Rake aborted使用faker为ruby项目上传图像
我正在关注Ruby on Rails指南并遇到使用gem“Faker”生成虚假内容的问题。 我安装了faker并按照说明将用户和照片填充到我的项目中。 我在lib / tasks / populate.rake中创建了这个文件
LIB /任务/ populate.rake
namespace :db do desc "Fill database with sample data" task populate: :environment do 10.times do |n| puts "[DEBUG] creating user #{n+1} of 10" name = Faker::Name.name email = "user-#{n+1}@example.com" password = "password" User.create!( name: name, email: email, password: password, password_confirmation: password) end User.all.each do |user| puts "[DEBUG] uploading images for user #{user.id} of #{User.last.id}" 10.times do |n| image = File.open(Dir.glob(File.join(Rails.root, 'sampleimages', '*')).sample) description = %w(cool awesome crazy wow adorbs incredible).sample user.pins.create!(image: image, description: description) end end end end 现在我应该做的就是在我的终端（和右侧文件夹）中放入“rake db：populate”。 当我这样做时，我得到：
rake db:populate [DEBUG] creating user 1 of 10 [DEBUG] creating user 2 of 10 [DEBUG] creating user 3 of 10 [DEBUG] creating user 4 of 10 [DEBUG] creating user 5 of 10 [DEBUG] creating user 6 of 10 [DEBUG] creating user 7 of 10 [DEBUG] creating user 8 of 10 [DEBUG] creating user 9 of 10 [DEBUG] creating user 10 of 10 [DEBUG] uploading images for user 15 of 25 rake aborted! can't convert nil into String /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:18:in `initialize' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:18:in `open' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:18:in `block (4 levels) in ' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:17:in `times' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:17:in `block (3 levels) in ' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:15:in `each' /Users/ScottDAlessandro/code/omrails/lib/tasks/populate.rake:15:in `block (2 levels) in ' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:246:in `call' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:241:in `each' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:101:in `each' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling' /usr/local/rvm/gems/ruby-1.9.3-p392/gems/rake-10.0.4/lib/rake/application.rb:70:in `run' Tasks: TOP => db:populate (See full trace by running task with --trace)
我最关心的是
“rake aborted！无法将nil转换为String”
它似乎创建了用户，但没有上传任何图片。
题：
a）为什么rake被中止？
b）如何删除我创建的用户？ 我知道的唯一方法是“User.all”然后是User.delete（在这里放一个数字）……有更有效的方法吗？
非常感谢帮助:)谢谢！
您的Dir.glob(...)返回一个空数组，当你调用sample它返回nil 。 当你调用File.open(nil)你得到exception并且rake File.open(nil) 。
如果要删除users表中的所有行，可以执行User.destroy_all 。