form.pm

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=item $form->param( $name, $value, ... )

=item $form->param( $name, \@values )

Alternative interface to examining and setting the values of the form.

If called without arguments then it returns the names of all the
inputs in the form.  The names will not repeat even if multiple inputs
have the same name.  In scalar context the number of different names
is returned.

If called with a single argument then it returns the value or values
of inputs with the given name.  If called in scalar context only the
first value is returned.  If no input exists with the given name, then
C<undef> is returned.

If called with 2 or more arguments then it will set values of the
named inputs.  This form will croak if no inputs have the given name
or if any of the values provided does not fit.  Values can also be
provided as a reference to an array.  This form will allow unsetting
all values with the given name as well.

This interface resembles that of the param() function of the CGI
module.

=cut

sub param {
    my $self = shift;
    if (@_) {
        my $name = shift;
        my @inputs;
        for ($self->inputs) {
            my $n = $_->name;
            next if !defined($n) || $n ne $name;
            push(@inputs, $_);
        }

        if (@_) {
            # set
            die "No '$name' parameter exists" unless @inputs;
	    my @v = @_;
	    @v = @{$v[0]} if @v == 1 && ref($v[0]);
            while (@v) {
                my $v = shift @v;
                my $err;
                for my $i (0 .. @inputs-1) {
                    eval {
                        $inputs[$i]->value($v);
                    };
                    unless ($@) {
                        undef($err);
                        splice(@inputs, $i, 1);
                        last;
                    }
                    $err ||= $@;
                }
                die $err if $err;
            }

	    # the rest of the input should be cleared
	    for (@inputs) {
		$_->value(undef);
	    }
        }
        else {
            # get
            my @v;
            for (@inputs) {
		if (defined(my $v = $_->value)) {
		    push(@v, $v);
		}
            }
            return wantarray ? @v : $v[0];
        }
    }
    else {
        # list parameter names
        my @n;
        my %seen;
        for ($self->inputs) {
            my $n = $_->name;
            next if !defined($n) || $seen{$n}++;
            push(@n, $n);
        }
        return @n;
    }
}


=item $form->try_others( \&callback )

This method will iterate over all permutations of unvisited enumerated
values (<select>, <radio>, <checkbox>) and invoke the callback for
each.  The callback is passed the $form as argument.  The return value
from the callback is ignored and the try_others() method itself does
not return anything.

=cut

sub try_others
{
    my($self, $cb) = @_;
    my @try;
    for (@{$self->{'inputs'}}) {
	my @not_tried_yet = $_->other_possible_values;
	next unless @not_tried_yet;
	push(@try, [\@not_tried_yet, $_]);
    }
    return unless @try;
    $self->_try($cb, \@try, 0);
}

sub _try
{
    my($self, $cb, $try, $i) = @_;
    for (@{$try->[$i][0]}) {
	$try->[$i][1]->value($_);
	&$cb($self);
	$self->_try($cb, $try, $i+1) if $i+1 < @$try;
    }
}


=item $request = $form->make_request

Will return an C<HTTP::Request> object that reflects the current setting
of the form.  You might want to use the click() method instead.

=cut

sub make_request
{
    my $self = shift;
    my $method  = uc $self->{'method'};
    my $uri     = $self->{'action'};
    my $enctype = $self->{'enctype'};
    my @form    = $self->form;

    if ($method eq "GET") {
	require HTTP::Request;
	$uri = URI->new($uri, "http");
	$uri->query_form(@form);
	return HTTP::Request->new(GET => $uri);
    }
    elsif ($method eq "POST") {
	require HTTP::Request::Common;
	return HTTP::Request::Common::POST($uri, \@form,
					   Content_Type => $enctype);
    }
    else {
	Carp::croak("Unknown method '$method'");
    }
}


=item $request = $form->click

=item $request = $form->click( $name )

=item $request = $form->click( $x, $y )

=item $request = $form->click( $name, $x, $y )

Will "click" on the first clickable input (which will be of type
C<submit> or C<image>).  The result of clicking is an C<HTTP::Request>
object that can then be passed to C<LWP::UserAgent> if you want to
obtain the server response.

If a $name is specified, we will click on the first clickable input
with the given name, and the method will croak if no clickable input
with the given name is found.  If $name is I<not> specified, then it
is ok if the form contains no clickable inputs.  In this case the
click() method returns the same request as the make_request() method
would do.

If there are multiple clickable inputs with the same name, then there
is no way to get the click() method of the C<HTML::Form> to click on
any but the first.  If you need this you would have to locate the
input with find_input() and invoke the click() method on the given
input yourself.

A click coordinate pair can also be provided, but this only makes a
difference if you clicked on an image.  The default coordinate is
(1,1).  The upper-left corner of the image is (0,0), but some badly
coded CGI scripts are known to not recognize this.  Therefore (1,1) was
selected as a safer default.

=cut

sub click
{
    my $self = shift;
    my $name;
    $name = shift if (@_ % 2) == 1;  # odd number of arguments

    # try to find first submit button to activate
    for (@{$self->{'inputs'}}) {
        next unless $_->can("click");
        next if $name && $_->name ne $name;
	next if $_->disabled;
	return $_->click($self, @_);
    }
    Carp::croak("No clickable input with name $name") if $name;
    $self->make_request;
}


=item @kw = $form->form

Returns the current setting as a sequence of key/value pairs.  Note
that keys might be repeated, which means that some values might be
lost if the return values are assigned to a hash.

In scalar context this method returns the number of key/value pairs
generated.

=cut

sub form
{
    my $self = shift;
    map { $_->form_name_value($self) } @{$self->{'inputs'}};
}


=item $form->dump

Returns a textual representation of current state of the form.  Mainly
useful for debugging.  If called in void context, then the dump is
printed on STDERR.

=cut

sub dump
{
    my $self = shift;
    my $method  = $self->{'method'};
    my $uri     = $self->{'action'};
    my $enctype = $self->{'enctype'};
    my $dump = "$method $uri";
    $dump .= " ($enctype)"
	if $enctype ne "application/x-www-form-urlencoded";
    $dump .= " [$self->{attr}{name}]"
    	if exists $self->{attr}{name};
    $dump .= "\n";
    for ($self->inputs) {
	$dump .= "  " . $_->dump . "\n";
    }
    print STDERR $dump unless defined wantarray;
    $dump;
}


#---------------------------------------------------
package HTML::Form::Input;

=back

=head1 INPUTS

An C<HTML::Form> objects contains a sequence of I<inputs>.  References to
the inputs can be obtained with the $form->inputs or $form->find_input
methods.

Note that there is I<not> a one-to-one correspondence between input
I<objects> and E<lt>inputE<gt> I<elements> in the HTML document.  An
input object basically represents a name/value pair, so when multiple
HTML elements contribute to the same name/value pair in the submitted
form they are combined.

The input elements that are mapped one-to-one are "text", "textarea",
"password", "hidden", "file", "image", "submit" and "checkbox".  For
the "radio" and "option" inputs the story is not as simple: All
E<lt>input type="radio"E<gt> elements with the same name will
contribute to the same input radio object.  The number of radio input
objects will be the same as the number of distinct names used for the
E<lt>input type="radio"E<gt> elements.  For a E<lt>selectE<gt> element
without the C<multiple> attribute there will be one input object of
type of "option".  For a E<lt>select multipleE<gt> element there will
be one input object for each contained E<lt>optionE<gt> element.  Each
one of these option objects will have the same name.

The following methods are available for the I<input> objects:

=over 4

=cut

sub new
{
    my $class = shift;
    my $self = bless {@_}, $class;
    $self;
}

sub add_to_form
{
    my($self, $form) = @_;
    push(@{$form->{'inputs'}}, $self);
    $self;
}

sub fixup {}


=item $input->type

Returns the type of this input.  The type is one of the following
strings: "text", "password", "hidden", "textarea", "file", "image", "submit",
"radio", "checkbox" or "option".

=cut

sub type
{
    shift->{type};
}

=item $name = $input->name

=item $input->name( $new_name )

This method can be used to get/set the current name of the input.

=item $value = $input->value

=item $input->value( $new_value )

This method can be used to get/set the current value of an
input.

If the input only can take an enumerated list of values, then it is an
error to try to set it to something else and the method will croak if
you try.

You will also be able to set the value of read-only inputs, but a
warning will be generated if running under C<perl -w>.

=cut

sub name
{
    my $self = shift;
    my $old = $self->{name};
    $self->{name} = shift if @_;
    $old;
}

sub value
{
    my $self = shift;
    my $old = $self->{value};
    $self->{value} = shift if @_;
    $old;
}

=item $input->possible_values

Returns a list of all values that an input can take.  For inputs that
do not have discrete values, this returns an empty list.

=cut

sub possible_values
{
    return;
}

=item $input->other_possible_values

Returns a list of all values not tried yet.

=cut

sub other_possible_values
{
    return;
}

=item $input->value_names

For some inputs the values can have names that are different from the
values themselves.  The number of names returned by this method will
match the number of values reported by $input->possible_values.

When setting values using the value() method it is also possible to
use the value names in place of the value itself.

=cut

sub value_names {
    return
}

=item $bool = $input->readonly

=item $input->readonly( $bool )

This method is used to get/set the value of the readonly attribute.
You are allowed to modify the value of readonly inputs, but setting
the value will generate some noise when warnings are enabled.  Hidden
fields always start out readonly.

=cut

sub readonly {
    my $self = shift;
    my $old = $self->{readonly};
    $self->{readonly} = shift if @_;
    $old;
}

=item $bool = $input->disabled

=item $input->disabled( $bool )

This method is used to get/set the value of the disabled attribute.
Disabled inputs do not contribute any key/value pairs for the form
value.

=cut

sub disabled {
    my $self = shift;
    my $old = $self->{disabled};
    $self->{disabled} = shift if @_;
    $old;
}

=item $input->form_name_value

Returns a (possible empty) list of key/value pairs that should be
incorporated in the form value from this input.

=cut

sub form_name_value
{
    my $self = shift;
    my $name = $self->{'name'};
    return unless defined $name;
    return if $self->{disabled};
    my $value = $self->value;
    return unless defined $value;
    return ($name => $value);
}

sub dump
{
    my $self = shift;
    my $name = $self->name;
    $name = "<NONAME>" unless defined $name;
    my $value = $self->value;
    $value = "<UNDEF>" unless defined $value;
    my $dump = "$name=$value";

    my $type = $self->type;

    $type .= " disabled" if $self->disabled;
    $type .= " readonly" if $self->readonly;
    return sprintf "%-30s %s", $dump, "($type)" unless $self->{menu};