If Statement inside Sinatra template

I'd like to to show a message only if on a specific route/page. Essentially, if on /route display a message.

I tried going through the Sinatra Docs, but I can't find a specific way to do it. Is there a Ruby method that will make this work?

EDIT: Here's an example of what I'd like to do.

get '/' do
    erb :index
end

get '/page1' do
    erb :page1
end

get '/page2' do
    erb :page2
end

*******************

<!-- Layout File -->
<html>
<head>
    <title></title>
</head> 
<body>
    <% if this page is 'page1' do something %>
    <% else do something else %>
    <% end %>

    <%= yield %>
</body>
</html>

No idea what how to target the current page using Ruby/Sinatra and structure it into an if statement.

There are several ways to approach this (and BTW, I'm going to use Haml even though you've used ERB because it's less typing for me and plainly an improvement). Most of them rely on the request helper, most often it will be request.path_info.

Conditional within a view.

Within any view, not just a layout:

%p
  - if request.path_info == "/page1"
    = "You are on page1"
  - else
    = "You are not on page1, but on #{request.path_info[1..]}"
%p= request.path_info == "/page1" ? "PAGE1!!!" : "NOT PAGE1!!!"

A conditional with a route.

get "/page1" do
  # you are on page1
  message = "This is page 1"
  # you can use an instance variable if you want, 
  # but reducing scope is a best practice and very easy.
  erb :page1, :locals => { message: message }
end

get "/page2" do
  message = nil # not needed, but this is a silly example
  erb :page2, :locals => { message: message }
end

get %r{/page(\d+)} do |digits|
  # you'd never reach this with a 1 as the digit, but again, this is an example
  message = "Page 1" if digits == "1"
  erb :page_any, :locals => { message: message }
end

# page1.erb
%p= message unless message.nil?

A `before` block.

before do
  @message = "Page1" if request.path_info == "/page1"
end

# page1.erb
%p= @message unless @message.nil?

or even better

before "/page1" do
  @message = "Hello, this is page 1"
end

or better again

before do
  @message = request.path_info == "/page1" ? "PAGE 1!" : "NOT PAGE 1!!"
end

# page1.erb
%p= @message

I would also suggest you take a look at Sinatra Partial if you're looking to do this, as it's a lot easier to handle splitting up views when you have a helper ready made for the job.

Sinatra has no "controller#action" Rail's like concept, so you wont find a way to instantiate the current route. In any case, you can check request.path.split('/').last to get a relative idea of what is the current route.

However, if you want something so be shown only if request.path == "x", a much better way is to put that content on the template, unless that content has to be rendered in a different place within your layout. In that case you can use something like Rail's content_for. Check sinatra-content-for.

来源：https://stackoverflow.com/questions/14079193/if-statement-inside-sinatra-template

标签

ruby

sinatra

If Statement inside Sinatra template

Conditional within a view.

A conditional with a route.

A before block.

A `before` block.