Eliir Ecto: 使用Whatwasit追踪模型的变更和版本化
Whatwasit 是一个跟踪Ecto模型变化的一个包, 用于审计和版本化. 审计在某些情况下是我们非常需要的, 比如我们需要知道谁在系统中修改了什么, 可以形成审计日志备后期进行审查.
注意: Whatwasit(读作: What was it) 需要Elixir 1.2的支持, 所以要使用 Whatwasit 请首先升级到Elixir 1.2以上
跟踪变化
使用 Whatwasit 很简单, 只需要添加在模型中添加两行代码即可, 下面我们来细说这个过程. 首先创建一个项目:
这里我们只是测试如何使用Whatwasit, 所以去掉前端库Brunch(--no-brunch).
mix phoenix.new whatwasit_example --no-brunch在mix.exs中增加依赖:
defp deps do [ ... {:whatwasit, "~> 0.2.1"} ]end切换到命令行执行
mix deps.get && mix compile运行下面的用于创建存储版本和变更的模型和数据库迁移脚本
➜ whatwasit_example mix whatwasit.install* creating priv/repo/migrations/20160801031533_create_whatwasit_version.exs* creating web/models/whatwasit/version.exAdd the following to your config/config.exs: config :whatwasit, repo: WhatwasitExample.RepoUpdate your models like this: defmodule WhatwasitExample.Post do use WhatwasitExample.Web, :model use Whatwasit # add this schema "posts" do field :title, :string field :body, :string timestamps end def changeset(model, params \ %{}) do model |> cast(params, ~w(title body)) |> validate_required(~w(title body)a) |> prepare_version # add this end end执行数据库迁移脚本
mix ecto.migrate命令行提示你在模块头部添加 use Whatwasit, 在changeset/2 方法的管道尾部添加 prepare_version函数追踪数据库的变更. 版本存储在 versions 表里面, 其结构如下:
图中的 object 字段是一个JSON数据, 存储了修改之前的快照版本. Whatwasit.Version 模型的定义如下:
schema "versions" do
field :item_type, :string
field :item_id, :integer
field :action, :string # ~w(update delete)
field :object, :map # versioned schema stored as a map
timestamps
end
其对应的数据库迁移脚本如下:
defmodule WhatwasitExample.Repo.Migrations.CreateWhatwasitVersion do
use Ecto.Migration
def change do
create table(:versions) do
add :item_type, :string, null: false
add :item_id, :integer, null: false
add :action, :string
add :object, :map, null: false
timestamps
end
end
end
下面是一个博客的示例
defmodule WhatwasitExample.Post do
use WhatwasitExample.Web, :model
use Whatwasit
alias WhatwasitExample.Repo
schema "posts" do
field :title, :string
field :body, :string
timestampsend
def getbypk(id) do
Repo.get(MODULE, id)
end
def updatebypk(changeset, changes) when is_map(changes) do
changeset = changeset |> Ecto.Changeset.change(changes)
changeset |> Repo.update
end
def user_changeset(struct, params \ %{}) do
cast/3 把浏览器POST过来的数据强制转换为schema中定义的数据类型
# validate_required/3 验证要求的字段, message选项为错误提示struct|> cast(params, [:title, :body])|> validate_required([:title, :body], [message: "标题和内容是必须的"])|> prepare_versionend
def insert(map) do
Map.merge(%MODULE{}, map) |> Repo.insert
end
def insert(params) do
changeset = user_changeset(%MODULE{}, params)
if changeset.valid? do
Repo.insert(changeset)
else
raise "Changeset is invalid."
end
end
@doc """
更新一条记录
"""
def update(params) do
从数据库获取一个 %WhatwasitExample.Post{} 结构
struct = getbypk(params[:id])case struct do nil -> raise "Record not exists." struct -> fields = Map.delete(params, :id) # 通过浏览器传过来的POST数据创建一个Ecto.Changeset changeset = user_changeset(struct, fields) if changeset.valid? do changeset |> Repo.update else raise "Changeset is invalid when update." endendend
@doc """
按主键ID删除一条记录
"""
@spec delete(map) :: Ecto.Schema.t | :no_return
def delete(%{"id" => id}) do
从数据库获取一个 %WhatwasitExample.Post{} 结构
# 从 %WhatwasitExample.Post{} 创建一个 Ecto.Changeset# 把这个 Ecto.Changeset 传递给 Ecto.Repo.delete!/2Repo.get!(__MODULE__, id)|> __MODULE__.user_changeset|> Repo.delete!end
end
跟踪谁修改了数据
首先需要添加 {:coherence, "~> 0.2.0"} 依赖, Coherence 是一个用户管理包, 提供了用户系统的常用功能, 包括:
注册, 注册新用户
邮件激活, 生成邮件激活链接通过邮件发送给用户
密码恢复, 生成密码找回连接通过邮件发送给用户
登录跟踪, 为每个保存了每次登录的时间, 次数, IP地址
锁定, 登录N次错误后自动锁定用户一段时间
解锁, 生成一个解锁连接通过邮件发送给用户
初始化 Coherence
mix coherence.install --full-invitable上述命令会执行如下步骤:
添加 coherence 的配置到 config/config.exs 文件的尾部.
如果用户模型不存在, 添加新的用户模型
添加数据库迁移脚本文件
timestamp_add_coherence_to_user.exs 如果用户模型已经存在
timestamp_create_coherence_user.exs 如果用户模型不存在
timestamp_create_coherence_invitable.exs
在 web/views/coherence/ 中添加相关的视图
在 web/templates/coherence 添加相关的模板
在 web/emails/coherence 中添加电子邮件模板
添加 web/coherence_web.ex 文件
最后查看一下 config/config.exs 文件编辑电子邮件的Key, 这里你可以申请一个 [mailgun]的(https://www.mailgun.com/)邮件服务key用于测试.
完整的命令输出
➜ whatwasit_example# mix coherence.install --full-invitableYour config/config.exs file was updated.Compiling 14 files (.ex)warning: unused import Ecto web/models/whatwasit/version.ex:7Generated whatwasit_example app* creating priv/repo/migrations/20160801060750_create_coherence_user.exs* creating web/models/coherence/user.ex* creating priv/repo/migrations/20160801060751_create_coherence_invitable.exs* creating web/coherence_web.ex* creating web/views/coherence/coherence_view.ex* creating web/views/coherence/email_view.ex* creating web/views/coherence/invitation_view.ex* creating web/views/coherence/layout_view.ex* creating web/views/coherence/coherence_view_helpers.ex* creating web/views/coherence/password_view.ex* creating web/views/coherence/registration_view.ex* creating web/views/coherence/session_view.ex* creating web/views/coherence/unlock_view.ex* creating web/templates/coherence/email/confirmation.html.eex* creating web/templates/coherence/email/invitation.html.eex* creating web/templates/coherence/email/password.html.eex* creating web/templates/coherence/email/unlock.html.eex* creating web/templates/coherence/invitation/edit.html.eex* creating web/templates/coherence/invitation/new.html.eex* creating web/templates/coherence/layout/app.html.eex* creating web/templates/coherence/layout/email.html.eex* creating web/templates/coherence/password/edit.html.eex* creating web/templates/coherence/password/new.html.eex* creating web/templates/coherence/registration/new.html.eex* creating web/templates/coherence/session/new.html.eex* creating web/templates/coherence/unlock/new.html.eex* creating web/emails/coherence/coherence_mailer.ex* creating web/emails/coherence/user_email.exAdd the following to your router.ex file.defmodule WhatwasitExample.Router do use WhatwasitExample.Web, :router use Coherence.Router # Add this pipeline :browser do plug :accepts, ["html"] plug :fetch_session plug :fetch_flash plug :protect_from_forgery plug :put_secure_browser_headers plug Coherence.Authentication.Session, login: true # Add this end pipeline :public do plug :accepts, ["html"] plug :fetch_session plug :fetch_flash plug :protect_from_forgery plug :put_secure_browser_headers plug Coherence.Authentication.Session # Add this end # Add this block scope "/" do pipe_through :public coherence_routes :public end # Add this block scope "/" do pipe_through :browser coherence_routes :private end scope "/", WhatwasitExample do pipe_through :public get "/", PageController, :index end scope "/", WhatwasitExample do pipe_through :browser # Add your protected routes here endendYou might want to add the following to your priv/repo/seeds.exs file.WhatwasitExample.Repo.delete_all WhatwasitExample.UserWhatwasitExample.User.changeset(%WhatwasitExample.User{}, %{name: "Test User", email: "testuser@example.com", password: "secret", password_confirmation: "secret"})|> WhatwasitExample.Repo.insert!Don't forget to run the new migrations and seeds with: $ mix ecto.setup删除之前生成的数据库迁移脚本
rm priv/repo/migrations/20160801064451_create_whatwasit_version.exs运行如下命令, 重新生成模型和数据库迁移脚本
whatwasit.install --whodoneit重新创建数据库
mix ecto.reset|> prepare_version 修改为 |> prepare_version(opts), 传入 opts 参数.
修改后的 Post 模型的 changeset 函数, 增加第三个参数 opts:
def user_changeset(struct, params \ %{}, opts \ %{}) do
cast/3 把浏览器POST过来的数据强制转换为schema中定义的数据类型
validate_required/3 验证要求的字段, message选项为错误提示
struct
|> cast(params, [:title, :body])
|> validate_required([:title, :body], [message: "标题和内容是必须的"])
|> prepare_version(opts)
end
上面的多个手工步骤可以用 mix phoenix.gen.html Post posts title:string body:string 自动生成控制器, 视图, 模型, 模板文件. 然后修改, 可以少些很多代码.
上述步骤都完成后, 可以通过命令 mix phoenix.routes 查看所有的HTTP端点
➜ whatwasit_example mix phoenix.routes session_path GET /sessions/new Coherence.SessionController :new session_path POST /sessions Coherence.SessionController :createregistration_path GET /registrations/:id/edit Coherence.RegistrationController :editregistration_path GET /registrations/new Coherence.RegistrationController :newregistration_path POST /registrations Coherence.RegistrationController :createregistration_path PATCH /registrations/:id Coherence.RegistrationController :update PUT /registrations/:id Coherence.RegistrationController :updateregistration_path DELETE /registrations/:id Coherence.RegistrationController :delete password_path GET /passwords/:id/edit Coherence.PasswordController :edit password_path GET /passwords/new Coherence.PasswordController :new password_path POST /passwords Coherence.PasswordController :create password_path PATCH /passwords/:id Coherence.PasswordController :update PUT /passwords/:id Coherence.PasswordController :update password_path DELETE /passwords/:id Coherence.PasswordController :delete unlock_path GET /unlocks/:id/edit Coherence.UnlockController :edit unlock_path GET /unlocks/new Coherence.UnlockController :new unlock_path POST /unlocks Coherence.UnlockController :create invitation_path GET /invitations/:id/edit Coherence.InvitationController :edit invitation_path GET /invitations/new Coherence.InvitationController :new invitation_path POST /invitations Coherence.InvitationController :create invitation_path POST /invitations/create Coherence.InvitationController :create_user invitation_path GET /invitations/:id/resend Coherence.InvitationController :resend session_path DELETE /sessions/:id Coherence.SessionController :delete page_path GET / WhatwasitExample.PageController :index post_path GET /posts WhatwasitExample.PostController :index post_path GET /posts/:id/edit WhatwasitExample.PostController :edit post_path GET /posts/new WhatwasitExample.PostController :new post_path GET /posts/:id WhatwasitExample.PostController :show post_path POST /posts WhatwasitExample.PostController :create post_path PATCH /posts/:id WhatwasitExample.PostController :update PUT /posts/:id WhatwasitExample.PostController :update post_path DELETE /posts/:id WhatwasitExample.PostController :delete这样一个基本的带用户注册, 密码找回, 用户激活, 等功能的应用程序的基本结构就完成了. 在此基础之上可以扩展功能实现更加完整的Web应用程序.
注意事项
目前模型里面的changeset需要重命名, PROJECT_NAME.Whatwasit.Version模块中的changeset函数和通过mix phoenix.gen.html 生成的模型中的changeset 函数名称冲突, 建议修改模型中的changeset函数为post_changeset
mix whatwasit.install --whodoneit-map 和 mix whatwasit.install --whodoneit区别是, mix whatwasit.install --whodoneit 在versions表中用两个字段分别存储用户名称和用户ID, 这是对users表的引用, mix whatwasit.install --whodoneit-map, 用一个字段whodoneit存储的是一个除密码之外的用户所有信息的一个JSON对象. 后者不依赖于用户信息的变更.
如果用户模型的主键类型为UUID, 可以使用 mix whatwasit.install --whodoneit-id-type=uuid
最后我们在浏览器中输入 http://127.0.0.1:4000/posts/new 创建一条记录, 并编辑, 编辑的日志输出为.
这里是这篇文章的仓库地址: https://github.com/developerw...
关键字：elixir, ecto
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