Thursday, November 25, 2010

Advantage of HttpHandler - A Certificate example


You are a developer at Grade Nineteen University. One of the recent requirments the management had is to create an online certificate.
So that the students that pass out should be able to view their Certificates online. This will definitely add some technological edge to the university.

The student will be given his own certification url as following:

On accessing the url, the following Certifcate image will be displayed for the student id: 100

(100.cert should be interpreted in server as "Show Certificate for Student Id as 100")

Easy Way of Implementation - But not the Best

The first thought of implementation would be to create jpg files for all the students and copy them into the cert folder of the website. This approach is feasible but the following overheads would exist:

  • For 1000 students that pass each year, 50 MB disk space would be required.
  • While backing up database of site, we have to do backup of jpg files too, which is tedious.
If we have to take a backup of the site, we have to copy the files separately and do the database backup separately.

Http Handlers for the Rescue - A better Approach

We can achieve the same behavior with little overheads รข€“ by avoiding files creation for certificates.

We can use the database records to dynamically create certificate based on the student url.

By default the ISAPI handlers, handle the .aspx url extensions. We have to create a new handler for .jpg file handling that would be redirected to our certificate creation code

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