCODE -  US postal code in format 12345 or 12345-6789
STATE   -  valid two-letter state in all uppercase
IPV4    -  valid IPv4 address
NETMASK -  valid IPv4 netmask
FILE    -  UNIX format filename (/usr/bin)
WINFILE -  Windows format filename (C:\windows\system)
MACFILE -  MacOS format filename (folder:subfolder:subfolder)
HOST    -  valid hostname (some-name)
DOMAIN  -  valid domainname (www.i-love-bacon.com)
ETHER   -  valid ethernet address using either : or . as separators

I know some of the above are US-centric, but then again that's where I live. :-) So if you need different processing just create your own regular expression and pass it in. If there's something really useful let me know and maybe I'll add it.

Note that any other options specified are passed to the <form> tag verbatim. For example, you could specify onsubmit or enctype to add the respective attributes.

render()

This function renders the form into HTML, and returns a string containing the form. The most common use is simply:

print $form->render;

You can also supply options to render(), just like you had called the accessor functions individually. These two uses are equivalent:

# this code:
$form->header(1);
$form->stylesheet('style.css');
print $form->render;

# is the same as:
print $form->render(header => 1,
                    stylesheet => 'style.css');

Note that both forms make permanent changes to the underlying object. So the next call to render() will still have the header and stylesheet options in either case.

field()

This method is used to both get at field values:

my $bday = $form->field('birthday');

As well as make changes to their attributes:

$form->field(name  => 'fname',
             label => "First Name");

A very common use is to specify a list of options and/or the field type:

$form->field(name    => 'state',
             type    => 'select',
             options => \@states);      # you supply @states

In addition, when you call field() without any arguments, it returns a list of valid field names in an array context:

my @fields = $form->field;

And a hashref of field/value pairs in scalar context:

my $fields = $form->field;
my $name = $fields->{name};

Note that if you call it in this manner, you only get one single value per field. This is fine as long as you don't have multiple values per field (the normal case). However, if you have a field that allows multiple options:

$form->field(name => 'color', options => \@colors,
             multiple => 1);        # allow multi-select

Then you will only get one value for color in the hashref. In this case you'll need to access it via field() to get them all:

my @colors = $form->field('color');

The name option is described first, and the remaining options are in order:

name => $name

The field to manipulate. The "name =>" part is optional if it's the only argument. For example:

my $email = $form->field(name => 'email');
my $email = $form->field('email');   # same thing

However, if you're specifying more than one argument, then you must include the name part:

$form->field(name => 'email', size => '40');

columns => 0 | $width

If set and the field is of type 'checkbox' or 'radio', then the options will be wrapped at the given width.

comment => $string

This prints out the given comment after the field. A good use of this is for additional help on what the field should contain:

$form->field(name    => 'dob',
             label   => 'D.O.B.',
             comment => 'in the format MM/DD/YY');

The above would yield something like this:

D.O.B. [____________] in the format MM/DD/YY

The comment is rendered verbatim, meaning you can use HTML links or code in it if you want.

cleanopts => 0 | 1

If set to 1 (the default), field options are escaped to make sure any special chars don't screw up the HTML. Set to 0 if you want to include verbatim HTML in your options, and know what you're doing.

cookies => 0 | 1

Controls whether to generate a cookie if sessionid has been set. This also requires that header be set as well, since the cookie is wrapped in the header. Defaults to 1, meaning it will automatically work if you turn on header.

force => 0 | 1

This is used in conjunction with the value option to forcibly override a field's value. See below under the value option for more details. For compatibility with CGI.pm, you can also call this option override instead, but don't tell anyone.

growable => 0 | 1 | $limit

This option adds a button and the appropriate JavaScript code to your form to allow the additional copies of the field to be added by the client filling out the form. Currently, this only works with text and file field types.

If you set growable to a positive integer greater than 1, that will become the limit of growth for that field. You won't be able to add more than $limit extra inputs to the form, and FormBuilder will issue a warning if the CGI params come in with more than the allowed number of values.

jsclick => $jscode

This is a cool abstraction over directly specifying the JavaScript action. This turns out to be extremely useful, since if a field type changes from select to radio or checkbox, then the action changes from onchange to onclick. Why?!?!

So if you said:

$form->field(name    => 'credit_card', 
             options => \@cards,
             jsclick => 'recalc_total();');

This would generate the following code, depending on the number of @cards:

<select name="credit_card" onchange="recalc_total();"> ...

<radio name="credit_card" onclick="recalc_total();"> ...

You get the idea.

jsmessage => $string

You can use this to specify your own custom message for the field, which will be printed if it fails validation. The jsmessage option affects the JavaScript popup box, and the message option affects what is printed out if the server-side validation fails. If message is specified but not jsmessage, then message will be used for JavaScript as well.

$form->field(name      => 'cc',
             label     => 'Credit Card',
             message   => 'Invalid credit card number',
             jsmessage => 'The card number in "%s" is invalid');

The %s will be filled in with the field's label.

label => $string

This is the label printed out before the field. By default it is automatically generated from the field name. If you want to be really lazy, get in the habit of naming your database fields as complete words so you can pass them directly to/from your form.

labels => \%hash

This option to field() is outdated. You can get the same effect by passing data structures directly to the options argument (see below). If you have well-named data, check out the nameopts option.

This takes a hashref of key/value pairs where each key is one of the options, and each value is what its printed label should be:

$form->field(name    => 'state',
             options => [qw(AZ CA NV OR WA)],
             labels  => {
                  AZ => 'Arizona',
                  CA => 'California',
                  NV => 'Nevada',
                  OR => 'Oregon',
                  WA => 'Washington
             });

When rendered, this would create a select list where the option values were "CA", "NV", etc, but where the state's full name was displayed for the user to select. As mentioned, this has the exact same effect:

$form->field(name    => 'state',
             options => [
                [ AZ => 'Arizona' ], 
                [ CA => 'California' ],
                [ NV => 'Nevada' ],
                [ OR => 'Oregon' ],
                [ WA => 'Washington ],
             ]);

I can think of some rare situations where you might have a set of predefined labels, but only some of those are present in a given field... but usually you should just use the options arg.

linebreaks => 0 | 1

Similar to the top-level "linebreaks" option, this one will put breaks in between options, to space things out more. This is useful with radio and checkboxes especially.

message => $string

Like jsmessage, this customizes the output error string if server-side validation fails for the field. The message option will also be used for JavaScript messages if it is specified but jsmessage is not. See above under jsmessage for details.

multiple => 0 | 1

If set to 1, then the user is allowed to choose multiple values from the options provided. This turns radio groups into checkboxes and selects into multi-selects. Defaults to automatically being figured out based on number of values.

nameopts => 0 | 1

If set to 1, then options for select lists will be automatically named using the same algorithm as field labels. For example:

$form->field(name     => 'department', 
             options  => qw[(molecular_biology
                             philosophy psychology
                             particle_physics
                             social_anthropology)],
             nameopts => 1);

This would create a list like:

<select name="department">
<option value="molecular_biology">Molecular Biology</option>
<option value="philosophy">Philosophy</option>
<option value="psychology">Psychology</option>
<option value="particle_physics">Particle Physics</option>
<option value="social_anthropology">Social Anthropology</option>
</select>

Basically, you get names for the options that are determined in the same way as the names for the fields. This is designed as a simpler alternative to using custom options data structures if your data is regular enough to support it.

other => 0 | 1 | \%attr

If set, this automatically creates an "other" field to the right of the main field. This is very useful if you want to present a present list, but then also allow the user to enter their own entry:

$form->field(name    => 'vote_for_president',
             options => [qw(Bush Kerry)],
             other   => 1);

That would generate HTML somewhat like this:

Vote For President:  [ ] Bush [ ] Kerry [ ] Other: [______]

If the "other" button is checked, then the box becomes editable so that the user can write in their own text. This "other" box will be subject to the same validation as the main field, to make sure your data for that field is consistent.

options => \@options | \%options | \&sub

This takes an arrayref of options. It also automatically results in the field becoming a radio (if < 5) or select list (if >= 5), unless you explicitly set the type with the type parameter:

$form->field(name => 'opinion',
             options => [qw(yes no maybe so)]);

From that, you will get something like this:

<select name="opinion">
<option value="yes">yes</option>
<option value="no">no</option>
<option value="maybe">maybe</option>
<option value="so">so</option>
</select>

Also, this can accept more complicated data structures, allowing you to specify different labels and values for your options. If a given item is either an arrayref or hashref, then the first element will be taken as the value and the second as the label. For example, this:

push @opt, ['yes', 'You betcha!'];
push @opt, ['no', 'No way Jose'];
push @opt, ['maybe', 'Perchance...'];
push @opt, ['so', 'So'];
$form->field(name => 'opinion', options => \@opt);

Would result in something like the following:

<select name="opinion">
<option value="yes">You betcha!</option>
<option value="no">No way Jose</option>
<option value="maybe">Perchance...</option>
<option value="so">So</option>
</select>

And this code would have the same effect:

push @opt, { yes => 'You betcha!' };
push @opt, { no  => 'No way Jose' };
push @opt, { maybe => 'Perchance...' };
push @opt, { so  => 'So' };
$form->field(name => 'opinion', options => \@opt);

As would, in fact, this code:

my @opt = (
    [ yes => 'You betcha!' ],
    [ no  => 'No way Jose' ],
    [ maybe => 'Perchance...' ],
    [ so  => 'So' ]
);
$form->field(name => 'opinion', options => \%opt);

Finally, you can specify a \&sub which must return either an \@arrayref or \%hashref of data, which is then expanded using the same algorithm.

required => 0 | 1

If set to 1, the field must be filled in:

$form->field(name => 'email', required => 1);

This is rarely useful - what you probably want are the validate and required options to new().

sortopts => 'NAME' | 'NUM' | 1 | \&sub

If set, and there are options, then the options will be sorted in the specified order. For example:

$form->field(name => 'category', options => \@cats,
             sortopts => 'NAME');

Would sort the @cats options in alphabetic (NAME) order. The option NUM would sort them in numeric order. If you specify "1", then an alphabetic sort is done, just like the default Perl sort.

In addition, you can specify a sub reference which takes pairs of values to compare and returns the appropriate return value that Perl sort() expects.

type => $type

The type of input box to create. Default is "text", and valid values include anything allowed by the HTML specs, including "select", "radio", "checkbox", "textarea", "password", "hidden", and so on.

By default, the type is automatically determined by FormBuilder based on the following algorithm:

Field options?
    No = text (done)
    Yes:
        Less than 'selectnum' setting?
            No = select (done)
            Yes:
                Is the 'multiple' option set?
                Yes = checkbox (done)
                No:
                    Have just one single option?
                        Yes = checkbox (done)
                        No = radio (done)

I recommend you let FormBuilder do this for you in most cases, and only tweak those you really need to.

value => $value | \@values

The value option can take either a single value or an arrayref of multiple values. In the case of multiple values, this will result in the field automatically becoming a multiple select list or radio group, depending on the number of options specified.

If a CGI value is present it will always win. To forcibly change a value, you need to specify the force option:

# Example that hides credit card on confirm screen
if ($form->submitted && $form->validate) {
    my $val = $form->field;

    # hide CC number
    $form->field(name => 'credit_card',
                 value => '(not shown)',
                 force => 1);

    print $form->confirm;
}

This would print out the string "(not shown)" on the confirm() screen instead of the actual number.

validate => '/regex/'

Similar to the validate option used in new(), this affects the validation just of that single field. As such, rather than a hashref, you would just specify the regex to match against.

This regex must be specified as a single-quoted string, and NOT as a qr// regex. The reason for this is it needs to be usable by the JavaScript routines as well.

$htmlattr => $htmlval

In addition to the above tags, the field() function can take any other valid HTML attribute, which will be placed in the tag verbatim. For example, if you wanted to alter the class of the field (if you're using stylesheets and a template, for example), you could say:

$form->field(name => 'email', class => 'FormField',
             size => 80);

Then when you call $form-render> you would get a field something like this:

<input type="text" name="email" class="FormField" size="80">

(Of course, for this to really work you still have to create a class called FormField in your stylesheet.)

See also the fieldattr option which provides global attributes to all fields.

cgi_param()

The above field() method will only return fields which you have explicitly defined in your form. Excess parameters will be silently ignored, to help ensure users can't mess with your form.

But, you may have some times when you want extra params so that you can maintain state, but you don't want it to appear in your form. Branding is an easy example:

http://hr-outsourcing.com/newuser.cgi?company=mr_propane

This could change your page's HTML so that it displayed the appropriate company name and logo, without polluting your form parameters.

This call simply redispatches to CGI.pm's param() method, so consult those docs for more information.

tmpl_param()

This allows you to manipulate template parameters directly. Extending the above example:

my $form = CGI::FormBuilder->new(template => 'some.tmpl');

my $company = $form->cgi_param('company');
$form->tmpl_param(company => $company);

Then, in your template:

Hello, <tmpl_var company> employee!
<p>
Please fill out this form:
<tmpl_var form-start>
<!-- etc... -->

For really precise template control, you can actually create your own template object and then pass it directly to FormBuilder. See CGI::FormBuilder::Template for more details.

sessionid()

This gets and sets the sessionid, which is stored in the special form field _sessionid. By default no session ids are generated or used. Rather, this is intended to provide a hook for you to easily integrate this with a session id module like CGI::Session.

Since you can set the session id via the _sessionid field, you can pass it as an argument when first showing the form:

http://mydomain.com/forms/update_info.cgi?_sessionid=0123-091231

This would set things up so that if you called:

my $id = $form->sessionid;

This would get the value 0123-091231 in your script. Conversely, if you generate a new sessionid on your own, and wish to include it automatically, simply set is as follows:

$form->sessionid($id);

If the sessionid is set, and header is set, then FormBuilder will also automatically generate a cookie for you.

See "EXAMPLES" for CGI::Session example.

submitted()

This returns the value of the "Submit" button if the form has been submitted, undef otherwise. This allows you to either test it in a boolean context:

if ($form->submitted) { ... }

Or to retrieve the button that was actually clicked on in the case of multiple submit buttons:

if ($form->submitted eq 'Update') {
    ...
} elsif ($form->submitted eq 'Delete') {
    ...
}

It's best to call validate() in conjunction with this to make sure the form validation works. To make sure you're getting accurate info, it's recommended that you name your forms with the name option described above.

If you're writing a multiple-form app, you should name your forms with the name option to ensure that you are getting an accurate return value from this sub. See the name option above, under render().

You can also specify the name of an optional field which you want to "watch" instead of the default _submitted hidden field. This is useful if you have a search form and also want to be able to link to it from other documents directly, such as:

mysearch.cgi?lookup=what+to+look+for

Normally, submitted() would return false since the _submitted field is not included. However, you can override this by saying:

$form->submitted('lookup');

Then, if the lookup field is present, you'll get a true value. (Actually, you'll still get the value of the "Submit" button if present.)

validate()

This validates the form based on the validation criteria passed into new() via the validate option. In addition, you can specify additional criteria to check that will be valid for just that call of validate(). This is useful is you have to deal with different geos:

if ($location eq 'US') {
    $form->validate(state => 'STATE', zipcode => 'ZIPCODE');
} else {
    $form->validate(state => '/^\w{2,3}$/');
}

Note that if you pass args to your validate() function like this, you will not get JavaScript generated or required fields placed in bold. So, this is good for conditional validation like the above example, but for most applications you want to pass your validation requirements in via the validate option to the new() function, and just call the validate() function with no arguments.

confirm()

The purpose of this function is to print out a static confirmation screen showing a short message along with the values that were submitted. It is actually just a special wrapper around render(), twiddling a couple options.

If you're using templates, you probably want to specify a separate success template, such as:

if ($form->submitted && $form->validate) {
    print $form->confirm(template => 'success.tmpl');
} else {
    print $form->render(template => 'fillin.tmpl');
}

So that you don't get the same screen twice.

mailconfirm()

This sends a confirmation email to the named addresses. The to argument is required; everything else is optional. If no from is specified then it will be set to the address auto-reply since that is a common quasi-standard in the web app world.

This does not send any of the form results. Rather, it simply prints out a message saying the submission was received.

mailresults()

This emails the form results to the specified address(es). By default it prints out the form results separated by a colon, such as:

name: Nathan Wiger
email: nate@wiger.org
colors: red green blue

And so on. You can change this by specifying the delimiter and joiner options. For example this:

$form->mailresults(to => $to, delimiter => '=', joiner => ',');

Would produce an email like this:

name=Nathan Wiger
email=nate@wiger.org
colors=red,green,blue

Note that now the last field ("colors") is separated by commas since you have multiple values and you specified a comma as your joiner.

mail()

This is a more generic version of the above; it sends whatever is given as the text argument via email verbatim to the to address. In addition, if you're not running sendmail you can specify the mailer parameter to give the path of your mailer. This option is accepted by the above functions as well.

COMPATIBILITY

The following methods are provided to make FormBuilder behave more like other modules, when desired.

Returns a CGI.pm header, but only if header => 1 is set.

param()

This is an alias for field(), provided for compatibility. However, while field() does act "compliantly" for easy use in CGI::Session, Apache::Request, etc, it is not 100% the same. As such, I recommend you use field() in your code, and let receiving objects figure the param() thing out when needed:

my $sess = CGI::Session->new(...);
$sess->save_param($form);   # will see param()

query_string()

This returns a query string similar to CGI.pm, but ONLY containing form fields and any keepextras, if specified. Other params are ignored.

self_url()

This returns a self url, similar to CGI.pm, but again ONLY with form fields.

script_name()

An alias for $form->action.

EXAMPLES

I find this module incredibly useful, so here are even more examples, pasted from sample code that I've written:

Ex1: order.cgi

This example provides an order form, complete with validation of the important fields, and a "Cancel" button to abort the whole thing.

#!/usr/bin/perl -w

use strict;
use CGI::FormBuilder;

my @states = my_state_list();   # you write this

my $form = CGI::FormBuilder->new(
                method => 'POST',
                fields => [
                    qw(first_name last_name
                       email send_me_emails
                       address state zipcode
                       credit_card expiration)
                ],

                header => 1,
                title  => 'Finalize Your Order',
                submit => ['Place Order', 'Cancel'],
                reset  => 0,

                validate => {
                     email   => 'EMAIL',
                     zipcode => 'ZIPCODE',
                     credit_card => 'CARD',
                     expiration  => 'MMYY',
                },
                required => 'ALL',
                jsfunc => <<EOJS,
// skip js validation if they clicked "Cancel"
if (this._submit.value == 'Cancel') return true;
EOJS
           );

# Provide a list of states
$form->field(name    => 'state',
             options => \@states,
             sortopts=> 'NAME');

# Options for mailing list
$form->field(name    => 'send_me_emails',
             options => [[1 => 'Yes'], [0 => 'No']],
             value   => 0,   # "No"

# Check for valid order
if ($form->submitted eq 'Cancel') {
    # redirect them to the homepage
    print $form->cgi->redirect('/');
    exit; 
}
elsif ($form->submitted && $form->validate) {
    # your code goes here to do stuff...
    print $form->confirm;
}
else {
    # either first printing or needs correction
    print $form->render;
}

This will create a form called "Finalize Your Order" that will provide a pulldown menu for the state, a radio group for send_me_emails, and normal text boxes for the rest. It will then validate all the fields, using specific patterns for those fields specified to validate.

Ex2: order_form.cgi

Here's an example that adds some fields dynamically, and uses the debug option spit out gook:

#!/usr/bin/perl -w

use strict;
use CGI::FormBuilder;

my $form = CGI::FormBuilder->new(
                method => 'POST',
                fields => [
                    qw(first_name last_name email
                       address state zipcode)
                ],
                header => 1,
                debug  => 2,    # gook
                required => 'NONE',
           );

# This adds on the 'details' field to our form dynamically
$form->field(name => 'details',
             type => 'textarea',
             cols => '50',
             rows => '10');

# And this adds user_name with validation
$form->field(name  => 'user_name',
             value => $ENV{REMOTE_USER},
             validate => 'NAME');

if ($form->submitted && $form->validate) {
    # ... more code goes here to do stuff ...
    print $form->confirm;
} else {
    print $form->render;
}

In this case, none of the fields are required, but the user_name field will still be validated if filled in.

Ex3: ticket_search.cgi

This is a simple search script that uses a template to layout the search parameters very precisely. Note that we set our options for our different fields and types.

#!/usr/bin/perl -w

use strict;
use CGI::FormBuilder;

my $form = CGI::FormBuilder->new(
                fields => [qw(type string status category)],
                header => 1,
                template => 'ticket_search.tmpl',
                submit => 'Search',     # search button
                reset  => 0,            # and no reset
           );

# Need to setup some specific field options
$form->field(name    => 'type',
             options => [qw(ticket requestor hostname sysadmin)]);

$form->field(name    => 'status',
             type    => 'radio',
             options => [qw(incomplete recently_completed all)],
             value   => 'incomplete');

$form->field(name    => 'category',
             type    => 'checkbox',
             options => [qw(server network desktop printer)]);

# Render the form and print it out so our submit button says "Search"
print $form->render;

Then, in our ticket_search.tmpl HTML file, we would have something like this:

<html>
<head>
  <title>Search Engine</title>
  <tmpl_var js-head>
</head>
<body bgcolor="white">
<center>
<p>
Please enter a term to search the ticket database.
<p>
<tmpl_var form-start>
Search by <tmpl_var field-type> for <tmpl_var field-string>
<tmpl_var form-submit>
<p>
Status: <tmpl_var field-status>
<p>
Category: <tmpl_var field-category>
<p>
</form>
</body>
</html>

That's all you need for a sticky search form with the above HTML layout. Notice that you can change the HTML layout as much as you want without having to touch your CGI code.

Ex4: user_info.cgi

This script grabs the user's information out of a database and lets them update it dynamically. The DBI information is provided as an example, your mileage may vary:

#!/usr/bin/perl -w

use strict;
use CGI::FormBuilder;
use DBI;
use DBD::Oracle

my $dbh = DBI->connect('dbi:Oracle:db', 'user', 'pass');

# We create a new form. Note we've specified very little,
# since we're getting all our values from our database.
my $form = CGI::FormBuilder->new(
                fields => [qw(username password confirm_password
                              first_name last_name email)]
           );

# Now get the value of the username from our app
my $user = $form->cgi_param('user');
my $sth = $dbh->prepare("select * from user_info where user = '$user'");
$sth->execute;
my $default_hashref = $sth->fetchrow_hashref;

# Render our form with the defaults we got in our hashref
print $form->render(values => $default_hashref,
                    title  => "User information for '$user'",
                    header => 1);

Ex5: add_part.cgi

This presents a screen for users to add parts to an inventory database. Notice how it makes use of the sticky option. If there's an error, then the form is presented with sticky values so that the user can correct them and resubmit. If the submission is ok, though, then the form is presented without sticky values so that the user can enter the next part.

#!/usr/bin/perl -w

use strict;
use CGI::FormBuilder;

my $form = CGI::FormBuilder->new(
                method => 'POST',
                fields => [qw(sn pn model qty comments)],
                labels => {
                    sn => 'Serial Number',
                    pn => 'Part Number'
                },
                sticky => 0,
                header => 1,
                required => [qw(sn pn model qty)],
                validate => {
                     sn  => '/^[PL]\d{2}-\d{4}-\d{4}$/',
                     pn  => '/^[AQM]\d{2}-\d{4}$/',
                     qty => 'INT'
                },
                font => 'arial,helvetica'
           );

# shrink the qty field for prettiness, lengthen model
$form->field(name => 'qty',   size => 4);
$form->field(name => 'model', size => 60);

if ($form->submitted) {
    if ($form->validate) {
        # Add part to database
    } else {
        # Invalid; show form and allow corrections
        print $form->render(sticky => 1);
        exit;
    }
}

# Print form for next part addition.
print $form->render;

With the exception of the database code, that's the whole application.

Ex6: Session Management

This creates a session via CGI::Session, and ties it in with FormBuilder:

#!/usr/bin/perl -w

use CGI::Session;
use CGI::FormBuilder;

my $form = CGI::FormBuilder->new(fields => \@fields);

# Initialize session
my $session = CGI::Session->new('driver:File',
                                $form->sessionid,
                                { Directory=>'/tmp' });

if ($form->submitted && $form->validate) {
    # Automatically save all parameters
    $session->save_param($form);
}

# Ensure we have the right sessionid (might be new)
$form->sessionid($session->id);

print $form->render;

Yes, it's pretty much that easy. See CGI::FormBuilder::Multi for how to tie this into a multi-page form.

FREQUENTLY ASKED QUESTIONS (FAQ)

There are a couple questions and subtle traps that seem to poke people on a regular basis. Here are some hints.

I'm confused. Why doesn't this work like CGI.pm?

If you're used to CGI.pm, you have to do a little bit of a brain shift when working with this module.

FormBuilder is designed to address fields as abstract entities. That is, you don't create a "checkbox" or "radio group" per se. Instead, you create a field for the data you want to collect. The HTML representation is just one property of this field.

So, if you want a single-option checkbox, simply say something like this:

$form->field(name    => 'join_mailing_list',
             options => ['Yes']);

If you want it to be checked by default, you add the value arg:

$form->field(name    => 'join_mailing_list',
             options => ['Yes'],
             value   => 'Yes');

You see, you're creating a field that has one possible option: "Yes". Then, you're saying its current value is, in fact, "Yes". This will result in FormBuilder creating a single-option field (which is a checkbox by default) and selecting the requested value (meaning that the box will be checked).

If you want multiple values, then all you have to do is specify multiple options:

$form->field(name    => 'join_mailing_list',
             options => ['Yes', 'No'],
             value   => 'Yes');

Now you'll get a radio group, and "Yes" will be selected for you! By viewing fields as data entities (instead of HTML tags) you get much more flexibility and less code maintenance. If you want to be able to accept multiple values, simply use the multiple arg:

$form->field(name     => 'favorite_colors',
             options  => [qw(red green blue)],
             multiple => 1);

In all of these examples, to get the data back you just use the field() method:

my @colors = $form->field('favorite_colors');

And the rest is taken care of for you.

How do I make a multi-screen/multi-mode form?

This is easily doable, but you have to remember a couple things. Most importantly, that FormBuilder only knows about those fields you've told it about. So, let's assume that you're going to use a special parameter called mode to control the mode of your application so that you can call it like this:

myapp.cgi?mode=list&...
myapp.cgi?mode=edit&...
myapp.cgi?mode=remove&...

And so on. You need to do two things. First, you need the keepextras option:

my $form = CGI::FormBuilder->new(..., keepextras => 1);

This will maintain the mode field as a hidden field across requests automatically. Second, you need to realize that since the mode is not a defined field, you have to get it via the cgi_param() method:

my $mode = $form->cgi_param('mode');

This will allow you to build a large multiscreen application easily, even integrating it with modules like CGI::Application if you want.

You can also do this by simply defining mode as a field in your fields declaration. The reason this is discouraged is because when iterating over your fields you'll get mode, which you likely don't want (since it's not "real" data).

Why won't CGI::FormBuilder work with POST requests?

It will, but chances are you're probably doing something like this:

use CGI qw(:standard);
use CGI::FormBuilder;

# Our "mode" parameter determines what we do
my $mode = param('mode');

# Change our form based on our mode
if ($mode eq 'view') {
    my $form = CGI::FormBuilder->new(
                    method => 'POST',
                    fields => [qw(...)],
               );
} elsif ($mode eq 'edit') {
    my $form = CGI::FormBuilder->new(
                    method => 'POST',
                    fields => [qw(...)],
               );
}

The problem is this: Once you read a POST request, it's gone forever. In the above code, what you're doing is having CGI.pm read the POST request (on the first call of param()).

Luckily, there is an easy solution. First, you need to modify your code to use the OO form of CGI.pm. Then, simply specify the CGI object you create to the params option of FormBuilder:

use CGI;
use CGI::FormBuilder;

my $cgi = CGI->new;

# Our "mode" parameter determines what we do
my $mode = $cgi->param('mode');

# Change our form based on our mode
# Note: since it is POST, must specify the 'params' option
if ($mode eq 'view') {
    my $form = CGI::FormBuilder->new(
                    method => 'POST',
                    fields => [qw(...)],
                    params => $cgi      # get CGI params
               );
} elsif ($mode eq 'edit') {
    my $form = CGI::FormBuilder->new(
                    method => 'POST',
                    fields => [qw(...)],
                    params => $cgi      # get CGI params
               );
}

Or, since FormBuilder gives you a cgi_param() function, you could also modify your code so you use FormBuilder exclusively, as in the previous question.

How can I change option XXX based on a conditional?

To change an option, simply use its accessor at any time:

my $form = CGI::FormBuilder->new(
                method => 'POST',
                fields => [qw(name email phone)]
           );

my $mode = $form->cgi_param('mode');

if ($mode eq 'add') {
    $form->title('Add a new entry');
} elsif ($mode eq 'edit') {
    $form->title('Edit existing entry');

    # do something to select existing values
    my %values = select_values();

    $form->values(\%values);
}
print $form->render;

Using the accessors makes permanent changes to your object, so be aware that if you want to reset something to its original value later, you'll have to first save it and then reset it:

my $style = $form->stylesheet;
$form->stylesheet(0);       # turn off
$form->stylesheet($style);  # original setting

You can also specify options to render(), although using the accessors is the preferred way.

How do I manually override the value of a field?

You must specify the force option:

$form->field(name  => 'name_of_field',
             value => $value,
             force => 1);

If you don't specify force, then the CGI value will always win. This is because of the stateless nature of the CGI protocol.

How do I make it so that the values aren't shown in the form?

Turn off sticky:

my $form = CGI::FormBuilder->new(... sticky => 0);

By turning off the sticky option, you will still be able to access the values, but they won't show up in the form.

I can't get "validate" to accept my regular expressions!

You're probably not specifying them within single quotes. See the section on validate above.

Can FormBuilder handle file uploads?

It sure can, and it's really easy too. Just change the enctype as an option to new():

use CGI::FormBuilder;
my $form = CGI::FormBuilder->new(
                enctype => 'multipart/form-data',
                method  => 'POST',
                fields  => [qw(filename)]
           );

$form->field(name => 'filename', type => 'file');

And then get to your file the same way as CGI.pm:

if ($form->submitted) {
    my $file = $form->field('filename');

    # save contents in file, etc ...
    open F, ">$dir/$file" or die $!;
    while (<$file>) {
        print F;
    }
    close F;

    print $form->confirm(header => 1);
} else {
    print $form->render(header => 1);
}

In fact, that's a whole file upload program right there.

REFERENCES

This really doesn't belong here, but unfortunately many people are confused by references in Perl. Don't be - they're not that tricky. When you take a reference, you're basically turning something into a scalar value. Sort of. You have to do this if you want to pass arrays intact into functions in Perl 5.

A reference is taken by preceding the variable with a backslash (\). In our examples above, you saw something similar to this:

my @fields = ('name', 'email');   # same as = qw(name email)

my $form = CGI::FormBuilder->new(fields => \@fields);

Here, \@fields is a reference. Specifically, it's an array reference, or "arrayref" for short.

Similarly, we can do the same thing with hashes:

my %validate = (
    name  => 'NAME';
    email => 'EMAIL',
);

my $form = CGI::FormBuilder->new( ... validate => \%validate);

Here, \%validate is a hash reference, or "hashref".

Basically, if you don't understand references and are having trouble wrapping your brain around them, you can try this simple rule: Any time you're passing an array or hash into a function, you must precede it with a backslash. Usually that's true for CPAN modules.

Finally, there are two more types of references: anonymous arrayrefs and anonymous hashrefs. These are created with [] and {}, respectively. So, for our purposes there is no real difference between this code:

my @fields = qw(name email);
my %validate = (name => 'NAME', email => 'EMAIL');

my $form = CGI::FormBuilder->new(
                fields   => \@fields,
                validate => \%validate
           );

And this code:

my $form = CGI::FormBuilder->new(
                fields   => [ qw(name email) ],
                validate => { name => 'NAME', email => 'EMAIL' }
           );

Except that the latter doesn't require that we first create @fields and %validate variables.

NOTES

Parameters beginning with a leading underscore are reserved for future use by this module. Use at your own peril.

The field() method has the alias param() for compatibility with other modules, allowing you to pass a $form around just like a $cgi object.

The output of the HTML generated natively may change slightly from release to release. If you need precise control, use a template.

Every attempt has been made to make this module taint-safe (-T). However, due to the way tainting works, you may run into the message "Insecure dependency" or "Insecure $ENV{PATH}". If so, make sure you are setting $ENV{PATH} at the top of your script.

ACKNOWLEDGEMENTS

This module has really taken off, thanks to very useful input, bug reports, and encouraging feedback from a number of people, including:

Norton Allen
Mark Belanger
Peter Billam
Brad Bowman
Jonathan Buhacoff
Godfrey Carnegie
Jakob Curdes
Bob Egert
Peter Eichman
Adam Foxson
Jorge Gonzalez
Florian Helmberger
Mark Houliston
Robert James Kaes
Dimitry Kharitonov
Randy Kobes
William Large
Kevin Lubic
Robert Mathews
Mehryar
Koos Pol
Shawn Poulson
Dan Collis Puro
David Siegal
Stephan Springl
Ryan Tate
John Theus
Remi Turboult
Andy Wardley
Raphael Wegmann
Emanuele Zeppieri

Thanks!

REVISION

$Id: FormBuilder.pm,v 1.58 2005/04/06 18:46:32 nwiger Exp $

AUTHOR

This module is free software; you may copy this under the terms of the GNU General Public License, or the Artistic License, copies of which should have accompanied your Perl kit.

To install CGI::FormBuilder, copy and paste the appropriate command in to your terminal.

cpanm

cpanm CGI::FormBuilder

CPAN shell

perl -MCPAN -e shell
install CGI::FormBuilder

For more information on module installation, please visit the detailed CPAN module installation guide.

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