discourse/lib/cooked_post_processor.rb

187 lines
5.2 KiB
Ruby

# Post processing that we can do after a post has already been cooked. For
# example, inserting the onebox content, or image sizes.
require_dependency 'oneboxer'
require_dependency 'image_optimizer'
class CookedPostProcessor
def initialize(post, opts={})
@dirty = false
@opts = opts
@post = post
@doc = Nokogiri::HTML::fragment(post.cooked)
@size_cache = {}
end
def dirty?
@dirty
end
# Bake onebox content into the post
def post_process_oneboxes
args = {post_id: @post.id}
args[:invalidate_oneboxes] = true if @opts[:invalidate_oneboxes]
result = Oneboxer.apply(@doc) do |url, element|
Oneboxer.onebox(url, args)
end
@dirty ||= result.changed?
end
# First let's consider the images
def post_process_images
images = @doc.search("img")
return unless images.present?
images.each do |img|
src = img['src']
src = Discourse.base_url_no_prefix + src if src =~ /^\/[^\/]/
if src.present?
if img['width'].blank? || img['height'].blank?
w, h = get_size_from_image_sizes(src, @opts[:image_sizes]) || image_dimensions(src)
if w && h
img['width'] = w.to_s
img['height'] = h.to_s
@dirty = true
end
end
if src != img['src']
img['src'] = src
@dirty = true
end
convert_to_link!(img)
img['src'] = optimize_image(img)
end
end
# Extract the first image from the first post and use it as the 'topic image'
if @post.post_number == 1
img = images.first
@post.topic.update_column :image_url, img['src'] if img['src'].present?
end
end
def optimize_image(img)
src = img["src"]
return src
# implementation notes: Sam
#
# I have disabled this for now, would like the following addressed.
#
# 1. We need a db record pointing the files on the file system to the post they are on,
# if we do not do that we have no way of purging any local optimised copies
#
# 2. We should be storing images in /uploads/site-name/_optimised ... it simplifies configuration
#
# 3. I don't want to have a folder with 10 million images, let split it so /uploads/site-name/_optimised/ABC/DEF/AAAAAAAA.jpg
#
# 4. We shoul confirm that that we test both saving as jpg and png and pick the more efficient format ... tricky to get right
#
# 5. All images should also be optimised using image_optim, it ensures that best compression is used
#
# 6. Admin screen should alert users of any missing dependencies (image magick, etc, and explain what it is for)
#
# 7. Optimise images should be a seperate site setting.
# supports only local uploads
return src if SiteSetting.enable_s3_uploads?
width, height = img["width"].to_i, img["height"].to_i
ImageOptimizer.new(src).optimized_image_url(width, height)
end
def convert_to_link!(img)
src = img["src"]
width, height = img["width"].to_i, img["height"].to_i
return unless src.present? && width > SiteSetting.auto_link_images_wider_than
original_width, original_height = get_size(src)
return unless original_width.to_i > width && original_height.to_i > height
parent = img.parent
while parent
return if parent.name == "a"
break unless parent.respond_to? :parent
parent = parent.parent
end
# not a hyperlink so we can apply
a = Nokogiri::XML::Node.new "a", @doc
img.add_next_sibling(a)
a["href"] = src
a["class"] = "lightbox"
a.add_child(img)
@dirty = true
end
def get_size_from_image_sizes(src, image_sizes)
if image_sizes.present?
if dim = image_sizes[src]
ImageSizer.resize(dim['width'], dim['height'])
end
end
end
def post_process
return unless @doc.present?
post_process_images
post_process_oneboxes
end
def html
@doc.try(:to_html)
end
def doc
@doc
end
def get_size(url)
# we need to find out whether it's an external image or an uploaded one
# an external image would be: http://google.com/logo.png
# an uploaded image would be: http://my.discourse.com/uploads/default/12345.png or http://my.cdn.com/uploads/default/12345.png
uri = url
# this will transform `http://my.discourse.com/uploads/default/12345.png` into a local uri
uri = "#{Rails.root}/public#{url[Discourse.base_url.length..-1]}" if url.start_with?(Discourse.base_url)
# this will do the same but when CDN has been defined in the configuration
uri = "#{Rails.root}/public#{url[ActionController::Base.asset_host.length..-1]}" if ActionController::Base.asset_host && url.start_with?(ActionController::Base.asset_host)
# return nil when it's an external image *and* crawling is disabled
return nil unless SiteSetting.crawl_images? || uri[0] == "/"
@size_cache[uri] ||= FastImage.size(uri)
rescue Zlib::BufError
# FastImage.size raises BufError for some gifs
return nil
end
def get_image_uri(url)
uri = URI.parse(url)
if %w(http https).include?(uri.scheme)
uri
else
nil
end
end
# Retrieve the image dimensions for a url
def image_dimensions(url)
uri = get_image_uri(url)
return nil unless uri
w, h = get_size(url)
ImageSizer.resize(w, h) if w && h
end
end