Question

I am getting this error when a new user account is getting created:

ActiveRecord::StatementInvalid in SessionsController#create

SQLite3::SQLException: cannot start a transaction within a transaction: begin transaction

I am using koala and omniauth gem to autenticate and fetch users friends. Why cant I start two transactions, why does it rollback the friends migration?

How does one fix this?

This is my SessionController:

class SessionsController < ApplicationController
  def create
    user = User.from_omniauth(env['omniauth.auth'])
    session[:user_id] = user.id
    redirect_to root_url, notice: "Signed in!"
  end

This is my user model:

class User < ActiveRecord::Base
  has_many :friends

  def self.from_omniauth(auth)
    where(auth.slice(:provider, :uid)).first_or_initialize.tap do |user|
      user.provider = auth["provider"]
      user.uid = auth["uid"]
      user.name = auth["info"]["name"] unless auth["info"].blank?
      user.first_name = auth["info"]["first_name"] unless auth["info"].blank?
      user.last_name = auth["info"]["last_name"] unless auth["info"].blank?
      user.image = auth["info"]["image"] unless auth["info"].blank?
      user.email = auth["info"]["email"] unless auth["info"].blank?
      user.gender = auth["extra"]["raw_info"]["gender"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"].blank?)
      user.location = auth["extra"]["raw_info"]["location"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"].blank? && !auth["extra"]["raw_info"]["location"].blank?)          
      user.token = auth["credentials"]["token"] unless auth["credentials"].blank?


        # highschool data
        user.highschool_name = auth["extra"]["raw_info"]["education"][0]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["school"].blank?)
        user.highschool_year = auth["extra"]["raw_info"]["education"][0]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["year"].blank?)
        # graduate school data
        user.graduateschool_name = auth["extra"]["raw_info"]["education"][1]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["school"].blank?)
        user.graduateschool_year = auth["extra"]["raw_info"]["education"][1]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["year"].blank?)
      user.add_friends  
      user.save!
      user
    end 
  end

  def add_friends
    facebook.get_connections("me", "friends").each do |hash|
      self.friends.where(:name => hash['name'], :uid => hash['id']).first_or_create
    end
  end

  private 

  def facebook
    @facebook ||= Koala::Facebook::API.new(token)
  end

end

Answer 1

The thing is, when the user hit the created method the method from_omniauth(auth) is checking if a user exists, if the user dosent exist its starting creating the user and grabbing all information from auth hash provided from Facebook. But before saving the user it calls the add_friends method, the user dosent exsist yet therefor the error!

So you have to save the user first and then call the add_friends method

And Sqlite3 is incapable of nested transactions!

cheers!