Extracting Tiles from PMTiles

There are a couple ways to extract map tiles from the various archives - the most popular being MBTiles and PMTiles these days. The best way, though, is using tile-join from felt/tippecanoe:

tile-join -e dir/ input.pmtiles

This will output all tiles as a hierarchy in dir - dir/{z}/{x}/{y}.{ext}. When working with vector tiles, you might need to specify -pC (no tile compression). By default, tiles are compressed in the archive, but if you need the raw tiles in a directory, specifying this option will output the raw, uncompressed files.

JavaScript Unit Tests in a Phoenix Application

February 8, 2016

There’s a guide to writing browser acceptance tests for Phoenix. Acceptance tests are nice, but sometimes you want to have unit tests. This is very easy to do with your Elixir code, but what about your JavaScript code that lives inside your Phoenix application?

I couldn’t find a good guide on this, so I’ll go over what I have set up for one of my latest Phoenix projects.

Setup

First, install mocha if you haven’t already. I’ll be using mocha, but you can use whatever test runner you want to. You’ll also need babel-register -- this will allow you to use Babel while the tests are being run in Node.

Elixir's StringIO may not be what you think it is

January 23, 2016

In Ruby, there is a very handy class called StringIO. Basically, it allows you to treat a string like you would an IO object, such as an open file, etc. Very useful for in-memory “files” that you may not want to write to a temporary file.

In Elixir, there is a module called StringIO in the standard library. At first glance, these seem pretty similar:

Ruby:

Pseudo I/O on String object.

Elixir:

Web Development Tools: Mailtrap

January 19, 2016

This is the inaugural article of my “Web Development Tools” series I plan on continuing for at least a few more posts, sharing some of the essential tools I use for web development every day. When I have the chance to work with new people, we always exchange useful information about the tools and libraries we use. This series is an attempt to organize this information.

Today’s pick: Mailtrap

Once upon a time, I was working on a 2.0 for a client. Major overhaul. The database schema was completely different. So, I wrote a data migration script. Runs fine locally. Then, it became time to import test data to the staging environment.

Brutal Simplicity

January 13, 2016

My favorite pizza is the pizza Margherita. Any pizzeria I go to, I will order the Margherita first.

Why? It’s brutally simple. Four ingredients: dough, tomato sauce, mozzarella cheese, basil.

I wish more websites and applications would be like a good Margherita.

Simple.

Delicious.

????

Homebrew and PostgreSQL 9.5 (or 9.6)

January 9, 2016

Edit Sept. 30 2016: PostgreSQL 9.6 was released today, and these instructions should work – just replace 9.4 with 9.5 and 9.5 with 9.6. I also have a guide using pg_upgradecluster on Ubuntu.

PostgreSQL 9.5 was released on Jan. 7, with lots of exciting new features.

I wrote a post about upgrading from 9.3 to 9.4 in the past, and many people found it useful, so I decided to update it a bit for the 9.4 to 9.5 upgrade.

.gitignore と .gitignore_global の分け方

January 5, 2016

(If you aren’t interested in my posts written in Japanese, please subscribe to the “English” feed.)

Git のレポジトリーの中の .gitignore というのは、レポジトリーにコミットしない（無視する）ファイルを定義するものです。

Git のバージョン管理システムでは、二つの gitignore ファイルがあります。一つ目の一番知られてるのはレポジトリー内の。こちらは、プロジェクトのルートダイレクトリーに置かれて、そのプロジェクトに対する無視するファイルなど定義されています。

Elixir Pattern Matching in Anonymous Funs

January 3, 2016

filter_zed_by = "1"
list = [
  %{"a" => "1", "b" => "2"},
  %{"a" => "1", "b" => "5"},
  %{"a" => "2", "b" => "5"},
  %{"z" => "1", "x" => "2"}
]
Enum.filter list, fn
  %{"z" => ^filter_zed_by} -> true
  _ -> false
end

# => [%{"z" => "1", "x" => "2"}]

case in a fun is usually redundant
if is even worse
keep it simple

Hosting a Single-Page App on S3, with proper URLs

November 24, 2015

Note (2019/07/05): I’ve posted a follow-up to this post about limitations about the technique used here, especially when hosting an API on the same domain.

Amazon S3 is a great place to store static files. You might want to even serve a single-page application (SPA) written in JavaScript there.

When you’re writing a single-page app, there are a couple ways to handle URLs:

A) http://example.com/#!/path/of/resource
B) http://example.com/path/of/resource

A is easy to serve from S3. The server only sees the http://example.com/ part, and so it serves that file to everyone.

Podcasts I'm Listening To (November 2015 Edition)

November 23, 2015

My wife Naoko wrote a reply to this post. It was fun comparing how different the podcasts we listen to are. :)

First, I’d like to plug a podcast that I’m a semi-regular guest on, techsTalking(5417), a podcast where technology people just talk about whatever is on our mind.

Here are some other podcasts that I’m currently subscribed to:

The Incomparable -- a podcast about anything geeky. Star Wars? Check. Star Trek? Check. Silly drafts? Check. Crazy movies? Check.
The Incomparable Game Show -- born from The Incomparable proper, regular panelists play crazy games for your entertainment. On the podcast.
Incomparable Radio Theater -- The Incomparable podcast, once upon a time, liked to do funny things on April Fools. Like, say: release a full-length episode in the format of old-time radio drama. Including equally funny sponsors (some fake, some real). Now, they’ve spun it off in to a separate podcast.
Random Trek -- Incomparable regular Scott McNulty hosts a podcast with non-random guests talking about random episodes of Star Trek.
Robot or Not? -- Is it a robot? Or not?
Astronomy Cast -- A weekly “facts-based journey through the cosmos”.
Reconcilable Differences -- Two of my favorite podcasters, John Siracusa and Merlin Mann, get together on one podcast.

A few other podcasts I listen to occasionally:

Runroller UI

November 9, 2015

I recently released a simple API to un-shorten URLs. A few people wanted a super-simple interface to this, so I whipped one up: /unroll/. Enjoy!

Some notes about the tools I’ve used:

React -- I’ve used React in portions of sites before, but this is the first, albeit simple, full-page React app I’ve made.
Brunch -- used by default in Phoenix apps, it’s just what I’m used to these days.

Just like the service that runs the API, the UI is also open-source. Hack away!