# Offline Development

I was recently on a long haul flight from Manchester to San Francisco with no Wi-Fi. As you can imagine, between regular snacks and naps, being off the grid for so long was quite the struggle. A few hours into the flight, I decided to pop out my laptop anyway and do some development—what happened next was a bit magical for me.

Without the helping hand of The Google or colleagues to pester with my questions I had to (wait for it) think for myself. It sounds a little bit ridiculous, but having to only use what little I keep in my head is something I haven't done in a very long time—and rightly so really, almost everything I need to know in my day–to–day life can be acquired with a few tap–a–tap–taps on my phone. I decided to just have some fun with it and see how far I'd get. Between you and I, it took me about 2 minutes before I realised just how little I knew (the time it took to get my laptop out of overhead storage, log in, sip tea, and open up a terminal).

Here's what I was working on.

I've recently been doing some API work and wanted to see how much of the OAuth 2 protocol I could remember. I wanted to make a simple Ruby program where I had models for an authorisation server and a resource server. I could then make a call to get an authorisation grant, swap it for a token, and then use that token to access a resource.

The first thing I wanted to do was have my tests run frequently. Usually, I'd use Guard for this (Guard runs the tests whenever a file is modified), but here's the thing—Guard is usually set up on projects I work on, and if it's not I'd just Google how to configure it. So what do? I wrote the following down on the back of a boomerang pillow receipt:

Things I don't know:

1. Guard

I then had to figure out a way to get the tests to run periodically. As a temporary hack something like this seemed reasonable:

while true
run tests
sleep 5 seconds
end


I thought something like that could be quite easily written in bash, so I focused my attention on the terminal and to my surprise, my hands didn't start typing—I couldn't remember the syntax for a while loop in bash. Well, no matter, I thought to myself, I'll just add it to my list:

Things I don't know:

1. Guard
2. While loop syntax in bash

This is when I started to feel excited, maybe even a bit creative. I could remember how to repeat a command multiple times using repeat, so I ended up using the following to get my tests to run periodically:

repeat 3000 rspec && sleep 5;


This runs the tests, takes a 5–second nap, then does it all again, 3000 times in total. It's not ideal, but it did the job and it meant I identified 2 things I didn't know. That's a win (I think).

Next, I started thinking about what I wanted my project to achieve. Here is my list of requirements:

1. Developers can register their application with my program
2. Users can go through an authorisation process with my program
3. A client program can access some resource if the user has completed authorisation

I couldn't remember what the OAuth 2 spec says about registering applications—something about the client sending a software statement and getting back some client credentials. It was the least known requirement for me, so I just added it to my growing list of Things Andy Doesn't Know.

Things I don't know:

1. Guard
2. While loop syntax in bash
3. OAuth 2—client registration

At this point, I began putting together an authorisation server. This would be a Plain Old Ruby Object that could be used to authorise a client's application with mine. I got a bit stumped around generating tokens—is there a secure way of achieving this? Is there an insecure way of doing this? I settled on using SecureRandom.uuid, but I added an extra item to my list anyway so I could read up on it later.

Things I don't know:

1. Guard
2. While loop syntax in bash
3. OAuth 2—client registration
4. How should I be generating tokens? Is SecureRandom.uuid the right thing to use?

Once I had a very basic authorisation server implemented I moved on to the resource server. The resource server takes an access token (provided by an authorisation server) and returns some resource in exchange. My resource server needed to talk to the authorisation server to verify access tokens. This meant I needed to remember how to include one file in another in Ruby. In Rails, you rarely need to think about this kind of thing due to the fancy autoloading of classes, so this had me stumped for a while. After some hacking, I found that require_relative seemed to do the trick, but I wasn't confident this is what is usually done.

After wiping the crumbs and spilled tea off the back of my, somewhat crumpled, receipt I updated it once more:

Things I don't know:

1. Guard
2. While loop syntax in bash
3. OAuth 2—client registration
4. How should I be generating tokens? Is SecureRandom.uuid the right thing to use?
5. Including files in Ruby land