I live in a small town that occasionally broadcasts announcements over the radio. For the past few years, I’ve been building a small Raspberry Pi appliance to transcribe these broadcasts to text. However, there are many broadcasts that don’t contain spoken content, so I wanted a way to recognize the kind of broadcast and make a decision whether to send it to the speech-to-text service or not.
Here’s what I have right now:
I attended my first Elixir-related meetup yesterday, tokyo.ex #1.
(If the slides don’t work here, I have also uploaded them to YouTube.)
In my 5-minute lightning talk, I talked about the basics of using Exfile. Exfile is a file upload persistence and processing library for Elixir with integrations for Ecto and Phoenix.
I’m a big Let’s Encrypt fan. They provide free SSL certificates for your web servers so you can protect the traffic from prying eyes. In fact, the connection between your web browser and my blog server is made private thanks to Let’s Encrypt.
Using Let’s Encrypt requires some setup and automation on your part if you want to use it in the AWS cloud, but AWS recently launched something called the AWS Certificate Manager or “ACM”. ACM takes care of issuing, renewing, and provisioning certificates for you – which is great because uploading SSL certificates to CloudFront and Elastic Load Balancers is not the most fun thing to do. I would pay for this, but Amazon has decided to give it to everyone for free. :-)
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.
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.
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:
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.
????
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.
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 redundantif is even worseNote (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.
So, this is a thing:
bundle install --without development:test
...
...
Bundle complete! XX Gemfile dependencies, XX gems now installed.
Gems in the groups development and test were not installed.
Now,
bundle install
...
...
Bundle complete! XX Gemfile dependencies, XX gems now installed.
Gems in the groups development and test were not installed.
Basically – you run bundle install --without <group> once, and that’s saved in .bundle/config. So next time you run bundle install without any arguments, it won’t install gems in the groups you specify.
Note: This blog post covers the legacy SSL Endpoint. Heroku now recommends the use of Heroku SSL, which can provide you with a free certificate and HTTPS (provided you are using the Hobby tier or higher).
If you use Heroku, you probably know a couple things:
I’m going to solve both of these problems with one stone: AWS CloudFront.