class RuboCop::Cop::Rails::OutputSafety

“<b>hi</b> <span><b>hi</b></span>”
=> ActiveSupport::SafeBuffer
safe_join([user_content, “ ”, content_tag(:span, user_content)])
# good
“hi <span>hi</span>”
=> ActiveSupport::SafeBuffer
(user_content + “ ” + content_tag(:span, user_content)).html_safe
# bad
=> trusted content<b>hi</b>
<%= result %>
# because when rendered in ERB the String will be escaped:
=> String “trusted contenthi”
result = out.concat(user_content)
out = “trusted content”
# safe, though maybe not good style
“<h1>trusted_content</h1><b>hi</b>”
=> ActiveSupport::SafeBuffer
out.concat(user_content)
out = “<h1>trusted content</h1>”.html_safe
# good
“<h1>trusted_content</h1>hi”
=> ActiveSupport::SafeBuffer
out.safe_concat(user_content)
out = “<h1>trusted content</h1>”.html_safe
# bad
“<li><b>hi</b></li><li><b>hi</b></li>”
=> ActiveSupport::SafeBuffer
safe_join(out)
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
out = []
# good
“<li>hi</li><li>hi</li>”
=> ActiveSupport::SafeBuffer
out.html_safe
out << “<li>#{user_content}</li>”
out << “<li>#{user_content}</li>”
out = “”
# bad
“<p><b>hi</b></p>”
=> ActiveSupport::SafeBuffer
content_tag(:p, user_content)
# good
“<p>hi</p>”
=> ActiveSupport::SafeBuffer
“<p>#{user_content}</p>”.html_safe
# bad
user_content = “hi”
@example
concatenate content and escape it, ensuring its safety.
use safe_join to join content and escape it and concat to
simply return a SafeBuffer containing the content as is. Instead,
raw, and safe_concat. These methods do not escape content. They
This cop checks for the use of output safety calls like html_safe,

def looks_like_rails_html_safe?(node)

def looks_like_rails_html_safe?(node)
  node.receiver && node.method?(:html_safe) && !node.arguments?
end

def looks_like_rails_raw?(node)

def looks_like_rails_raw?(node)
  node.command?(:raw) && node.arguments.one?
end

def looks_like_rails_safe_concat?(node)

def looks_like_rails_safe_concat?(node)
  node.method?(:safe_concat) && node.arguments.one?
end

def on_send(node)

def on_send(node)
  return unless looks_like_rails_html_safe?(node) ||
                looks_like_rails_raw?(node) ||
                looks_like_rails_safe_concat?(node)
  add_offense(node, :selector)
end