添加视频地址
我们的菜谱现在有对应的节目名、哪一季哪一集，如果能直接附上视频的链接，就更完美了。
我们需要一个数据库迁移（migration）文件：
$ mix ecto.gen.migration add_url_to_recipe
* creating priv/repo/migrations
* creating priv/repo/migrations/20170211030550_add_url_to_recipe.exs修改新建的迁移文件：
diff --git a/priv/repo/migrations/20170211030550_add_url_to_recipe.exs b/priv/repo/migrations/20170211030550_add_url_to_recipe.exs
index 01e5f17..f0918c6 100644
--- a/priv/repo/migrations/20170211030550_add_url_to_recipe.exs
+++ b/priv/repo/migrations/20170211030550_add_url_to_recipe.exs
@@ -2,6 +2,8 @@ defmodule TvRecipe.Repo.Migrations.AddUrlToRecipe do
use Ecto.Migration
def change do
-
+ alter table(:recipes) do
+ add :url, :string
+ end
end
end接着将 :url 加入 schema 中：
diff --git a/web/models/recipe.ex b/web/models/recipe.ex
index 230f290..104db50 100644
--- a/web/models/recipe.ex
+++ b/web/models/recipe.ex
@@ -6,6 +6,7 @@ defmodule TvRecipe.Recipe do
field :title, :string
field :season, :integer, default: 1
field :episode, :integer, default: 1
+ field :url, :string
field :content, :string
belongs_to :user, TvRecipe.User
@@ -17,7 +18,7 @@ defmodule TvRecipe.Recipe do
"""
def changeset(struct, params \\ %{}) do
struct
- |> cast(params, [:name, :title, :season, :episode, :content])
+ |> cast(params, [:name, :title, :season, :episode, :content, :url])
|> validate_required([:name, :title, :season, :episode, :content], message: "请填写")
|> validate_number(:season, greater_than: 0, message: "请输入大于 0 的数字")
|> validate_number(:episode, greater_than: 0, message: "请输入大于 0 的数字")最后，执行 mix ecto.migrate：
$ mix ecto.migrate
Compiling 13 files (.ex)
11:53:37.646 [info] == Running TvRecipe.Repo.Migrations.AddUrlToRecipe.change/0 forward
11:53:37.646 [info] alter table recipes
11:53:37.676 [info] == Migrated in 0.0s接着新增一个测试，我们需要验证 url 的有效性：
diff --git a/test/models/recipe_test.exs b/test/models/recipe_test.exs
index 8b093ed..f1ba3f9 100644
--- a/test/models/recipe_test.exs
+++ b/test/models/recipe_test.exs
@@ -60,4 +60,9 @@ defmodule TvRecipe.RecipeTest do
assert %{user_id: ["does not exist"]} = errors_on(changeset)
end
+ test "url should be valid" do
+ attrs = Map.put(@valid_attrs, :url, "fjsalfa")
+ assert %{url: ["url 错误"]} = errors_on(%Recipe{}, attrs)
+ end
+
end运行测试：
mix test
...............................
1) test url should be valid (TvRecipe.RecipeTest)
test/models/recipe_test.exs:63
Assertion with in failed
code: %{url: ["url 错误"]} = errors_on(%Recipe{}, attrs)
left: %{url: ["url 错误"]}
right: %{}
stacktrace:
test/models/recipe_test.exs:65: (test)
...........................
Finished in 1.0 seconds
59 tests, 1 failure那么我们要如何在 recipe.ex 文件中验证 url 的有效性？
我们可以考虑用正则表达式配合 validate_format，但有个更好的办法，是直接引用 Erlang 的方法：
diff --git a/web/models/recipe.ex b/web/models/recipe.ex
index 104db50..3b849c8 100644
--- a/web/models/recipe.ex
+++ b/web/models/recipe.ex
@@ -22,6 +22,16 @@ defmodule TvRecipe.Recipe do
|> validate_required([:name, :title, :season, :episode, :content], message: "请填写")
|> validate_number(:season, greater_than: 0, message: "请输入大于 0 的数字")
|> validate_number(:episode, greater_than: 0, message: "请输入大于 0 的数字")
+ |> validate_url(:url)
|> foreign_key_constraint(:user_id)
end
+
+ defp validate_url(changeset, field, _options \\ []) do
+ validate_change changeset, field, fn _, url ->
+ with %{host: _, scheme: scheme} <- :uri_string.parse(url),
+ true <- String.starts_with?(scheme, "http") do
+ []
+ else
+ _ -> [url: "url 错误"]
+ end
+ end
+ end
end我们在 recipe.ex 文件中新增了一个 validate_url 私有方法，并调用 Ecto 提供的 validate_change 函数来验证属性是否有效。http_uri 是 Erlang 的模块，在 Elixir 中，我们能够以 :http_uri 的形式调用。
我们所有的 recipe 模板都需要做调整 - 此时，我想你可能已经意识到测试驱动的好处了，如果我们给各个模板添加过测试，那么有新特性加入时，我们先在测试中体现我们的目的，然后运行测试，就知道需要修改哪些文件来达到我们的目的。
参照前一节的代码，我们来进一步完善 RecipeViewTest 模块的代码：
diff --git a/test/views/recipe_view_test.exs b/test/views/recipe_view_test.exs
index 8174c14..9695647 100644
--- a/test/views/recipe_view_test.exs
+++ b/test/views/recipe_view_test.exs
- @recipe1 %{id: "1", name: "淘米", title: "侠饭", season: "1", episode: "1", content: "洗掉米表面的淀粉", user_id: "999"}
- @recipe2 %{id: "2", name: "煮饭", title: "侠饭", season: "1", episode: "1", content: "浸泡", user_id: "888"}
# 使用带有 url field 的数据
+ @recipe1 %{id: "1", name: "淘米", title: "侠饭", season: "1", episode: "1", content: "洗掉米表面的淀粉", user_id: "999", url: "http://localhost"}
+ @recipe2 %{id: "2", name: "煮饭", title: "侠饭", season: "1", episode: "1", content: "浸泡", user_id: "888", url: "http://localhost"}
@@ -28,4 +28,23 @@ defmodule TvRecipe.RecipeViewTest do
end
end
+ test "render new.html", %{conn: conn} do
+ changeset = Recipe.changeset(%Recipe{}, %{})
+ content = render_to_string(TvRecipe.RecipeView, "new.html", conn: conn, changeset: changeset)
+ assert String.contains?(content, "url")
+ end
+
+ test "render show.html", %{conn: conn} do
+ recipe = struct(Recipe, @recipe1)
+ content = render_to_string(TvRecipe.RecipeView, "show.html", conn: conn, recipe: recipe)
+ assert String.contains?(content, @recipe1.url)
+ end
+
+ test "render edit.html", %{conn: conn} do
+ recipe = struct(Recipe, @recipe1)
+ changeset = Recipe.changeset(%Recipe{}, @recipe1)
+ content = render_to_string(TvRecipe.RecipeView, "edit.html", conn: conn, changeset: changeset, recipe: recipe)
+ assert String.contains?(content, @recipe1.url)
+ end
+
end然后运行测试：
mix test
Compiling 1 file (.ex)
...
1) test render new.html (TvRecipe.RecipeViewTest)
test/views/recipe_view_test.exs:31
Expected truthy, got false
code: String.contains?(content, "url")
stacktrace:
test/views/recipe_view_test.exs:34: (test)
2) test render show.html (TvRecipe.RecipeViewTest)
test/views/recipe_view_test.exs:37
Expected truthy, got false
code: String.contains?(content, recipe.url())
stacktrace:
test/views/recipe_view_test.exs:40: (test)
.
3) test render edit.html (TvRecipe.RecipeViewTest)
test/views/recipe_view_test.exs:43
Expected truthy, got false
code: String.contains?(content, recipe.url())
stacktrace:
test/views/recipe_view_test.exs:47: (test)
.......................................................
Finished in 0.9 seconds
62 tests, 3 failures根据测试结果，我们修改文件：
diff --git a/web/templates/recipe/form.html.eex b/web/templates/recipe/form.html.eex
index 3bf90ff..ab12be3 100644
--- a/web/templates/recipe/form.html.eex
+++ b/web/templates/recipe/form.html.eex
@@ -30,6 +30,12 @@
</div>
<div class="form-group">
+ <%= label f, :url, class: "control-label" %>
+ <%= text_input f, :url, class: "form-control" %>
+ <%= error_tag f, :url %>
+ </div>
+
+ <div class="form-group">
<%= label f, :content, class: "control-label" %>
<%= textarea f, :content, class: "form-control" %>
<%= error_tag f, :content %>
diff --git a/web/templates/recipe/show.html.eex b/web/templates/recipe/show.html.eex
index 3ef437d..f4ea463 100644
--- a/web/templates/recipe/show.html.eex
+++ b/web/templates/recipe/show.html.eex
@@ -23,6 +23,11 @@
</li>
<li>
+ <strong>Url:</strong>
+ <%= @recipe.url %>
+ </li>
+
+ <li>
<strong>Content:</strong>
<%= @recipe.content %>
</li>最后再运行一次测试：
mix test
Compiling 1 file (.ex)
..............................................................
Finished in 0.9 seconds
62 tests, 0 failures测试全部通过。
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