discourse/lib/url_helper.rb

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# frozen_string_literal: true
class UrlHelper
MAX_URL_LENGTH = 2_000
# At the moment this handles invalid URLs that browser address bar accepts
# where second # is not encoded
#
# Longer term we can add support of simpleidn and encode unicode domains
def self.relaxed_parse(url)
url, fragment = url.split("#", 2)
uri = URI.parse(url)
if uri
# Addressable::URI::CharacterClasses::UNRESERVED is used here because without it
# the # in the fragment is not encoded
fragment =
Addressable::URI.encode_component(
fragment,
Addressable::URI::CharacterClasses::UNRESERVED,
) if fragment&.include?("#")
uri.fragment = fragment
uri
end
rescue URI::Error
end
# Heuristic checks to determine if the URL string is a valid absolute URL, path or anchor
def self.is_valid_url?(url)
uri = URI.parse(url)
return true if uri.is_a?(URI::Generic) && url.starts_with?("/") || url.match?(/\A\#([^#]*)/)
if uri.scheme
return true if uri.is_a?(URI::MailTo)
if url.match?(%r{\A#{uri.scheme}://[^/]}) &&
(
uri.is_a?(URI::HTTP) || uri.is_a?(URI::HTTPS) || uri.is_a?(URI::FTP) ||
uri.is_a?(URI::LDAP)
)
return true
end
end
false
rescue URI::InvalidURIError
false
end
def self.encode_and_parse(url)
URI.parse(Addressable::URI.encode(url))
end
def self.encode(url)
Addressable::URI.encode(url)
end
def self.unencode(url)
Addressable::URI.unencode(url)
end
def self.encode_component(url_component)
Addressable::URI.encode_component(url_component)
end
def self.is_local(url)
url.present? &&
(
Discourse.store.has_been_uploaded?(url) ||
!!(url =~ Regexp.new("^#{Discourse.base_path}/(assets|plugins|images)/")) ||
url.start_with?(Discourse.asset_host || Discourse.base_url_no_prefix)
)
end
def self.absolute(url, cdn = Discourse.asset_host)
cdn = "https:#{cdn}" if cdn && cdn =~ %r{\A//}
url =~ %r{\A/[^/]} ? (cdn || Discourse.base_url_no_prefix) + url : url
end
def self.absolute_without_cdn(url)
self.absolute(url, nil)
end
def self.schemaless(url)
url.sub(/\Ahttp:/i, "")
end
def self.secure_proxy_without_cdn(url)
self.absolute(Upload.secure_uploads_url_from_upload_url(url), nil)
end
def self.normalized_encode(uri)
url = uri.to_s
if url.length > MAX_URL_LENGTH
raise ArgumentError.new("URL starting with #{url[0..100]} is too long")
end
# Ideally we will jump straight to `Addressable::URI.normalized_encode`. However,
# that implementation has some edge-case issues like https://github.com/sporkmonger/addressable/issues/472.
# To temporaily work around those issues for the majority of cases, we try parsing with `::URI`.
# If that fails (e.g. due to non-ascii characters) then we will fall back to addressable.
# Hopefully we can simplify this back to `Addressable::URI.normalized_encode` in the future.
# edge case where we expect mailto:test%40test.com to normalize to mailto:test@test.com
return normalize_with_addressable(url) if url.match(/\Amailto:/)
# If it doesn't pass the regexp, it's definitely not gonna parse with URI.parse. Skip
# to addressable
return normalize_with_addressable(url) if !url.match?(/\A#{URI.regexp}\z/)
begin
normalize_with_ruby_uri(url)
rescue URI::Error
normalize_with_addressable(url)
end
end
def self.rails_route_from_url(url)
path = URI.parse(encode(url)).path
Rails.application.routes.recognize_path(path)
rescue Addressable::URI::InvalidURIError, URI::InvalidComponentError
nil
end
def self.cook_url(url, secure: false, local: nil)
is_secure = SiteSetting.secure_uploads && secure
local = is_local(url) if local.nil?
return url if !local
url = is_secure ? secure_proxy_without_cdn(url) : absolute_without_cdn(url)
# we always want secure uploads to come from
# Discourse.base_url_no_prefix/secure-uploads
# to avoid asset_host mixups
return schemaless(url) if is_secure
# PERF: avoid parsing url except for extreme conditions
# this is a hot path used on home page
filename = url
if url.include?("?")
uri = URI.parse(url)
filename = File.basename(uri.path)
end
# this technically requires a filename, but will work with a URL as long as it end with the
# extension and has no query params
is_attachment = !FileHelper.is_supported_media?(filename)
no_cdn = SiteSetting.login_required || SiteSetting.prevent_anons_from_downloading_files
unless is_attachment && no_cdn
url = Discourse.store.cdn_url(url)
url = local_cdn_url(url) if Discourse.store.external?
end
schemaless(url)
rescue URI::Error
url
end
def self.local_cdn_url(url)
return url if Discourse.asset_host.blank?
if url.start_with?("/#{Discourse.store.upload_path}/")
"#{Discourse.asset_host}#{url}"
else
url.sub(Discourse.base_url_no_prefix, Discourse.asset_host)
end
end
private
def self.normalize_with_addressable(url)
u = Addressable::URI.normalized_encode(url, Addressable::URI)
u.host = ::Addressable::IDNA.to_ascii(u.host) if u.host && !u.host.ascii_only?
u.to_s
end
def self.normalize_with_ruby_uri(url)
u = URI.parse(url)
u.scheme = u.scheme.downcase if u.scheme && u.scheme != u.scheme.downcase
u.host = u.host.downcase if u.host && u.host != u.host.downcase
u.to_s
end
end