下载之前获取文件大小＆amp;计算已经下载了多少（http + ruby​​）

Question

任何人都可以帮我

• 在开始下载
之前获取文件大小
• 显示已下载的％

require 'net/http'
require 'uri'

url = "http://www.onalllevels.com/2009-12-02TheYangShow_Squidoo_Part 1.flv"

url_base = url.split('/')[2]
url_path = '/'+url.split('/')[3..-1].join('/')

Net::HTTP.start(url_base) do |http|
  resp = http.get(URI.escape(url_path))
  open("test.file", "wb") do |file|
    file.write(resp.body)
  end
end
puts "Done."

Answer 1

使用request_head方法。喜欢这个

response = http.request_head('http://www.example.com/remote-file.ext')
file_size = response['content-length']

file_size将以字节为单位。

请按照以下两个链接获取更多信息。

http://ruby-doc.org/stdlib/libdoc/net/http/rdoc/classes/Net/HTTP.html#M000695

http://curl.haxx.se/mail/archive-2002-07/0070.html

Answer 2

所以即使使用进度条也让它工作....

require 'net/http'
require 'uri'
require 'progressbar'

url = "url with some file"


url_base = url.split('/')[2]
url_path = '/'+url.split('/')[3..-1].join('/')
@counter = 0

Net::HTTP.start(url_base) do |http|
  response = http.request_head(URI.escape(url_path))
  ProgressBar#format_arguments=[:title, :percentage, :bar, :stat_for_file_transfer]
  pbar = ProgressBar.new("file name:", response['content-length'].to_i)
  File.open("test.file", 'w') {|f|
    http.get(URI.escape(url_path)) do |str|
      f.write str
  @counter += str.length 
  pbar.set(@counter)
    end
   }
end
pbar.finish
puts "Done."

Answer 3

文件大小在HTTP Content-Length响应标头中可用。如果不存在，则无法执行任何操作。要计算％，就像小学数学一样（部分/总计* 100）。

Answer 4

这里是下载前获取文件详细信息的完整代码

require 'net/http'
response = nil
uri = URI('http://hero.com/abc.mp4')
Net::HTTP.start(uri.host, uri.port) do |http|
  response = http.head(uri)
end
response.header.each_header {|key,value| puts "#{key} = #{value}" }