discourse/app/services/external_upload_manager.rb

202 lines
6.2 KiB
Ruby

# frozen_string_literal: true
class ExternalUploadManager
DOWNLOAD_LIMIT = 100.megabytes
SIZE_MISMATCH_BAN_MINUTES = 5
BAN_USER_REDIS_PREFIX = "ban_user_from_external_uploads_"
UPLOAD_TYPES_EXCLUDED_FROM_UPLOAD_PROMOTION = ["backup"].freeze
class ChecksumMismatchError < StandardError
end
class DownloadFailedError < StandardError
end
class CannotPromoteError < StandardError
end
class SizeMismatchError < StandardError
end
attr_reader :external_upload_stub
def self.ban_user_from_external_uploads!(user:, ban_minutes: 5)
Discourse.redis.setex("#{BAN_USER_REDIS_PREFIX}#{user.id}", ban_minutes.minutes.to_i, "1")
end
def self.user_banned?(user)
Discourse.redis.get("#{BAN_USER_REDIS_PREFIX}#{user.id}") == "1"
end
def self.create_direct_upload(current_user:, file_name:, file_size:, upload_type:, metadata: {})
store = store_for_upload_type(upload_type)
url = store.signed_url_for_temporary_upload(file_name, metadata: metadata)
key = store.s3_helper.path_from_url(url)
upload_stub =
ExternalUploadStub.create!(
key: key,
created_by: current_user,
original_filename: file_name,
upload_type: upload_type,
filesize: file_size,
)
{ url: url, key: key, unique_identifier: upload_stub.unique_identifier }
end
def self.create_direct_multipart_upload(
current_user:,
file_name:,
file_size:,
upload_type:,
metadata: {}
)
content_type = MiniMime.lookup_by_filename(file_name)&.content_type
store = store_for_upload_type(upload_type)
multipart_upload = store.create_multipart(file_name, content_type, metadata: metadata)
upload_stub =
ExternalUploadStub.create!(
key: multipart_upload[:key],
created_by: current_user,
original_filename: file_name,
upload_type: upload_type,
external_upload_identifier: multipart_upload[:upload_id],
multipart: true,
filesize: file_size,
)
{
external_upload_identifier: upload_stub.external_upload_identifier,
key: upload_stub.key,
unique_identifier: upload_stub.unique_identifier,
}
end
def self.store_for_upload_type(upload_type)
if upload_type == "backup"
if !SiteSetting.enable_backups? ||
SiteSetting.backup_location != BackupLocationSiteSetting::S3
raise Discourse::InvalidAccess.new
end
BackupRestore::BackupStore.create
else
Discourse.store
end
end
def initialize(external_upload_stub, upload_create_opts = {})
@external_upload_stub = external_upload_stub
@upload_create_opts = upload_create_opts
@store = ExternalUploadManager.store_for_upload_type(external_upload_stub.upload_type)
end
def can_promote?
external_upload_stub.status == ExternalUploadStub.statuses[:created]
end
def transform!
raise CannotPromoteError if !can_promote?
external_upload_stub.update!(status: ExternalUploadStub.statuses[:uploaded])
# We require that the file size is specified ahead of time, and compare
# it here to make sure that people are not uploading excessively large
# files to the external provider. If this happens, the user will be banned
# from uploading to the external provider for N minutes.
if external_size != external_upload_stub.filesize
ExternalUploadManager.ban_user_from_external_uploads!(
user: external_upload_stub.created_by,
ban_minutes: SIZE_MISMATCH_BAN_MINUTES,
)
raise SizeMismatchError.new(
"expected: #{external_upload_stub.filesize}, actual: #{external_size}",
)
end
if UPLOAD_TYPES_EXCLUDED_FROM_UPLOAD_PROMOTION.include?(external_upload_stub.upload_type)
move_to_final_destination
else
promote_to_upload
end
rescue StandardError
if !SiteSetting.enable_upload_debug_mode
# We don't need to do anything special to abort multipart uploads here,
# because at this point (calling promote_to_upload!), the multipart
# upload would already be complete.
@store.delete_file(external_upload_stub.key)
external_upload_stub.destroy!
else
external_upload_stub.update(status: ExternalUploadStub.statuses[:failed])
end
raise
end
private
def promote_to_upload
# This could be legitimately nil, if it's too big to download on the
# server, or it could have failed. To this end we set a should_download
# variable as well to check.
tempfile = nil
should_download = external_size < DOWNLOAD_LIMIT
if should_download
tempfile = download(external_upload_stub.key, external_upload_stub.upload_type)
raise DownloadFailedError if tempfile.blank?
actual_sha1 = Upload.generate_digest(tempfile)
raise ChecksumMismatchError if external_sha1 && external_sha1 != actual_sha1
end
opts = {
type: external_upload_stub.upload_type,
existing_external_upload_key: external_upload_stub.key,
external_upload_too_big: external_size > DOWNLOAD_LIMIT,
filesize: external_size,
}.merge(@upload_create_opts)
UploadCreator.new(tempfile, external_upload_stub.original_filename, opts).create_for(
external_upload_stub.created_by_id,
)
ensure
tempfile&.close!
end
def move_to_final_destination
content_type = MiniMime.lookup_by_filename(external_upload_stub.original_filename).content_type
@store.move_existing_stored_upload(
existing_external_upload_key: external_upload_stub.key,
original_filename: external_upload_stub.original_filename,
content_type: content_type,
)
Struct.new(:errors).new([])
end
def external_stub_object
@external_stub_object ||= @store.object_from_path(external_upload_stub.key)
end
def external_etag
@external_etag ||= external_stub_object.etag
end
def external_size
@external_size ||= external_stub_object.size
end
def external_sha1
@external_sha1 ||= external_stub_object.metadata["sha1-checksum"]
end
def download(key, type)
url = @store.signed_url_for_path(external_upload_stub.key)
FileHelper.download(
url,
max_file_size: DOWNLOAD_LIMIT,
tmp_file_name: "discourse-upload-#{type}",
follow_redirect: true,
)
end
end