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HOWTO : Information on using arrays with forms (part 1 of n) :
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A few array/form questions have popped up recently so here begins a HOWTO
on dealing with them. We'll be using $form within our examples so without
further ado, let's talk a little about arrays and forms.
Arrays can be called as usual, such as :
<input type="text" name="form[]">
<input type="text" name="form[]">
<input type="text" name="form[]">
To create this with PHP use a for loop OR quickly try this :
$max = 3;
echo str_repeat('<input type="text" name="form[]">',$max);
When submitted by the user this will create an array with 3 elements
named 0-2, it'll look something like :
$form = array( 0 => 'philip', 1 => '[EMAIL PROTECTED]', 2 => 'me.com' );
Also, associative arrays work with forms, like this :
<input type="text" name="form[name]">
<input type="text" name="form[email]">
<input type="text" name="form[url]">
Here's a quick simple way to create this form with PHP :
$names = array('name','email','url');
foreach ($names as $name) {
echo '<input type="text" name="form['. $name .']">';
}
Upon submittion this gives us an associative array similar to :
$form = array( 'name'=>'philip', 'email'=>'[EMAIL PROTECTED]', 'url'=>'me.com' );
In both cases, our form processor reads this submitted array and does its
thing. It's here we get creative and make the user well aware of what's
happening and what needs to happen. Doing so means printing existing
values within the form when resubmition is required. We want to inform
the user what went wrong (not long enough, must be alphanumeric, etc.) and
what to do about it (<b>fill this out!</b>). We'll deal with this later.
It's good to know about these (and other) PHP and Environment variables :
REQUEST_METHOD = What method the form has made, such as POST and GET
HTTP_POST_VARS = Array of POSTed information
HTTP_GET_VARS = Array of GETed information
QUERY_STRING = String of GET information ?a=b&c=d&e=f
GLOBALS = An array that contains all global variables. This is
freely available within functions too.
More are seen through a call to phpinfo() and listed here :
http://www.php.net/manual/en/language.variables.predefined.php
It's also good to know about these (and other) settings :
register_globals = When enabled, variables automatically enter the
GLOBAL space. If enabled, $form can be called
directly otherwise the variables are to be read by
other means, like with HTTP_GET_VARS and
QUERY_STRING. Something like this :
$form_data_array = $HTTP_POST_VARS['form'];
magic_quotes_gpc = If on, data is escaped automagically on Get,Post and
Cookies (GPC). This can also be done manually with
addslashes() and if data is viewed while slashes
still exist use stripslashes() to strip them first.
Also get_magic_quotes_gpc() tells us the current
setting.
Read about php.ini settings here :
http://www.php.net/manual/en/configuration.php
Current settings can be seen through phpinfo(). In our next installment
(when?) we'll talk a little about processing our form arrays.
All words welcome.
Regards,
Philip
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