There are multiple Options available for Drupal Multi-Site installation. Couple of them are listed down here;

• Each site can have its own database
• All the sites can share the same database
• Each site can have own content database & shared user database. This can be done in two different ways either by creating a separate DB for User related tables (or) considering one of the site as a base  &  the hold the user tables in that DB

Approach for single sign-on

If  the option of having different content database for all sites & using one site as base (for User tables) is selected, then the following snippet might help you implementing the solutions. I’m providing snippet (or) information to this implementation because the drupal.org, have solutions for all the other implementation.

Solution :

Step 1: Install & Configure Drupal Multi-Site , remember to setup all the drupal instance with different database.  After the installation is complete you should be having multiple site running with multiple database on one code base

Step 2: As per the  Module developer Guide, Drupal can connect to different databases with elegance and ease.  Please note, it has to be of the same database type. So we convert the $db_url variable to an array.

$db_url['default'] = 'mysql://drupal:drupal@localhost/drupal';
$db_url['base'] = 'mysql://user:pwd@localhost/anotherdb';

now, we need to establish connect to the base database  using the drupal function db_set_active() as & when required.  db_set_active() function can be used to change where database queries are sent. If the database has not yet been used, it is initialized using the URL specified for that name in Drupal’s configuration file. If this name is not defined, a duplicate of the default connection is made instead.Be sure to change the connection back to the default when done with custom code.

db_set_active($name = 'default');

Parameters
$name The name assigned to the newly active database connection. If omitted, the default connection will be made active.
Return value
the name of the previously active database or FALSE if non was found.

Note : This only works with two databases of the same type.

Alternative Implementation of the Solution:

Now there is one challenge of  harding coding the base DB informations, as its not a good practice,because if the DB connection parameter value changes you may need to update multiple place. So to avoid this, you can use the following code snippet.

Base Site’s Setting - Add this line after the $db_url

$db_url=array('default'=>$db_url, 'base'=>$db_url);

Child Site’s Custom Setting – Add the below snippet after your $db_url declaration of the respective child sites.

 // Folder name of the site which you consider as base. Please remember in multi-site environment you are going to have folder for ever site
$dName='example.com';
require_once "sites/$dName/settings.php";
$b_db_url=$db_url['base'];
$db_url=array('default'=>$db_url, 'base'=>$b_db_url);

Some Alternatives : http://drupal.org/project/sso,

This solution will be applicable only if you wish to host the User database on your server, else you can use Open ID authentication

Updated on Jan 07,2010 : This solution can be implemented for the Drupal sites which is running as Separate instance & in the same server (Shared Hosting). Provide the complete path of the BASE Site’s default folder.

For Ex :

[phpull]include_once[/phpull](“/srv/www/sites/www_xyz_com/sites/default/settings.php”);

To make this solution, completely configurable one, please create a variable to hold the Base site folder Name

• File ? as usual similar to what you have in google doc and spreadsheet, with Start Presentation option as extra over here.
• Edit & review tabs
• New Slide, Duplicate Slide , Delete Slide ? these are the option to work on the slides available on your presentation
• Insert Image ? it lets you to insert an image to your current presentation. You can upload it from you local machine
• Insert Text ? adds a text control to your slide, where you can add your text
• Change theme ? a set of themes available for making your presentation

Apart from the above mentioned option there is a list of common option available like format the text, color, etc. We have option to rearrange the slides

Public URL for my sample presentation : http://docs.google.com/Present?docid=dfth9zxq_16d6k7bk&fs=true
I have presentation online, may be you can check this out http://docs.google.com/Present?docid=dfth9zxq_16d6k7bk&invite=dh4d5btx

• File as usual similar to what you have in Google doc and spreadsheet, with Start Presentation option as extra over here.
• Edit & review tabs
• New Slide, Duplicate Slide , Delete Slide ? these are the option to work on the slides available on your presentation
• Insert Image it lets you to insert an image to your current presentation. You can upload it from you local machine
• Insert Text adds a text control to your slide, where you can add your text
• Change theme a set of themes available for making your presentation

Apart from the above mentioned option there is a list of common option available like format the text, color, etc. We have option to rearrange the slides

Public URL for my sample presentation : http://docs.google.com/Present?docid=dfth9zxq_16d6k7bk&fs=true
I have presentation online, may be you can check this out http://docs.google.com/Present?docid=dfth9zxq_16d6k7bk&invite=dh4d5btx

Apart from these two services used by wordpress, i ping some other services which i have listed below. Some of you might be interested in these services. Here is the list of blog pinging services:

http://api.feedster.com/ping

http://api.moreover.com/ping

http://api.my.yahoo.com/rss/ping

http://blogsearch.google.com/ping/RPC2

http://ping.amagle.com/

http://ping.bitacoras.com

http://ping.blo.gs/

http://ping.feedburner.com

http://ping.rootblog.com/rpc.php

http://ping.syndic8.com/xmlrpc.php

http://ping.weblogalot.com/rpc.php

http://rcs.datashed.net/RPC2/

http://rpc.blogbuzzmachine.com/RPC2

http://rpc.blogrolling.com/pinger/

http://rpc.icerocket.com:10080/

http://rpc.newsgator.com/

http://rpc.weblogs.com/RPC2

http://topicexchange.com/RPC2

http://www.blogdigger.com/RPC2

http://www.blogoole.com/ping/

http://www.blogoon.net/ping/

http://www.blogsnow.com/ping

http://www.blogstreet.com/xrbin/xmlrpc.cgi

http://www.lasermemory.com/lsrpc/

http://www.newsisfree.com/RPCCloud

http://www.popdex.com/addsite.php

http://www.snipsnap.org/RPC2

http://www.wasalive.com/ping/

http://www.weblogues.com/RPC/

A file with all these url is available for download. You can download it here

Apart from these two services used by wordpress, i ping some other services which i have listed below. Some of you might be interested in these services. Here is the list of blog pinging services:

http://api.feedster.com/ping

http://api.moreover.com/ping

http://api.my.yahoo.com/rss/ping

http://blogsearch.google.com/ping/RPC2

http://ping.amagle.com/

http://ping.bitacoras.com

http://ping.blo.gs/

http://ping.feedburner.com

http://ping.rootblog.com/rpc.php

http://ping.syndic8.com/xmlrpc.php

http://ping.weblogalot.com/rpc.php

http://rcs.datashed.net/RPC2/

http://rpc.blogbuzzmachine.com/RPC2

http://rpc.blogrolling.com/pinger/

http://rpc.icerocket.com:10080/

http://rpc.newsgator.com/

http://rpc.weblogs.com/RPC2

http://topicexchange.com/RPC2

http://www.blogdigger.com/RPC2

http://www.blogoole.com/ping/

http://www.blogoon.net/ping/

http://www.blogsnow.com/ping

http://www.blogstreet.com/xrbin/xmlrpc.cgi

http://www.lasermemory.com/lsrpc/

http://www.newsisfree.com/RPCCloud

http://www.popdex.com/addsite.php

http://www.snipsnap.org/RPC2

http://www.wasalive.com/ping/

http://www.weblogues.com/RPC/

A file with all these url is available for download. You can download it here

I am talking about two plugins the first one is All in One SEO Pack and the other one is Google Sitemap Generator . I have been benefited by using both the plugins. I will give a little idea about both these plugins.

• All in one SEO Pack – This plugin allows you to write good title & meta data (keywords) to you post / pages.
• Sitemap generator – its generators search engine friendly sitemap. The generated XML-Sitemap compliant sitemap . The format is supported by various search engines like google,yahoo, msn

I have suggested this plugin to some of my friends as it work good for me. I strong agree with the purpose of this plugin.

Blogged with Flock