views:

7018

answers:

5

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?

+2  A: 

You can probably encode the tar file in Base64. Base 64 will give you a pure ASCII representation of the file that you can store in a plain text file. Then you can retrieve the tar file by decoding the text back.

You do something like:

require 'base64'

file_contents = Base64.encode64(tar_file_data)

Have look at the Base64 Rubydocs to get a better idea.

Great, this looks like it'll work too! I'll have to check it out if for some reason reading the binary contents goes sour.
Chris Bunch
A: 

on os x these are the same for me... could this maybe be extra "\r" in windows?

in any case you may be better of with:

contents = File.read("e.tgz")
newFile = File.open("ee.tgz", "w")
newFile.write(contents)
Purfideas
+17  A: 

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

then you should have the entire file in a string.

David Nehme
Awesome, that did it! Thanks David!
Chris Bunch
That doesn't work outside of Windows platforms. Either that or you had a small file and happened to get the whole thing read in the first buffer.
Otto
+7  A: 

To avoid leaving the file open, it is best to pass a block to File.open. This way, the file will be closed after the block executes.

contents = File.open('path-to-file.tar.gz', 'rb') { |f| f.read }
Aaron Hinni
+16  A: 

If you need binary mode, you'll need to do it the hard way:

s = File.open(filename, 'rb') { |f| f.read }

If not, shorter and sweeter is:

s = IO.read(filename)