discourse/lib/onebox/helpers.rb

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# frozen_string_literal: true
require "addressable"
module Onebox
module Helpers
class DownloadTooLarge < StandardError
end
IGNORE_CANONICAL_DOMAINS ||= %w[www.instagram.com medium.com youtube.com]
def self.clean(html)
html.gsub(/<[^>]+>/, " ").gsub(/\n/, "")
end
# Fetches the HTML response body for a URL.
#
# Note that the size of the response body is capped at `Onebox.options.max_download_kb`. When the limit has been reached,
# this method will return the response body that has been downloaded up to the limit.
def self.fetch_html_doc(url, headers = nil, body_cacher = nil)
response =
(
begin
fetch_response(url, headers:, body_cacher:, raise_error_when_response_too_large: false)
rescue StandardError
nil
end
)
doc = Nokogiri.HTML(response)
uri = Addressable::URI.parse(url)
ignore_canonical_tag = doc.at('meta[property="og:ignore_canonical"]')
should_ignore_canonical =
IGNORE_CANONICAL_DOMAINS.map { |hostname| uri.hostname.match?(hostname) }.any?
if !(ignore_canonical_tag && ignore_canonical_tag["content"].to_s == "true") &&
!should_ignore_canonical
# prefer canonical link
canonical_link = doc.at('//link[@rel="canonical"]/@href')
canonical_uri = Addressable::URI.parse(canonical_link)
if canonical_link && canonical_uri &&
"#{canonical_uri.host}#{canonical_uri.path}" != "#{uri.host}#{uri.path}"
uri =
FinalDestination.new(
canonical_link,
Oneboxer.get_final_destination_options(canonical_link),
).resolve
if uri.present?
response =
(
begin
fetch_response(
uri.to_s,
headers:,
body_cacher:,
raise_error_when_response_too_large: false,
)
rescue StandardError
nil
end
)
doc = Nokogiri.HTML(response) if response
end
end
end
doc
end
def self.fetch_response(
location,
redirect_limit: 5,
domain: nil,
headers: nil,
body_cacher: nil,
raise_error_when_response_too_large: true,
allow_cross_domain_cookies: false
)
redirect_limit = Onebox.options.redirect_limit if redirect_limit >
Onebox.options.redirect_limit
raise Net::HTTPError.new("HTTP redirect too deep", location) if redirect_limit == 0
uri = Addressable::URI.parse(location)
uri = Addressable::URI.join(domain, uri) if !uri.host
use_body_cacher = body_cacher && body_cacher.respond_to?("fetch_cached_response_body")
if use_body_cacher
response_body = body_cacher.fetch_cached_response_body(uri.to_s)
return response_body if response_body.present?
end
result = StringIO.new
FinalDestination::HTTP.start(
uri.host,
uri.port,
open_timeout: Onebox.options.connect_timeout,
use_ssl: uri.normalized_scheme == "https",
) do |http|
http.read_timeout = Onebox.options.timeout
http.verify_mode = OpenSSL::SSL::VERIFY_NONE # Work around path building bugs
headers ||= {}
if Onebox.options.user_agent && !headers["User-Agent"]
headers["User-Agent"] = Onebox.options.user_agent
end
request = Net::HTTP::Get.new(uri.request_uri, headers)
start_time = Time.now
size_bytes = Onebox.options.max_download_kb * 1024
http.request(request) do |response|
if cookie = response.get_fields("set-cookie")
headers["Cookie"] = cookie.join("; ") if allow_cross_domain_cookies
# HACK: If this breaks again in the future, use HTTP::CookieJar from gem 'http-cookie'
# See test: it "does not send cookies to the wrong domain"
redir_header = { "Cookie" => cookie.join("; ") }
end
redir_header = nil unless redir_header.is_a? Hash
code = response.code.to_i
unless code === 200
response.error! if [301, 302, 303, 307, 308].exclude?(code)
return(
fetch_response(
response["location"],
redirect_limit: redirect_limit - 1,
domain: "#{uri.scheme}://#{uri.host}",
headers: allow_cross_domain_cookies ? headers : redir_header,
allow_cross_domain_cookies: allow_cross_domain_cookies,
)
)
end
response.read_body do |chunk|
result.write(chunk)
if result.size > size_bytes
raise_error_when_response_too_large ? raise(DownloadTooLarge.new) : break
end
raise Timeout::Error.new if (Time.now - start_time) > Onebox.options.timeout
end
if use_body_cacher && body_cacher.cache_response_body?(uri)
body_cacher.cache_response_body(uri.to_s, result.string)
end
return result.string
end
end
end
def self.fetch_content_length(location)
uri = URI(location)
FinalDestination::HTTP.start(
uri.host,
uri.port,
open_timeout: Onebox.options.connect_timeout,
use_ssl: uri.is_a?(URI::HTTPS),
) do |http|
http.read_timeout = Onebox.options.timeout
if uri.is_a?(URI::HTTPS)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE
end
http.request_head([uri.path, uri.query].join("?")) do |response|
return response.code.to_i == 200 ? response.content_length.presence : nil
end
end
end
def self.pretty_filesize(size)
conv = %w[B KB MB GB TB PB EB]
scale = 1024
ndx = 1
return "#{(size)} #{conv[ndx - 1]}" if (size < 2 * (scale**ndx))
size = size.to_f
[2, 3, 4, 5, 6, 7].each do |i|
return "#{"%.2f" % (size / (scale**(i - 1)))} #{conv[i - 1]}" if (size < 2 * (scale**i))
end
ndx = 7
"#{"%.2f" % (size / (scale**(ndx - 1)))} #{conv[ndx - 1]}"
end
def self.click_to_scroll_div(width = 690, height = 400)
"<div style=\"background:transparent;position:relative;width:#{width}px;height:#{height}px;top:#{height}px;margin-top:-#{height}px;\" onClick=\"style.pointerEvents='none'\"></div>"
end
def self.truncate(string, length = 50)
return string if string.nil?
string.size > length ? string[0...(string.rindex(" ", length) || length)] + "..." : string
end
def self.get(meta, attr)
(meta && meta[attr].present?) ? sanitize(meta[attr]) : nil
end
def self.sanitize(value, length = 50)
return nil if value.blank?
Sanitize.fragment(value).strip
end
def self.normalize_url_for_output(url)
return "" unless url
url = url.dup
# expect properly encoded url, remove any unsafe chars
url.gsub!(" ", "%20")
url.gsub!("'", "&apos;")
url.gsub!('"', "&quot;")
url.gsub!(/[^\w\-`.~:\/?#\[\]@!$&'\(\)*+,;=%\p{M}]/, "")
parsed = Addressable::URI.parse(url)
return "" unless parsed.host
url
end
def self.get_absolute_image_url(src, url)
begin
URI.parse(url).merge(src).to_s
rescue ArgumentError, URI::BadURIError, URI::InvalidURIError
src
end
end
# Percent-encodes a URI string per RFC3986 - https://tools.ietf.org/html/rfc3986
def self.uri_encode(url)
return "" unless url
uri = Addressable::URI.parse(url)
encoded_uri =
Addressable::URI.new(
scheme:
Addressable::URI.encode_component(
uri.scheme,
Addressable::URI::CharacterClasses::SCHEME,
),
authority:
Addressable::URI.encode_component(
uri.authority,
Addressable::URI::CharacterClasses::AUTHORITY,
),
path:
Addressable::URI.encode_component(
uri.path,
Addressable::URI::CharacterClasses::PATH + "\\%",
),
query:
Addressable::URI.encode_component(
uri.query,
"a-zA-Z0-9\\-\\.\\_\\~\\$\\&\\*\\,\\=\\:\\@\\?\\%",
),
fragment:
Addressable::URI.encode_component(
uri.fragment,
"a-zA-Z0-9\\-\\.\\_\\~\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=\\:\\/\\?\\%",
),
)
encoded_uri.to_s
end
def self.uri_unencode(url)
Addressable::URI.unencode(url)
end
def self.image_placeholder_html
"<div class='onebox-placeholder-container'><span class='placeholder-icon image'></span></div>"
end
def self.video_placeholder_html
"<div class='onebox-placeholder-container'><span class='placeholder-icon video'></span></div>"
end
def self.audio_placeholder_html
"<div class='onebox-placeholder-container'><span class='placeholder-icon audio'></span></div>"
end
def self.map_placeholder_html
"<div class='onebox-placeholder-container'><span class='placeholder-icon map'></span></div>"
end
def self.generic_placeholder_html
"<div class='onebox-placeholder-container'><span class='placeholder-icon generic'></span></div>"
end
end
end