Run

You can use the run middleware to run an inline rack application. The alternative way to mount a rack application is to use a rackup_file middleware.

You can mount several rack applications to run simultaneously within a single Itsi application, using different location blocks. Depending on where you mount the app, the application will receive different values for PATH_INFO, SCRIPT_NAME.

Configuration

Simple inline Rack app.

run ->(env){ [200, { 'content-type' => 'text/plain' }, ['OK']] }

Rack app using Rack::Builder

run(Rack::Builder.app do
  use Rack::CommonLogger
  run ->(env) { [200, { 'content-type' => 'text/plain' }, ['OK']] }
end)

Rack app mounted at a subpath

require 'rack'
location "/subpath/*" do
  run(Rack::Builder.app do
    use Rack::CommonLogger
    run ->(env) { [200, { 'content-type' => 'text/plain' }, [[env['SCRIPT_NAME'], env['PATH_INFO']].join(":") ]  ] }
  end)
end

run(Rack::Builder.app do
  use Rack::CommonLogger
  run ->(env) { [200, { 'content-type' => 'text/plain' }, [[env['SCRIPT_NAME'], env['PATH_INFO']].join(":") ]  ] }
end)

$ curl http://0.0.0.0:3000/subpath/child_path
/subpath:/child_path

$ curl http://0.0.0.0:3000/root/child_path
:/root/child_path

SCRIPT_NAME and PATH_INFO Rack ENV variables.

Rack applications mounted at a subpath will, by default, receive a SCRIPT_NAME value that includes the subpath at which the app is mounted, and a PATH_INFO value that is relative to the subpath at which the rack app is mounted. If you wish to use location blocks only to control the middleware that applies to a rack app, but still have it behave as if it were mounted elsewhere (e.g. at the root), you can explicitly set the script_name option. E.g.

location "/subpath/*" do
  run(Rack::Builder.app do
    use Rack::CommonLogger
    run ->(env) { [200, { 'content-type' => 'text/plain' }, [[env['SCRIPT_NAME'], env['PATH_INFO']].join(":") ]  ] }
  end, script_name: '/')
end

# Our script-name override kicks in here, even though the app is mounted under `/subpath`
$ curl http://0.0.0.0:3000/subpath/child_path
/:/subpath/child_path

Options

• nonblocking (default false). Determines whether requests sent to this Rack application should be run on non-blocking threads. Only applies if running in hybrid (non-blocking and blocking thread pool) mode. Otherwise this is a no-op and will run in whatever mode is set globally.
• sendfile (default true). Determines whether Itsi should respect the X-Sendfile header set by the Rack application and use the sendfile function to efficiently send files. (Despite the name, this does not use the OS-level sendfile system call). Note. Itsi enforces the restriction that the referenced file must be within a child directory of the application root.

e.g.

run ->(env){ [200, { 'content-type' => 'text/plain' }, ['OK']] }, nonblocking: true, sendfile: false