How to Get Sinatra to Auto-Reload the File After Each Change

How to get Sinatra to auto-reload the file after each change?

See the Sinatra FAQ,

"How do I make my Sinatra app reload on changes?"

First off, in-process code reloading in Ruby is hard and having a
solution that works for every scenario is technically impossible.

Which is why we recommend you to do out-of-process reloading.

First you need to install rerun if you haven’t already:

 $ gem install rerun

Now if you start your Sinatra app like this:

$ ruby app.rb

All you have to do for reloading is instead do this:

$ rerun 'ruby app.rb'

If you are for instance using rackup, instead do
the following:

$ rerun 'rackup'

You get the idea.

If you still want in-process reloading, check out Sinatra::Reloader.

How to get Sinatra to auto-reload the file after each change?

See the Sinatra FAQ,

"How do I make my Sinatra app reload on changes?"

First off, in-process code reloading in Ruby is hard and having a
solution that works for every scenario is technically impossible.

Which is why we recommend you to do out-of-process reloading.

First you need to install rerun if you haven’t already:

 $ gem install rerun

Now if you start your Sinatra app like this:

$ ruby app.rb

All you have to do for reloading is instead do this:

$ rerun 'ruby app.rb'

If you are for instance using rackup, instead do
the following:

$ rerun 'rackup'

You get the idea.

If you still want in-process reloading, check out Sinatra::Reloader.

Rack::Reloader not picking up changes

See here for a detailed explanation of what's happening. Essentialy everytime your file is changed, Rack::Reloader re-requires it.

Unfortunately with Sinatra, if you redefine a route a second time (which is what happens when you re-require), sinatra ignores the new definition since get '/' do end is already defined!

What you will need to do is reset any defined routes you have as well:

# inside app.rb

require 'sinatra'
require 'rack'

configure :development do
    Sinatra::Application.reset!
    use Rack::Reloader
end

get '/' do
  'hi'
end

Note that sometimes it takes a few seconds (5s on my machine) for the changes to be reloaded and I recommend you take a look at the alternatives here

Sinatra requires restart

The book has something on the topic now: http://sinatra-book.gittr.com/#automatic_code_reloading

Sinatra view doesn't refresh after some delete requests

There is reloading a page and there is redirecting to a page.

When you use the redirect method of Sinatra it responds with a 302 or 303 status code.

# @see https://github.com/sinatra/sinatra/blob/v2.0.0/lib/sinatra/base.rb#L271
# Halt processing and redirect to the URI provided.
def redirect(uri, *args)
  if env['HTTP_VERSION'] == 'HTTP/1.1' and env["REQUEST_METHOD"] != 'GET'
    status 303
  else
    status 302
  end

  # According to RFC 2616 section 14.30, "the field value consists of a
  # single absolute URI"
  response['Location'] = uri(uri.to_s, settings.absolute_redirects?, settings.prefixed_redirects?)
  halt(*args)
end

By calling redirect "/" you are asking the browser to redirect to "/", which would normally trigger a fresh page. However, you're already on that page, so the jQuery code is receiving a redirect and you're asking for a reload via location.reload() upon success. Success is generally indicated by responding with a 2xx code, so I'd posit that the redirect means the success handler isn't firing, and because the browser realises you're already on the page the redirect has asked for it doesn't attempt a redirect either and you end up with no fresh data.

The route should probably look more like this:

delete '/delete/:record_id' do
  id = get_record_id
  delete_record id
  halt 200 # think about handling errors too
end

The success handler should now fire. Moral of the story, be explicit in what you want to do, don't rely on side effects (like a redirect sharing some properties of a reload) to do what you want.

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