File: Form.pm

package info (click to toggle)
libhtml-form-perl 6.12-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 352 kB
  • sloc: perl: 2,052; makefile: 2
file content (1068 lines) | stat: -rw-r--r-- 33,389 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
package HTML::Form;

use strict;
use URI;
use Carp   ();
use Encode ();

use HTML::Form::TextInput   ();
use HTML::Form::IgnoreInput ();
use HTML::Form::ListInput   ();
use HTML::Form::SubmitInput ();
use HTML::Form::ImageInput  ();
use HTML::Form::FileInput   ();
use HTML::Form::KeygenInput ();

our $VERSION = '6.12';

my %form_tags = map { $_ => 1 } qw(input textarea button select option);

my %type2class = (
    text     => "TextInput",
    password => "TextInput",
    hidden   => "TextInput",
    textarea => "TextInput",

    "reset" => "IgnoreInput",

    radio    => "ListInput",
    checkbox => "ListInput",
    option   => "ListInput",

    button => "SubmitInput",
    submit => "SubmitInput",
    image  => "ImageInput",
    file   => "FileInput",

    keygen => "KeygenInput",
);

# The new HTML5 input types
%type2class = (
    %type2class,
    map { $_ => 'TextInput' } qw(
        tel search url email
        datetime date month week time datetime-local
        number range color
    )
);

# ABSTRACT: Class that represents an HTML form element

sub parse {
    my $class = shift;
    my $html  = shift;
    unshift( @_, "base" ) if @_ == 1;
    my %opt = @_;

    require HTML::TokeParser;
    my $p = HTML::TokeParser->new(
        ref($html) ? $html->decoded_content( ref => 1 ) : \$html );
    Carp::croak "Failed to create HTML::TokeParser object" unless $p;

    my $base_uri = delete $opt{base};
    my $charset  = delete $opt{charset};
    my $strict   = delete $opt{strict};
    my $verbose  = delete $opt{verbose};

    if ($^W) {
        Carp::carp("Unrecognized option $_ in HTML::Form->parse")
            for sort keys %opt;
    }

    unless ( defined $base_uri ) {
        if ( ref($html) ) {
            $base_uri = $html->base;
        }
        else {
            Carp::croak("HTML::Form::parse: No \$base_uri provided");
        }
    }
    unless ( defined $charset ) {
        if ( ref($html) and $html->can("content_charset") ) {
            $charset = $html->content_charset;
        }
        unless ($charset) {
            $charset = "UTF-8";
        }
    }

    my @forms;
    my $f;    # current form

    my %openselect;    # index to the open instance of a select

    while ( my $t = $p->get_tag ) {
        my ( $tag, $attr ) = @$t;
        if ( $tag eq "form" ) {
            my $action = delete $attr->{'action'};
            $action = "" unless defined $action;
            $action = URI->new_abs( $action, $base_uri );
            $f      = $class->new(
                $attr->{'method'},
                $action,
                $attr->{'enctype'}
            );
            $f->accept_charset( $attr->{'accept-charset'} )
                if $attr->{'accept-charset'};
            $f->{default_charset} = $charset;
            $f->{attr}            = $attr;
            $f->strict(1) if $strict;
            %openselect = ();
            push( @forms, $f );
            my ( %labels, $current_label );
            while ( my $t = $p->get_tag ) {
                my ( $tag, $attr ) = @$t;
                last if $tag eq "/form";

                if ( $tag ne 'textarea' ) {

                    # if we are inside a label tag, then keep
                    # appending any text to the current label
                    if ( defined $current_label ) {
                        $current_label = join " ",
                            grep { defined and length } $current_label,
                            $p->get_phrase;
                    }
                }

                if ( $tag eq "input" ) {
                    $attr->{value_name}
                        = exists $attr->{id} && exists $labels{ $attr->{id} }
                        ? $labels{ $attr->{id} }
                        : defined $current_label ? $current_label
                        :                          $p->get_phrase;
                }

                if ( $tag eq "label" ) {
                    $current_label = $p->get_phrase;
                    $labels{ $attr->{for} } = $current_label
                        if exists $attr->{for};
                }
                elsif ( $tag eq "/label" ) {
                    $current_label = undef;
                }
                elsif ( $tag eq "input" ) {
                    my $type = delete $attr->{type} || "text";
                    $f->push_input( $type, $attr, $verbose );
                }
                elsif ( $tag eq "button" ) {
                    my $type = delete $attr->{type} || "submit";
                    $f->push_input( $type, $attr, $verbose );
                }
                elsif ( $tag eq "textarea" ) {
                    $attr->{textarea_value} = $attr->{value}
                        if exists $attr->{value};
                    my $text = $p->get_text("/textarea");
                    $attr->{value} = $text;
                    $f->push_input( "textarea", $attr, $verbose );
                }
                elsif ( $tag eq "select" ) {

                    # rename attributes reserved to come for the option tag
                    for ( "value", "value_name" ) {
                        $attr->{"select_$_"} = delete $attr->{$_}
                            if exists $attr->{$_};
                    }

                    # count this new select option separately
                    my $name = $attr->{name};
                    $name = "" unless defined $name;
                    $openselect{$name}++;

                    while ( $t = $p->get_tag ) {
                        my $tag = shift @$t;
                        last if $tag eq "/select";
                        next if $tag =~ m,/?optgroup,;
                        next if $tag eq "/option";
                        if ( $tag eq "option" ) {
                            my %a = %{ $t->[0] };

                            # rename keys so they don't clash with %attr
                            for ( keys %a ) {
                                next if $_ eq "value";
                                $a{"option_$_"} = delete $a{$_};
                            }
                            while ( my ( $k, $v ) = each %$attr ) {
                                $a{$k} = $v;
                            }
                            $a{value_name} = $p->get_trimmed_text;
                            $a{value}      = delete $a{value_name}
                                unless defined $a{value};
                            $a{idx} = $openselect{$name};
                            $f->push_input( "option", \%a, $verbose );
                        }
                        else {
                            warn("Bad <select> tag '$tag' in $base_uri\n")
                                if $verbose;
                            if (   $tag eq "/form"
                                || $tag eq "input"
                                || $tag eq "textarea"
                                || $tag eq "select"
                                || $tag eq "keygen" ) {

                                # MSIE implicitly terminates the <select> here, so we
                                # try to do the same.  Actually the MSIE behaviour
                                # appears really strange:  <input> and <textarea>
                                # do implicitly close, but not <select>, <keygen> or
                                # </form>.
                                my $type = ( $tag =~ s,^/,, ) ? "E" : "S";
                                $p->unget_token( [ $type, $tag, @$t ] );
                                last;
                            }
                        }
                    }
                }
                elsif ( $tag eq "keygen" ) {
                    $f->push_input( "keygen", $attr, $verbose );
                }
            }
        }
        elsif ( $form_tags{$tag} ) {
            warn("<$tag> outside <form> in $base_uri\n") if $verbose;
        }
    }
    for (@forms) {
        $_->fixup;
    }

    wantarray ? @forms : $forms[0];
}

sub new {
    my $class = shift;
    my $self  = bless {}, $class;
    $self->{method}  = uc( shift || "GET" );
    $self->{action}  = shift || Carp::croak("No action defined");
    $self->{enctype} = lc( shift || "application/x-www-form-urlencoded" );
    $self->{accept_charset}  = "UNKNOWN";
    $self->{default_charset} = "UTF-8";
    $self->{inputs}          = [@_];
    $self;
}

sub push_input {
    my ( $self, $type, $attr, $verbose ) = @_;
    $type = lc $type;
    my $class = $type2class{$type};
    unless ($class) {
        Carp::carp("Unknown input type '$type'") if $verbose;
        $class = "TextInput";
    }
    $class = "HTML::Form::$class";
    my @extra;
    push( @extra, readonly => 1 ) if $type eq "hidden";
    push( @extra, strict   => 1 ) if $self->{strict};
    if ( $type eq "file" && exists $attr->{value} ) {

        # it's not safe to trust the value set by the server
        # the user always needs to explicitly set the names of files to upload
        $attr->{orig_value} = delete $attr->{value};
    }
    delete $attr->{type};    # don't confuse the type argument
    my $input = $class->new( type => $type, %$attr, @extra );
    $input->add_to_form($self);
}

BEGIN {
    # Set up some accessors
    for my $m (qw(method action enctype accept_charset)) {
        no strict 'refs';
        *{$m} = sub {
            my $self = shift;
            my $old  = $self->{$m};
            $self->{$m} = shift if @_;
            $old;
        };
    }
    *uri = \&action;    # alias
}

sub attr {
    my $self = shift;
    my $name = shift;
    return undef unless defined $name;

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

sub strict {
    my $self = shift;
    my $old  = $self->{strict};
    if (@_) {
        $self->{strict} = shift;
        for my $input ( @{ $self->{inputs} } ) {
            $input->strict( $self->{strict} );
        }
    }
    return $old;
}

sub inputs {
    my $self = shift;
    @{ $self->{'inputs'} };
}

sub find_input {
    my ( $self, $selector, $type, $no ) = @_;
    Carp::croak "Invalid index $no"
        if defined $no && $no < 1;
    if (wantarray) {
        warn "find_input called in list context with index specified\n"
            if defined $no;
        my @res;
        my $c;
        for ( @{ $self->{'inputs'} } ) {
            if ( defined($selector) ) {

                # an input that explicitly has no name
                if ( ref($selector) eq 'SCALAR' ) {
                    next
                        if !defined($$selector) && $_->{name};
                }

                # an input that does not fit this selector
                else {
                    next
                        if !$_->selected($selector);
                }
            }
            next if $type && $type ne $_->{type};
            $c++;
            next if $no && $no != $c;
            push( @res, $_ );
        }
        return @res;

    }
    else {
        $no ||= 1;
        for ( @{ $self->{'inputs'} } ) {
            if ( defined($selector) ) {

                # an input that explicitly has no name
                if ( ref($selector) eq 'SCALAR' ) {
                    next
                        if !defined($$selector) && $_->{name};
                }

                # an input that does not fit this selector
                else {
                    next
                        if !$_->selected($selector);
                }
            }
            next if $type && $type ne $_->{type};
            next if --$no;
            return $_;
        }
        return undef;
    }
}

sub fixup {
    my $self = shift;
    for ( @{ $self->{'inputs'} } ) {
        $_->fixup;
    }
}

sub value {
    my $self  = shift;
    my $key   = shift;
    my $input = $self->find_input($key);
    unless ($input) {
        Carp::croak("No such field '$key'") if $self->{strict};
        return undef unless @_;
        $input = $self->push_input( "text", { name => $key, value => "" } );
    }
    local $Carp::CarpLevel = 1;
    $input->value(@_);
}

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
            Carp::croak "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 ||= $@;
                }
                Carp::croak $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;
    }
}

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;
    }
}

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

    my $charset
        = $self->accept_charset eq "UNKNOWN"
        ? $self->{default_charset}
        : $self->accept_charset;
    foreach my $fi (@form) {
        $fi = Encode::encode( $charset, $fi ) unless ref($fi);
    }

    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'");
    }
}

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 $name && !$_->selected($name);
        next if $_->disabled;
        return $_->click( $self, @_ );
    }
    Carp::croak("No clickable input with name $name") if $name;
    $self->make_request;
}

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

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;
}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

HTML::Form - Class that represents an HTML form element

=head1 VERSION

version 6.12

=head1 SYNOPSIS

 use HTML::Form;
 $form = HTML::Form->parse($html, $base_uri);
 $form->value(query => "Perl");

 use LWP::UserAgent;
 $ua = LWP::UserAgent->new;
 $response = $ua->request($form->click);

=head1 DESCRIPTION

Objects of the C<HTML::Form> class represents a single HTML
C<E<lt>formE<gt> ... E<lt>/formE<gt>> instance.  A form consists of a
sequence of inputs that usually have names, and which can take on
various values.  The state of a form can be tweaked and it can then be
asked to provide L<HTTP::Request> objects that can be passed to the
request() method of L<LWP::UserAgent>.

The following methods are available:

=over 4

=item @forms = HTML::Form->parse( $html_document, $base_uri )

=item @forms = HTML::Form->parse( $html_document, base => $base_uri, %opt )

=item @forms = HTML::Form->parse( $response, %opt )

The parse() class method will parse an HTML document and build up
C<HTML::Form> objects for each <form> element found.  If called in scalar
context only returns the first <form>.  Returns an empty list if there
are no forms to be found.

The required arguments is the HTML document to parse ($html_document) and the
URI used to retrieve the document ($base_uri).  The base URI is needed to resolve
relative action URIs.  The provided HTML document should be a Unicode string
(or US-ASCII).

By default HTML::Form assumes that the original document was UTF-8 encoded and
thus encode forms that don't specify an explicit I<accept-charset> as UTF-8.
The charset assumed can be overridden by providing the C<charset> option to
parse().  It's a good idea to be explicit about this parameter as well, thus
the recommended simplest invocation becomes:

    my @forms = HTML::Form->parse(
        Encode::decode($encoding, $html_document_bytes),
        base => $base_uri,
	charset => $encoding,
    );

If the document was retrieved with LWP then the response object provide methods
to obtain a proper value for C<base> and C<charset>:

    my $ua = LWP::UserAgent->new;
    my $response = $ua->get("http://www.example.com/form.html");
    my @forms = HTML::Form->parse($response->decoded_content,
	base => $response->base,
	charset => $response->content_charset,
    );

In fact, the parse() method can parse from an L<HTTP::Response> object
directly, so the example above can be more conveniently written as:

    my $ua = LWP::UserAgent->new;
    my $response = $ua->get("http://www.example.com/form.html");
    my @forms = HTML::Form->parse($response);

Note that any object that implements a decoded_content(), base() and
content_charset() method with similar behaviour as L<HTTP::Response> will do.

Additional options might be passed in to control how the parse method
behaves.  The following are all the options currently recognized:

=over

=item C<< base => $uri >>

This is the URI used to retrieve the original document.  This option is not optional ;-)

=item C<< charset => $str >>

Specify what charset the original document was encoded in.  This is used as
the default for accept_charset.  If not provided this defaults to "UTF-8".

=item C<< verbose => $bool >>

Warn (print messages to STDERR) about any bad HTML form constructs found.
You can trap these with $SIG{__WARN__}.  The default is not to issue warnings.

=item C<< strict => $bool >>

Initialize any form objects with the given strict attribute.
If the strict is turned on the methods that change values of the form will croak if you try
to set illegal values or modify readonly fields.
The default is not to be strict.

=back

=item $form->push_input( $type, \%attr, $verbose )

This method adds additional inputs to the form.
The first argument is the type of input (e.g. hidden, option, etc.).
The second argument is a reference to a hash of the input attributes.
The third argument is optional, and will issue warnings about unknown input types.

Example:

    push_input( 'hidden', {
        name  => 'NewFormElement',
        id    => 'NewFormElementId',
        value => 'some value',
    });

=item $method = $form->method

=item $form->method( $new_method )

This method is gets/sets the I<method> name used for the
L<HTTP::Request> generated.  It is a string like "GET" or "POST".

=item $action = $form->action

=item $form->action( $new_action )

This method gets/sets the URI which we want to apply the request
I<method> to.

=item $enctype = $form->enctype

=item $form->enctype( $new_enctype )

This method gets/sets the encoding type for the form data.  It is a
string like "application/x-www-form-urlencoded" or "multipart/form-data".

=item $accept = $form->accept_charset

=item $form->accept_charset( $new_accept )

This method gets/sets the list of charset encodings that the server processing
the form accepts. Current implementation supports only one-element lists.
Default value is "UNKNOWN" which we interpret as a request to use document
charset as specified by the 'charset' parameter of the parse() method.

=item $value = $form->attr( $name )

=item $form->attr( $name, $new_value )

This method give access to the original HTML attributes of the <form> tag.
The $name should always be passed in lower case.

Example:

   @f = HTML::Form->parse( $html, $foo );
   @f = grep $_->attr("id") eq "foo", @f;
   die "No form named 'foo' found" unless @f;
   $foo = shift @f;

=item $bool = $form->strict

=item $form->strict( $bool )

Gets/sets the strict attribute of a form.  If the strict is turned on
the methods that change values of the form will croak if you try to
set illegal values or modify readonly fields.  The default is not to be strict.

=item @inputs = $form->inputs

This method returns the list of inputs in the form.  If called in
scalar context it returns the number of inputs contained in the form.
See L</INPUTS> for what methods are available for the input objects
returned.

=item $input = $form->find_input( $selector )

=item $input = $form->find_input( $selector, $type )

=item $input = $form->find_input( $selector, $type, $index )

=item @inputs = $form->find_input( $selector )

=item @inputs = $form->find_input( $selector, $type )

This method is used to locate specific inputs within the form.  All
inputs that match the arguments given are returned.  In scalar context
only the first is returned, or C<undef> if none match.

If C<$selector> is not C<undef>, then the input's I<name>, I<id> or I<class>
attribute must match.
A selector prefixed with '#' must match the I<id> attribute of the input.
A selector prefixed with '.' matches the I<class> attribute. A selector prefixed
with '^' or with no prefix matches the I<name> attribute.

    my @by_id         = $form->find_input( '#some-id' );
    my @by_class      = $form->find_input( '.some-class' );
    my @by_name       = $form->find_input( '^some-name' );
    my @also_by_name  = $form->find_input( 'some-name' );

If you want to find an input that has no I<name> at all, pass in a reference
to C<undef>.

    my @nameless_inputs = $form->find_input( \undef );

If C<$type> is not C<undef>, then the input must have the specified type.
The following type names are used: "text", "password", "hidden",
"textarea", "file", "image", "submit", "radio", "checkbox" and "option".

The C<$index> is the sequence number of the input matched where 1 is the
first.  If combined with C<$selector> and/or C<$type>, then it selects the
I<n>th input with the given I<name> and/or type.

=item $value = $form->value( $selector )

=item $form->value( $selector, $new_value )

The value() method can be used to get/set the value of some input.  If
strict is enabled and no input has the indicated name, then this method will croak.

If multiple inputs have the same name, only the first one will be
affected.

The call:

    $form->value('foo')

is basically a short-hand for:

    $form->find_input('foo')->value;

=item @names = $form->param

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

=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.

=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.

=item $request = $form->make_request

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

=item $request = $form->click

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

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

=item $request = $form->click( $selector, $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 L<HTTP::Request>
object that can then be passed to L<LWP::UserAgent> if you want to
obtain the server response.

If a $selector is specified, we will click on the first clickable input
matching the selector, and the method will croak if no matching clickable
input is found.  If $selector 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.  See description of the find_input() method above for how
the $selector is specified.

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.

=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.

=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.

=back

=head1 NAME

HTML::Form - Class that represents an HTML form element

=head1 INPUTS

An C<HTML::Form> object 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

=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".

=item $name = $input->name

=item $input->name( $new_name )

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

=item $input->id

=item $input->class

These methods can be used to get/set the current id or class attribute for the input.

=item $input->selected( $selector )

Returns TRUE if the given selector matched the input.  See the description of
the find_input() method above for a description of the selector syntax.

=item $value = $input->value

=item $input->value( $new_value )

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

If strict is enabled and 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>.

=item $autocomplete = $input->autocomplete

=item $input->autocomplete( $new_autocomplete )

This method can be used to get/set the current value (if any) of C<autcomplete> for the input.

=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.

=item $input->other_possible_values

Returns a list of all values not tried yet.

=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.

=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.

=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.

=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.

=item $input->check

Some input types represent toggles that can be turned on/off.  This
includes "checkbox" and "option" inputs.  Calling this method turns
this input on without having to know the value name.  If the input is
already on, then nothing happens.

This has the same effect as:

    $input->value($input->possible_values[1]);

The input can be turned off with:

    $input->value(undef);

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

Some input types (currently "submit" buttons and "images") can be
clicked to submit the form.  The click() method returns the
corresponding L<HTTP::Request> object.

=back

If the input is of type C<file>, then it has these additional methods:

=over 4

=item $input->file

This is just an alias for the value() method.  It sets the filename to
read data from.

For security reasons this field will never be initialized from the parsing
of a form.  This prevents the server from triggering stealth uploads of
arbitrary files from the client machine.

=item $filename = $input->filename

=item $input->filename( $new_filename )

This get/sets the filename reported to the server during file upload.
This attribute defaults to the value reported by the file() method.

=item $content = $input->content

=item $input->content( $new_content )

This get/sets the file content provided to the server during file
upload.  This method can be used if you do not want the content to be
read from an actual file.

=item @headers = $input->headers

=item input->headers($key => $value, .... )

This get/set additional header fields describing the file uploaded.
This can for instance be used to set the C<Content-Type> reported for
the file.

=back

=head1 SEE ALSO

L<LWP>, L<LWP::UserAgent>, L<HTML::Parser>

=head1 AUTHOR

Gisle Aas <gisle@activestate.com>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 1998 by Gisle Aas.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut