PHP and MySQL Web Development - P122 pdf

577
Implementation
(headline, story_text, page, writer, created, modified)
values
('$headline', '$story_text', '$page', '"
.$HTTP_SESSION_VARS['auth_user']."', $time, $time)";
}
$result = mysql_query($sql, $conn);
if (!$result) {
print "There was a database error when executing <pre>$sql</pre>";
print mysql_error();
exit;
}
if ( (isset($HTTP_POST_FILES['picture']['name']) &&
is_uploaded_file($HTTP_POST_FILES['picture']['tmp_name'])))
{
if (!isset($story))
$story = mysql_insert_id();
$type = basename($HTTP_POST_FILES['picture']['type']);
switch ($type) {
case 'jpeg':
case 'pjpeg': $filename = "pictures/$story.jpg";
move_uploaded_file($HTTP_POST_FILES['picture']['tmp_name'],
$filename);
$sql = "update stories
set picture = '$filename'
where id = $story";
$result = mysql_query($sql, $conn);
break;
default: print 'Invalid picture format: '.
$HTTP_POST_FILES['picture']['type'];

}
}
header('Location: '.$HTTP_POST_VARS['destination']);
?>
The delete story link calls delete_story.php, which actions a simple DELETE statement
and returns the writer to the calling page.The code for
delete_story.php is shown in
Listing 26.8.
Listing 26.7 Continued
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578
Chapter 26 Building a Content Management System
Listing 26.8 delete_story.php—Is Used to Delete a Story from the Database
<?php
// delete_story.php
include('include_fns.php');
$conn = db_connect();
$story = $HTTP_GET_VARS['story'];
$sql = "delete from stories where id = $story";
$result = mysql_query($sql, $conn);
header('Location: '.$HTTP_SERVER_VARS['HTTP_REFERER']);
?>
Searching
Clicking the keywords link on the stories list brings up a new form for entering key-
words against the story.There is no limit to the number of keywords that can be entered,
and each keyword is given a weight value, with a higher value indicating that it is more
relevant.
Figure 26.7 shows the screen used to set keywords against a particular story.
Figure 26.7 Setting keywords for a story.
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Implementation
The script keywords.php is fairly straightforward, so we won’t look at it in any detail. It
is included on the CD-ROM.
This script triggers the keyword_add.php and keyword_delete.php scripts.These
scripts are also straightforward, and are therefore not included here.
The script keyword_add.php uses the following query to add new keywords to the
database:
insert into keywords (story, keyword, weight)
values ($story, '$keyword', $weight)
In a similar vein, keyword_delete.php uses the following query to remove a keyword:
delete from keywords where story = $story and keyword = '$keyword'
What is interesting is the way in which the weight values are used to calculate a percent-
age relevance figure when searching.
The search form in search_form.php contains a single field for keywords, and sub-
mits to search.php, which queries the database of live stories to find matching content.
The source for search.php is shown in Listing 26.9.
Listing 26.9 search.php—Finds Matching Stories and Calculates a Percentage Match
Score
<?php
include('include_fns.php');
include('header.php');
$conn = db_connect();
if ($HTTP_POST_VARS['keyword']) {
$k = split(' ', $HTTP_POST_VARS['keyword']);
$num_keywords = count($k);
for ($i=0; $i<$num_keywords; $i++) {
if ($i)
$k_string .= "or k.keyword = '".$k[$i]."' ";
else

$k_string .= "k.keyword = '".$k[$i]."' ";
}
$and .= "and ($k_string) ";
$sql = "select s.id,
s.headline,
10 * sum(k.weight) / $num_keywords as score
from stories s, keywords k
where s.id = k.story
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Chapter 26 Building a Content Management System
$and
group by s.id, s.headline
order by score desc, s.id desc";
$result = mysql_query($sql, $conn);
}
print '<h2>Search results</h2>';
if ($result && mysql_num_rows($result)) {
print '<table>';
while ($qry = mysql_fetch_array($result)) {
print '<tr><td>';
print $qry['headline'];
print '</td><td>';
print floor($qry['score']).'%';
print '</td></tr>';
}
print '</table>';
}
else {
print 'No matching stories found';

}
include('footer.php');
?>
First, the keyword string passed into the script is split up into individual search words.
We are not using any advanced search techniques in this example, such as allowing the
searcher to use AND or OR keywords or group words together into a phrase.
if ($HTTP_POST_VARS['keyword']) {
$k = split(' ', $HTTP_POST_VARS['keyword']);
$num_keywords = count($k);
for ($i=0; $i<$num_keywords; $i++) {
if ($i)
$k_string .= "or k.keyword = '".$k[$i]."' ";
else
$k_string .= "k.keyword = '".$k[$i]."' ";
}
$and .= "and ($k_string) ";
This code uses the PHP function split() to create an array containing each word in
the keyword string separated by a space character. If only one word is specified, it still
returns a single element array and the subsequent loop is executed once. Ultimately the
condition stored in $and will look something similar to
and (k.keyword = 'keyword1' or k.keyword = 'keyword2' or k.keyword = 'keyword3')
Listing 26.9 Continued
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Implementation
The search query built based on the previous code would be
select s.id,
s.headline,
10 * sum(k.weight) / $num_keywords as score
from stories s, keywords k

where s.id = k.story
and (k.keyword = 'keyword1'
or k.keyword = 'keyword2'
or k.keyword = 'keyword3')
group by s.id, s.headline
order by score desc, s.id desc
The calculation for the score is the sum of the weights from all matching keywords
divided by the number of keywords searched for and then multiplied by ten.This favors
searches in which all the keywords entered match the keywords in the database.
Because the weights range from 1 to 10, the maximum value for the score is 100.A
search for three keywords would only be a 100% match with a story if all three were
found for that story and each had a weight of 10.
Editor Screen
The only part of the system we haven’t covered is how a story actually gets published
after it has been written.The script publish.php makes a story live. It is shown in
Listing 26.10.
Listing 26.10 publish.php—Lists All Documents So the Editor Can Choose Which
Ones Are Shown on the Live Site
<?php
include('include_fns.php');
$conn = db_connect();
$sql = 'select * from stories order by modified desc';
$result = mysql_query($sql, $conn);
print '<h2>Editor admin</h2>';
print '<table>';
print '<tr><th>Headline</th><th>Last modified</th></tr>';
while ($story = mysql_fetch_array($result)) {
print '<tr><td>';
print $story['headline'];
print '</td><td>';

print date('M d, H:i', $story['modified']);
print '</td><td>';
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