7_forms.php

<?php
// Chapter-7: Exercises

// Question-1

// 1. What does $_POST look like when the following form is submitted with the third option in the Braised Noodles menu selected, 
// the first and last options in the Sweet menu selected, and 4 entered into the text box? ?>
<form method="POST" action="order.php">
    Braised Noodles with: <select name="noodle">
        <option>crab meat</option>
        Chapter Summary | 153
        <option>mushroom</option>
        <option>barbecued pork</option>
        <option>shredded ginger and green onion</option>
    </select>
    <br />
    Sweet: <select name="sweet[]" multiple>
        <option value="puff"> Sesame Seed Puff
        <option value="square"> Coconut Milk Gelatin Square
        <option value="cake"> Brown Sugar Cake
        <option value="ricemeat"> Sweet Rice and Meat
    </select>
    <br />
    Sweet Quantity: <input type="text" name="sweet_q">
    <br />
    <input type="submit" name="submit" value="Order">
</form><?php

// Answer-1

$_POST['noodle'] = 'barbecued pork';
$_POST['sweet'] = ['puff', 'ricemeat'];
$_POST['sweet_q'] = '4';
$_POST['submit'] = 'Order';

// Question-2 

// 2. Write a process_form() function that prints out all submitted form parameters and their values. 
// You can assume that form parameters have only scalar values.

// Answer-2

// Since this is operating on form data, it looks directly at $_POST instead of a validated $input array
function process_form()
{
    print '<ul>';
    foreach ($_POST as $k => $v) {
        print '<li>' . htmlentities($k) . '=' . htmlentities($v) . '</li>';
    }
    print '</ul>';
}

// Question-3

// 3. Write a program that does basic arithmetic. 
// Display a form with text box inputs for two operands and a <select> menu to choose an operation: addition, subtraction, multiplication, or division. 
// Validate the inputs to make sure that they are numeric and appropriate for the chosen operation. 
// The processing function should display the operands, the operator, and the result. 
// For example, if the operands are 4 and 2 and the operation is multiplication, 
// the processing function should display something like 4 * 2 = 8.

// Answer-3

// This assumes FormHelper.php is in the same directory as this file.
require 'FormHelper.php';
// Set up the arrays of choices in the select menu.
// This is needed in display_form(), validate_form(), and process_form(), so it is declared in the global scope.
$ops = array('+', '-', '*', '/');

// The main page logic:
// - If the form is submitted, validate and then process or redisplay
// - If it's not submitted, display
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    // If validate_form() returns errors, pass them to show_form()
    list($errors, $input) = validate_form();
    if ($errors) {
        show_form($errors);
    } else {
        // The submitted data is valid, so process it
        process_form($input);

        // And then show the form again to do another calculation
        show_form();
    }
} else {
    // The form wasn't submitted, so display
    show_form();
}
function show_form($errors = array())
{
    $defaults = array(
        'num1' => 2,
        'op' => 2, // the index of '*' in $ops
        'num2' => 8
    );
    // Set up the $form object with proper defaults
    $form = new FormHelper($defaults);
    // All the HTML and form display is in a separate file for clarity
    include 'math-form.php';
}

function validate_form()
{
    $input = array();
    $errors = array();
    // op is required
    $input['op'] = $GLOBALS['ops'][$_POST['op']] ?? '';
    if (!in_array($input['op'], $GLOBALS['ops'])) {
        $errors[] = 'Please select a valid operation.';
    }
    // num1 and num2 must be numbers
    $input['num1'] = filter_input(INPUT_POST, 'num1', FILTER_VALIDATE_FLOAT);
    if (is_null($input['num1']) || ($input['num1'] === false)) {
        $errors[] = 'Please enter a valid first number.';
    }
    $input['num2'] = filter_input(INPUT_POST, 'num2', FILTER_VALIDATE_FLOAT);
    if (is_null($input['num2']) || ($input['num2'] === false)) {
        $errors[] = 'Please enter a valid second number.';
    }
    // Can't divide by zero
    if (($input['op'] == '/') && ($input['num2'] == 0)) {
        $errors[] = 'Division by zero is not allowed.';
    }
    return array($errors, $input);
}

function process_form2($input)
{
    $result = 0;
    if ($input['op'] == '+') {
        $result = $input['num1'] + $input['num2'];
    } else if ($input['op'] == '-') {
        $result = $input['num1'] - $input['num2'];
    } else if ($input['op'] == '*') {
        $result = $input['num1'] * $input['num2'];
    } else if ($input['op'] == '/') {
        $result = $input['num1'] / $input['num2'];
    }
    $message =
        "{$input['num1']} {$input['op']} {$input['num2']} = $result";
    print "<h3>$message</h3>";
}

// The code relies on the FormHelper.php file discussed in Chapter 7. 
// The mathform.php file referenced, which displays the form HTML, contains: ?>

<form method="POST" action="<?= $form->encode($_SERVER['PHP_SELF']) ?>">
    <table>
        <?php if ($errors) { ?>
            <tr>
                <td>You need to correct the following errors:</td>
                <td>
                    <ul>
                        <?php foreach ($errors as $error) { ?>
                            <li><?= $form->encode($error) ?></li>
                        <?php } ?>
                    </ul>
                </td>
            <?php } ?>
        <tr>
            <td>First Number:</td>
            <td><?= $form->input('text', ['name' => 'num1']) ?></td>
        </tr>
        <tr>
            <td>Operation:</td>
            <td><?= $form->select($GLOBALS['ops'], ['name' => 'op']) ?></td>
        </tr>
        <tr>
            <td>Second Number:</td>
            <td><?= $form->input('text', ['name' => 'num2']) ?></td>
        </tr>
        <tr>
            <td colspan="2" align="center"><?= $form->input(
                'submit',
                ['value' => 'Calculate']
            ) ?>
            </td>
        </tr>
    </table><?php

    // Question-4
    
    // 4. Write a program that displays, validates, and processes a form for entering information about a package to be shipped.
    // The form should contain inputs for the from and to addresses for the package, dimensions of the package, and weight of the package.
    // The validation should check (at least) that the package weighs no more than 150 pounds and that no dimension of the package is more than 36 inches.
    // You can assume that the addresses entered on the form are both US addresses,
    // but you should check that a valid state and a zip code with valid syntax are entered.
    // The processing function in your program should print out the information about the package in an organized, formatted report.
    
    // Answer-4
    
    // This assumes FormHelper.php is in the same directory as this file.
    require 'FormHelper.php';
    // Set up the array of choices in the select menu.
    // This is needed in display_form(), validate_form(),
    // and process_form(), so it is declared in the global scope.
    $states = [ 'AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DC', 'DE', 'FL', 'GA',
    'HI', 'ID', 'IL', 'IN', 'IA', 'KS', 'KY', 'LA', 'ME', 'MD', 'MA', 'MI', 'MN',
    'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ', 'NM', 'NY', 'NC', 'ND', 'OH', 'OK',
    'OR', 'PA', 'RI', 'SC', 'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI',
    'WY' ];

    // The main page logic:
    // - If the form is submitted, validate and then process or redisplay
    // - If it's not submitted, display
    if ($_SERVER['REQUEST_METHOD'] == 'POST') {
        // If validate_form() returns errors, pass them to show_form()
        list($errors, $input) = validate_form();
        if ($errors) {
            show_form($errors);
        } else {
            // The submitted data is valid, so process it
            process_form2($input);
        }
    } else {
        // The form wasn't submitted, so display
        show_form();
    }
    function show_form2($errors = array())
    {
        // Set up the $form object with proper defaults
        $form = new FormHelper();
        // All the HTML and form display is in a separate file for clarity
        include 'shipping-form.php';
    }

    function validate_form2()
    {
        $input = array();
        $errors = array();
        foreach (['from', 'to'] as $addr) {
            // Check required fields
            foreach (['Name' => 'name', 'Address 1' => 'address1', 'City' => 'city', 'State' => 'state'] as $label => $field) {
                $input[$addr . '_' . $field] = $_POST[$addr . '_' . $field] ?? '';
                if (strlen($input[$addr . '_' . $field]) == 0) {
                    $errors[] = "Please enter a value for $addr $label.";
                }
            }
            // Check state
            $input[$addr . '_state'] =
                $GLOBALS['states'][$input[$addr . '_state']] ?? '';
            if (!in_array($input[$addr . '_state'], $GLOBALS['states'])) {
                $errors[] = "Please select a valid $addr state.";
            }
            // Check zip code
            $input[$addr . '_zip'] = filter_input(
                INPUT_POST,
                $addr . '_zip',
                FILTER_VALIDATE_INT,
                [
                    'options' => [
                        'min_range' => 10000,
                        'max_range' => 99999
                    ]
                ]
            );
            if (is_null($input[$addr . '_zip']) || ($input[$addr . '_zip'] === false)) {
                $errors[] = "Please enter a valid $addr ZIP";
            }
            // Don't forget about address2!
            $input[$addr . '_address2'] = $_POST[$addr . '_address2'] ?? '';
        }
        // height, width, depth, weight must all be numbers > 0
        foreach (['height', 'width', 'depth', 'weight'] as $field) {
            $input[$field] = filter_input(INPUT_POST, $field, FILTER_VALIDATE_FLOAT);
            // Since 0 is not valid, we can just test for truth rather than
            // null or exactly false
            if (!($input[$field] && ($input[$field] > 0))) {
                $errors[] = "Please enter a valid $field.";
            }
        }
        // Check weight
        if ($input['weight'] > 150) {
            $errors[] = "The package must weigh no more than 150 lbs.";
        }
        // Check dimensions
        foreach (['height', 'width', 'depth'] as $dim) {
            if ($input[$dim] > 36) {
                $errors[] = "The package $dim must be no more than 36 inches.";
            }
        }
        return array($errors, $input);
    }

    function process_form3($input)
    {
        // Make a template for the report
        $tpl = <<<HTML
            <p>Your package is {height}" x {width}" x {depth}" and weighs {weight} lbs.</p>
            <p>It is coming from:</p>
            <pre>
            {from_name}
            {from_address}
            {from_city}, {from_state} {from_zip}
            </pre>
            <p>It is going to:</p>
            <pre>
            {to_name}
            {to_address}
            {to_city}, {to_state} {to_zip}
            </pre>
            HTML;
        // Adjust addresses in $input for easier output
        foreach (['from', 'to'] as $addr) {
            $input[$addr . '_address'] = $input[$addr . '_address1'];
            if (strlen($input[$addr . '_address2'])) {
                $input[$addr . '_address'] .= "\n" . $input[$addr . '_address2'];
            }
        }
        // Replace each template variable with the corresponding value
        // in $input
        $html = $tpl;
        foreach ($input as $k => $v) {
            $html = str_replace('{' . $k . '}', $v, $html);
        }
        // Print the report
        print $html;
    }

    // The code relies on the FormHelper.php file discussed in Chapter 7. 
    // The shipping-form.php file referenced, which displays the form HTML, contains: ?>
    <form method="POST" action="<?= $form->encode($_SERVER['PHP_SELF']) ?>">
        <table>
            <?php if ($errors) { ?>
                <tr>
                    <td>You need to correct the following errors:</td>
                    <td>
                        <ul>
                            <?php foreach ($errors as $error) { ?>
                                <li><?= $form->encode($error) ?></li>
                            <?php } ?>
                        </ul>
                    </td>
                <?php } ?>
            <tr>
                <th>From:</th>
                <td></td>
            </tr>
            <tr>
                <td>Name:</td>
                <td><?= $form->input('text', ['name' => 'from_name']) ?></td>
            </tr>
            <tr>
                <td>Address 1:</td>
                <td><?= $form->input('text', ['name' => 'from_address1']) ?></td>
            </tr>
            <tr>
                <td>Address 2:</td>
                <td><?= $form->input('text', ['name' => 'from_address2']) ?></td>
            </tr>
            <tr>
                <td>City:</td>
                <td><?= $form->input('text', ['name' => 'from_city']) ?></td>
            </tr>
            <tr>
                <td>State:</td>
                <td><?= $form->select($GLOBALS['states'], ['name' => 'from_state']) ?>
                </td>
            </tr>
            <tr>
                <td>ZIP:</td>
                <td><?= $form->input('text', ['name' => 'from_zip', 'size' => 5]) ?>
                </td>
            </tr>
            <tr>
                <th>To:</th>
                <td></td>
            </tr>
            <tr>
                <td>Name:</td>
                <td><?= $form->input('text', ['name' => 'to_name']) ?></td>
            </tr>
            <tr>
                <td>Address 1:</td>
                <td><?= $form->input('text', ['name' => 'to_address1']) ?></td>
            </tr>
            <tr>
                <td>Address 2:</td>
                <td><?= $form->input('text', ['name' => 'to_address2']) ?></td>
            </tr>
            <tr>
                <td>City:</td>
                <td><?= $form->input('text', ['name' => 'to_city']) ?></td>
            </tr>
            <tr>
                <td>State:</td>
                <td><?= $form->select($GLOBALS['states'], ['name' => 'to_state']) ?>
                </td>
            </tr>
            <tr>
                <td>ZIP:</td>
                <td><?= $form->input('text', ['name' => 'to_zip', 'size' => 5]) ?>
                </td>
            </tr>
            <tr>
                <th>Package:</th>
                <td></td>
            </tr>
            <tr>
                <td>Weight:</td>
                <td><?= $form->input('text', ['name' => 'weight']) ?></td>
            </tr>
            <tr>
                <td>Height:</td>
                <td><?= $form->input('text', ['name' => 'height']) ?></td>
            </tr>
            <tr>
                <td>Width:</td>
                <td><?= $form->input('text', ['name' => 'width']) ?></td>
            </tr>
            <tr>
                <td>Depth:</td>
                <td><?= $form->input('text', ['name' => 'depth']) ?></td>
            </tr>
            <tr>
                <td colspan="2" align="center">
                    <?= $form->input('submit', ['value' => 'Ship!']) ?>
                </td>
            </tr>
        </table>
    </form><?php


    // Question-5
    
    // 5. (Optional) Modify your process_form() function that enumerates all submitted form parameters 
    // and their values so that it correctly handles submitted form parameters that have array values.
    // Remember, those array values could themselves contain arrays.
    
    // Answer-5
    
    function print_array($ar)
    {
        print '<ul>';
        foreach ($ar as $k => $v) {
            if (is_array($v)) {
                print '<li>' . htmlentities($k) . ':</li>';
                print_array($v);
            } else {
                print '<li>' . htmlentities($k) . '=' . htmlentities($v) . '</li>';
            }
        }
        print '</ul>';
    }
    /* Since this is operating on form data, it looks directly at $_POST
    instead of a validated $input array */
    function process_form4()
    {
        print_array($_POST);
    }