Write and read a file with utf-8 encoding

If i execute your code i get an error on the special character. Can you try this code ?

# encoding: UTF-8
File.open("test.txt", "w:UTF-8") do |f| 
  f.write "test \u00A9 foo" 
end 

#Encoding.filesystem = "UTF-8"
p Encoding.find("filesystem") 
File.open("test.txt", "r:UTF-8") do |f| 
  puts f.read 
end 

On my windows box i then get

#<Encoding:Windows-1252>
test © foo

I have no idea why the  is there..

Read the file with less code:

# encoding: UTF-8
file_content = File.open("test.txt", "r:UTF-8", &:read)

On which OS does your application run? It could be that the default encoding for the file is ASCII. Does it help if you add w:utf-8 and r:utf-8 to the open parameters?