Class: GlobalSession::Rack::Middleware

Inherits:
Object
  • Object
show all
Defined in:
lib/global_session/rack.rb

Overview

Global session middleware. Note: this class relies on Rack::Cookies being used higher up in the chain.

Constant Summary collapse

LOCAL_SESSION_KEY = 
"rack.session".freeze

Instance Method Summary collapse

Constructor Details

#initialize(app, configuration, directory, &block) ⇒ Middleware

Make a new global session.

The optional block here controls an alternate ticket retrieval method. If no ticket is stored in the cookie jar, this function is called. If it returns a non-nil value, that value is the ticket.

Parameters

app(Rack client): application to run configuration(String or Configuration): global_session configuration. If a string, is interpreted as a filename to load the config from. directory(String or Directory): Directory object that provides trust services to the global session implementation. If a string, is interpreted as a filesystem directory containing the public and private keys of authorities, from which default trust services will be initialized.

block: optional alternate ticket retrieval function



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# File 'lib/global_session/rack.rb', line 54

def initialize(app, configuration, directory, &block)
  @app = app

  if configuration.instance_of?(String)
    @configuration = Configuration.new(configuration, ENV['RACK_ENV'] || 'development')
  else
    @configuration = configuration
  end

  begin
    klass_name = @configuration['directory'] || 'GlobalSession::Directory'

    #Constantize the type name that was given as a string
    parts = klass_name.split('::')
    namespace = Object
    namespace = namespace.const_get(parts.shift.to_sym) until parts.empty?
    directory_klass = namespace
  rescue Exception => e
    raise GlobalSession::ConfigurationError, "Invalid/unknown directory class name #{@configuration['directory']}"
  end

  if directory.instance_of?(String)
    @directory = directory_klass.new(@configuration, directory)
  else
    @directory = directory
  end

  @cookie_retrieval = block
  @cookie_name = @configuration['cookie']['name']
end

Instance Method Details

#call(env) ⇒ Object

Rack request chain. Sets up the global session ticket from the environment and passes it up the chain.



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# File 'lib/global_session/rack.rb', line 87

def call(env)
  env['rack.cookies'] = {} unless env['rack.cookies']

  begin
    err = nil
    read_authorization_header(env) || read_cookie(env) || create_session(env)
  rescue Exception => read_err
    err = read_err

    # Catch "double whammy" errors
    begin
      env['global_session'] = @directory.create_session
    rescue Exception => create_err
      err = create_err
    end

    handle_error('reading session cookie', env, err)
  end

  tuple = nil

  begin
    tuple = @app.call(env)
  rescue Exception => read_err
    handle_error('processing request', env, read_err)
    return tuple
  else
    renew_cookie(env)
    update_cookie(env)
    return tuple
  end
end

#cookie_domain(env) ⇒ Object

Determine the domain name for which we should set the cookie. Uses the domain specified in the configuration if one is found; otherwise, uses the SERVER_NAME from the request but strips off the first component if the domain name contains more than two components.

Parameters

env(Hash)

the Rack environment hash



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# File 'lib/global_session/rack.rb', line 292

def cookie_domain(env)
  if @configuration['cookie'].key?('domain')
    # Use the explicitly provided domain name
    domain = @configuration['cookie']['domain']
  else
    # Use the server name, but strip off the most specific component
    parts = env['SERVER_NAME'].split('.')
    parts = parts[1..-1] if parts.length > 2
    domain = parts.join('.')
  end

  domain
end

#create_session(env) ⇒ Object

Ensure that the Rack environment contains a global session object; create a session if necessary.

Parameters

env(Hash): Rack environment.

Return

true

always returns true



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# File 'lib/global_session/rack.rb', line 177

def create_session(env)
  env['global_session'] ||= @directory.create_session

  true
end

#handle_error(activity, env, e) ⇒ Object

Handle exceptions that occur during app invocation. This will either save the error in the Rack environment or raise it, depending on the type of error. The error may also be logged.

Parameters

activity(String): name of activity in which error happened env(Hash): Rack environment e(Exception): error that happened



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# File 'lib/global_session/rack.rb', line 254

def handle_error(activity, env, e)
  if env['rack.logger']
    msg = "#{e.class} while #{activity}: #{e}"
    msg += " #{e.backtrace}" unless e.is_a?(ExpiredSession)
    env['rack.logger'].error(msg)
  end

  if e.is_a?(ClientError) || e.is_a?(SecurityError)
    env['global_session.error'] = e
    wipe_cookie(env)
  elsif e.is_a? ConfigurationError
    env['global_session.error'] = e
  else
    raise e
  end
end

#perform_invalidation_callbacks(env, old_session, new_session) ⇒ Object

Perform callbacks to directory and/or local session informing them that this session has been invalidated.

Parameters

env(Hash)

the rack environment

old_session(GlobalSession)

the now-invalidated session

new_session(GlobalSession)

the new session that will be sent to the client



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# File 'lib/global_session/rack.rb', line 278

def perform_invalidation_callbacks(env, old_session, new_session)
  if (local_session = env[LOCAL_SESSION_KEY]) && local_session.respond_to?(:rename!)
    local_session.rename!(old_session, new_session)
  end

  true
end

#read_authorization_header(env) ⇒ Object

Read a global session from the HTTP Authorization header, if present. If an authorization header was found, also disable global session cookie update and renewal by setting the corresponding keys of the Rack environment.

Parameters

env(Hash): Rack environment.

Return

result(true,false)

Returns true if the environment was populated, false otherwise



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# File 'lib/global_session/rack.rb', line 129

def read_authorization_header(env)
  if env.has_key? 'X-HTTP_AUTHORIZATION'
    # RFC2617 style (preferred by OAuth 2.0 spec)
    header_data = env['X-HTTP_AUTHORIZATION'].to_s.split
  elsif env.has_key? 'HTTP_AUTHORIZATION'
    # Fallback style (generally when no load balancer is present, e.g. dev/test)
    header_data = env['HTTP_AUTHORIZATION'].to_s.split
  else
    header_data = nil
  end

  if header_data && header_data.size == 2 && header_data.first.downcase == 'bearer'
    env['global_session.req.renew'] = false
    env['global_session.req.update'] = false
    env['global_session'] = @directory.load_session(header_data.last)
    true
  else
    false
  end
end

#read_cookie(env) ⇒ Object

Read a global session from HTTP cookies, if present.

Parameters

env(Hash): Rack environment.

Return

result(true,false)

Returns true if the environment was populated, false otherwise



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# File 'lib/global_session/rack.rb', line 157

def read_cookie(env)
  if @cookie_retrieval && (cookie = @cookie_retrieval.call(env))
    env['global_session'] = @directory.load_session(cookie)
    true
  elsif env['rack.cookies'].has_key?(@cookie_name)
    env['global_session'] = @directory.load_session(env['rack.cookies'][@cookie_name])
    true
  else
    false
  end
end

#renew_cookie(env) ⇒ Object

Renew the session ticket.

Parameters

env(Hash): Rack environment



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# File 'lib/global_session/rack.rb', line 187

def renew_cookie(env)
  return unless @directory.local_authority_name
  return if env['global_session.req.renew'] == false

  if (renew = @configuration['renew']) && env['global_session'] &&
      env['global_session'].expired_at < Time.at(Time.now.utc + 60 * renew.to_i)
    env['global_session'].renew!
  end
end

#update_cookie(env) ⇒ Object

Update the cookie jar with the revised ticket.

Parameters

env(Hash): Rack environment



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# File 'lib/global_session/rack.rb', line 201

def update_cookie(env)
  return unless @directory.local_authority_name
  return if env['global_session.req.update'] == false

  session = env['global_session']

  if session
    unless session.valid?
      old_session = session
      session = @directory.create_session
      perform_invalidation_callbacks(env, old_session, session)
      env['global_session'] = session
    end

    value = session.to_s
    expires = @configuration['ephemeral'] ? nil : session.expired_at
    unless env['rack.cookies'][@cookie_name] == value
      env['rack.cookies'][@cookie_name] =
          {:value => value,
           :domain => cookie_domain(env),
           :expires => expires,
           :httponly=>true}
    end
  else
    # write an empty cookie
    wipe_cookie(env)
  end
rescue Exception => e
  wipe_cookie(env)
  raise e
end

#wipe_cookie(env) ⇒ Object

Delete the global session cookie from the cookie jar.

Parameters

env(Hash): Rack environment



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# File 'lib/global_session/rack.rb', line 237

def wipe_cookie(env)
  return unless @directory.local_authority_name
  return if env['global_session.req.update'] == false

  env['rack.cookies'][@cookie_name] = {:value => nil,
                                       :domain => cookie_domain(env),
                                       :expires => Time.at(0)}
end