steipete/SDURLCache — pull request #13 by tibr (2012-04-11 08:51:58+00:00)
Title: Adding error handling when trying to unarchive an invalid archive

```[NSKeyedUnarchiver unarchiveObjectWithFile:]``` might throw an error that looks like this and results in a crash:

```
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSKeyedUnarchiver initForReadingWithData:]: incomprehensible archive (0x62, 0x70, 0x6c, 0x69, 0x73, 0x74, 0x30, 0x30)'
```

I added a catch block to handle the error. If the file is not a valid archive the cached response is removed and nil is returned as response.