discourse/lib/upload_creator.rb
Blake Erickson b93b6c4299
FIX: Blurry onebox favicon images (#15258)
This is a fix to address blurry onebox favicon images if the site you
are linking to happens to have a favicon.ico file that contains multiple
images.

This fix detects of we are trying to create an upload for a favicon.ico
file. We then convert it to a png and not a jpeg like we were doing. We
want a png because it will preserve transparency, otherwise if we
convert it to a jpeg we lose that and it looks bad on dark themed sites.

This fix also addresses the fact that .ico files can include multiple
images. The blurry images we were producing was caused by the
ImageMagick `-flatten` option when the .ico file had multiple images
which then squishes them all together. So for .ico files we are no
longer flattening them and instead we are grabbing the last image in the
.ico bundle and converting that single image to a png.
2021-12-10 12:25:50 -07:00

565 lines
19 KiB
Ruby

# frozen_string_literal: true
require "fastimage"
class UploadCreator
TYPES_TO_CROP ||= %w{avatar card_background custom_emoji profile_background}.each(&:freeze)
ALLOWED_SVG_ELEMENTS ||= %w{
circle clipPath defs ellipse feGaussianBlur filter g line linearGradient
marker path polygon polyline radialGradient rect stop style svg text
textPath tref tspan use
}.each(&:freeze)
include ActiveSupport::Deprecation::DeprecatedConstantAccessor
deprecate_constant 'WHITELISTED_SVG_ELEMENTS', 'UploadCreator::ALLOWED_SVG_ELEMENTS'
# Available options
# - type (string)
# - origin (string)
# - for_group_message (boolean)
# - for_theme (boolean)
# - for_private_message (boolean)
# - pasted (boolean)
# - for_export (boolean)
# - for_gravatar (boolean)
# - skip_validations (boolean)
def initialize(file, filename, opts = {})
@file = file
@filename = (filename || "").gsub(/[^[:print:]]/, "")
@upload = Upload.new(original_filename: @filename, filesize: 0)
@opts = opts
@filesize = @opts[:filesize] if @opts[:external_upload_too_big]
@opts[:validate] = opts[:skip_validations].present? ? !ActiveRecord::Type::Boolean.new.cast(opts[:skip_validations]) : true
# TODO (martin) Validate @opts[:type] to make sure only blessed types are passed
# in, since the clientside can pass any type it wants.
end
def create_for(user_id)
if filesize <= 0
@upload.errors.add(:base, I18n.t("upload.empty"))
return @upload
end
@image_info = FastImage.new(@file) rescue nil
is_image = FileHelper.is_supported_image?(@filename)
is_image ||= @image_info && FileHelper.is_supported_image?("test.#{@image_info.type}")
is_image = false if @opts[:for_theme]
# if this is present then it means we are creating an upload record from
# an external_upload_stub and the file is > ExternalUploadManager::DOWNLOAD_LIMIT,
# so we have not downloaded it to a tempfile. no modifications can be made to the
# file in this case because it does not exist; we simply move it to its new location
# in S3
#
# TODO (martin) I've added a bunch of external_upload_too_big checks littered
# throughout the UploadCreator code. It would be better to have two seperate
# classes with shared methods, rather than doing all these checks all over the
# place. Needs a refactor.
external_upload_too_big = @opts[:external_upload_too_big]
sha1_before_changes = Upload.generate_digest(@file) if @file
DistributedMutex.synchronize("upload_#{user_id}_#{@filename}") do
# We need to convert HEIFs early because FastImage does not consider them as images
if convert_heif_to_jpeg? && !external_upload_too_big
convert_heif!
is_image = FileHelper.is_supported_image?("test.#{@image_info.type}")
end
if is_image && !external_upload_too_big
extract_image_info!
return @upload if @upload.errors.present?
if @image_info.type == :svg
clean_svg!
elsif @image_info.type == :ico
convert_favicon_to_png!
elsif !Rails.env.test? || @opts[:force_optimize]
convert_to_jpeg! if convert_png_to_jpeg? || should_alter_quality?
fix_orientation! if should_fix_orientation?
crop! if should_crop?
optimize! if should_optimize?
downsize! if should_downsize?
return @upload if is_still_too_big?
end
# conversion may have switched the type
image_type = @image_info.type.to_s
end
# compute the sha of the file and generate a unique hash
# which is only used for secure uploads
if !external_upload_too_big
sha1 = Upload.generate_digest(@file)
end
if SiteSetting.secure_media || external_upload_too_big
unique_hash = generate_fake_sha1_hash
end
# we do not check for duplicate uploads if secure media is
# enabled because we use a unique access hash to differentiate
# between uploads instead of the sha1, and to get around various
# access/permission issues for uploads
if !SiteSetting.secure_media && !external_upload_too_big
# do we already have that upload?
@upload = Upload.find_by(sha1: sha1)
# make sure the previous upload has not failed
if @upload && @upload.url.blank?
@upload.destroy
@upload = nil
end
# return the previous upload if any
if @upload
add_metadata!
UserUpload.find_or_create_by!(user_id: user_id, upload_id: @upload.id) if user_id
return @upload
end
end
fixed_original_filename = nil
if is_image && !external_upload_too_big
current_extension = File.extname(@filename).downcase.sub("jpeg", "jpg")
expected_extension = ".#{image_type}".downcase.sub("jpeg", "jpg")
# we have to correct original filename here, no choice
# otherwise validation will fail and we can not save
# TODO decide if we only run the validation on the extension
if current_extension != expected_extension
basename = File.basename(@filename, current_extension).presence || "image"
fixed_original_filename = "#{basename}#{expected_extension}"
end
end
# create the upload otherwise
@upload = Upload.new
@upload.user_id = user_id
@upload.original_filename = fixed_original_filename || @filename
@upload.filesize = filesize
@upload.sha1 = (SiteSetting.secure_media? || external_upload_too_big) ? unique_hash : sha1
@upload.original_sha1 = SiteSetting.secure_media? ? sha1 : nil
@upload.url = ""
@upload.origin = @opts[:origin][0...1000] if @opts[:origin]
@upload.extension = image_type || File.extname(@filename)[1..10]
if is_image && !external_upload_too_big
if @image_info.type.to_s == 'svg'
w, h = [0, 0]
# identify can behave differently depending on how it's compiled and
# what programs (e.g. inkscape) are installed on your system.
# 'MSVG:' forces ImageMagick to use internal routines and behave
# consistently whether it's running from our docker container or not
begin
w, h = Discourse::Utils
.execute_command("identify", "-ping", "-format", "%w %h", "MSVG:#{@file.path}", timeout: Upload::MAX_IDENTIFY_SECONDS)
.split(' ').map(&:to_i)
rescue
# use default 0, 0
end
else
w, h = @image_info.size
end
@upload.thumbnail_width, @upload.thumbnail_height = ImageSizer.resize(w, h)
@upload.width, @upload.height = w, h
@upload.animated = animated?
end
add_metadata!
if SiteSetting.secure_media
secure, reason = UploadSecurity.new(@upload, @opts.merge(creating: true)).should_be_secure_with_reason
attrs = @upload.secure_params(secure, reason, "upload creator")
@upload.assign_attributes(attrs)
end
# Callbacks using this event to validate the upload or the file must add errors to the
# upload errors object.
#
# Can't do any validation of the file if external_upload_too_big because we don't have
# the actual file.
if !external_upload_too_big
DiscourseEvent.trigger(:before_upload_creation, @file, is_image, @upload, @opts[:validate])
end
return @upload unless @upload.errors.empty? && @upload.save(validate: @opts[:validate])
should_move = false
upload_changed = \
if external_upload_too_big
false
else
Upload.generate_digest(@file) != sha1_before_changes
end
if @opts[:existing_external_upload_key] && Discourse.store.external?
should_move = external_upload_too_big || !upload_changed
end
if should_move
# move the file in the store instead of reuploading
url = Discourse.store.move_existing_stored_upload(
existing_external_upload_key: @opts[:existing_external_upload_key],
upload: @upload
)
else
# store the file and update its url
File.open(@file.path) do |f|
url = Discourse.store.store_upload(f, @upload)
end
end
if url.present?
@upload.url = url
@upload.save!(validate: @opts[:validate])
else
@upload.errors.add(:url, I18n.t("upload.store_failure", upload_id: @upload.id, user_id: user_id))
end
if @upload.errors.empty? && is_image && @opts[:type] == "avatar" && @upload.extension != "svg"
Jobs.enqueue(:create_avatar_thumbnails, upload_id: @upload.id)
end
if @upload.errors.empty?
UserUpload.find_or_create_by!(user_id: user_id, upload_id: @upload.id) if user_id
end
@upload
end
ensure
if @file
@file.respond_to?(:close!) ? @file.close! : @file.close
end
end
def extract_image_info!
@image_info = FastImage.new(@file) rescue nil
@file.rewind
if @image_info.nil?
@upload.errors.add(:base, I18n.t("upload.images.not_supported_or_corrupted"))
elsif filesize <= 0
@upload.errors.add(:base, I18n.t("upload.empty"))
elsif pixels == 0 && @image_info.type.to_s != 'svg'
@upload.errors.add(:base, I18n.t("upload.images.size_not_found"))
elsif max_image_pixels > 0 && pixels >= max_image_pixels * 2
@upload.errors.add(:base, I18n.t("upload.images.larger_than_x_megapixels", max_image_megapixels: SiteSetting.max_image_megapixels * 2))
end
end
MIN_PIXELS_TO_CONVERT_TO_JPEG ||= 1280 * 720
def convert_png_to_jpeg?
return false unless @image_info.type == :png
return true if @opts[:pasted]
return false if SiteSetting.png_to_jpg_quality == 100
pixels > MIN_PIXELS_TO_CONVERT_TO_JPEG
end
MIN_CONVERT_TO_JPEG_BYTES_SAVED = 75_000
MIN_CONVERT_TO_JPEG_SAVING_RATIO = 0.70
def convert_favicon_to_png!
png_tempfile = Tempfile.new(["image", ".png"])
from = @file.path
to = png_tempfile.path
OptimizedImage.ensure_safe_paths!(from, to)
from = OptimizedImage.prepend_decoder!(from, nil, filename: "image.#{@image_info.type}")
to = OptimizedImage.prepend_decoder!(to)
from = "#{from}[-1]" # We only want the last(largest) image of the .ico file
opts = { flatten: false } # Preserve transparency
begin
execute_convert(from, to, opts)
rescue
# retry with debugging enabled
execute_convert(from, to, opts.merge(debug: true))
end
@file.respond_to?(:close!) ? @file.close! : @file.close
@file = png_tempfile
extract_image_info!
end
def convert_to_jpeg!
return if @opts[:for_site_setting]
return if filesize < MIN_CONVERT_TO_JPEG_BYTES_SAVED
jpeg_tempfile = Tempfile.new(["image", ".jpg"])
from = @file.path
to = jpeg_tempfile.path
OptimizedImage.ensure_safe_paths!(from, to)
from = OptimizedImage.prepend_decoder!(from, nil, filename: "image.#{@image_info.type}")
to = OptimizedImage.prepend_decoder!(to)
opts = {}
desired_quality = [SiteSetting.png_to_jpg_quality, SiteSetting.recompress_original_jpg_quality].compact.min
target_quality = @upload.target_image_quality(from, desired_quality)
opts = { quality: target_quality } if target_quality
begin
execute_convert(from, to, opts)
rescue
# retry with debugging enabled
execute_convert(from, to, opts.merge(debug: true))
end
new_size = File.size(jpeg_tempfile.path)
keep_jpeg = new_size < filesize * MIN_CONVERT_TO_JPEG_SAVING_RATIO
keep_jpeg &&= (filesize - new_size) > MIN_CONVERT_TO_JPEG_BYTES_SAVED
if keep_jpeg
@file.respond_to?(:close!) ? @file.close! : @file.close
@file = jpeg_tempfile
extract_image_info!
else
jpeg_tempfile.close!
end
end
def convert_heif_to_jpeg?
File.extname(@filename).downcase.match?(/\.hei(f|c)$/)
end
def convert_heif!
jpeg_tempfile = Tempfile.new(["image", ".jpg"])
from = @file.path
to = jpeg_tempfile.path
OptimizedImage.ensure_safe_paths!(from, to)
begin
execute_convert(from, to)
rescue
# retry with debugging enabled
execute_convert(from, to, { debug: true })
end
@file.respond_to?(:close!) ? @file.close! : @file.close
@file = jpeg_tempfile
extract_image_info!
end
MAX_CONVERT_FORMAT_SECONDS = 20
def execute_convert(from, to, opts = {})
command = [
"convert",
from,
"-auto-orient",
"-background", "white",
"-interlace", "none",
]
command << "-flatten" unless opts[:flatten] == false
command << "-debug" << "all" if opts[:debug]
command << "-quality" << opts[:quality].to_s if opts[:quality]
command << to
Discourse::Utils.execute_command(
*command,
failure_message: I18n.t("upload.png_to_jpg_conversion_failure_message"),
timeout: MAX_CONVERT_FORMAT_SECONDS
)
end
def should_alter_quality?
return false if animated?
desired_quality = @image_info.type == :png ? SiteSetting.png_to_jpg_quality : SiteSetting.recompress_original_jpg_quality
@upload.target_image_quality(@file.path, desired_quality).present?
end
def should_downsize?
max_image_size > 0 && filesize >= max_image_size && !animated?
end
def downsize!
3.times do
original_size = filesize
down_tempfile = Tempfile.new(["down", ".#{@image_info.type}"])
from = @file.path
to = down_tempfile.path
OptimizedImage.ensure_safe_paths!(from, to)
OptimizedImage.downsize(
from,
to,
"50%",
scale_image: true,
raise_on_error: true
)
@file.respond_to?(:close!) ? @file.close! : @file.close
@file = down_tempfile
extract_image_info!
return if filesize >= original_size || pixels == 0 || !should_downsize?
end
rescue
@upload.errors.add(:base, I18n.t("upload.optimize_failure_message"))
end
def is_still_too_big?
if max_image_pixels > 0 && pixels >= max_image_pixels
@upload.errors.add(:base, I18n.t("upload.images.larger_than_x_megapixels", max_image_megapixels: SiteSetting.max_image_megapixels))
true
elsif max_image_size > 0 && filesize >= max_image_size
@upload.errors.add(:base, I18n.t(
"upload.images.too_large_humanized", max_size: ActiveSupport::NumberHelper.number_to_human_size(max_image_size)
))
true
else
false
end
end
def clean_svg!
doc = Nokogiri::XML(@file)
doc.xpath(svg_allowlist_xpath).remove
doc.xpath("//@*[starts-with(name(), 'on')]").remove
doc.css('use').each do |use_el|
if use_el.attr('href')
use_el.remove_attribute('href') unless use_el.attr('href').starts_with?('#')
end
end
File.write(@file.path, doc.to_s)
@file.rewind
end
def should_fix_orientation?
# orientation is between 1 and 8, 1 being the default
# cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
@image_info.orientation.to_i > 1
end
MAX_FIX_ORIENTATION_TIME = 5
def fix_orientation!
path = @file.path
OptimizedImage.ensure_safe_paths!(path)
path = OptimizedImage.prepend_decoder!(path, nil, filename: "image.#{@image_info.type}")
Discourse::Utils.execute_command('convert', path, '-auto-orient', path, timeout: MAX_FIX_ORIENTATION_TIME)
extract_image_info!
end
def should_crop?
return false if ['profile_background', 'card_background', 'custom_emoji'].include?(@opts[:type]) && animated?
TYPES_TO_CROP.include?(@opts[:type])
end
def crop!
max_pixel_ratio = Discourse::PIXEL_RATIOS.max
filename_with_correct_ext = "image.#{@image_info.type}"
case @opts[:type]
when "avatar"
width = height = Discourse.avatar_sizes.max
OptimizedImage.resize(@file.path, @file.path, width, height, filename: filename_with_correct_ext)
when "profile_background"
max_width = 850 * max_pixel_ratio
width, height = ImageSizer.resize(@image_info.size[0], @image_info.size[1], max_width: max_width, max_height: max_width)
OptimizedImage.downsize(@file.path, @file.path, "#{width}x#{height}\>", filename: filename_with_correct_ext)
when "card_background"
max_width = 590 * max_pixel_ratio
width, height = ImageSizer.resize(@image_info.size[0], @image_info.size[1], max_width: max_width, max_height: max_width)
OptimizedImage.downsize(@file.path, @file.path, "#{width}x#{height}\>", filename: filename_with_correct_ext)
when "custom_emoji"
OptimizedImage.downsize(@file.path, @file.path, "100x100\>", filename: filename_with_correct_ext)
end
extract_image_info!
end
def should_optimize?
# GIF is too slow (plus, we'll soon be converting them to MP4)
# Optimizing SVG is useless
return false if @file.path =~ /\.(gif|svg)$/i
# Safeguard for large PNGs
return pixels < 2_000_000 if @file.path =~ /\.png/i
# Everything else is fine!
true
end
def optimize!
OptimizedImage.ensure_safe_paths!(@file.path)
FileHelper.optimize_image!(@file.path)
extract_image_info!
end
def filesize
@filesize || File.size?(@file.path).to_i
end
def max_image_size
@max_image_size ||= SiteSetting.max_image_size_kb.kilobytes
end
def max_image_pixels
@max_image_pixels ||= SiteSetting.max_image_megapixels * 1_000_000
end
def pixels
@image_info.size&.reduce(:*).to_i
end
def svg_allowlist_xpath
@@svg_allowlist_xpath ||= "//*[#{ALLOWED_SVG_ELEMENTS.map { |e| "name()!='#{e}'" }.join(" and ") }]"
end
def add_metadata!
@upload.for_private_message = true if @opts[:for_private_message]
@upload.for_group_message = true if @opts[:for_group_message]
@upload.for_theme = true if @opts[:for_theme]
@upload.for_export = true if @opts[:for_export]
@upload.for_site_setting = true if @opts[:for_site_setting]
@upload.for_gravatar = true if @opts[:for_gravatar]
end
private
def animated?
return @animated if @animated != nil
@animated ||= begin
is_animated = FastImage.animated?(@file)
type = @image_info.type.to_s
if is_animated != nil
# FastImage will return nil if it cannot determine if animated
is_animated
elsif type == "gif" || type == "webp"
# Only GIFs, WEBPs and a few other unsupported image types can be animated
OptimizedImage.ensure_safe_paths!(@file.path)
command = ["identify", "-format", "%n\\n", @file.path]
frames = Discourse::Utils.execute_command(*command, timeout: Upload::MAX_IDENTIFY_SECONDS).to_i rescue 1
frames > 1
else
false
end
end
end
def generate_fake_sha1_hash
SecureRandom.hex(20)
end
end