How to set a default url in a Rails form

Question

In my app users can list someone's instagram profile, but they would have to copy and paste the entire url in the form.

<%= f.url_field :url,required: true,label: "URL (required)" %>

How do i set the default url in my form as instagram.com/ so that they would only need to enter the username?

Answer 1

You can just ask for username and later in controller/form model remove @ (and whole ' http://instagram.com/ ' prefix if someone pastes url instead of username)

<%= f.text_field :instagram_username, required: true, label: "instagram.com/" %>

Controller something like:

 obj = Model.new(model_params)
 if (username = params.dig(:some_model, :instagram_username))
   username = username.gsub(%r{https?://instagram.com/}, '').gsub(/^@/, '')
   obj.url = "https://instagram.com/#{CGI.escape username}"
 end