“Another day, another framework”, you might think. And yes, Opa is yet another web framework that is going to revolutionize web development. But don’t judge it too soon, it has a few tricks up its sleeve that might convince you to try it out. Read on for my first hour of Opa.
This is a first in what I hope will become a regular feature: I give myself one hour to try out something new and decide whether I will pursue it or not. Feel free to send any suggestions my way.
First Impressions and How to Deploy
I love to try out new technology for pet projects and one thing I always worry about is small scale, cheap deployment. I could not find anywhere on the site how you’d deploy Opa. Is there support for PaaS providers like Heroku? It appears not, you need to have access to and full control over your own VPS (there’s some limited information on AWS)
OCaml
<figcaption class="wp-caption-text">Opa is Dutch for grandfather</figcaption></figure>
I don’t understand why the website says the Opa language is JavaScript-like. As soon as you start writing your own thing, you’ll notice there are some major differences between Opa and JavaScript, so be prepared to learn a new language
Opa is based on OCaml, an objective functional language that has been around for a while and seems to mostly live inside academiccircles.. I first used it in 2000, the memories 🙂
Windows Version
I tried the all-in-one Windows installer.
It automatically installs a plugin for Sublime Text. The plugin itself has a build-in mini tutorial. Which is nice if you’re a Sublime Text 2 user. Keep in mind that your Opa file must be in the root of the folder tree, otherwise the run command won’t find the correct file. The plugin also couldn’t kill the processes it started, which made the build/run integration useless.
Later on, I also discovered that the installer had deleted my path setting. I assume this is a small bug that will be solved in the next release.
HTML and NoSQL
Opa only supports NoSQL databases and I have a feeling you’re in for a lot of hurt if you try to connect to a relational one.
HTML doesn’t need to be quoted and the compiler checks for correctly closed tags. That’s pretty cool.
Type System
<figcaption class="wp-caption-text">Static typing without the overhead</figcaption></figure>
Opa uses static typing with type inference which made me think of Scala: it gets out of your way, but it’s there if you mess up. It’s probably a great feature if you are used to static typed languages but may be an annoyance if you are not.
Client/Server
Running the Hello world counter example and clicking on the header results in 5 POSTS. The last running to closed. Probabfurthers ever push communication. 5 posts just to transmit one number worries me. It’s also all Ajax, so no SEO here.
The first tutorial is a chat application. I can understand that this is a great demonstration of the language and API, but this is an application only 1% (or less) of the developers ever needs to write.
The chat application is concise, yet I can’t help but ask myself how you’d ask a web designer to work on this project. You could argue that CSS is all he needs, but in practice it very rarely works like that. Maybe there’s a way to externalize the HTML in seperate Opa files (like you’d split a PHP app in a controlling part and a template part, even though both are technically PHP files) Going over the table of contents, I can’t really see this explained anywhere
Integration
Going to the wiki example, I learn that aside from Bootstrap, also Markdown is built into the API. This is nice. I’ve always liked Markdown as a simple language for creating content. This has me browsing the API documentation, where I also see support for Google Charts, Canvas, Facebook and Twitter. And I also scroll past a “template” package, so my fears from the previous paragraph seem to be unfounded.
Wrapping Up
<figcaption class="wp-caption-text">An hour is too short</figcaption></figure>
Because I’m nearing the end of my one hour, I quickly scoop over the rest of the documentation. I do encounter a more detailed explanation of the client/server keywords and their usage. If I pick up Opa for a new project in the future, it will probably be the first thing I’ll read.
The one thing that keeps bugging me is the absence of any information on deploying. The Scalability chapter touches on this, but it’s very unclear to me. Probably because I’m too impatient and I should just try it out. From what I understand the “opa-cloud” application will distribute your application over SSH. However, does this also work between operating systems (the command lines presented seem to indicate that it just copies the “exe” file that was produced).
Throughout the entire hour, I also can’t help but think “Why bother learning Opa, when Node.JS offers a fairly similar model in a language all developers already know”. It’s a valid question and others have looked at it in much more detail. One of the most important things I picked up from that test was how concise Opa applications seem to be. This is probably related to its OCaml heritage.
Why would you use Opa?
You can write all of the code for your web application in one concise and type-safe language. Out-of-the-box Opa supports an interesting selection of integrations and its first-class language support for HTML and NoSQL databases is top notch.
Why would you not use Opa?
You just want to get started and don’t feel like learning a new language. You prefer a large community backing your choice framework.
<figcaption class="wp-caption-text">Opa is Dutch for grandfather</figcaption></figure>
<figcaption class="wp-caption-text">Static typing without the overhead</figcaption></figure>
<figcaption class="wp-caption-text">An hour is too short</figcaption></figure>