Dynamic fields using Sinatra

Question

In Rails this is a relatively simple task. But I couldn’t find anything in the Sinatra documentation that said it was possible. I want to add fields to a form dynamically. User clicks on a link and a new field is added. If you wish, click on another link and the field is removed. On the front end the task is super quiet, I know. But to persist an arbitrary number of fields in the database? What would it be like?

Answer 1

Documentation says Sinatra also supports query Parameters optional:

Routes may also use query Parameters:

get '/posts' do
  # matches "GET /posts?title=foo&author=bar"
  title = params[:title]
  author = params[:author]
  # uses title and author variables; query is optional to the /posts route
end

Source: http://www.sinatrarb.com/intro.html

So you can use one if simple to find out if a parameter exists:

require "sinatra"

get "/foo" do
  params[:bar] if params[:bar]
end

In the above example:

localhost:5678/foo            # retorna uma página em branco
localhost:5678/foo?bar=foobar # retorna "foobar"

So I think one way to solve your problem would be to create each field with a number on the back:

<input type="text" name="campo1"/>
<input type="text" name="campo2"/>
<input type="text" name="campo3"/>
<input type="text" name="campo4"/>

And then you could use a loop loop to check if the field exists and do what you need with it.