C.9 Chapter 10
C.9.1 Exercise 1:
Here's a sample template
file, article.html:
<html>
<head><title>{title}</title></head>
<body>
<h1>{headline}</h1>
<h2>By {byline}</h2>
{article}
<hr/>
<h4>Page generated: {date}</h4>
</body>
</html>
Here's the program that replaces the template fields
with actual values. It stores the field names and values in an array
and then uses foreach( ) to iterate through that
array and do the replacement:
<?php
$page = file_get_contents('article.html');
if ($page = = = false) {
die("Can't read article.html: $php_errormsg");
}
$vars = array('{title}' => 'Man Bites Dog',
'{headline}' => 'Man and Dog Trapped in Biting Fiasco',
'{byline}' => 'Ireneo Funes',
'{article}' => "<p>While walking in the park today,
Bioy Casares took a big juicy bite out of his dog, Santa's Little
Helper. When asked why he did it, he said, \"I was hungry.\"</p>",
'{date}' => date('l, F j, Y'));
foreach ($vars as $field => $new_value) {
$page = str_replace($field, $new_value, $page);
}
$result = file_put_contents('dog-article.html', $page);
if (($result = = = false) || ($result = = -1)) {
die("Couldn't write dog-article.html: $php_errormsg");
}
?>
C.9.2 Exercise 2:
Here's a sample addresses.txt:
brilling@tweedledee.example.com
slithy@unicorn.example.com
uffish@knight.example.net
slithy@unicorn.example.com
jubjub@sheep.example.com
tumtum@queen.example.org
slithy@unicorn.example.com
uffish@knight.example.net
manxome@king.example.net
beamish@lion.example.org
uffish@knight.example.net
frumious@tweedledum.example.com
tulgey@carpenter.example.com
vorpal@crow.example.org
beamish@lion.example.org
mimsy@walrus.example.com
frumious@tweedledum.example.com
raths@owl.example.net
frumious@tweedledum.example.com
Here's the program to count the addresses:
<?php
$in_fh = fopen('addresses.txt','rb');
if (! $in_fh) {
die("Can't open addresses.txt: $php_errormsg");
}
// We'll count addresses with this array
$addresses = array( );
for ($line = fgets($in_fh); ! feof($in_fh); $line = fgets($in_fh)) {
if ($line = = = false) {
die("Error reading line: $php_errormsg");
} else {
$line = trim($line);
// Use the address as the key in $addresses
// the value is the number of times that the
// address has appeared
$addresses[$line] = $addresses[$line] + 1;
}
}
if (! fclose($in_fh)) {
die("Can't close addresses.txt: $php_errormsg");
}
$out_fh = fopen('addresses-count.txt','wb');
if (! $out_fh) {
die("Can't open addresses-count.txt: $php_errormsg");
}
// Reverse sort $addresses by element value
arsort($addresses);
foreach ($addresses as $address => $count) {
// Don't forget the newline!
if (fwrite($out_fh, "$count,$address\n") = = = false) {
die("Can't write $count,$address: $php_errormsg");
}
}
if (! fclose($out_fh)) {
die("Can't close addresses-count.txt: $php_errormsg");
}
?>
C.9.3 Exercise 3:
<?php
$fh = fopen('csvdata.csv', 'rb');
if (! $fh) {
die("Can't open csvdata.csv: $php_errormsg");
}
print "<table>\n";
for ($line = fgetcsv($fh, 1024); ! feof($fh); $line = fgetcsv($fh, 1024)) {
// Use implode as in Example 4.21
print '<tr><td>' . implode('</td><td>', $line) . "</td></tr>\n";
}
print '</table>';
?>
C.9.4 Exercise 4:
<?php
// Load the form element helper functions
require 'formhelpers.php';
if ($_POST['_submit_check']) {
// If validate_form( ) returns errors, pass them to show_form( )
if ($form_errors = validate_form( )) {
show_form($form_errors);
} else {
// The submitted data is valid, so process it
process_form( );
}
} else {
// The form wasn't submitted, so display
show_form( );
}
function show_form($errors = '') {
if ($errors) {
print 'You need to correct the following errors: <ul><li>';
print implode('</li><li>',$errors);
print '</li></ul>';
}
// the beginning of the form
print '<form method="POST" action="'.$_SERVER['PHP_SELF'].'">';
// the file name
print' File name: ';
input_text('filename', $_POST);
print '<br/>';
// the submit button
input_submit('submit','Show File');
// the hidden _submit_check variable
print '<input type="hidden" name="_submit_check" value="1"/>';
// the end of the form
print '</form>';
}
function validate_form( ) {
$errors = array( );
// filename is required
if (! strlen(trim($_POST['filename']))) {
$errors[ ] = 'Please enter a file name.';
} else {
// build the full file name from the web server document root
// directory, a slash, and the submitted value
$filename = $_SERVER['DOCUMENT_ROOT'] . '/' . $_POST['filename'];
// Use realpath to resolve any .. sequences
$filename = realpath($filename);
// make sure $filename begins with the document root directory
$docroot_len = strlen($_SERVER['DOCUMENT_ROOT']);
if (substr($filename, 0, $docroot_len) != $_SERVER['DOCUMENT_ROOT']) {
$errors[ ] = 'File name must be under the document root directory.';
}
}
return $errors;
}
function process_form( ) {
// reconstitute the full file name, as in validate_form( )
$filename = $_SERVER['DOCUMENT_ROOT'] . '/' . $_POST['filename'];
$filename = realpath($filename);
// print the contents of the file
print file_get_contents($filename);
}
?>
C.9.5 Exercise 5:
The new validate_form( ) function that implements
the additional rule:
function validate_form( ) {
$errors = array( );
// filename is required
if (! strlen(trim($_POST['filename']))) {
$errors[ ] = 'Please enter a file name.';
} else {
// build the full file name from the web server document root
// directory, a slash, and the submitted value
$filename = $_SERVER['DOCUMENT_ROOT'] . '/' . $_POST['filename'];
// Use realpath to resolve any .. sequences
$filename = realpath($filename);
// make sure $filename begins with the document root directory
$docroot_len = strlen($_SERVER['DOCUMENT_ROOT']);
if (substr($filename, 0, $docroot_len) != $_SERVER['DOCUMENT_ROOT']) {
$errors[ ] = 'File name must be under the document root directory.';
} elseif (strcasecmp(substr($filename, -5), '.html') != 0) {
$errors[ ] = 'File name must end in .html';
}
}
return $errors;
}
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