Error: Attempt to call private method

Question

Coming from a long history of C-style syntax and now trying to learn Ruby (on Rails), I've been having my share of issues with its idioms and such, but today I hit one I didn't expect to have a problem with and I can't see whatever it is that must be right in front of my face. I have a Binary class that includes a private method to derive a URI value from a path value (uri and path are attributes of the class). I'm calling `self.get_uri_from_path()` from within `Binary.upload()`, but I get: ``` Attempt to call private method ``` A snippet of the model looks like this: ``` class Binary < ActiveRecord::Base has_one :image def upload( uploaded_file, save = false ) save_as = File.join( self.get_bin_root(), '_tmp', uploaded_file.original_path ) # write the file to a temporary directory # set a few object properties self.path = save_as.sub( Rails.root.to_s + '/', '' ) self.uri = self.get_uri_from_path() end private def get_uri_from_path return self.path.sub( 'public', '' ) end end ``` Am I…

Accepted Answer

Don't do

```
self.get_uri_from_path()
```

do

```
get_uri_from_path()
```

Because...

```
  class AccessPrivate
    def a
    end
    private :a # a is private method

def accessing_private
      a              # sure! 
      self.a         # nope! private methods cannot be called with an explicit receiver at all, even if that receiver is "self"
      other_object.a # nope, a is private, you can't get it (but if it was protected, you could!)
    end
  end
```

via

Error: Attempt to call private method

Solution

Problem