Making a new format (ex ".rcb")

Question

I am wondering if it is possible to make a completely new format. Mac use a .text file for text and .mov for movies so is it possible to make a new format that i can put into a iOS application that it will use off and export off, for example the application pages exports a .pages file, and if so what is a good tutorial site or script that u can use.

Answer 1

A few thoughts:

1. File extensions

   If this is just a file that your app uses internally, it doesn't matter too much what extension you use. Use whatever you want.

   If you're going to be sharing files, however, you should ensure that you pick an extension that you're confident is unique. For example, it looks like RCB extension is used by Easy Resume Creator Pro (I don't know it, but that's what a quick google of that extension reports).

2. How to do it.

   I'd simply advise you refer to How to Import and Export App Data on Ray Wenderlich's site, which describes how you can define a UTI for your app's data files. Also refer to this Stack Overflow answer.

3. How to store the information.

   In terms of how to store the data in the file, you can obviously do whatever you want, but I'd encourage you to consider, if dealing with text data, using an established format (even if you're using your own custom extension). For example, if dealing with simple Cocoa objects like arrays or dictionaries of strings, numbers, dates, etc., I might suggest using a property lists (see Apple's Property List Programming Guide which writes data in an XML format.

   Alternatively, if using your own NSObject subclasses, you can use a binary property list format as enabled by NSKeyedArchiver and NSKeyedUnarchiver which are discussed in Apple's Archives and Serializations Programming Guide.

   There are lots of other formats that are open to you, but these two approaches take advantage of well established interfaces for reading and writing data and can be done with a minimum of effort

4. Alternatives to new file format.

   Depending upon precisely what you're trying to do, if you're exchanging trivial amounts of information, a custom URL scheme might be sufficient. This bypasses the issue of dealing with custom file formats and enables a few other workflows.

Hopefully this is enough to let you start researching the different alternatives.