WIP: StringIO, set_encoding

docs.ruby-lang.org

# cp932
io = ...
io.string.encoding -> UTF-8

io = get_s3_client.get_object({
          bucket: "bucket",
          key: "key",
          :response_content_encoding => 'CP932',
          :response_content_type => 'text/csv'
}).body
# :response_content_encoding 意味ない、、、
# StringIOのencodingが設定されると思ったが

csv = CSV.new(io)
-> ArgumentError: invalid byte sequence in UTF-8

# 明示的に設定しないとダメっぽい
p io.set_encoding('CP932')

csv = CSV.new(io)

-> <#CSV io_type:StringIO encoding:Windows-31J lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">