1HTML::Form(3) User Contributed Perl Documentation HTML::Form(3)
2
6 HTML::Form - Class that represents an HTML form element
7
9 use HTML::Form;
10 $form = HTML::Form->parse($html, $base_uri);
11 $form->value(query => "Perl");
12 use LWP::UserAgent;
14 $ua = LWP::UserAgent->new;
15 $response = $ua->request($form->click);
16
18 Objects of the "HTML::Form" class represents a single HTML "<form> ...
19 </form>" instance. A form consists of a sequence of inputs that usu‐
20 ally have names, and which can take on various values. The state of a
21 form can be tweaked and it can then be asked to provide "HTTP::Request"
22 objects that can be passed to the request() method of "LWP::UserAgent".
23 The following methods are available:
25 @forms = HTML::Form->parse( $response )
27 @forms = HTML::Form->parse( $html_document, $base )
28 @forms = HTML::Form->parse( $html_document, %opt )
29 The parse() class method will parse an HTML document and build up
30 "HTML::Form" objects for each <form> element found. If called in
31 scalar context only returns the first <form>. Returns an empty
32 list if there are no forms to be found.
33 The $base is the URI used to retrieve the $html_document. It is
35 needed to resolve relative action URIs. If the document was
36 retrieved with LWP then this this parameter is obtained from the
37 $response->base() method, as shown by the following example:
38 my $ua = LWP::UserAgent->new;
40 my $response = $ua->get("http://www.example.com/form.html");
41 my @forms = HTML::Form->parse($response->decoded_content,
42 $response->base);
43 The parse() method can parse from an "HTTP::Response" object
45 directly, so the example above can be more conveniently written as:
46 my $ua = LWP::UserAgent->new;
48 my $response = $ua->get("http://www.example.com/form.html");
49 my @forms = HTML::Form->parse($response);
50 Note that any object that implements a decoded_content() and base()
52 method with similar behaviour as "HTTP::Response" will do.
53 Finally options might be passed in to control how the parse method
55 behaves. The following options are currently recognized:
56 "base"
58 Another way to provide the base URI.
59 "verbose"
61 Print messages to STDERR about any bad HTML form constructs
62 found.
63 $method = $form->method
65 $form->method( $new_method )
66 This method is gets/sets the method name used for the
67 "HTTP::Request" generated. It is a string like "GET" or "POST".
68 $action = $form->action
70 $form->action( $new_action )
71 This method gets/sets the URI which we want to apply the request
72 method to.
73 $enctype = $form->enctype
75 $form->enctype( $new_enctype )
76 This method gets/sets the encoding type for the form data. It is a
77 string like "application/x-www-form-urlencoded" or "multi‐
78 part/form-data".
79 $value = $form->attr( $name )
81 $form->attr( $name, $new_value )
82 This method give access to the original HTML attributes of the
83 <form> tag. The $name should always be passed in lower case.
84 Example:
86 @f = HTML::Form->parse( $html, $foo );
88 @f = grep $_->attr("id") eq "foo", @f;
89 die "No form named 'foo' found" unless @f;
90 $foo = shift @f;
91 @inputs = $form->inputs
93 This method returns the list of inputs in the form. If called in
94 scalar context it returns the number of inputs contained in the
95 form. See "INPUTS" for what methods are available for the input
96 objects returned.
97 $input = $form->find_input( $name )
99 $input = $form->find_input( $name, $type )
100 $input = $form->find_input( $name, $type, $index )
101 This method is used to locate specific inputs within the form. All
102 inputs that match the arguments given are returned. In scalar con‐
103 text only the first is returned, or "undef" if none match.
104 If $name is specified, then the input must have the indicated name.
106 If $type is specified, then the input must have the specified type.
108 The following type names are used: "text", "password", "hidden",
109 "textarea", "file", "image", "submit", "radio", "checkbox" and
110 "option".
111 The $index is the sequence number of the input matched where 1 is
113 the first. If combined with $name and/or $type then it select the
114 nth input with the given name and/or type.
115 $value = $form->value( $name )
117 $form->value( $name, $new_value )
118 The value() method can be used to get/set the value of some input.
119 If no input has the indicated name, then this method will croak.
120 If multiple inputs have the same name, only the first one will be
122 affected.
123 The call:
125 $form->value('foo')
127 is a short-hand for:
129 $form->find_input('foo')->value;
131 @names = $form->param
133 @values = $form->param( $name )
134 $form->param( $name, $value, ... )
135 $form->param( $name, \@values )
136 Alternative interface to examining and setting the values of the
137 form.
138 If called without arguments then it returns the names of all the
140 inputs in the form. The names will not repeat even if multiple
141 inputs have the same name. In scalar context the number of differ‐
142 ent names is returned.
143 If called with a single argument then it returns the value or val‐
145 ues of inputs with the given name. If called in scalar context
146 only the first value is returned. If no input exists with the
147 given name, then "undef" is returned.
148 If called with 2 or more arguments then it will set values of the
150 named inputs. This form will croak if no inputs have the given
151 name or if any of the values provided does not fit. Values can
152 also be provided as a reference to an array. This form will allow
153 unsetting all values with the given name as well.
154 This interface resembles that of the param() function of the CGI
156 module.
157 $form->try_others( \&callback )
159 This method will iterate over all permutations of unvisited enumer‐
160 ated values (<select>, <radio>, <checkbox>) and invoke the callback
161 for each. The callback is passed the $form as argument. The
162 return value from the callback is ignored and the try_others()
163 method itself does not return anything.
164 $request = $form->make_request
166 Will return an "HTTP::Request" object that reflects the current
167 setting of the form. You might want to use the click() method
168 instead.
169 $request = $form->click
171 $request = $form->click( $name )
172 $request = $form->click( $x, $y )
173 $request = $form->click( $name, $x, $y )
174 Will "click" on the first clickable input (which will be of type
175 "submit" or "image"). The result of clicking is an "HTTP::Request"
176 object that can then be passed to "LWP::UserAgent" if you want to
177 obtain the server response.
178 If a $name is specified, we will click on the first clickable input
180 with the given name, and the method will croak if no clickable
181 input with the given name is found. If $name is not specified,
182 then it is ok if the form contains no clickable inputs. In this
183 case the click() method returns the same request as the
184 make_request() method would do.
185 If there are multiple clickable inputs with the same name, then
187 there is no way to get the click() method of the "HTML::Form" to
188 click on any but the first. If you need this you would have to
189 locate the input with find_input() and invoke the click() method on
190 the given input yourself.
191 A click coordinate pair can also be provided, but this only makes a
193 difference if you clicked on an image. The default coordinate is
194 (1,1). The upper-left corner of the image is (0,0), but some badly
195 coded CGI scripts are known to not recognize this. Therefore (1,1)
196 was selected as a safer default.
197 @kw = $form->form
199 Returns the current setting as a sequence of key/value pairs. Note
200 that keys might be repeated, which means that some values might be
201 lost if the return values are assigned to a hash.
202 In scalar context this method returns the number of key/value pairs
204 generated.
205 $form->dump
207 Returns a textual representation of current state of the form.
208 Mainly useful for debugging. If called in void context, then the
209 dump is printed on STDERR.
210
212 An "HTML::Form" objects contains a sequence of inputs. References to
213 the inputs can be obtained with the $form->inputs or $form->find_input
214 methods.
215 Note that there is not a one-to-one correspondence between input
217 objects and <input> elements in the HTML document. An input object
218 basically represents a name/value pair, so when multiple HTML elements
219 contribute to the same name/value pair in the submitted form they are
220 combined.
221 The input elements that are mapped one-to-one are "text", "textarea",
223 "password", "hidden", "file", "image", "submit" and "checkbox". For
224 the "radio" and "option" inputs the story is not as simple: All <input
225 type="radio"> elements with the same name will contribute to the same
226 input radio object. The number of radio input objects will be the same
227 as the number of distinct names used for the <input type="radio"> ele‐
228 ments. For a <select> element without the "multiple" attribute there
229 will be one input object of type of "option". For a <select multiple>
230 element there will be one input object for each contained <option> ele‐
231 ment. Each one of these option objects will have the same name.
232 The following methods are available for the input objects:
234 $input->type
236 Returns the type of this input. The type is one of the following
237 strings: "text", "password", "hidden", "textarea", "file", "image",
238 "submit", "radio", "checkbox" or "option".
239 $name = $input->name
241 $input->name( $new_name )
242 This method can be used to get/set the current name of the input.
243 $value = $input->value
245 $input->value( $new_value )
246 This method can be used to get/set the current value of an input.
247 If the input only can take an enumerated list of values, then it is
249 an error to try to set it to something else and the method will
250 croak if you try.
251 You will also be able to set the value of read-only inputs, but a
253 warning will be generated if running under "perl -w".
254 $input->possible_values
256 Returns a list of all values that an input can take. For inputs
257 that do not have discrete values, this returns an empty list.
258 $input->other_possible_values
260 Returns a list of all values not tried yet.
261 $input->value_names
263 For some inputs the values can have names that are different from
264 the values themselves. The number of names returned by this method
265 will match the number of values reported by $input->possible_val‐
266 ues.
267 When setting values using the value() method it is also possible to
269 use the value names in place of the value itself.
270 $bool = $input->readonly
272 $input->readonly( $bool )
273 This method is used to get/set the value of the readonly attribute.
274 You are allowed to modify the value of readonly inputs, but setting
275 the value will generate some noise when warnings are enabled. Hid‐
276 den fields always start out readonly.
277 $bool = $input->disabled
279 $input->disabled( $bool )
280 This method is used to get/set the value of the disabled attribute.
281 Disabled inputs do not contribute any key/value pairs for the form
282 value.
283 $input->form_name_value
285 Returns a (possible empty) list of key/value pairs that should be
286 incorporated in the form value from this input.
287 $input->check
289 Some input types represent toggles that can be turned on/off. This
290 includes "checkbox" and "option" inputs. Calling this method turns
291 this input on without having to know the value name. If the input
292 is already on, then nothing happens.
293 This has the same effect as:
295 $input->value($input->possible_values[1]);
297 The input can be turned off with:
299 $input->value(undef);
301 $input->click($form, $x, $y)
303 Some input types (currently "submit" buttons and "images") can be
304 clicked to submit the form. The click() method returns the corre‐
305 sponding "HTTP::Request" object.
306 If the input is of type "file", then it has these additional methods:
308 $input->file
310 This is just an alias for the value() method. It sets the filename
311 to read data from.
312 $filename = $input->filename
314 $input->filename( $new_filename )
315 This get/sets the filename reported to the server during file
316 upload. This attribute defaults to the value reported by the
317 file() method.
318 $content = $input->content
320 $input->content( $new_content )
321 This get/sets the file content provided to the server during file
322 upload. This method can be used if you do not want the content to
323 be read from an actual file.
324 @headers = $input->headers
326 input->headers($key => $value, .... )
327 This get/set additional header fields describing the file uploaded.
328 This can for instance be used to set the "Content-Type" reported
329 for the file.
330
332 LWP, LWP::UserAgent, HTML::Parser
333
335 Copyright 1998-2005 Gisle Aas.
336 This library is free software; you can redistribute it and/or modify it
338 under the same terms as Perl itself.
339perl v5.8.8 2004-04-06 HTML::Form(3)