1. The Architecture of the Facebook Platform
INAM SOOMRO & OLGUN CAKABEY
INTRODUCTION
Facebook has become one of the most important social networking sites around the globe for almost
people of all ages. In addition to provide its own services and features and contents to its users,
Facebook also allows the developers and other communities to extend their social services and
approaches. Social networking focuses on linking and making online communication between friends
who share their thoughts and activities and who are willing to know the activities and interests of
other friends. A social platform goes further than that, it lets developer and other communities to
create external applications and it gives a chance to Facebook user to interact with each other in
different ways and on different applications. Behind Facebook’s complex technology there are
hundreds of millions of real people with real relationships. They want to communicate in different
ways and want to search for new friends, join different interested groups and share information.
In May 2007, user involvement on Facebook grasped new peaks with the introduction of Facebook
Platform. Facebook Platform’s release brings fresh ideas and immense interest to not only the users
of Facebook, but to the industry as a whole.
Facebook Platform
The Facebook platform is a framework that offers a set of API ( Application Programming Interface )
and services and other tools that help third parties to integrate and run their applications with
Facebook. Facebook developers define Facebook platform as “A standards-based Web Service with
methods for accessing and contributing to Facebook data”. This service is what that enables to create
an application to communicate and integrate with Facebook services
The framework of Facebook platform consisted of the following technologies and hence can be
considered as a High Level platform components
o Graph API (Application Programming o Facebook markup Language
Interface) o Facebook Query Language
o Authentication o Facebook JavaScript
o Social Plugins o Facebook Connect
o Open Graph Protocol
Basic Architecture of the Facebook Application Platform
Facebook sets as an example of the architecture built around useful data of its consumers, the data
includes personal relationship mappings, bio-data, media contents and other important data. The
Facebook engineers built the architecture of the Facebook keeping in mind the philosophy of
displaying and manipulation of the social data. The site’s business logic is carefully related to this

2. data, such as flow of the information and access patterns, News Feed contents and search
implementation, privacy and visibility settings, Account settings and friends’ information.
Facebook is abstractly a standard n-tier architecture that brings data from Facebook’s internal
libraries, which are processed through the Facebook logic to be outputted on the view tier of the
site. Facebook engineers realized the practicality of this data beyond the confines of its container.
They allow the outside application to integrate with the Facebook data access system with the
creation of Facebook Platform with the users data at the center of the architecture; the platform has
developed a range of Facebook web services to join application developers’ system.
Third party application do not live on Facebook server somewhat they live on external servers, they
are called when a user request for a specific application. The developers provide a canvas page URL
and a callback URL for that application. A user initiates an HTTP request to Facebook server
through canvas page URL then a Facebook server sends a request to the external server
based on callback URL where the application is hosted, then the application calls the
Facebook API or FQL (Facebook Query Language) to access data. After all the required data
has been accessed, the application server returns the FBML(Facebook Markup language) to
the Facebook server that in turn processes the FBML and converts it to HTML and the output
is rendered to the browser. With the help of Facebook Platform technologies:
o Application can access useful social data through the Facebook platform Data
Services.
o Application can publish their display using the data driven markup language FBML to
integrate with Facebook.
o With the change in architecture that FBML requires, developers can use Facebook
Platform Cookies and Facebook JavaScript FBJS to minimize the changes needed to
add an application presence to http://facebook.com
o Finally, applications have these capabilities without sacrificing the privacy and
expectations about user experience that Facebook has built around its user data and
display.
Facebook Data as an XML Web Service
Facebook data can be accessible through an externally accessible web service, In addition to
Facebook API to Facebook Architecture begins the relationship between external
applications and Facebook through the Facebook Platform, essentially adding Facebook’s
data to the External application stack. Facebook user authorizes the external application to
access the data from the Facebook; in this case the external application stack consumes the
Facebook data as an XML Web Service, Facebook simply makes available two simple remote
procedure call methods (RPC), this is established with the exposure of two remote methods
Function friends_get($session_user);
Function users_getInfo($session_user, $input_users, $inputFields);
for its users to consume Facebook data as a web service and in return Facebook send user
data as an xml document. Facebook platform maintains the authentication credentials and

3. session specific to user’s application through an assigned “API key”, “User Session Key” and a
“request signature”. Web Service wrap the Facebook data through the use of appropriate
metadata by a code generator called Thrift. Employing the beautiful tool like “Thrift”
provides benefits over others:
o Automatic Type Synchronization o Automatic documentation
o Automatic Binding generation o Cross language Synchronization
A Social Data Query Service: Facebook Query Language ( FQL )
FQL is a way to access/query data from the Facebook like with API functions but with the SQL style
interface having the same syntax as SQL, e-g:
SELECT [fields] FROM Table WHERE [condition]
The benefits that developers get by FQL over traditional Facebook API is
o FQL is more efficient
o FQL reduces number of necessary requests
o FQL is Language independent.
Facebook Markup Language (FBML)
FBML is a particular example of XML with many tags from HTML, and extended with some special
tags for platform for displaying on facebook. Also FBML incorporates with FQL. As you understand,
they are modifying known standards like HTML, SQL into FBML, FQL etc. in the Facebook Platform.
Moreover in FBML the developer is very flexible. The FBML lets him to control the display and logic
executed on the server through the FBML data. This is very good example of data at the center of
execution. As we said FBML includes tags, attributes and content. These tags are divided into some
categories: Briefly they are direct HTML tags, data-display tags, data-execution tags, design-only tags,
replacement HTML tags, functionality package tags.
Facebook JavaScript (FBJS)
Facebook provides a solution for developers to use javascript in their facebook applications. It is
called FBJS. Actually, as concept there is no difference between javascript and facebook javascript
just there are some differences like function and variable names, and also the usage of the code is
quite different. Moreover there are some restrictions of using some functions regarding safety
issues.
Applications on Facebook
We can create applications on facebook with three different methods:
1. Directly rendering HTML, CSS, and JS

4. To create an application on facebook, first option is configurating an external application
with small changes, adding two fields into application like application_name and callback_url.
A request coming to the facebook application page basically fetches HTML, CSS, and JS codes
from the application servers and shows it as the main content of the page on Facebook. This
makes web site as an HTML web service.
2. Iframes
Second option is using iframes which relies on a technology that have been already inside the
browser. As we mentioned in directly rendering HTML, CSS, and JS option, we are using the
same mappings for the iframes with different syntax like application url link results in HTML
output with iframe tags.
3. Facebook Markup Language as data-driven execution markup
Third option is quite different from the others. Here we are not sending HTML back instead
of this, we are returning a data driven execution markup specialized for facebook named
FBML which includes many HTML elements but adds also some special Facebook-defined
tags inside. Then interpreter for FBML transforms this markup language into its own data,
execution and display when the application page is being rendered.
Conclusion
One of the main objectives of Facebook has always been to make it easy for user to benefit
from one another’s knowledge and Facebook Platform conveys the knowledge to users and
developers universally. It brings a platform on which developers can build rich applications.
Within its ever evolving website Facebook is making its platform architecture available as a
model for other social networking sites. Facebook’s desire is not only to capture the entirety
of human connectedness, but also to be able to share the human information as well.