如何在Ruby中通过电子邮件发送图表而不保存到磁盘？

Question

我正在使用Ruby脚本和"mail"gem来发送电子邮件.

问题 - 如何在Ruby中通过电子邮件发送图表而不保存到磁盘？这可能吗？你会推荐哪种图形工具,"mail"gem支持以某种方式将其流出来？(或者它必须首先保存到磁盘)如果它可能/简单的示例代码行应该如何将是伟大的....

Answer 1

你完整的答案.

为简单起见,它使用纯Ruby PNG图; 真实世界的应用程序可能会使用SVG,快速本机代码或图形API.

#!/usr/bin/env ruby
=begin

How to send a graph via email in Ruby without saving to disk
Example code by Joel Parker Henderson at SixArm, joel@sixarm.com

    http://stackoverflow.com/questions/9779565

You need two gems:

    gem install chunky_png
    gem install mail

Documentation:

    http://rdoc.info/gems/chunky_png/frames
    https://github.com/mikel/mail

=end


# Create a simple PNG image from scratch with an x-axis and y-axis.
# We use ChunkyPNG because it's pure Ruby and easy to write results;
# a real-world app would more likely use an SVG library or graph API.

require 'chunky_png'
png = ChunkyPNG::Image.new(100, 100, ChunkyPNG::Color::WHITE)
png.line(0, 50, 100, 50, ChunkyPNG::Color::BLACK)  # x-axis
png.line(50, 0, 50, 100, ChunkyPNG::Color::BLACK)  # y-axis

# We do IO to a String in memory, rather than to a File on disk.
# Ruby does this by using the StringIO class which akin to a stream.
# For more on using a string as a file in Ruby, see this blog post:
# http://macdevelopertips.com/ruby/using-a-string-as-a-file-in-ruby.html

io = StringIO.new
png.write(io) 
io.rewind

# Create a mail message using the Ruby mail gem as usual. 
# We create it item by item; you may prefer to create it in a block.

require 'mail'
mail = Mail.new
mail.to = 'alice@example.com'
mail.from = 'bob@example.com'
mail.subject = 'Hello World'

# Attach the PNG graph, set the correct mime type, and read from the StringIO

mail.attachments['graph.png'] = {
  :mime_type => 'image/png', 
  :content => io.read 
}

# Send mail as usual. We choose sendmail because it bypasses the OpenSSL error.
mail.delivery_method :sendmail
mail.deliver

Answer 2

我不明白为什么你不能.在邮件文档中,您可以看到以下示例代码:

mail = Mail.new do
  from     'me@test.lindsaar.net'
  to       'you@test.lindsaar.net'
  subject  'Here is the image you wanted'
  body     File.read('body.txt')
  add_file :filename => 'somefile.png', :content => File.read('/somefile.png')
end

mail.deliver!

您只需将目标替换:content => ...为内存中的文件内容即可.这应该足够了.实际上并不需要将附件保存到磁盘,即使是临时保存到磁盘,因为它们在base64中重新编码并在邮件末尾添加.

对于你问题的第二部分,那里有许多情节/图表库.例如,请参阅此问题或此lib.

对于这类问题,其他人并没有真正优于其他人.有许多用于许多不同用途的库,您必须选择更符合您需求和限制的内容.