Elixir 用Phoenix,Postgresql和Ecto创建一个书单应用

本文通过一个书单应用简要介绍使用Phoenix框架创建一个Web应用程序的基本步骤.

安装Phoenix

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git clone http s://github. com/phoenixframework/phoenix.git cd phoenix git checkout v0. 5.0 mix do deps. get, compile

创建书单项目

在phoenix源代码目录中运行如下命令创建一个phoenix项目目录结构

1	mix phoenix. new book_store ../book_store

目录../book_store不必事先存在, phoenix会自动创建.

添加依赖库

编辑mix.exs文件, 修改后如下:

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defmodule BookStore.Mixfile do use Mix.Project def project do [ app: :book_store, version: "0.0.1", elixir: "~> 1.0", elixirc_paths: [ "lib", "web"], compilers: [ :phoenix] ++ Mix.compilers, deps: deps] end # Configuration for the OTP application # # Type `mix help compile.app` for more information def application do [ mod: { BookStore, []}, applications: [ :phoenix, :cowboy, :logger, :postgrex, :ecto]] end # Specifies your project dependencies # # Type `mix help deps` for examples and options defp deps do [{ :phoenix, "0.5.0"}, { :cowboy, "~> 1.0"}, { :postgrex, "~> 0.5"}, { :ecto, "~> 0.2.0"}] end end

和修改之前的mix.exs文件相比有两个变更处:

• 在application函数中增加了两个依赖的应用程序 :postgres 和 :ecto (16行)
• 在deps函数增加两个依赖库{:postgrex, "~> 0.5"}和{:ecto, "~> 0.2.0"}(24,25行)

运行

1	mix do deps. get, compile

创建一个仓库(Repo)

创建文件web/models/repo.ex,内容如下:

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defmodule BookStore.Repo do use Ecto.Repo, adapter: Ecto.Adapters.Postgres def conf do parse_url "ecto://postgres:postgres@localhost/book_store" end def priv do app_dir( :book_store, "priv/repo") end end

创建数据库:

1	createdb book_store -U postgres --encoding='utf- 8' --locale=en_US. UTF- 8 -- template=template0

修改lib/book_store.ex为, 如下:

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defmodule BookStore do use Application # See http://elixir-lang.org/docs/stable/elixir/Application.html # for more information on OTP Applications def start(_type, _args) do import Supervisor.Spec, warn: false children = [ # Define workers and child supervisors to be supervised worker( BookStore.Repo, []) ] opts = [ strategy: :one_for_one, name: BookStore.Supervisor] Supervisor.start_link(children, opts) end end

编译

1	mix compile

创建模型

创建文件web/models/books.ex, 内容如下:

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defmodule BookStore.Books do use Ecto.Model schema "books" do field :title, :string field :description, :string field :author, :string field :publisher, :string end end

创建数据库移植脚本

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$ mix ecto.gen.migration Bookstore.Repo create_book Compiled web /models/books.ex Generated bookstore.app * creating priv /repo/migrations * creating priv /repo/migrations /20141112170140_create_book.exs

编辑生成的priv/repo/migrations/20141112170140_create_book.exs脚本, 内容如下:

defmodule BookStore.Repo.Migrations.CreateBook do use Ecto.Migration def up do ["CREATE TABLE books(\
        id serial primary key, \
        title varchar(125), \
        description text, \
        author varchar(255), \
        publisher varchar(255))",\ "INSERT INTO books(title, description, author, publisher) \
             VALUES ( \
                'Programming Elixir', \
                'Programming Elixir: Functional |> Concurrent |> Pragmatic |> Fun', \
                'Dave Thomas', \
                'The Pragmatic Bookshelf')" ] end def down do "DROP TABLE books" end end

运行移植脚本

1	mix ecto.migrate BookStore.Repo

创建查询

创建文件web/models/queries.ex, 内容如下:

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defmodule BookStore.Queries do import Ecto. Query def books_query do query = from book in BookStore.Books, select: book BookStore.Repo. all( query) end end

配置路由

打开文件web/router.ex, 修改为如下:

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defmodule BookStore.Router do use Phoenix.Router scope "/" do # Use the default browser stack. pipe_through :browser # get "/", BookStore.PageController, : index, as: :pages get "/", BookStore.BookController, : index, as: :books end # Other scopes may use custom stacks. # scope "/api" do # pipe_through :api # end end

创建控制器

创建文件web/controllers/book_controller.ex, 内容如下:

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defmodule BookStore.BookController do use Phoenix.Controller plug :action def index(conn, _params) do books = BookStore.Queries.books_query render conn, "index", books: books end end

创建书单视图

创建文件web/views/book_view.ex, 内容如下:

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defmodule BookStore.BookView do use BookStore.Views end

创建目录

1	mkdir web/templates/book

并添加文件web/templates/book/index.html.eex, 内容如下:

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<h1>我的图书 </h1> <table class='table table-bodered table-striped'> <thead> <tr> <th># </th> <th>标题 </th> <th>描述 </th> <th>作者 </th> <th>出版社 </th> </tr> </thead> <tbody> <%= for book <- @books do %> <tr> <td> <%= book.id %> </td> <td> <%= book.title %> </td> <td> <%= book.description %> </td> <td> <%= book.author %> </td> <td> <%= book.publisher %> </td> </tr> <% end %> </tbody> </table>

启动应用,并刷新页面

1	mix phoenix.start

我的书单应用

完成!

参考资料

1. Book Listing App With Elixir, Phoenix, Postgres and Ecto
   http://learnelixir.com/blog/2014/10/05/build-web-app-with-elixir/