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97 lines
2.5 KiB
Ruby
97 lines
2.5 KiB
Ruby
#
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# This class is used to download and optimize images.
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#
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require 'image_sorcery'
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require 'digest/sha1'
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require 'open-uri'
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class ImageOptimizer
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attr_accessor :url
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# url is a url of an image ex:
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# 'http://site.com/image.png'
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# '/uploads/site/image.png'
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def initialize(url)
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@url = url
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# make sure directories exists
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FileUtils.mkdir_p downloads_dir
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FileUtils.mkdir_p optimized_dir
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end
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# return the path of an optimized image,
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# if already cached return cached, else download and cache
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# at the original size.
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# if size is specified return a resized image
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# if height or width are nil maintain aspect ratio
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#
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# Optimised image is the "most efficient" storage for an image
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# at the basic level it runs through image_optim https://github.com/toy/image_optim
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# it also has a failsafe that converts jpg to png or the opposite. if jpg size is 1.5*
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# as efficient as png it flips formats.
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def optimized_image_url (width = nil, height = nil)
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begin
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unless has_been_uploaded?
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return @url unless SiteSetting.crawl_images?
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# download the file if it hasn't been cached yet
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download! unless File.exists?(cached_path)
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end
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# resize the image using Image Magick
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result = ImageSorcery.new(cached_path).convert(optimized_path, resize: "#{width}x#{height}")
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return optimized_url if result
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@url
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rescue
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@url
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end
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end
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private
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def public_dir
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@public_dir ||= "#{Rails.root}/public"
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end
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def downloads_dir
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@downloads_dir ||= "#{public_dir}/downloads/#{RailsMultisite::ConnectionManagement.current_db}"
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end
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def optimized_dir
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@optimized_dir ||= "#{public_dir}/images/#{RailsMultisite::ConnectionManagement.current_db}"
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end
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def has_been_uploaded?
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@url.start_with?(Discourse.base_url_no_prefix)
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end
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def cached_path
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@cached_path ||= if has_been_uploaded?
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"#{public_dir}#{@url[Discourse.base_url_no_prefix.length..-1]}"
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else
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"#{downloads_dir}/#{file_name(@url)}"
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end
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end
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def optimized_path
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@optimized_path ||= "#{optimized_dir}/#{file_name(cached_path)}"
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end
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def file_name (uri)
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image_info = FastImage.new(uri)
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name = Digest::SHA1.hexdigest(uri)[0,16]
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name << ".#{image_info.type}"
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name
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end
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def download!
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File.open(cached_path, "wb") do |f|
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f.write open(@url, "rb", read_timeout: 20).read
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end
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end
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def optimized_url
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@optimized_url ||= Discourse.base_url_no_prefix + "/images/#{RailsMultisite::ConnectionManagement.current_db}/#{file_name(cached_path)}"
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end
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end
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