Knop Code Examples

A few simple examples of Knop code

Usage of the Knop custom types. Also see the online API reference.

Simple form

// Example 1 - A Simple Form

// Create a new form object
var: 'form'=knop_form;

// Add text fields and a submit button
$form -> (addfield: -type='text', -name='firstname', -label='First name');
$form -> (addfield: -type='text', -name='lastname', -label='Last name');
$form -> (addfield: -type='textarea', -name='message', -label='Message');
$form -> (addfield: -type='submit', -name='button_send', -value='Send message');

// Show the form on the page

<form action="simple-form-response.lasso">
	[$form -> renderform]
</form>

simple-form-response.lasso

// Example 1 - A Simple Form, response page

// Create the same form object again
var: 'form'=(knop_form);
$form -> (addfield: -type='text', -name='firstname', -label='First name');
$form -> (addfield: -type='text', -name='lastname', -label='Last name');
$form -> (addfield: -type='textarea', -name='message', -label='Message');
$form -> (addfield: -type='submit', -name='button_send', -value='Send message');

// Load field values from the submission
$form -> loadfields;

// Look at the fielvalues
$form -> updatefields;

/* Use the form input in an inline, for example like this:

	inline: -database=...,
		$form -> updatefields,
		-add;
	/inline;

*/

Form and Database

form-and-database-config.lasso

// Create a database object
var: 'db'=(knop_database: -database='knopdemo', -table='customer', -keyfield='id', -username='knop', -password='knop');

// Create a form object
var: 'form'=(knop_form: -formaction='form-and-database-response.lasso', -database=$db);

// Add text fields and a submit button
$form -> (addfield: -type='text', -name='firstname', -label='First name');
$form -> (addfield: -type='text', -name='lastname', -label='Last name');
$form -> (addfield: -type='textarea', -name='message', -label='Message');
$form -> (addfield: -type='addbutton', -value='Send message');

form-and-database.lasso

// Example 2 - A form talks to a database

// Configure database and form objects in an include
include: 'form-and-database-config.lasso';

// Show the form on the page, this time the form object is a complete html form
$form -> renderform;

form-and-database-response.lasso

// Configure database and form objects in an include
include: 'form-and-database-config.lasso';

// Handle the form submission
$form -> process;

// Show the result

[$form -> (renderhtml: -excludetype='submit')]
Adding record [$db -> error_msg]

Site navigation with knop_nav

nav/index.lasso

//Example 3 - Knop_nav

// Create the parent nav object. 
var: 'nav'=(knop_nav: -navmethod='param', -currentmarker=' »');

// Define the site structure
$nav -> (insert: -key='home', -label='Home Page');

// Create a child nav object 
var: 'subnav'=knop_nav;
$subnav -> (insert: -key='latest', -label='Latest News');
$subnav -> (insert: -key='archive', -label='News Archive');

$nav -> (insert: -key='news', -label='News', -children=$subnav);

// Determine current location so the nav object knows where we are
$nav -> getlocation;

// Generate navigation menu
$nav -> renderhtml;

// Generate a breadcrumb
$nav -> renderbreadcrumb;

<h1>The current page is [$nav -> label]</h1>
<p>The current framework path is [$nav -> path]</p>

Records listing with knop_grid

grid.lasso

// Example 4 - A Grid to show a record listing

// Configuration

// Create a database object
var: 'db'=(knop_database: -database='knopdemo', -table='customer', -keyfield='id', -username='knop', -password='knop');

// Create a grid object
var: 'grid'=(knop_grid: -database=$db);
$grid -> (addfield: -name='firstname', -label='First Name');
$grid -> (addfield: -name='lastname', -label='Last Name');

// Prepare page output

// Perform a search
$db -> (select: ($grid -> sortparams));
($grid -> sortparams);

// Generate the grid

$grid -> renderhtml;

Form input validation

validate-form.lasso

// A Simple Form with validated input using compund expression

// define a few validations
var('namevalidation'={return(params -> size > 0)},
	'passwordvalidation'={
		local('result'=0); // assume input is ok
		if(params -> size < 4);
			#result = 'The password must be at least four characters';
		else(string_findregexp(params, -find='\d') -> size == 0 
			|| string_findregexp(params, -find='\D') -> size == 0);
			#result = 'The password should contain a mix of numbers and letters';
		else(string_findregexp(params, -find='\s') -> size);
			#result = 'The password should contain any spaces';
		/if;
		return(#result);
	});

// Create a new form object
var: 'form'=knop_form;

// Add text fields and a submit button
$form -> (addfield: -type='text', -name='firstname', -label='First name', -validate=$namevalidation);
$form -> (addfield: -type='text', -name='lastname', -label='Last name', -validate=$namevalidation);
$form -> (addfield: -type='text', -name='password', -label='Password', -validate=$passwordvalidation);
$form -> (addfield: -type='textarea', -name='message', -label='Message', -rows=10);
$form -> (addfield: -type='submit', -name='button_send', -value='Send message');

// load field values from form submission
$form -> loadfields;
// perform validation
$form -> validate;

// Show the form on the page

	<form action="validate-form.lasso">
[$form -> renderform]
</form>

if($form -> isvalid);
	'The form input is OK';
else;
	'<p style="color: red">The form has input errors<br>';
	iterate($form -> errors, var('errorfield'));
		if($errorfield -> isa('pair'));
			$form -> getlabel($errorfield -> name) + ': ' + $errorfield -> value;
		else;
			$form -> getlabel($errorfield) + ': The field must not be empty';
		/if;
		'<br>';
	/iterate;
	'</p>';
/if;

Author: Johan Sölve
Created: 12 Oct 2009
Last Modified: 16 Mar 2011