Sinatra CRUD Reference

This is a reference app for CRUD applications with Sinatra

Routes

• GET /trees - list all trees
• GET /trees/new - get the new tree form
• POST /trees - create a new tree
• GET /trees/:id/edit - get the edit tree form
• PATCH /trees/:id - update a tree
• DELETE /trees/:id - delete a tree

Method Overriding

HTML forms cannot send PATCH or DELETE requests. In Sinatra, we get around that shortcoming by sending a hidden parameter along with our forms:

Sending a PATCH request

<form action="/trees/<%= tree["id"] %>" method="post">
  <input type="hidden" name="_method" value="patch"/>
  <ul>
    <li>
      <label for="name">Name</label>
      <input type="text" name="name" id="name" value="<%= tree["name"] %>"/>
    </li>
    <li>
      <label for="species">Species</label>
      <input type="text" name="species" id="species" value="<%= tree["species"] %>"/>
    </li>
    <li>
      <label for="country">Country</label>
      <input type="text" name="country" id="country" value="<%= tree["country"] %>"/>
    </li>
    <li>
      <label for="image">Image</label>
      <input type="text" name="image" id="image" value="<%= tree["image"] %>"/>
    </li>
    <li>
      <input type="submit" value="Update Tree"/>
    </li>
  </ul>
</form>

The "_method" hidden field is set to "patch". This tells Sinatra to interpret this as a PATCH request. This would map to a Sinatra action that looks like this:

  patch "/trees/:id" do
    ...
  end

Sending a DELETE request:

<form method="post" action="/trees/<%= tree["id"] %>">
  <input type="hidden" name="_method" value="delete"/>
  <input type="submit" value="Delete Tree"/>
</form>

The "_method" hidden field here is set to "delete". This tells Sinatra to interpret this as a DELETE request. This would map to a Sinatra action that looks like this:

delete "/trees/:id" do
  @trees_table.delete(params[:id])

  flash[:notice] = "Tree deleted"

  redirect "/"
end