Ruby 如何写入临时文件
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Ruby how to write to Tempfile
提问by Siva
I am trying to create a Tempfile and write some text into it. But I get this strange behaviour in rails console
我正在尝试创建一个临时文件并向其中写入一些文本。但是我在 rails 控制台中得到了这种奇怪的行为
t = Tempfile.new("test_temp") # => #<File:/tmp/test_temp20130805-28300-1u5g9dv-0>
t << "Test data" # => #<File:/tmp/test_temp20130805-28300-1u5g9dv-0>
t.write("test data") # => 9
IO.read t.path # => ""
I also tried cat /tmp/test_temp20130805-28300-1u5g9dv-0but the file is empty
我也试过了，cat /tmp/test_temp20130805-28300-1u5g9dv-0但是文件是空的
Am I missing anything ? Or what's the proper way to write to Tempfile?
我错过了什么吗？或者写信的正确方法是Tempfile什么？
FYI I'm using ruby 1.8.7 and rails 2.3.12
仅供参考，我正在使用 ruby 1.8.7 和 rails 2.3.12
回答by squiguy
You're going to want to close the temp file after writing to it. Just add a t.closeto the end. I bet the file has buffered output.
在写入临时文件后，您将要关闭它。只需t.close在末尾添加一个。我敢打赌该文件已缓冲输出。
回答by Debadatt
Try this
run t.rewindbefore read
t.rewind在阅读之前尝试此运行
require 'tempfile'
t = Tempfile.new("test_temp")
t << "Test data"
t.write("test data") # => 9
IO.read t.path # => ""
t.rewind
IO.read t.path # => "Test datatest data"
回答by Lev Lukomsky
closeor rewindwill actually write out content to file. And you may want to delete it after using:
close或者rewind实际上将内容写入文件。您可能想在使用后将其删除：
file = Tempfile.new('test_temp')
begin
file.write <<~FILE
Test data
test data
FILE
file.close
puts IO.read(file.path) #=> Test data\ntestdata\n
ensure
file.delete
end
回答by Artur Beljajev
It's worth mentioning, calling .rewindis a must, or any subsequent .readcall will just return empty value
值得一提的是，调用.rewind是必须的，否则任何后续.read调用都只会返回空值
