Class: Percy::Capybara::Loaders::SprocketsLoader

Inherits:
BaseLoader
  • Object
show all
Defined in:
lib/percy/capybara/loaders/sprockets_loader.rb

Overview

Resource loader that loads assets via Sprockets (ie. the Rails asset pipeline).

Constant Summary collapse

SKIP_RESOURCE_EXTENSIONS = 
[
  '.map', # Ignore source maps.
  '.gz', # Ignore gzipped files.
].freeze
MAX_FILESIZE_BYTES =

15 MB.

15 * 1024**2

Constants inherited from BaseLoader

BaseLoader::URL_REGEX

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ SprocketsLoader

Returns a new instance of SprocketsLoader.



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 22

def initialize(options = {})
  @sprockets_environment = options[:sprockets_environment]
  @sprockets_options = options[:sprockets_options]
  super
end

Instance Attribute Details

#page ⇒ Object (readonly)

Returns the value of attribute page.



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 12

def page
  @page
end

#sprockets_environment ⇒ Object (readonly)

Returns the value of attribute sprockets_environment.



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 13

def sprockets_environment
  @sprockets_environment
end

#sprockets_options ⇒ Object (readonly)

Returns the value of attribute sprockets_options.



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 14

def sprockets_options
  @sprockets_options
end

Instance Method Details

#_asset_logical_paths ⇒ Object 



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 95

def _asset_logical_paths
  # Re-implement the same technique that "rake assets:precompile" uses to generate the
  # list of asset paths to include in compiled assets. https://goo.gl/sy2R4z
  # We can't just use environment.each_logical_path without any filters, because then
  # we will attempt to compile assets before they're rendered (such as _mixins.css).
  precompile_list = sprockets_options.precompile
  logical_paths = sprockets_environment.each_logical_path(*precompile_list).to_a
  logical_paths += precompile_list.flatten.select do |filename|
    Pathname.new(filename).absolute? if filename.is_a?(String)
  end
  logical_paths.uniq
end

#_rails ⇒ Object 



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 91

def _rails
  Rails if defined?(Rails)
end

#build_resources ⇒ Object 



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 32

def build_resources
  resources = []
  loaded_resource_urls = Set.new

  # Load resources from the asset pipeline.
  _asset_logical_paths.each do |logical_path|
    next if SKIP_RESOURCE_EXTENSIONS.include?(File.extname(logical_path))

    asset = sprockets_environment.find_asset(logical_path)

    # Skip large files, these are hopefully downloads and not used in page rendering.
    next if asset.length > MAX_FILESIZE_BYTES

    content = asset.to_s
    sha = Digest::SHA256.hexdigest(content)

    if defined?(ActionController)
      # Ask Rails where this asset is (this handles asset_hosts, digest paths, etc.).
      resource_url = ActionController::Base.helpers.asset_path(logical_path)
    else
      # TODO: more robust support for Sprockets usage outside Rails, ie Sinatra.
      # How do we find the correct path in that case?
      path = sprockets_options.digest ? asset.digest_path : logical_path
      resource_url = URI.escape("/assets/#{path}")
    end

    next if SKIP_RESOURCE_EXTENSIONS.include?(File.extname(resource_url))

    loaded_resource_urls.add(resource_url)
    resources << Percy::Client::Resource.new(resource_url, sha: sha, content: content)
  end

  # Load resources from the public/ directory, if a Rails app.
  if _rails
    public_path = _rails.public_path.to_s
    Find.find(public_path).each do |path|
      # Skip directories.
      next unless FileTest.file?(path)
      # Skip certain extensions.
      next if SKIP_RESOURCE_EXTENSIONS.include?(File.extname(path))
      # Skip large files, these are hopefully downloads and not used in page rendering.
      next if File.size(path) > MAX_FILESIZE_BYTES

      # Strip the public_path from the beginning of the resource_url.
      # This assumes that everything in the Rails public/ directory is served at the root
      # of the app.
      resource_url = path.sub(public_path, '')

      # Skip precompiled files already included via the asset pipeline.
      next if loaded_resource_urls.include?(resource_url)

      sha = Digest::SHA256.hexdigest(File.read(path))
      resources << Percy::Client::Resource.new(resource_url, sha: sha, path: path)
    end
  end

  resources
end

#snapshot_resources ⇒ Object 



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# File 'lib/percy/capybara/loaders/sprockets_loader.rb', line 28

def snapshot_resources
  [root_html_resource] + iframes_resources
end