引导闪存不适用于Rails 4.1.4和simple_form

Question

I'm having difficulties getting flashes to work with bootstrap_flash helper. Here's a snippet of my code:

application.html.erb

...
<div class="container">
  <%= bootstrap_flash  %>
  <%= yield %> 
</div>
...

bootstrap_flash_helper.rb

ALERT_TYPES = [:error, :info, :success, :warning] unless const_defined?(:ALERT_TYPES)

def bootstrap_flash
  flash_messages = []
  flash.each do |type, message|
    # Skip empty messages, e.g. for devise messages set to nothing in a locale file.
    next if message.blank?

    type = type.to_sym
    type = :success if type.to_s == :notice.to_s
    type = :error   if type.to_s == :alert.to_s
    next unless ALERT_TYPES.include?(type)

    Array(message).each do |msg|
      text = content_tag(:div, content_tag(:button, raw("×"), :class => "close", "data-dismiss" => "alert") + msg.html_safe, :class => "alert fade in alert-#{type}")
      flash_messages << text if msg
    end
  end
    flash_messages.join("\n").html_safe
end
end   

and I'm calling flash[:notice] in my controller actions.

Can somebody give me a hint on this one? Thanks!

Answer 1

On a first glance the last end in your code is one too many.

On a second glance there are some flaws in your code in my opinion:

(1) Avoid casting back and forth:

type = type.to_sym
type = :success if type.to_s == :notice.to_s
type = :error   if type.to_s == :alert.to_s

You're casting type to a symbol, only to cast it back to a string while casting a constant symbol to a string to compare them. If you omit the to_s calls you can achieve the same thing without having to cast:

type = type.to_sym
type = :success if type == :notice
type = :error   if type == :alert

(2) Use map instead of a helper variable + each :

flash_messages = []
flash.each do |type, message|
  # ...
end
flash_messages.join("\n")

Instead of creating a temporary variable to turn the hash into an array, you can use Enumerable 's map or collect method to create a new array:

flash.map do |type, message|
  # ...
end.join("\n")

(3) Use a mappings hash to map to CSS classes:

ALERT_TYPES = {
 :alert => :error, :info => :info, :notice => :success, :warning => :warning
}

By using a hash like this you can simply do a lookup for the match, instead of having several if statements to determine the correct class

content_tag(:div, message, class: "alert alert-#{ALERT_TYPES[type.to_sym]}")

Overall, this would be a far more readable, shorter and expandable solution, I think:

ALERT_TYPES = { :alert => :error, :info => :info, :notice => :success, :warning => :warning } unless const_defined?(:ALERT_TYPES)

def bootstrap_flash
  flash.map do |type, message|
    # Skip empty messages, e.g. for devise messages set to nothing in a locale file.
    # This will leave a nil value in the resulting array
    next if message.blank?

    # Skip if it's not a valid alert type
    # This will leave a nil value in the resulting array
    type = type.to_sym
    next unless ALERT_TYPES.keys.include?(type)

    # return the markup for the alert
    content_tag(:div, class: "alert alert-#{ALERT_TYPES[type]} fade in") do
      # use safe_concat() to avoid using html_safe()
      content_tag(:button, raw("×"), class: "close", data: { dismiss: "alert" }).safe_concat(message)
    end
  end.join('') # no need to join with \n --> this way nil values will be ignored as well
end