[RUBY] Draw a graph with Sinatra and Chartkick

Introduction

I improved the * family todo list* created last time and tried to draw a graph.

Completion screen

Setting

main.rb

require 'sinatra'
require 'sinatra/reloader'
require 'date'
require 'active_record'
require 'rack/csrf'
require 'chartkick'　　#add to

bash.sh

$ ls public/
chartkick.js  main.js  style.css

Put chartkick.js in public

Source

main.rb

get '/' do
  con = ActiveRecord::Base.connection
  dat = con.execute("select users.name, scores.score, scores.point from users inner join scores on users.id = scores.user_id where scores.flag=0 order by users.name, scores.point")
  h = {name: '', data: {}}
  @graph_data = []
  tname = ''
  dat.each do |x|
    if x["name"] == tname
      h[:data][x["point"]] = x["score"]
    else
      tname = x["name"]
      if h[:name] != ''
        @graph_data << h.dup
      end
      h[:name] = x["name"]
      h[:data] = {}
      h[:data][x["point"]] = x["score"]
    end
  end
  @graph_data << h.dup
  erb :index
end

Originally, you should use ʻActiveRecord well, but you can get the data by typing SQL` directly.

index.erb

<%= line_chart @graph_data, min: 40, max: 100 %>

It is thanks to gem that it is drawn beautifully.

Summary

• Thank you to the author of Chartkick
• I drew a graph with Sinatra

Referenced site Create beautiful JavaScript charts with one line of Ruby

• Implementing a graph using Chartkick in Rails (easy, but I can't reach the itchy place) --Qiita *
• If you want to handle simple graphs in Rails, use chartkick rather than chart-js-rails --Qiita *