Class: Camping::Reloader

Inherits:
Object show all
Defined in:
lib/camping/reloader.rb

Overview

The Camping Reloader

Camping apps are generally small and predictable. Many Camping apps are contained within a single file. Larger apps are split into a handful of other Ruby libraries within the same directory.

Since Camping apps (and their dependencies) are loaded with Ruby’s require method, there is a record of them in $LOADED_FEATURES. Which leaves a perfect space for this class to manage auto-reloading an app if any of its immediate dependencies changes.

Wrapping Your Apps

Since bin/camping and the Camping::Server class already use the Reloader, you probably don’t need to hack it on your own. But, if you’re rolling your own situation, here’s how.

Rather than this:

require 'yourapp'

Use this:

require 'camping/reloader'
reloader = Camping::Reloader.new('/path/to/yourapp.rb')
blog = reloader.apps[:Blog]
wiki = reloader.apps[:Wiki]

The blog and wiki objects will behave exactly like your Blog and Wiki, but they will update themselves if yourapp.rb changes.

You can also give Reloader more than one script.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file, &blk) ⇒ Reloader

Returns a new instance of Reloader.



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# File 'lib/camping/reloader.rb', line 37

def initialize(file, &blk)
  @file = file
  @mtime = Time.at(0)
  @requires = []
  @apps = {}
  @callback = blk

end

Instance Attribute Details

#file ⇒ Object (readonly)

Returns the value of attribute file.



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# File 'lib/camping/reloader.rb', line 35

def file
  @file
end

Instance Method Details

#==(other) ⇒ Object

Checks if both scripts watches the same file.



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# File 'lib/camping/reloader.rb', line 133

def ==(other)
  @file == other.file
end

#apps ⇒ Object 



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# File 'lib/camping/reloader.rb', line 137

def apps
  if @app
    { name => @app }
  else
    @apps
  end
end

#load_apps(old_apps) ⇒ Object

Loads the apps available in this script. Use apps to get the loaded apps.



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# File 'lib/camping/reloader.rb', line 57

def load_apps(old_apps)
  all_requires = $LOADED_FEATURES.dup
  all_apps = Camping::Apps.dup

  load_file
ensure
  @requires = []
  dirs = []
  new_apps = Camping::Apps - all_apps

  @apps = new_apps.inject({}) do |hash, app|
    if file = app.options[:__FILE__]
      full = File.expand_path(file)
      @requires << [file, full]
      dirs << full.sub(/\.[^.]+$/, '')
    end

    key = app.name.to_sym
    hash[key] = app

    if !old_apps.include?(key)
      @callback.call(app) if @callback
      app.create if app.respond_to?(:create)
    end

    hash
  end

  ($LOADED_FEATURES - all_requires).each do |req|
    full = full_path(req)
    @requires << [req, full] if dirs.any? { |x| full.index(x) == 0 }
  end

  @mtime = mtime

  self
end

#load_file ⇒ Object

load_file

Rack::Builder is mainly used to parse a config.ru file and to build a rack app with middleware from that.



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# File 'lib/camping/reloader.rb', line 99

def load_file
  if @file =~ /\.ru$/
    @app = Rack::Builder.parse_file(@file)
  else
    load(@file)
  end
end

#name ⇒ Object 



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# File 'lib/camping/reloader.rb', line 46

def name
  @name ||= begin
    base = @file.dup
    base = File.dirname(base) if base =~ /\bconfig\.ru$/
    base.sub!(/\.[^.]+/, '')
    File.basename(base).to_sym
  end
end

#reload ⇒ Object

Reloads the file if needed. No harm is done by calling this multiple times, so feel free call just to be sure.



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# File 'lib/camping/reloader.rb', line 123

def reload
  return if @mtime >= mtime rescue nil
  reload!
end

#reload! ⇒ Object 



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# File 'lib/camping/reloader.rb', line 128

def reload!
  load_apps(remove_apps)
end

#remove_apps ⇒ Object

Removes all the apps defined in this script.



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# File 'lib/camping/reloader.rb', line 108

def remove_apps
  @requires.each do |(path, full)|
    $LOADED_FEATURES.delete(path)
  end

  @apps.each do |name, app|
    Camping::Apps.delete(app)
    Object.send :remove_const, name
  end.dup
ensure
  @apps.clear
end