wojtha

"""Utility functions"""

from functools import reduce
from operator import getitem
from typing import Any, Mapping, Union


def getdeep(data: Mapping, map_list: Union[list, str], default: Any = None) -> Any:
    """Iterate nested dictionary|list and can return default value if key not found

wojtha

*.c     diff=cpp
*.h     diff=cpp
*.c++   diff=cpp
*.h++   diff=cpp
*.cpp   diff=cpp
*.hpp   diff=cpp
*.cc    diff=cpp
*.hh    diff=cpp
*.m     diff=objc
*.mm    diff=objc

wojtha

This is an example of how I combine interaction/service classes with Wisper event broadcasting in Rails.

In this example, I show a UsersController#create API, a corresponding service object, and all the test code/listeners to make it all happen.

The outcome is:

• Concepts in your system ("Signing up a user", "Creating an order") have a single entry point in your codebase, vs. making raw ActiveRecord calls to object.save in dozens of places.
• Since your concept has one entry point (the service class), you can easily grep for usage of it.
• Stupid easy to attach listeners to the service class
• All event listeners are very small and easily unit tested

wojtha

# A simple way to create private constants without all the noise of ruby's 'private_constant'
# 
# Before:
# class Foo
#   FOO = "bar"
#   private_constant :FOO
# end
#
# After:
# class Foo

wojtha

Ruby and Rails Interview Questions

Ruby

• What is a class?
• What is an object?
• What is a module? Can you tell me the difference between classes and modules?
• Can you tell me the three levels of method access control for classes and modules? What do they imply about the method?
• There are three ways to invoke a method in ruby. Can you give me at least two?
• Explain this ruby idiom: a ||= b

wojtha

Answers to [Ruby Interview Questions][1]

What is a class?

A text-book answer: classes are a blue-print for constructing computer models for real or virtual objects... boring.

In reality: classes hold data, have methods that interact with that data, and are used to instantiate objects.

Like this.

wojtha

This list is based on aliases_spec.rb.

You can see also Module: RSpec::Matchers API.

matcher	aliased to	description
a_truthy_value	be_truthy	a truthy value
a_falsey_value	be_falsey	a falsey value
be_falsy	be_falsey	be falsy
a_falsy_value	be_falsey	a falsy value

wojtha

An incomplete cheatsheet for rails 3. Things are added as they are required.

## Debugging

Check errors

@user = User.new(:email => email)
puts @user.valid?
@user.errors.each { |e| puts "#{e}: #{@user.errors[e]}" }

wojtha

----- Esc -----
Quick change directory: Esc + c
Quick change directory history: Esc + c and then Esc + h
Quick change directory previous entry: Esc + c and then Esc + p
Command line history: Esc + h
Command line previous command: Esc + p
View change: Esc + t (each time you do this shortcut a new directory view will appear)
Print current working directory in command line: Esc + a
Switch between background command line and MC: Ctrl + o
Search/Go to directory in active panel: Esc + s / Ctrl + s then start typing directory name

wojtha

Adding an audit log to your Rails app

If you have any sort of administrative interface on your web site, you can easily imagine an intruder gaining access and mucking about. How do you know the extent of the damage? Adding an audit log to your app is one quick solution. An audit log should record a few things:

• controller entry points with parameter values
• permanent information about the user, like user_id
• transient information about the user, like IP and user_agent

Using the Rails framework, this is as simple as adding a before_action to your admin controllers. Here’s a basic version that I’m using in production.