Showing posts with the label rails

unterminated string meets end of file +rails

 This error is because you are trying to instert special symbol in record. User.last.update(password: "!@#$") User.last.update(password: "!@/#$") //it will not throw any errors.

Some important and unknown(least used) ruby methods.

 1) inject or reduce      When called, the inject method will pass each element and accumulate each sequentially.     ex:         [1,2,3].inject(:+)    => ((1+2)+3))   //we have can any operator here i.e +,-,*,/,%         OR         [1,2,3].inject{|sum, value| sum + value } => 1 iteration:  (1 + 2)                                                                                             =>  2 iteration: (3(1st iteration sum)+3)            we  can also pass it a default value or base value for the accumulator.     ex:          [1,2,3].inject(0, :+)    => (0+(1+2)+3)) //so here initial value for sum is 0.          We can also use inject menthods for building hash's from the array's     ex:           [[:book, "data structure"], [:price, "400rs"]].inject({}) do |result, element|               result[element.first] = element.last               result           end            #=> {:book=>"data structure", :price=>"400rs&qu

Setup a cron job or scheduler for your rails application using whenever gem.

cd path to your project. gem 'whenever', require: false   add it to your gemfile run bundle install bundle exec wheneverize .   //This will create an initial config/schedule.rb Now create your job call it  from config/schedule.rb whenever --update-crontab   //update crontab crontab -l   //list all cron job set :output, "log/cron.log"    //if you want to set log file for cron job then that this line at the top of config/schedule.rb         in production server:                   after deployment :  bundle exec whenever whenever --update-crontab crontab -l source:

Setup ruby god for rails application || Daemons setup for rails application

 1) Install god on Ubuntu/Linux machine      sudo apt update      sudo apt install ruby-god 2) Create new rails application if you don't have existing 3) In your Gemfile add new gem       gem 'god', '~> 0.13.7', require: false 4) Then run bundle install 5) create a folder named daemons inside your  lib folder 6) create a file name daemons.god inside daemons folder (this file name or folder name can be anything its totally up to you) 7) Then paste this on you daemons.god file      ENV["RAILS_ENV"] = "development"      RAILS_ENV  = ENV.fetch('RAILS_ENV', 'production')      RAILS_ROOT = File.expand_path('../../..', __FILE__)      require 'shellwords'      # Create non-default log/daemons directory.      require 'fileutils'      FileUtils.mkdir_p "#{RAILS_ROOT}/log/daemons"      def daemon(name, options = {}) do |w|          command        = "bundle exec ruby lib/daemons/#{op

lambda proc and block in rails

this all things basically we used in block level coding and for some custom queries in rails model class Main   [ 1 , 2 , 3 ].each do | num |     puts num   end end def block_method   yield end block_method { puts "Test"} def arg_method   yield   yield 1 end arg_method { |i| puts i*1 rescue nil} # explicit block def explicit_block(&block) #same as yield end explicit_block {puts "This is explicit block"} # lambda lambda_test = -> {puts "This is lambda"} lambda_test.() lambda_test[] # lambda with args arg_lambda = -> (i){ puts i}"test") my_proc = { |x| puts x } # Should work my_lambda = -> { return 1 } puts "Lambda result: #{}" # Should raise exception my_proc = { return 1 } puts "Proc result: #{}" def call_proc   puts "Before proc"   my_proc = Proc.n

unable to install ruby 2.2 in ubuntu 18.04

Try with this commands 1) Install rvm following instructions for Ubuntu on 2) rvm install ruby 2.2.10 3) rvm install ruby 2.2.10 --with-gcc=gcc if its not work then try with this  1. sudo apt purge libssl-dev && sudo apt install libssl1.0-dev 2. rvm install 2.3.5 --autolibs=disable

rails redirect after login devise

devise_scope :user do  authenticated :user do    root 'dashboard#index', as: :authenticated_root  end  unauthenticated do    root 'home#index', as: :unauthenticated_root  end end

Data Scrapping in rails

go to your terminal create a directory mkdir ruby_data_scrapping create directory mkdir lib cd lib/ touch scraper.rb gem install nokogiri  // install gems in local gem install httparty gem install byebug Write code in your scraper.rb require "httparty" require "nokogiri" require "byebug" class Scraper   attr_accessor :parse_page   def initialize       doc = HTTParty.get("")       @parse_page ||= Nokogiri::HTML(doc)   end   def get_prices      item_container.first(2){|x| x.text}   end   private     def item_container        parse_page.css(".tv-data-table__tbody").first.css(".tv-screener-table__result-row").css(".tv-screener-table__cell")     end   prices =   (0...prices.size).each do |index|       puts "Price: #{prices[index]}"   end end now run this scraper ruby scraper.rb

rails scope with argument or dynamic value and join tables

scope :get_by_currency, -> (currency) {find_by(currency_id: currency)} scope :by_role, ->(role) { joins(:roles).where(roles: { name: role }) } //it will work in rails 4 and previous version scope :by_role, ->(role) { joins(:roles).where(' ? ', #{role} ) } //it will work in all versions of rails validate  :validate_mimimum_amount, unless: -> (order) { order.ord_type=='market' || order.ord_type=='manual' }

some minor things in rails

For Date format  .utc.strftime('%d-%m-%Y %H:%M:%S') Alternative to html_safe (raw("<strong class='text-danger'>Decline</strong")). select tag for form_for  <%=, options_for_select({|x|}, f.object.payment_currency), {include_blank: "Select Currency"}, { :class => 'form-control', required: true }) %> zip -r folder_name

Convert numbers in rails like binary to decimal

value.to_i(from).to_s(to) i.e "1000".to_i(2).to_s(10) //here we are converting binary to decimal

decimal to binary converter in rails

def dec2bin(number)     number = Integer(number) //number that you have to convert     if(number == 0) then 0 end              new_num = ""     while(number != 0)         new_num = String(number % 2) + new_num         number = number / 2     end     new_num // return new number end

Authentication via JWT in rails api's

gem 'jwt' add this gem to your gem file bundle install create a file in lib/json_web_token.rb and paste following code class JsonWebToken      SECRET_KEY = Rails.application.secrets.secret_key_base. to_s      def self.encode(payload, exp = 15.days.from_now)         payload[:exp] = exp.to_i        JWT.encode(payload, SECRET_KEY)      end     def self.decode(token)        decoded = JWT.decode(token, SECRET_KEY)[0] decoded     end end create another file config/initializers/jwt.rb and paste following code require 'json_web_token' Now inside controller/api/v1/ we will a parent class for our all end-points: api/v1/api_controller.rb class Api::V1::ApiController < ActionController::Base      protect_from_forgery with: :null_session      def autheticate_user         header = request.headers['Authorization']         header = header.split(' ').last if header         begin             @decoded = JsonWebToken.decode

best way to compile your assets in rails

rake assets:precompile tmp:clear

Write simple html text in into rails tags

You can write simple text inside rails tag like link_to button_tag, submit_tag, text_field_tag etc.. (raw("<strong class='text-danger'>Decline</strong")) example : <%= link_to  (raw("<strong class='text-danger'>Decline</strong")), welcome_path %>

how to make separate routes for different user in rails

how to make separate routes for different user in rails  Make another routes file in your config folder           config/routes/admin.rb   //i made new file routes/admin.rb inside config folder Now inside your config/routes.rb file paste this           class ActionDispatch::Routing::Mapper             def draw(routes_name)              instance_eval("config/routes/#{routes_name}.rb")))             end           end        // paste this code above this Rails.application.routes.draw line now side your main route file(config/routes.rb) make new routes for admin file like draw :admin Now config/routes.rb will be look like this Rails.application.routes.draw do   draw :admin end Now you can make routes for admin or admin dashboard separately inside your config/routes/admin.rb file resources :admin

ActiveRecord::Base.connection.execute, robust record execute in rails

ActiveRecord::Base.transaction do          ActiveRecord::Base.connection.execute("UPDATE deposits SET amount = #{params[:adjust_amount].to_f} WHERE type = '#{@deposit.type}' AND id = #{} AND currency_id = '#{@deposit.currency_id}'").as_json if params[:adjust_amount].present?          ## update comment          if params[:mt5_history_id].present?            mt5_withdraw_history = Mt5History.find_by_id(params[:mt5_history_id])            mt5_withdraw_history.update(comment: params[:comment])          end        end This do loop will run until all parameter will execute if any record updatation is failed due to some reason all previous record update will be rollback!   

Wicked-PDF not showing images, 'wicked_pdf_image_tag' undefined

Wicked-PDF not showing images, 'wicked_pdf_image_tag' undefined <div>   <%= wicked_pdf_image_tag 'logo.jpg' %> </div> def save   pdf =                         render_to_string(                           template: 'example/pdf_view.pdf.erb',                           layout: 'layouts/application.pdf.erb'))   send_data(pdf,             filename: 'file_name.pdf',             type: 'application/pdf',             disposition: 'attachment')  end 

Download pdf by ajax or javascript or angular js

Click on button for generate pdf  $("#print_selected_label").on("click", function(){    data = []    $("input:checkbox.print_label:checked").each(function(){      data.push($(this).attr("id"));    });   //getting all information of checked checkbox    if(data.length > 0){    // if data is not null       In angular js controller         // var redirect_new = "/admin/v2/orders/print_multiple_label.pdf?" + jQuery.param(data);        // var pdf =, 'Map PDF', '');      By Creating a link by javascript       // var mydiv = document.getElementById("download_pdf");      // var aTag = document.createElement('a');      // var link = " admin/v2/orders/print_multiple_label.pdf?id="+data ;      // aTag.setAttribute('href',link);      // aTag.innerHTML = "link text";      // mydiv.appendChild(aTag);      //; By making http request    

Create worker in rails by sidekiq and redis

Add sidekiq to your Gemfile: Add this to your Gemfile gem 'sidekiq' Run bundle install bundle install Create worker rails g sidekiq:worker Test #will create app/workers/test_worker.rb class TestWorker   include Sidekiq::Worker   def perform(id, name)     # do something   end end Call worker without any time boundation TestWorker.perform_async(5, 'rahul') //use this anywhere from your rails app(controller, model, helpers..) Call worker within particular time period TestWorker.perform_in(5.minutes, 5, 'rahul')  //use this anywhere from your rails app(controller, model, helpers..) Call worker after specific time interval once only TestWorker.perform_at(5.minutes.from_now, 5, 'rahul')  //use this anywhere from your rails app(controller, model, helpers..) Start sidekiq on development bundle exec sidekiq Start sidekiq on production bundle exec sidekiq -d //run this first if you get some error then use second one bundle exec si