Today I had this disconcerting experience.
I'm working on a project that relies on various data sources that are updated and added to periodically. Because I'll be giving a paper on the topic next week, I've kept the project set up to reach out across the Internet and load the latest versions of the data sources every time I work on it.
Unfortunately, the web site for the most important data source is down today, and virtually all my other work depends on these particular data. Fortunately I haven't yet gotten around to deleting a duplicate version of the data, so I should still be able to work on the project later today. (Messiness has its virtues.)
But this raises an important set of issues. The <project home>/data/file.url that loads these data simply contains the url of the data source (a csv file) and a separator character. ProjectTemplate's documentation
for such files makes no mention of error checking, nor does it seem error checking is discussed in the documentation for other kinds of sources.
Because ProjectTemplate does certain things "under the hood," it's not clear how to use R's standard error detection and handling facilities. For example, in my case I'd want something like this:
url: <data source url>
if data loaded successfully
use an older version of the data
issue a warning message
So what's the recommended way to accomplish this?
And please modify the documentation to discuss this crucial topic.