Read binary file as string in Ruby

Question

I need an easy way to take a tar file and convert it into a string (and vice versa). Is there a way to do this in Ruby? My best attempt was this:

file = File.open("path-to-file.tar.gz")
contents = ""
file.each {|line|
  contents << line
}

I thought that would be enough to convert it to a string, but then when I try to write it back out like this...

newFile = File.open("test.tar.gz", "w")
newFile.write(contents)

It isn't the same file. Doing ls -l shows the files are of different sizes, although they are pretty close (and opening the file reveals most of the contents intact). Is there a small mistake I'm making or an entirely different (but workable) way to accomplish this?

Answer 1

First, you should open the file as a binary file. Then you can read the entire file in, in one command.

file = File.open("path-to-file.tar.gz", "rb")
contents = file.read

That will get you the entire file in a string.

After that, you probably want to file.close. If you don’t do that, file won’t be closed until it is garbage-collected, so it would be a slight waste of system resources while it is open.