How can I make a delayed job for this custom method? - ruby-on-rails

Question

Here is my Lesson model:
#encoding: utf-8
class Lesson < ActiveRecord::Base
attr_accessible :content, :title, :parsed_content, :html_content, :user_id
serialize :parsed_content, Array
serialize :html_content, Array
serialize :pinyin_content, Array
serialize :defined_content, Array
serialize :literal_content, Array
validates :title, :presence => true
validates :content, :presence => true
belongs_to :user
before_update do |lesson|
lesson.makesandwich
end
before_save do |lesson|
lesson.delay.makesandwich
end
def makesandwich
require 'rmmseg'
#require 'to_lang'
require 'bing_translator'
require 'ruby-pinyin'
self.parsed_content = []
RMMSeg::Dictionary.load_dictionaries
content = self.content
paragraphs = content.split(/\r\n\r\n/) #convert to array of paragraphs
self.parsed_content = paragraphs
paragraphs.each_with_index do |text, ti|
text = text.gsub("。", "^^.")
text = text.gsub("？", "~~?")
text = text.gsub("！", "||!")
text = text.gsub(":", "：") #fix missing colons
text = text.split(/[.?!]/u) #convert to an array
text.each do |s|
s.gsub!("^^", "。")
s.gsub!("~~", "？")
s.gsub!("||", "！")
#s.gsub!("———————————",":")
end
text.each_with_index do |val, index|
algor = RMMSeg::Algorithm.new(text[index])
splittext = []
loop do
tok = algor.next_token
break if tok.nil?
tex = tok.text.force_encoding('UTF-8')
splittext << tex
text[index] = splittext
end
paragraphs[ti] = text
end
end
bing = BingTranslator.new(BING_API)
self.parsed_content = paragraphs
textarray = Marshal.load(Marshal.dump(paragraphs))
self.defined_content = Marshal.load(Marshal.dump(paragraphs))
self.literal_content = Marshal.load(Marshal.dump(paragraphs))
self.pinyin_content = Marshal.load(Marshal.dump(paragraphs))
textarray.each_with_index do |paragraph, pi|
paragraph.each_with_index do |sentence, si|
sentence.each_with_index do |word, wi|
if DictionaryEntry.find_by_simplified(word) != nil
self.defined_content[pi][si][wi] = DictionaryEntry.find_by_simplified(word).definition
#self.literal_content is down below
self.pinyin_content[pi][si][wi] = DictionaryEntry.find_by_simplified(word).pinyin
else
self.defined_content[pi][si][wi] = bing.translate(word, :from => 'zh-CHS', :to => 'en')
#self.defined_content[pi][si][wi] = word
#self.literal_content is down below
if PinYin.of_string(word, true).length > 1 #for punctuation
self.pinyin_content[pi][si][wi] = PinYin.of_string(word, true).join(" ").downcase
else
self.pinyin_content[pi][si][wi] = word
end
end
end
end
end
#Literal
literalarray = Marshal.load(Marshal.dump(paragraphs))
literalarray.each_with_index do |paragraph, pi|
paragraph.each_with_index do |sentence, si| #iterate array of sentence
literalarray[pi][si] = []
sentence.each_with_index do |word, wi| #iterate sentence's array of words
entrytobesliced = DictionaryEntry.find_by_simplified(word)
slicedentry = []
if entrytobesliced == nil
if word.length > 1 && word !~ /\w/ #/^\s*\w\d+\s*$/ #number regex #for cases where there is no DictionaryEntry
split = []
wordarray = word.split("").each_with_index() do |ws, wsi|
split << [DictionaryEntry.find_by_simplified(ws).definition]
end
literalarray[pi][si] << split
else
literalarray[pi][si] << [word] #in case none of the above work
end
else
entrytobesliced.simplified.each_char do |w|
singlechar = DictionaryEntry.find_by_simplified(w)
slicedentry << singlechar.definition.split("\", \"")
end
literalarray[pi][si] << slicedentry
end
self.literal_content = literalarray #slicedentry #literalarray
end
end
end
end
end
When I try to create a new lesson it errors like this: Jobs cannot be created for records before they've been persisted
But if I change it to after_save instead of before_save then I can see the work run, but it doesn't update the serialized arrays in the database.
Can someone please help me implement delayed_jobs for this? It was working when I had:
before_save do |lesson|
lesson.makesandwich #no delay
end

Answer 1

I think you're getting these errors:
Jobs cannot be created for records before they've been persisted
because your Lesson instances won't have an id until they've been saved and without an id, DJ has no way to know which instance it should be working with. So you have to use an after_save so that your Lesson has an id and can be uniquely identified. But then your updates from the delayed job won't be saved because, well, nothing asks for them to be saved. You should be able to get around that simply by adding a self.save or self.save! call at the end of makesandwich.