Parsing and validating arbitrary date formats in ruby (on rails)

Question

I have a requirement to handle custom date formats in an existing app. The idea is that the users have to do with multiple formats from outside sources they have very little control over. We will need to be able to take the format and both validate Dates against it, as well as parse strings specifically in that format. The other thing is that these can be completely arbitrary, like JA == January, FE == February, etc...

to my understanding, chronic only handles parsing (and does it in a more magical way then I can use), and enter code here DateTime#strptime comes close, but doesn't really handle the whole two character month scenario, even with custom formatters. The 'nuclear' option is to write in custom support for edge cases like this, but I would prefer to use a library if something like this exists.

Answer 1

I don't think something that handles all these problems exists if the format is really very arbitrary. It would probably be easiest to "mold" your input into a form that can be handled by Date.parse, Date.strptime, or another existing tool, even though that could mean quite a bit of work.

How many different formats are we talking about? Do any of them conflict? It seems like you could just gsub like so: input_string.gsub(/\bJA\b/i, 'January'). Is this part of an import routine, or are the users going to be typing in dates in different formats?

There's a related question here: http://stackoverflow.com/questions/1208743/parse-italian-date-with-ruby