rails 中的 url helper 文档在哪里?

问题描述：

我如何知道 url 助手在 Rails 中采用什么参数?例如，我怎么知道 url helper 只接受下面的一个参数?我知道这些方法是元编程的，但它们的文档在哪里?

How do I know what arguments url helpers take in Rails? For example, how do I know url helper takes just one parameter below? I know these methods are metaprogrammed but where is their documentation?

link_to "New Ticket", new_project_ticket_path(@project)

答

您可以通过查看路由定义来确定路由助手需要多少个参数.

You can determine how many parameters a route helper requires by looking at the route definition.

例如，你可能有这个路由文件:

For example, you might have this routes file:

resources :users

如果你在命令行运行 rake routes 你会看到这样的:

If you ran rake routes at the command line you would see something like this:

    users GET    /users(.:format)          users#index
          POST   /users(.:format)          users#create
 new_user GET    /users/new(.:format)      users#new
edit_user GET    /users/:id/edit(.:format) users#edit
     user GET    /users/:id(.:format)      users#show
          PUT    /users/:id(.:format)      users#update
          DELETE /users/:id(.:format)      users#destroy

第一列为您提供路线名称.您可以附加 _path 或 _url 以获取路由助手的名称.

The first column gives you the name of the route. You can append _path or _url to get the name of a route helper.

第三列显示模式.在这里你可以弄清楚参数是什么.参数是以冒号为前缀的部分，可选参数显示在括号中.例如，edit_user 路由的模式为 /users/:id/edit(.:format)，其中包含一个必需的参数 (id) 和一个可选参数(format)，它告诉我我需要将至少一个参数传递给 edit_user_path 或 edit_user_url 助手:

The third column shows the pattern. This is where you can figure out what the arguments are. Arguments are the parts prefixed with a colon, and optional arguments are shown in parentheses. For example the edit_user route has the pattern /users/:id/edit(.:format) which contains one required argument (id) and one optional argument (format), which tells me I need to pass at least one argument to the edit_user_path or edit_user_url helper:

edit_user_path(1) # => "/users/1/edit"
edit_user_path(2, :html) # => "/users/2/edit.html"

您还可以使用模式中的参数名称作为散列中的键:

You can also use the argument names from the pattern as keys in a hash:

edit_user_path(id: 3, format: 'js') # => "/users/3/edit.js"

最后，您可以添加额外的参数，这些参数将成为查询字符串的一部分:

Finally, you can add extra arguments which will become part of the query string:

edit_user_path(id: 4, format: 'json', foo: 1) # => "/users/4/edit.json?foo=1"
edit_user_path(5, bar: 2) # => "/users/5/edit?bar=2"

查看Rails 路由指南中关于列出现有路由的部分了解更多信息关于rake 路线的信息.

See the Rails Routing Guide's section on Listing Existing Routes for more information about rake routes.

rails 中的 url helper 文档在哪里?

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