krisleech

Ruby 2.6 on Ubuntu with Bundler 2.x

# Dockerfile

FROM ubuntu

RUN apt-get update
RUN apt-get install -y build-essential wget gcc automake autoconf autogen libtool make cmake bison unzip flex libqt4-dev zlib1g zlib1g-dev libqtwebkit-dev libreadline6 libreadline-dev  libreadline6-dev libssl-dev libfontconfig1-dev chrpath mysql-client libxml2-dev libxslt1-dev libxslt-dev libmysqlclient-dev libsqlite3-dev git git-core xvfb socat libyaml-dev libgdbm-dev libncurses5-dev libffi-dev

krisleech

In Rails migrations now need a version number:

class ActiveRecord::Migration[5.2]
  # ...
end

I haven't looked at the code in Rails for this, but one way it could be done would be as such:

krisleech

plain #new method

module Foo  
  class Bar < Module
    def initialize(options = {})
      super()
      puts options
    end
  end

krisleech

Often we have Integer's but don't have a clue what the unit is unless we encode it in a varible name. How can we prevent adding two numbers which are of different or incompatible units...

class IntegerWithUnit < SimpleDelegator
  attr_reader :unit
  
  def initialize(integer, unit)   
    @unit = unit.to_sym.freeze
    super(integer)
 end 

krisleech

Lets say we have some object which performs a command:

class ReportAbnormalTempratures
  def self.call; new.call; end
  
  def call
    Temprature.greater_than(Tolerance.today).each do |temprature|     
      # do something...      
    end

krisleech

We want to query out database, but not generate ActiveRecord models (which takes additional resources).

Since this report displays a LOT of rows of data we are aiming for speed.

sql = Recruitment::Patient.order(reference: :desc).select(patient_attrs).to_sql

results = ActiveRecord::Base.connection.execute(sql).map do |row|
  Hash[patient_attrs.zip(row)].transform_values(&method(:format_value))
end

krisleech

These are the possible configurations we want to support:

config = :invited_on

config = [:invited_on, :started_on]

config = lambda { |s| s.started_on }

config = ResolveValue.new # object which `responds_to?(:call)`

krisleech

header, *rows = CSV.read(Rails.root.join('my-data.csv'))

rows.map! { |row| Hash[header.zip(row)] } # convert to Array of Hash

rows.map do |row|
  row.transform_values(&method(:format_value))
end

def format_value(value)

krisleech

Merge two hashes with double splat:

{ **{a: 1 }, b: 2 }

krisleech

Setup

Ensure commits are always signed: git config commit.gpgsign true

The gem signing private key should exist at ~/.ssh/gem-private_key.pem (see gemspec).

CHANGELOG

Double check the CHANGELOG reflects all commits since last version and all authors are included.