如果使用Ruby找到字符串，如何从$ stdout中搜索特定字符串并将整个$ stdout存储在文本文件中？

Question

I want to search particular string that will be there in $stdout that I print on console using http.set_debug_output($stdout) . I want to search string "Access-Control-Allow-Origin: *\\r\\n" from $stdout and if string found want to store $stdout in text file.

Answer 1

$stdout has some special restrictions in ruby. By default it is opened for reading only (obviously), so to seek/read lines that you've written, you have to replace it as a File . This will suffice:

$stdout = File.new("stdout", "w+")
puts "some string"

Kernel#puts will use $stdout by default, so this sets you up perfectly. What you have to implement is checking, it can be a little tricky, but here's one way to approach it.

$stdout = File.new("stdout", "w+")
puts "some string"
old = $stdout
$stdout = IO.try_convert(STDOUT)
old.rewind
old.lines.each do |line|
  puts 'contains requested data' if line == "some string\n"
end

Few things to note on the comparison, puts places \\n automatically at the end of your string. To escape that \\n so it matches the previous input, you have to put it in the "" quotes.