At the Forge - Databases and Calendars
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.
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.
|PostgreSQL, the NoSQL Database||Jan 29, 2015|
|HPC Cluster Grant Accepting Applications!||Jan 28, 2015|
|Sharing Admin Privileges for Many Hosts Securely||Jan 28, 2015|
|Red Hat Enterprise Linux 7.1 beta available on IBM Power Platform||Jan 23, 2015|
|Designing with Linux||Jan 22, 2015|
|Wondershaper—QOS in a Pinch||Jan 21, 2015|
- PostgreSQL, the NoSQL Database
- Sharing Admin Privileges for Many Hosts Securely
- HPC Cluster Grant Accepting Applications!
- Internet of Things Blows Away CES, and it May Be Hunting for YOU Next
- Designing with Linux
- Red Hat Enterprise Linux 7.1 beta available on IBM Power Platform
- Ideal Backups with zbackup
- Wondershaper—QOS in a Pinch
- Slow System? iotop Is Your Friend
- January 2015 Issue of Linux Journal: Security
Editorial Advisory Panel
Thank you to our 2014 Editorial Advisors!
- Jeff Parent
- Brad Baillio
- Nick Baronian
- Steve Case
- Chadalavada Kalyana
- Caleb Cullen
- Keir Davis
- Michael Eager
- Nick Faltys
- Dennis Frey
- Philip Jacob
- Jay Kruizenga
- Steve Marquez
- Dave McAllister
- Craig Oda
- Mike Roberts
- Chris Stark
- Patrick Swartz
- David Lynch
- Alicia Gibb
- Thomas Quinlan
- Carson McDonald
- Kristen Shoemaker
- Charnell Luchich
- James Walker
- Victor Gregorio
- Hari Boukis
- Brian Conner
- David Lane