FC6 MediaWiki

FC6 MediaWiki
"MediaWiki is a free software wiki package originally written for Wikipedia. It is now used by several other projects of the non-profit Wikimedia Foundation and by many other wikis." I use it for one of my classes, simply because I am trying to introduce new technology that students are familiar with into the classroom. In general, a wiki can be edited by anyone — however, in my case, I only want the wiki to be edited by my students. To circumvent this problem, many Wiki's are setup so that you can only edit a page if you have logged in. Even so, this still does not preclude an unknown person from registering, logging in, and editing the pages. As a result, I setup my Wiki to include security contexts and groups, meaning that if a user does not have the proper permissions to edit the page, the page cannot be edited. Period.

Installation of MediaWiki requires first heading getting Apache, PHP, and MySQL running. I also find it useful to have phpMyAdmin installed as well. See the appropriate pages if you need help. I also strongly recommend reading over the Installation Guide on MediaWiki's web site.

Assuming that you have the appropriate software installed and configured, head over to their website:

http://www.mediawiki.org/wiki/MediaWiki

Click on the Downloads from SVN link at the left, followed by the mediawiki-1.9.1.tar.gz link on the right, which is the current version of the software (at the time of this writing). Once the file downloads, move the source tarball to the /var/www/html directory:

~> sudo mv ~/Desktop/mediawiki-1.9.1.tar.gz /var/www/html/.

Change into the /var/www/html directory:

~> cd /var/www/html

and decompress the source:

~> sudo tar vfzx mediawiki-1.9.1.tar.gz

Once the package has been decompressed, delete the source file, and move the mediawiki-1.9.1 directory to mediawiki.

~> sudo rm mediawiki-1.9.1.tar.gz
~> sudo mv mediawiki-1.8.1 mediawiki

Before changing into the directory, we need to set the security context and change the ownership:

~> sudo chcon -R system_u:object_r:httpd_sys_content_t mediawiki
~> sudo chown -R apache.apache mediawiki

In this case, we want Apache to have control over the directory so that we can upload files to the Wiki. Then change into the directory and make the config directory writable by all:

~> cd mediawiki
~> sudo chmod go+w config

Next, open up Firefox and go to:

http://[host].[domain].[name]/mediawiki/

Click on the set up the wiki link. If everything is setup properly, you should see a green bullet point that says "Environment checked. You can install MediaWiki". Scroll down to Wiki name and type the Wiki name for your site. My Wiki name is "Professor Kriehn". Verify the contact e-mail address, the language, and click on the appropriate copyright license that you want to use. Choose an Admin username (in this case, I have changed "WikiSysop" to another username), and type in the Password for your Admin user. Since I am maintaining a small Wiki, I do not have Shared memory caching enabled. After this, click on the appropriate e-mail authentication options.

Under Database config, click on the MySQL button. The Database host is "localhost", and choose and appropriate Database name (in this case, I have changed it to "mediawiki"). Pick an appropriate DB username ("mediawiki" is fine), and choose a DB password. Since we have not created the database ahead of time, click on the User superuser account option, and type in the superuser password. Finally, type "mw_" for the Database table prefix. Then click Install MediaWiki.

After MediaWiki installs, you should see another green bullet point that says "Installation successful!" We now need to move the config/LocalSettings.php file to the parent directory:

~> sudo mv config/LocalSettings.php .

While we are at it, we might as well make a backup of the LocalSettings.php file (we are going to be editing it extensively):

~> sudo cp LocalSettings.php LocalSettings.php.bak

Finally, correct the write permissions on the config directory:

~> sudo chmod go-w config

With this done, look again at the last line, indicating that installation was successful. Notice that when the LocalSettings.php file is moved from the config directory, you can click on the "this link" to go to your Wiki. Do so now.

Customizing the Wiki
Most of the customization of the Wiki occurs through the LocalSettings.php file. Before we begin editing that, click on the log in link and log into the Wiki with your Admin username and password. Next, go to the MediaWiki:Sidebar page, meaning that the web address is:

http://[host].[domain].[name]/mediawiki/index.php/MediaWiki:Sidebar

After you are there, click on the edit link and remove line that says

** sitesupport-url|sitesupport

This will remove the Donations link in the Navigation menu on the left. Click the Save page button when finished.

Next, open up the LocalSettings.php file in a text editor. We are going to customize things like the logo up in the top left corner of the Wiki, create a re-direct for the Wiki so that it no longer displays "index.php" in the web address, along with a number of other changes. If you want to understand what each of the configuration options does, go to:

http://www.mediawiki.org/wiki/Help:Configuration_settings

and read about the different Configuration settings.

The first thing we will configure is allow for users to upload files to the Wiki. Perform a search for $wgEnableUploads. Change the setting from "false" to "true" so that the line reads:

$wgEnableUploads = true;

Scroll down a few lines, to the $wgImageMagickConvertCommand option. Under it, add the following lines:

$wgFileExtensions = array( 'png', 'gif', 'jpg', 'jpeg', 'tif', 'tiff', 'txt');
$wgMimeDetectorCommand = "file -bi";

The first line restricts what kinds of files are allowed to be uploaded to the Wiki, and the second line performs MIME detection so that the Wiki knows how to handle various file types. If you want to allow other extensions, add them in the $wgFileExtenstions setting.

Scroll down a few lines and uncomment the $wgHashedUploadDirectory option to upload figures under safe mode:

$wgHashedUploadDirectory = false;

We will have to create the images/archive, images/thumb, and images/temp directories. In another terminal window type:

~> cd /var/www/html/mediawiki/images
~> sudo mkdir archive
~> sudo mkdir thumb
~> sudo mkdir temp
~> sudo chown apache.apache *

Next, scroll down to the very bottom of the LocalSettings.php file, just above the "?>" line. Add the following:

# User Defined Settings

The first setting that we are going to define is the location of the logo in the upper left corner of the screen. Add the following lines:

# Set default skin directory and logo path
$wgStylePath        = "$wgScriptPath/skins";
$wgStyleDirectory   = "$IP/skins";
$wgLogo             = "$wgStylePath/common/images/[figure].[ext]";

Notice that the Wiki is going to look for the logo in /var/www/html/mediawiki/skins/common/images/. Copy the figure that you want to use there.

~> sudo cp <image location> /var/www/html/mediawiki/skins/common/images/.

Let's also fix the timezone:

#Set Default Timezone
$wgLocaltimezone = "America/Los_Angeles";

#Calculate the timezone offset with UTC
$oldtz = getenv("TZ");
putenv("TZ=$wgLocaltimezone");
$wgLocalTZoffset = date("Z") / 60 + date("I") * 60;
putenv("TZ=$oldtz");

Assuming that you do not live in the Pacific Time Zone, you can check for the proper value of $wgLocaltimezone at the Time Zone Descriptions link. Next, we are going to create a redirect from mediawiki to wiki, so that we can use short URLs and remove "index.php" from the web address. The first step in this process involves using the $wgArticlePath option. Add the following lines:

# Redirect path
$wgArticlePath = "/wiki/$1";

Save and exit. This forces MediaWiki to look in the /var/www/html/wiki directory for the article files, even though it does not exist. But this can be done by merely creating an alias from the nonexistent /wiki directory to the /mediawiki directory, which can be done through the configuration file for Apache.

Open the /etc/httpd/conf/httpd.conf file. Scroll down to the very bottom of the file, just above the AcceptPathInfo On option. Above it, add the following:

Alias /wiki /var/www/html/mediawiki/index.php

Save, exit, and restart the Apache daemon:

~> sudo restart service httpd

You should see httpd successfully stop and restart:

Stopping httpd: [ OK ]
Starting httpd: [ OK ]

We have now created an alias that points back to the mediawiki directory that also includes the index.php file. As a result, even though the MediaWiki now looks for articles in the Wiki directory (which, again, does not exist), the directory is aliased back to mediawiki/index.php. If you go to http://[host].[domain].[name]/mediawiki/, instead of seeing the following address:

http://[host].[domain].[name]/mediawiki/index.php/Main_Page

you will now see

http://[host].[domain].[name]/wiki/Main_Page

Much nicer.

Security using NamespacePermissions.php
Some tightened security can be added fairly easily with the NamespacePermissions Extension. In my case, I like to prevent automatic registrations, and only allow users with specific permissions to edit certain kinds of pages. The NamespacePermissions Extension is provided on the WikiMedia website (which is basically a Wiki for the MediaWiki software). Head over to the following address:

http://meta.wikimedia.org/wiki/NamespacePermissions_Extension

Spend some time reading through the web page, before scrolling down to the Source of NamespacePermissions.php file section. Open and editor and copy/paste the PHP code into the editor. Basically, what you are pasting is:

<?php
/* NamespacePermissions - MediaWiki extension
*
* provides separate permissions for each action (read,edit,create,move)
* on articles in custom namespaces for fine access management
*
* Author: Petr Andreev
*
* Sample usage:3
*
* $wgExtraNamespaces = array(100 => "Foo", 101 => "Foo_Talk");
* // optional (example): allow registered users to view and edit articles in Foo
* $wgGroupPermissions[ 'user' ][ 'ns100_read' ] = true;
* $wgGroupPermissions[ 'user' ][ 'ns100_edit' ] = true;
* // end of optional
* require('extensions/NamespacePermissions.php');
*
* Permissions provided:
* # ns{$num}_read
* # ns{$num}_edit
* # ns{$num}_create
* # ns{$num}_move
* where {$num} - namespace number (e.g. ns100_read, ns101_create)
*
* Groups provided:
* # ns{$title}RW - full access to the namespace {$title}
* # ns{$title}RO - read-only access to the namespace {$title}
* e.g. nsFoo_talkRW, nsFooRO
*/

// permissions for autocreated groups should be set now,
// before the User object for current user is instantiated
namespacePermissionsCreateGroups();
// other stuff should better be done via standard mechanism of running extensions
$wgExtensionFunctions[] = "wfNamespacePermissions";

// create groups for each custom namespace
function namespacePermissionsCreateGroups() {
global $wgExtraNamespaces, $wgGroupPermissions;
foreach ( $wgExtraNamespaces as $num => $title ) {
$wgGroupPermissions[ "ns{$title}RW" ][ "ns{$num}_edit" ] = true;
$wgGroupPermissions[ "ns{$title}RW" ][ "ns{$num}_read" ] = true;
$wgGroupPermissions[ "ns{$title}RW" ][ "ns{$num}_create" ] = true;
$wgGroupPermissions[ "ns{$title}RW" ][ "ns{$num}_move" ] = true;
$wgGroupPermissions[ "ns{$title}RO" ][ "ns{$num}_read" ] = true;
}
}

function wfNamespacePermissions() {
global $wgHooks;

// use the userCan hook to check permissions
$wgHooks[ 'userCan' ][] = 'namespacePermissionsCheckNamespace';
}

function namespacePermissionsCheckNamespace( $title, $user, $action, $result ) {
if ( ( $ns = $title->getNamespace() ) >= 100 ) {
if ( ! $user->isAllowed("ns{$ns}_{$action}") ) {
$result = false;
return false;
}
}
return null;
}
?>

Save the file as NamespacePermissions.php, and move it over to the /var/www/html/mediawiki/extensions/ directory:

~> sudo mv NamespacePermissions.php /var/www/html/mediawiki/extensions/.

Now open the /var/www/html/LocalSettings.php file using sudo. Scroll down again to the User Defined Settings section, and add the following:

# This snippet prevents new registrations from anonymous users
# (Sysops can still create user accounts)
$wgGroupPermissions['*']['createaccount'] = false;
# This snippet prevents editing from anonymous users
$wgGroupPermissions['*']['edit'] = false;
# This snippet removes the IP address for non-logged in users
$wgShowIPinHeader = false;

# Define namespaces
$wgExtraNamespaces =
        array(100 => "[Namespace #1]",
              102 => "[Namespace #2]",
             );

$wgGroupPermissions[ '*' ][ 'ns100_read' ] = true;
$wgGroupPermissions[ '*' ][ 'ns102_read' ] = true;
require('extensions/NamespacePermissions.php');

#include READ_ONLY in default search
$wgNamespacesToBeSearchedDefault = array(
        NS_MAIN         => true,
        NS_HELP         => true,
        NS_TEMPLATE     => true,
);

Replace [Namespace #1] and [Namespace #2] with group names for your personal settings. You can remove "102 => "[Namespace #2]"," if you only need to define one group, or add more lines, if necessary. The $wgGroupPermissions option sets the permissions (in this case read only) for the pages that belong to these groups. If you only use one Namespace, delete the second $wgGroupPermissions line; if you want to add more, add additional lines. If you want to change the permissions, see the NamespacePermissions webpage for additional information. As a final note, the convention for Namespaces seems to be using even numbers for read only permissions and odd numbers for read-write permissions.

The next time you login to the Wiki, click on the Special pages link under the toolbox (toward the bottom left). Scroll down to the very bottom of the page that comes up and click on User rights management. If you type in a username and click Edit User Groups, you will notice that the Namespaces that you defined are now available. You can provide users with read only (ns...RO) permissions, or read-write (ns...RW) permissions, as necessary. If you want to create a Wiki page that contains a specific Namespace, meaning that only users who are a part of that Namespace can edit it, then use the following code when creating a link for the page:

[[[Namespace]:[Link Page Name]|[Link Page Name]]

[Namespace]:[Link Page Name] creates a space with a specific Namespace, in this case [Namespace]. The link will appear as a "normal" link, however, due to the "|[Link Page Name]" code. If this is confusing, you can read about Namespaces in general at:

http://meta.wikimedia.org/wiki/Namespace

Again, the Wikimedia website is an extremely valuable source of information. In general, I find Namespaces a slick way of adding security contexts to my Wiki.

Any Wiki can be heavily customized and configured, and obviously, what was presented here is just the tip of the iceberg. I suggest delving into the WikiMedia website, and gleaning as much information as possible from it. I find it to be an extremely valuable resource.

Upgrading MediaWiki
To upgrade MediaWiki, move the mediawiki directory to mediawiki-bak:

~> sudo mv /var/www/html/phpmyadmin /var/www/html/phpmyadmin-bak

Install the new version of MediaWiki. The installation script should automatically preserve tables in the database, and make changes to the tables wherever necessary. When you are done, copy over the images and extensions directories, and other modifications:

~> sudo cp -r /var/www/html/mediawiki-bak/images /var/www/html/mediawiki/.
~> sudo cp -r /var/www/html/phpmyadmin-bak/extensions /var/www/html/phpmyadmin/.

Make the appropriate changes to the LocalSettings.php file. You can now delete the old version of MediaWiki:

~> sudo rm -r /var/www/html/phpmyadmin-bak

The upgrade should now be complete.

FC6 Server & General Setup — MediaWiki