Lua - How can I save data from server on my pc? - file-io

Question

How can I read and save data from my server on PC?
a=io.open(path.."/datafile","wb")
a:write("nonsense")
a:close()
Is it the same way or a other way?
I want to read an save this file from my server to my PC, but how can I do that?
I hope someone can help me

Answer 1

It is not completely clear what you are trying to do. If you want to copy a file from one machine to another one, the following is a way to do it. Note that it will work by reading the whole file content into memory before copying it to destination, so it is not suitable for really huge files, say >~100MB (YMMV).
local SOURCE_PATH = "my/source/path/datafile.txt"
local DESTINATION_PATH = "another/path/datafile.txt"
local fh = assert( io.open( SOURCE_PATH, "rb" ) )
local content = fh:read "*all"
fh:close()
local fh_out = assert( io.open( DESTINATION_PATH, "wb" ) )
fh_out:write( content )
fh_out:close()
EDIT
Following a suggestion by #lhf here is a version which can cope with huge files. It reads and then writes the files in small chunks:
local SOURCE_PATH = "my/source/path/datafile.txt"
local DESTINATION_PATH = "another/path/datafile.txt"
local BUFFER_SIZE = 4096 -- in bytes
local fh = assert( io.open( SOURCE_PATH, "rb" ) )
local fh_out = assert( io.open( DESTINATION_PATH, "wb" ) )
local data = fh:read( BUFFER_SIZE )
while data do
fh_out:write( data )
data = fh:read( BUFFER_SIZE )
end
fh:close()
fh_out:close()