Application Mashup

Application mash up is a interesting web application programming paradigm. While technically it is interesting, it also throws up quite a number of legal & ethical questions. Well Mash ups are application which sources data from different domains and come up with an interesting newer application by combining the services for different other available applications.

Mashups gives us a lots of flexibility and will define the way application interact with each other in future. Yahoo already has provided a lots of web services for use, while google has done its fair share. Yahoo Pipes is another interesting web system for churning out mashups Google has come up with Mash up editor.[it is still not yet open to general public]

Web browsers does not allow cross domain sourcing of data for security reasons. Because of this, cross domain restrictions, mash up need to bring in other hack methods like having a web proxy in the server from where the browser can source data.

Below is one stand alone web application which service all user request alone. It is basically a self contained web application.

Above is the conceptual diagram of a self contained application.

However, in real world we need application which talk to other applications in some agreed upon formats. Conceptual diagram for the same is given below.

In the above, the web application talks to some other application to service some request of the user.

Now what has mash up got to do with all the above? Well, in the web scenario, the other application that we see above can be any web application. That means our application can potentially talk to millions of other web application which are available. So mash up is one such application which talks to other application to source data/service.

With AJAX application, mash up throws up a new paradigm. We start asking why does the browser need to come to my server to get details from say some other server like Yahoo. They can directly get the data [ & hence save the bandwidth of my server :-) & faster] from the data source. However, due to single source restriction in browser known as single domain restriction of web browser, such thing is not possible. Conceptual diagram given as below.

Above will be dream come true for Mashers but unfortunately, above is not possible.

The above can be overcome by three ways:

1. Using a Web Proxy in the Web server to source the data.
   
2. Using Apache Mod rewrite.
   
3. Using JSON with Javascript call back.

Of the above three methods, the 3rd option above resemble the most to the above diagram. However, the other domains need to give JSON & a serve it as a javascript function. The other 2 looks like the diagram below.



Until the single domain restriction is removed from web browser, I guess we will have to live with the above hacks.