Pre-requisites

You’ll server will need to have the following configuration.

• PHP (>=4)
• MySQL (>=4)
• Linux (Distro of your choice)

Step 1:  Download PdfToText

PdfToText is a program written in C that will quickly convert the contents of a PDF to text.  We’re going to use it just for that purpose.  You download the file at ftp://ftp.foolabs.com/pub/xpdf/xpdf-3.02pl4-linux.tar.gz.  Once you have downloaded the file, go ahead and place it somewhere in your web site directory and extract it (on most linux systems “tar -xzf [file]” will do the trick).  Once it’s unzipped, you’ll see a program called “pdftotext”, which is what we’re after.

Step 2:  Convert the PDF to Text

As an astute reader, you’ve probably noticed by now that PdfToText is not a PHP file.  So how are we going to use it?  Well, we’re going to use the “backtick” (the ~ [tilda] key) operator.

function convert_to_text($pdf) {
$output = `./pdftotext {$pdf} temp.txt`;

return $output
}

The backtick operator will execute any command on the command line, trap it’s output, and return it to the caller.  It’s worth noting that the backtick operator will only return output from standard out.

This is probably the hardest part of this tutorial.  There may be problems with write permissions on the directory, or ownership problems, but if you can get it to work, you’re all set.

Step 3:  Read the Text

Now that the PDF has been converted to a text file, we need to get that information back in to PHP.  To do that, we use the file_get_contents functions.

function get_text() {
$text = file_get_contents("temp.txt");

return $text;
}

Step 4:  Store the Data

This part of the tutorial assumes 2 things.  1) That you have a table named pdf_data, and 2) That the table has a column called pdf_contents that is full-text searchable (If you need help setting this sort of thing up, leave a comment).

function store_data() {
$text = mysql_real_escape_string(get_text());
$query = "INSERT INTO pdf_data (pdf_contents) VALUES ('{$text}')";
mysql_query($query);
}

Step 5:  Search the Data

The final step is actually searching the data.  To do that, we’ll use the full-text searching capability of MySQL.

function search_data($term) {
$term = mysql_real_escape_string($term);
$query = "SELECT * FROM pdf_data MATCH(pdf_contents) AGAINST ('$term')";
$result = mysql_query($query);

while($row = mysql_fetch_array($result)) {
//Do stuff with returned data.
}
}

Where “Do stuff with returned data” is, you can do whatever you want.  MySQL is going to return the rows to you in order of relevance (descending).  The most relevant result will be first, followed by the second most, and third most, and so on.

Other Notes

• PdfToText may or may not be the best way to do this, but it is one of the simplest.  There are a handful of libraries out there for creating PDFs in PHP, but surprisingly few for something as common as reading a PDF.
• There are binaries and source files available for PdfToText on their web site(here).
• This tutorial could be expanded a lot.  If you have questions or requests, please ask!

That has yet to materialize, but the community has come to the rescue.  A plugin called Power Code Editor exists that does simple syntax highlighting and improves font that is used in the editor.  After applying the plugin, your code editor will look like this.

If you’re interested, you can download the plugin here.  Or, from within the WordPress plugin installation menu search for “power code editor“.

<form method=POST action='<?=$_SERVER['PHP_SELF']?>'>

or

<a href='<?=$_SERVER['REQUEST_URI']?>'>Click Here</a>

The problem with this code is that it’s easily exploitable.  Remember, the behavior for REQUEST_URI and PHP_SELF are to take whatever the entrance URL was and return it to the caller.  So how can this effect your pages?  Since the user can append anything that they’d like to the initial entrance URL, it becomes the vector for attack.

So how can you submit forms and links back to themselves without these variables?  For forms, just leave the action blank or don’t include it at all.

<form method=POST>

<form method=POST action=''>

And for links, using the # sign will link back to your current page.

<a href='#'>Click here!</a>

If a plugin developer absolutely MUST use server variables, just make sure to escape them accordingly.   Use the WordPress function esc_url().

<a href='<?=esc_url($_SERVER['PHP_SELF']?>'>Click Me!</a>

In reality, it’s bad practice to use the PHP $_SERVER variables at all.  So try to avoid doing it at all costs.

The 6 default roles are Super Admin, Administrator, Editor, Author, Contributor, and Subscriber.

• Super Admin - The Super Admin is a role only available in WordPress 3 when the multi-user (multi-site) features are turned on.  This role allows the super admin to administrate the entire network of sites.
• Administrator - This role allows the user to access all of the administration features of a site, including themes, plugins, and comment moderation.
• Editor - An editor can manage all pages, posts, and comments.  They don’t have to own them either, they can be authored by other users.
• Author - An author is a user that you trust to publish their own posts.
• Contributor - This is a user who is allowed to write posts, but they have to be approved by an editor before they get published.  This is handy if you have a guest that you would like to write an article, but want to review the content first.
• Subscriber - This user is only allowed to edit and maintain their profile on your site.

If these roles aren’t enough to suit your needs (perhaps you need finer-grain permissions), there are plugins that exist in the WordPress Plugin Repository that can help.

Unfortunately, most themes don’t have support for custom menus yet.  Wordpress makes it easy to add them as widgets, but if you want real menus, they need to be enabled in your theme.

Step 1:  Enable Custom Menus

The first thing that you need to do in order to get custom menus working in WordPress 3 is enable them.  To do that, open up your theme’s functions.php file, and drop in the following code.

function register_custom_menu() {
register_nav_menu('custom_menu', __('Custom Menu'));
}
add_action('init', 'register_custom_menu');

Once you have done that, go to Appearance -> Menus and you should see something like this.

Step 2:  Add the Menu to Your Theme

Assuming that you’ve created a custom menu and want to display it, you’ll need to add the display function to your theme.  In most cases, you’ll need to open up the header.php file, and the area that looks like a menu.  This changes for every theme, but it should be fairly obvious.  Once you find it, insert the following code.

<?php wp_nav_menu(array('menu' => 'custom_menu')); ?>

After that, you’re menu should display in your navigation bar.  Good luck!

function exclude_my_plugin( $r, $url ) {

if ( 0 !== strpos( $url, 'http://api.wordpress.org/plugins/update-check' ) )
>return $r;
$plugins = unserialize( $r['body']['plugins'] );
unset( $plugins->plugins[ plugin_basename( __FILE__ ) ] );
unset( $plugins->active[ array_search( plugin_basename( __FILE__ ), $plugins->active ) ] );
$r['body']['plugins'] = serialize( $plugins );

return $r;
}
add_filter( 'http_request_args', 'exclude_my_plugin', 5, 2);

Attribute:  This code is originally from a lead WordPress Developer, Mark Jaquith (thanks Mark!)

But how does this exclude your plugin from the update?  First, it takes the HTTP Request args and unserializes the ['body']['plugins'] part of it.  From there, it’s as simple as unsetting your plugin from the array, then re-serializing the request args.  Also the first part checks to see if this is actually and update check.  If it’s not, you exit the function.

add_custom_background();

After that, under the Appearance menu you should have a “Background” option link.  When clicked, it will look like this.

From there, upload your custom background and bask in your own glory!

Note:  The full source code for this plugin can be found here.

Every time you go to WordPress blog and see items in the sidebar, it’s likely that they are widgets.  There are thousands of them for download on WordPress.org, but what if you want to create your own?  How would you code it? That’s what I will answer in this quick How-To.

<?php
/*
Plugin Name: Sweet Math Widget
Plugin URI: http://www.re-cycledair.com
Description: A math widget that takes the post id and multiplies it by 5.

Author: Jack Slingerland
Version: 0.1

Author URI: http://www.re-cycledair.com
*/
function sweetMathWidget() {

global $post;
echo "{$post->ID} x 5 = ";
echo $post->ID*5;
}
?>

function sweetMathWidgetInit() {
register_sidebar_widget(__('Sweet Math Widget'), 'sweetMathWidget');
}
add_action("plugins_loaded", "sweetMathWidgetInit");

function sweetMathWidget($args) {

global $post;
extract($args);
echo $before_widget;
echo $before_title;
echo "<h2> Sweet Math Widget </h2>";
echo $after_title;
echo "{$post->ID} x 5 = ";echo $post->ID*5;
echo $after_widget;
}