How to require a ruby file from another directory

ruby-on-rails ruby ruby-on-rails-3 ruby-on-rails-3.2 require
thedarkknight228 picture thedarkknight228 · May 31, 2013 · Viewed 58.7k times · Source

I am trying to require a rake file that I have created inside another file I have. These two files are inside two different directories. I have require at the top of my first file with the name of the second file inside the quotes after the require. It is telling me that it can't load such file. Does that mean because its in different directory it can't find it? I tried sticking in the full path to the second file but it still can't load the file. Does anyone know how I can load the second file into the first?

Thanks in advance

Answer

Charles Caldwell picture Charles Caldwell · May 31, 2013

require will search for files in only a set of locations referred to as the "Load Path." You can view the load path by using the global variable $LOAD_PATH in a script or irb session. If it is not in the load path, it won't find it.

Ruby 1.9 introduced require_relative which searches using the current file's location as a starting point. 

# Will search $LOAD_PATH for file. 
require 'test/unit'
# Notice the '/' which tells it to look in the 
# 'test' folder for a file named 'unit.rb'

# Will look in current folder of file
require_relative 'my_folder/my_file'
# Will search in 'my_folder' for the file 'my_file.rb'

Note that require_relative will not work in irb.

Also note, that if you really want to use require, you can start your script by adding a location to the $LOAD_PATH variable.

$LOAD_PATH << File.join('users', 'yourusername', 'your_folder')
# or
$LOAD_PATH << File.dirname(__FILE__)
# The second one enables you to move the file around on your
# system and still operate correctly
require 'my_file'

Here's some additional documentation from Ruby-Doc:

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