TIL: Elixir's EEx Module
November 10th, 2022
I've been writing a lot of Elixir in my free time lately. I'm kind of all over the place with Elixir scripts and random Phoenix projects - often sparked with a "how would I do this?.." One such question that popped into my head was whether wkhtmltopdf had a supported package within the ecosystem. And there is! So I set about generating PDFs for fun and... fun.
I've done this sort of thing in Ruby before. For Ruby, I know I can
use .erb templates, inject some variables into them, and
use those to generate PDFs. Pretty simple stuff. Doing this in Elixir
was different in that I had no idea what I needed. Initially, I
found my way to Phoenix
Views. At first glance this seemed right, I mean, you have
.heex files, you can inject dynamic data into them, and
views were what I was after. Surprise (probably), I couldn't get this
to work as I wanted. So, what exactly did I learn?
What I learned is that I needed Elixir's (not Phoenix's) EEx
module - eval_file in particular.
data = %{
name: someones_name,
date: some_date,
}
html = EEx.eval_file("lib/some_template.html.heex", assigns: data)
In the example above, you can see we're creating some data
and then passing in the .heex file along with said data.
This results in html which can then be passed to wkhtmltopdf.