我一直在努力与这几天，并希望有人可以帮助。 可能有一些明显的是，我见了！
我使用的社插件轨道上载PDF文件和产生的缩略为第一页。 PDF被装载在指定的存储空间和缩略也越来越创造和获得排序相同的位置。 但是我不能够显示的略图。
初始化程序:
require "shrine"
require "shrine/storage/file_system"
#require "shrine/storage/memory"
Shrine.storages = {
cache: Shrine::Storage::FileSystem.new("public", prefix: "uploads/cache"),
store: Shrine::Storage::FileSystem.new("public", prefix: "uploads/store")
}
Shrine.plugin :activerecord # loads Active Record integration
Shrine.plugin :cached_attachment_data # enables retaining cached file across form redisplays
Shrine.plugin :restore_cached_data # extracts metadata for assigned cached files
Shrine.plugin :determine_mime_type
Shrine.plugin :validation_helpers
Shrine.plugin :validation
Shrine.plugin :derivatives
#Shrine.plugin :model, cache: false
上传:
require "image_processing/mini_magick"
class FileUploader < Shrine
include ImageProcessing::MiniMagick
plugin :processing # allows hooking into promoting
plugin :versions # enable Shrine to handle a hash of files
plugin :derivatives
plugin :default_url
# plugin :delete_raw # delete processed files after uploading
Attacher.validate do
validate_max_size 5*1024*1024, message: "is too large (max is 5 MB)"
validate_mime_type %w[application/pdf]
end
Attacher.derivatives do |original|
magick = ImageProcessing::MiniMagick.source(original).loader(page:0).convert("jpeg")
{
thumb: magick.resize_to_limit!(200, 200)
}
end
end
检查看：
<p id="notice"><%= notice %></p>
<p>
<strong>Number:</strong>
<%= @issue.number %>
</p>
<p>
<strong>Title:</strong>
<%= @issue.title %>
</p>
<p>
<strong>Data:</strong>
<%= @issue.file_data %>
</p>
<p>
<strong>Issue Preview</strong>
<embed src="<%= @issue.file_url %>" width="80" height="160" />
</p>
<p>
<strong>Issue Thumbnail:</strong>
<%= image_tag @issue.file_url(:thumb) if @issue.file %>
</p>
<p>
<strong>Issue:</strong>
<%= image_tag @issue.file_url if @issue.file %>
</p>
<%= link_to 'Edit', edit_issue_path(@issue) %> |
<%= link_to 'Back', issues_path %>
此外，当我看看数据存储在file_data场我看没有任何信息添加的略图。
文件数据：{"id":"fccd20a9323aa5b63fd912f4ca833ebb.pdf","storage":"store","metadata":{"filename":"pdf_sample.pdf","size":351987,"mime_type":"application/pdf"}}