At the Forge - Databases and Calendars

Building with the iCalendar standard, it's time to extract schedule information from a database and build calendars on the fly.
What More Can We Do?

Sure enough, the result of invoking db-calendar.py is a fully iCalendar-compliant file, suitable for importing into Sunbird or any other calendar program. Moreover, simply by modifying the contents of our Events database table, we can ensure that everyone who subscribes to our calendar gets the latest version.

We can go one step further than this, modifying db-calendar.py such that it includes only certain events in its result. For example, perhaps the calendar needs to contain only events in the future; there is no need to clutter someone's calendar (and bandwidth) with events from the past. By adding a simple WHERE clause to our SQL query, we easily can remove all of the events from the past.

More intriguing is the possibility of supporting different groups and access levels to a calendar. HTTP supports authentication with user names and passwords, and although Sunbird doesn't support such protections at the present time, I would expect it (and other programs) to do so in the future. Given that a CGI program easily can determine the user name of the person making an authenticated HTTP request, it's not too far-fetched to say that db-calendar.py could produce different output for different users, depending on a set of assigned permissions or roles.

Finally, although we have focused on iCalendar-format output for the last few months, there isn't any reason why we can turn only the contents of the database into an iCalendar file. Indeed, it's quite possible that we would want to display our events database in plain-old HTML, as well as in iCalendar. Once again, it's easy to see how we could do that using HTML tables—demonstrating once again that relational databases make it easy to display a set of data in a number of different ways.

Conclusion

This month, we have seen how to use a database to store event information that eventually will be transformed into an iCalendar-compliant file. Using a database makes us not only more confident that stored data is valid, but it allows us to create dynamically generated files quickly and easily that are suitable for use in programs that use the iCalendar format.

Resources for this article: /article/8263.

Reuven M. Lerner, a longtime Web/database consultant and developer, now is a graduate student in the Learning Sciences program at Northwestern University. His Weblog is at altneuland.lerner.co.il, and you can reach him at reuven@lerner.co.il.

______________________

Comments

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Problems with 'from iCalendar import UTC'

superbenk's picture

I don't see any class named 'UTC' in the iCalendar modules from mxm.dk. Am I missing something?

Benjamin Krein
www.superk.org

White Paper
Linux Management with Red Hat Satellite: Measuring Business Impact and ROI

Linux has become a key foundation for supporting today's rapidly growing IT environments. Linux is being used to deploy business applications and databases, trading on its reputation as a low-cost operating environment. For many IT organizations, Linux is a mainstay for deploying Web servers and has evolved from handling basic file, print, and utility workloads to running mission-critical applications and databases, physically, virtually, and in the cloud. As Linux grows in importance in terms of value to the business, managing Linux environments to high standards of service quality — availability, security, and performance — becomes an essential requirement for business success.

Learn More

Sponsored by Red Hat

White Paper
Private PaaS for the Agile Enterprise

If you already use virtualized infrastructure, you are well on your way to leveraging the power of the cloud. Virtualization offers the promise of limitless resources, but how do you manage that scalability when your DevOps team doesn’t scale? In today’s hypercompetitive markets, fast results can make a difference between leading the pack vs. obsolescence. Organizations need more benefits from cloud computing than just raw resources. They need agility, flexibility, convenience, ROI, and control.

Stackato private Platform-as-a-Service technology from ActiveState extends your private cloud infrastructure by creating a private PaaS to provide on-demand availability, flexibility, control, and ultimately, faster time-to-market for your enterprise.

Learn More

Sponsored by ActiveState