DEV Community: Piotr Romańczuk

When VCR seems to heavy try cURL & WebMock

Piotr Romańczuk — Wed, 21 Apr 2021 19:31:03 +0000

Do you want to mock exact response (body and headers) for some file download?

VCR is overkill for such small task. One can handcraft it and pass to WebMock's stub_request. I'd rather go with saving full real response.

There are fine istructions in WebMock README. I want to share it here for reference:

Replaying raw responses recorded with curl -is

In console:

curl -is www.example.com > /tmp/example_curl_-is_output.txt

In your test:

raw_response_file = File.new("/tmp/example_curl_-is_output.txt")
stub_request(:get, "www.example.com").to_return(raw_response_file)

One wireguard connection to solve two person's problems

Piotr Romańczuk — Tue, 20 Apr 2021 17:58:59 +0000

Several years ago my uncle needed to start using e-mail. E-mail and simple one page text documents were supposed to be his only computer activities at that time.

I installed Linux Mint 13 Cinnamon 32 bit on my unused Thinkpad T61 and I gave it to him.
All was working without any hiccups. Recently his printer has died.
I visited him to install drivers and configure new printer. Unfortunately it was not so easy. Old Mint had no drivers for that very new Brother wi-fi printer. I managed to download and install it manualy via famous CUPS webpanel http://localhost:631

But the very next day ...

Uncle is calling:

Hi, my printer does not print.
Are there any messages on screen?
No.
What is the status of the printer in the printer panel?
Let me check ... oops ... I deleted it by mistake.

Did I mention that my uncle lives 40km from me?

New times, new challenges, new possibilities

My uncle said that he has another used laptop. He acquired it from someone in hope to be faster and usable with youtube and video conferencing. But this laptop has had Win10 on HDD. It was slow like hell!
And uncle doesn't want to learn Windows. He wants to feel at home with green folders of Linux Mint ;)

Decision made: Put SSD into that newer laptop. Install current Linux Mint Cinnamon 19.3 64bit. Copy all the data.

Easy peasy. Half an hour of work. But what about 40km? WireGurad!

Luckily I have working WireGuard installation on my OpenWRT 19.07 router.

Step by step instructions

For future me, if my aunt calls me with similar problem.

Generate wireguard keys pair

wg genkey | tee uncle-george.key | wg pubkey > uncle-george.pub

Add wg peer on OpenWRT router

Network -> Interfaces -> Edit your WG interface -> Peers tab

Add peer button on the bottom

Save, Apply changes, restart WG interface

Remote access to ubuntu based desktop

apt install ssh

Desktop sharing Linux Mint 19.3 Cinnamon

apt install vino dconf-editor

Add vino-server to autosart

/usr/lib/vino/vino-server

Because of cinnamon you have to use dconf to configure vino. Preferences does not work.

dconf path:

/org/gnome/desktop/remote‐access

Install and configure WG on ubuntu based desktop

Linux mint 19.3, uncle's machine

apt install wireguard

Add wg-qucik configuration file, i.e. /etc/wireguard/wg0.conf

[Interface]
Address = x.x.x.6/24
#here goes uncle private key
PrivateKey = OJBB**************************4W0o=

[Peer]
#here goes router public key
PublicKey = RpPL5n9bBX**************************mGzofYTFw=
Endpoint = 1.2.3.4:1234
PersistentKeepalive = 25
AllowedIPs = x.x.x.0/24, y.y.y.0/24

enable and start wg service

sudo systemctl enable wg-quick@wg0.service
sudo systemctl daemon-reload
sudo systemctl start wg-quick@wg0

wg-quick automatically adds routes for all AllowedIPs

Transparently serialize and deserialize ValueObjects to JSON

Piotr Romańczuk — Mon, 19 Apr 2021 19:03:16 +0000

This is the way I choose when I want to serialize and deserialize ValueObjects transparently to JSON in Rails app

Put serialization methods into module

module ValueObjectJsonSerialization
  def to_json(*args)
    #override AtiveSupport to_json extensions if active
    args = JSON::SAFE_STATE_PROTOTYPE.dup if args == []
    {
      :json_class => self.class.to_s,
    }.merge(as_json).to_json(*args)
  end

  def as_json(_=nil)
    # unused argument to satisfy ActiveSupport as_json signature
    { :json_class => self.class.to_s }.merge(_as_json)
  end
end

Use them in your ValueObject class and make it transparently serializable

class PublicationDate
  include ValueObjectJsonSerialization
  def initialize(y, m=nil, d=nil)
    @y, @m, @d = y, m, d 
  end

  def self.json_create(h)
    new(h['y'], h['m'], h['d'])
  end

  def _as_json
    { y: @y, m: @m, d: @d }.compact
  end
end

DEMO

require 'json'
[9] pry(main)> PublicationDate.new(2021, 4)
=> #<PublicationDate:0x00005652cd6a5c40 @d=nil, @m=4, @y=2021>
[10] pry(main)> PublicationDate.new(2021, 4, 19).to_json
=> "{\"json_class\":\"PublicationDate\",\"y\":2021,\"m\":4,\"d\":19}
[11] pry(main)> JSON.load PublicationDate.new(2021, 4, 19).to_json
=> #<PublicationDate:0x00005652cd717d18 @d=19, @m=4, @y=2021>