Wednesday, July 9, 2008

Desktop publishing tools and PENS

I've written before about how PENS can be used to enable one-click publishing from a publishing system (authoring tool or LCMS). Herewith, some notes on using PENS with desktop, as opposed to web-based, tools.

PENS requires that, when a publishing system sends a request to the LMS to “collect” a content package, it supplies a URL (typically using one of http, https or ftp for the URL scheme) from which the package can be collected. If the publishing system is web-based, then this URL will typically refer back to the publishing system itself.

For a desktop publishing system, this requirement effectively means that there needs to be a server, separate from the desktop software, to which the content can be uploaded prior to being collected by the LMS. Typically this will be an FTP server, although it could in principle be a web server.

Ideally, the desktop software will enable the user to configure details of this FTP server (including host, user name and password) in addition to the LMS details. When a course is published, the software should perform the following actions:

  • package the content into a zip file;
  • upload the content package to the FTP server using the configured host, user name and password; and
  • send a PENS request to the LMS instructing it to collect the content package from the FTP server.

In principle, it would be possible to manually upload the content package to the FTP server if the desktop software does not do this automatically. In practice, though, this really defeats the purpose of using PENS, since it would be simpler to create a SCORM or AICC content package on the desktop machine, and then upload the package directly to the LMS.

Another theoretical possibility would be to run a web or FTP server on the desktop machine itself. However, this would require that the desktop machine has a stable IP address and/or host name that the LMS can call back to, and that HTTP or FTP requests to the desktop machine are not blocked by hardware or software firewalls. In other words, it's almost guaranteed not to work in practice.

In summary, a desktop publishing system can theoretically “support” PENS without also supporting the automatic FTP upload step. However, without this automatic FTP upload, PENS is unlikely to provide any practical benefit.

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