我想存储一个包含3个元素的数组:帖子的最后3条评论.我知道我可以将评论表加入Post一个,但我会避免为扩展目的做这个繁重的请求.
所以我想知道存储这3个元素的最佳方法是什么,因为我想在每次发表新评论时轻松更新它们:删除最后一条评论并添加新评论.
这样做的正确方法是什么？将它存储在序列化数组或JSON对象中？
我一直在关注Michael Heartl教程来创建一个跟随系统,但我有一个奇怪的错误:"未定义的方法`find_by'为[]:ActiveRecord :: Relation".我正在使用设计进行身份验证.
我的观点/users/show.html.erb看起来像这样:
.
.
.
<% if current_user.following?(@user) %>
<%= render 'unfollow' %>
<% else %>
<%= render 'follow' %>
<% end %>
用户模型'models/user.rb':
class User < ActiveRecord::Base
devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable
has_many :authentications
has_many :relationships, foreign_key: "follower_id", dependent: :destroy
has_many :followed_users, through: :relationships, source: :followed
has_many :reverse_relationships, foreign_key: "followed_id", class_name: "Relationship", dependent: :destroy
has_many :followers, through: :reverse_relationships, source: :follower
def following?(other_user)
relationships.find_by(followed_id: other_user.id)
end
def follow!(other_user)
relationships.create!(followed_id: other_user.id)
end
def unfollow!(other_user)
relationships.find_by(followed_id: other_user.id).destroy …我正在尝试通过Windows终端使用zstd v1.4.0解压缩大量压缩文件，然后“ ag”搜索：
zstd -dc -r . | ag -z -i "term"
进行时它给我以下错误：
zstd：错误70：写入错误：管道损坏（无法写入解码块）
我花了数小时寻找解决方案，尝试了该zstd命令的其他选项，但无法解决。
我有很大的 zstd 压缩文本文件。
我怎样才能对它们进行快速搜索？
我可以使用 AG（The Silver Searcher）或类似的东西吗？
我试过 AG 但它不起作用，我有一个“加载失败错误”：
ag -z -i "term"
我正在使用Koala 1.7.0rc1和新的Facebook图形api面临一个问题.我正在尝试使用此请求检索帖子的数量[object_id]/likes?summary=1.此查询适用于Facebook Graph Explorer,但我无法使用Koala访问"摘要":
likes = graph.get_object("5718732097_10151698726822098", summary: 1){|data| data['likes']}
# OR
likes = graph.get_object("5718732097_10151698726822098/likes?summary=1")
我在Windows机器上使用Ruby 2.1.5,Rails 4.1.6和PostgreSQL 9.3.5.
当我尝试时bundle exec rails server,我最终得到以下错误:
DL is deprecated, please use Fiddle
c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require': cannot load such file -- 2.1/pg_ext (LoadError)
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `block in re...re'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:232:in `load_dependancy'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:10:in `rescue in <top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:3:in `<top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `each'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `block in require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `each'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler.rb:133:in `require'
from C:/....../config/application.rb:5:in `<top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `require' …我一直在开发一个关于localhost的网站,它很好.今天早上,我尝试使用命令"git push heroku master"将其推送到heroku,然后"heroku run rake db:migrate".当我尝试做第二个时,我有一个错误:
Connecting to database specified by DATABASE_URL
Migrating to DeviseCreateUsers (20130427200347)
Migrating to CreateAuthentications (20130427210108)
Migrating to AddTokenToAuth (20130427233400)
Migrating to AddNotificationToAuth (20130427234836)
Migrating to AddNotifToUser (20130428031013)
Migrating to AddDeviseToUsers (20130712103048)
== AddDeviseToUsers: migrating ===============================================
-- change_table(:users)
rake aborted!
An error has occurred, this and all later migrations canceled:
PGError: ERROR: column "email" of relation "users" already exists
: ALTER TABLE "users" ADD COLUMN "email" character varying(255) DEFAULT '' NOT N
sql_adapter.rb:652:in `async_exec'
我找到了一个有同样问题的人( …
我有一个后台工作使用Sidekiq连接到我的另一个服务,如下所示:
def perform(id)
user = ABCClient.instance.user(id)
...
end
有时这个ABCClient已关闭,我想在这种情况下重新安排"执行"工作.像这样:
def perform(id)
begin
user = ABCClient.instance.user(id)
rescue => e
# Reschedule job
end
...
end