Stream-like processing of files in Ruby - ruby

Question

I would like to understand how I can add filters/transformations in a stream starting from a source, going to a sink.
As an example, consider reading a CSV file. That would be
CSV.foreach(file) { |row| ... }
If I want to read from a zipped file, that would become
stream = Zlib::GzipReader.open('/tmp/foo.csv.gz')
csv = CSV.new(stream)
csv.each { |row| ... }
Now, possibly I would like to add transformations on between gunzip and csv. What is the best way to achieve this goal in Ruby?
Currently I'm doing this:
gzip = Zlib::GzipReader.open('/tmp/foo.psv.gz') # Pipe Separated Value (fake example).
trans = IOTransform.new(gzip) { |line| line&.tr('|', ',') } # A simple example.
csv = CSV.new(trans)
csv.each do |row|
puts row.inspect
end
using the following class
class IOTransform
def initialize(io, &block)
#io = io
#block = block
#inbuf = +''
end
def gets(...)
if !#io.eof?
#inbuf << #io.gets(...)
end
res = nil
remainder = nil
#inbuf&.each_line { |line|
if line[-1] == "\n"
res ||= +''
res << #block.call(line)
else
remainder = line
end
}
#inbuf = remainder
res
end
end
but it feels like I really missed something: I very much doubt that there's no easy way to process streams in Ruby.
Thanks in advance!