轨道 3 + 载波:文件无法使用 MiniMagick 进行操作，也许它不是图像?原始错误:迷你魔法::无效

Question

嗨，我正在尝试为我的 Rails 项目设置载波。我看过其他答案，但似乎没有任何效果。当我尝试创建图像时，它会给我这个：

    1.9.3p392 :003 > bi = BookCoverImage.new
     => #<BookCoverImage id: nil, file: nil, created_at: nil, updated_at: nil, book_id: nil, category_id: nil, collection_id: nil, creator_id: nil, group: "BookCoverImage", homepage_slide_id: nil> 
    1.9.3p392 :004 > bi.file = File.open("#{Rails.root}/spec/support/sample_img.jpg")
     => #<File:/Users/emai/Documents/mysite/spec/support/sample_img.jpg> 
    1.9.3p392 :005 > bi.save
       (0.1ms)  SAVEPOINT active_record_1
       (0.1ms)  ROLLBACK TO SAVEPOINT active_record_1
     => false 
    1.9.3p392 :006 > bi.valid?
     => false 
    1.9.3p392 :007 > bi.errors.full_messages
     => ["File Failed to manipulate with MiniMagick, maybe it is not an image? Original Error: MiniMagick::Invalid"] 

我正在使用Ruby 1.9.3，Mac Mavericks和自制软件。谁能帮忙？

书籍封面图像模型：

class BookCoverImage < Image
  default_scope { where(group: self.name) }
  belongs_to :book
  mount_uploader :file, BookCoverImageUploader
end

它继承自图像：

class Image < ActiveRecord::Base
  attr_accessible :file
  after_initialize :set_group
  before_save :set_group
  private
    def set_group
      self.group = self.class.name
    end
end

我的书封面图片上传器：

# encoding: utf-8
class BookCoverImageUploader < CarrierWave::Uploader::Base
  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  include CarrierWave::MiniMagick
  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog
  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    if Rails.env.test? || Rails.env.cucumber?
      "#{Rails.root}/public/test/file_uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    else
      "uploads/#{model.class.to_s.underscore}/#{model.id}"
    end
  end
  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end
  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end
  # Create different versions of your uploaded files:
  version :thumb do
    process :resize_to_fit => [80, 10000]
  end
  version :medium do
    process :resize_to_fit => [159, 10000]
  end
  version :main do
    process :resize_to_fit => [238, 10000]
  end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  def extension_white_list
    %w(jpg jpeg gif png)
  end
  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end
end

Answer 1

如果ImageMagick无法将给定文件identify为图像，则会引发错误File Failed to manipulate with MiniMagick, maybe it is not an image? Original Error: MiniMagick::Invalid。

在命令提示符下尝试此操作：（替换为您的文件名）

> identify spec/support/facebook.jpg 
### If image identified correctly, outputs as below
spec/support/facebook.jpg JPEG 400x267 400x267+0+0 8-bit sRGB 13.4KB 0.000u 0:00.000
> identify spec/support/test.png
### If image is invalid, outputs as below
identify: improper image header `spec/support/test.png' @ error/png.c/ReadPNGImage/4003.