Question

我想从旧网站导入一些图标。这些图标的大小小于10kb。因此，当我尝试将图标导入其返回的stringio.txt文件时。

require "open-uri"
class Category < ActiveRecord::Base
   has_attached_file :icon,  :path => ":rails_root/public/:attachment/:id/:style/:basename.:extension"
  def icon_from_url(url)
    self.icon = open(url)
   end    
end

在rake任务中。

   category = Category.new
   category.icon_from_url "https://xyz.com/images/dog.png"
   category.save

Answer 1

尝试：

def icon_from_url(url)
  extname = File.extname(url)
  basename = File.basename(url, extname)

  file = Tempfile.new([basename, extname])
  file.binmode

  open(URI.parse(url)) do |data|  
    file.write data.read
  end

  file.rewind

  self.icon = file
end

Answer 2

要覆盖Paperclip中的“假文件上传”的默认文件名（小文件上的stringio.txt或较大文件上几乎随机的临时名称），您有两种主要的可能性：

在IO上定义original_filename：

def icon_from_url(url)
  io = open(url)
  io.original_filename = "foo.png"
  self.icon = io
end

您还可以从URI获取文件名：

io.original_filename = File.basename(URI.parse(url).path)

或替换:basename中的:path：

has_attached_file :icon, :path => ":rails_root/public/:attachment/:id/:style/foo.png", :url => "/:attachment/:id/:style/foo.png"

请务必在更改:url时更改:path，否则icon.url方法将出错。

您还可以定义自己的custom interpolations（例如:rails_root/public/:whatever）。

Answer 3

我认为你几乎就在那里，尝试打开解析的uri，而不是字符串。

require "open-uri"
class Category < ActiveRecord::Base
   has_attached_file :icon,  :path =>:rails_root/public/:attachment/:id/:style/:basename.:extension"
  def icon_from_url(url)
    self.icon = open(URI.parse(url))
  end    
end

当然这不会处理错误

Answer 4

您也可以禁用OpenURI创建StringIO对象，并强制它创建临时文件。看到这个答案：

Why does Ruby open-uri's open return a StringIO in my unit test, but a FileIO in my controller?

Answer 5

过去，我发现检索远程文件的最可靠方法是使用命令行工具“wget”。以下代码主要直接从现有的生产（Rails 2.x）应用程序中复制，并进行一些调整以适合您的代码示例：

class CategoryIconImporter
  def self.download_to_tempfile (url)
    system(wget_download_command_for(url))
    @@tempfile.path
  end

  def self.clear_tempfile
    @@tempfile.delete if @@tempfile && @@tempfile.path && File.exist?(@@tempfile.path)
    @@tempfile = nil
  end

  def self.set_wget
    # used for retrieval in NrlImage (and in future from other sies?)
    if !@@wget
      stdin, stdout, stderr = Open3.popen3('which wget')
      @@wget = stdout.gets
      @@wget ||= '/usr/local/bin/wget'
      @@wget.strip!
    end
  end
  def self.wget_download_command_for (url)
    set_wget
    @@tempfile = Tempfile.new url.sub(/\?.+$/, '').split(/[\/\\]/).last
    command = [ @@wget ]
    command << '-q'
    if url =~ /^https/
      command << '--secure-protocol=auto'
      command << '--no-check-certificate'
    end
    command << '-O'
    command << @@tempfile.path
    command << url
    command.join(' ')
  end

  def self.import_from_url (category_params, url)
    clear_tempfile

    filename = url.sub(/\?.+$/, '').split(/[\/\\]/).last
    found = MIME::Types.type_for(filename)
    content_type = !found.empty? ? found.first.content_type : nil

    download_to_tempfile url

    nicer_path = RAILS_ROOT + '/tmp/' + filename
    File.copy @@tempfile.path, nicer_path

    Category.create(category_params.merge({:icon => ActionController::TestUploadedFile.new(nicer_path, content_type, true)}))
  end
end

rake任务逻辑可能如下所示：

[
  ['Cat', 'cat'],
  ['Dog', 'dog'],
].each do |name, icon|
  CategoryIconImporter.import_from_url {:name => name}, "https://xyz.com/images/#{icon}.png"
end

这使用mime-types gem进行内容类型发现：

gem 'mime-types', :require => 'mime/types'

使用大小小于10kb的开放URI和回形针存储图像

5 个答案: