Rails Rails upload file error about “No such file or directory @ rb_sysopen”
参考 rails5 的 guides，下面的代码出现 Rails upload file error about“No such file or directory @ rb_sysopen,/Users/jayzen/workshop/upload_demo/public/uploads/demo.pdf”。
def upload
uploaded_io = params[:tag][:attachment]
File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
file.write(uploaded_io.read)
end
我对代码中 Rails.root.join 的参数个数做了修改，只是去掉“uploads”参数，代码如下，下面的代码按照预期运行，并且上传文件成功。
def upload
uploaded_io = params[:tag][:attachment]
File.open(Rails.root.join('public', uploaded_io.original_filename), 'wb') do |file|
file.write(uploaded_io.read)
end
问题：当 Rails.root.join 中的参数个数小于等于 2 时候，能够正常运行，但是参数个数大于 2 时，则会出现如上的问题，为何？
其他辅助代码
#支架
rails g scaffold tag name
#model中设置虚拟属性
class Tag < ActiveRecord
attr_accessor :attachment
end
#controller中设置attachment白名单
params.require(:tag).permit(:name, :attachment)
#controller中添加upload方法
class TagsController < ApplicationController
def create
@tag = Tag.new(tag_params)
if @tag.save
upload
......
end
private
def upload
....
end
end
环境：mac, ruby2.4.0, rails5.1.2
runup
#5
2017年06月28日
问题解决： 原本打算将 pdf 文件存储在对应 id 目录的文件下面，代码如下所示
def upload
uploaded_io = params[:tag][:attachment]
File.open(Rails.root.join('public','uploads', "#{@tag.id}", uploaded_io.original_filename), 'wb') do |file|
file.write(uploaded_io.read)
end
end
报如上提到的错误，按照楼上的提示，添加新建文件夹语句，修改后的代码如下
def upload
uploaded_io = params[:tag][:attachment]
demo = Dir.mkdir(File.join(Rails.root, 'public', 'uploads', "#{@tag.id}"))
File.open(Rails.root.join('public','uploads', "#{@tag.id}", uploaded_io.original_filename), 'wb') do |file|
file.write(uploaded_io.read)
end
end