I’ve written before about handling errors in Clojure without using exceptions, by making use of ad-hoc monads. In that post, I also referenced Andrew Brehaut’s error monad implementation.
Since then, I’ve written a number of projects that use similar handling, and I thought the time had come to wrap it up in a library, which I’m calling Failjure.
My long-standing complaint about Clojurescript is that it’s a pain to get running. People who prefer Leiningen seem to have gotten a handle on this with figwheel; however, those of us who have jumped on the Boot train (it’s newer and therefore better!) still have to do some assembly to get the live-reloading auto-compiling repl setup that’s become the standard for Clojurescript development.
Like many problems in the Clojure universe, this is less a problem of technology and more a problem of approachable documentation. With just a little bit of configuration and some understanding, you too can assemble that perfect Clojurescript dev setup using Boot.
Pallet is a Clojure DevOps platform/library designed to automate blah blah blah. We all know what these things are supposed to do, the question is how they do it, and Pallet takes the agreeable tack of just being a Clojure library that you can run in a repl and do devops stuff.
When it comes to database access, I’ve become less particular over the years as I’ve gotten more and more comfortable with SQL. These days I’m happier to write the SQL to get just the thing I want, than wrestle with an ORM to produce the same thing...
In my previous post, I gave a quick overview of how the Buddy auth library for Clojure. Today, I’ll give a more fleshed-out example of how to use it to add session-based password authentication to an app.
A while back, I wrote about using Friend to handle auth in Clojure. I neglected to mention (or look at, in particular) the other auth framework making waves in the Clojure community, aptly named Buddy.
Buddy is, well, another authentication/authorization framework. It also contains some lower-level crypto utilities, but the main use right now seems to be handling auth for web applications in Ring. I had heard good things about how Buddy works, so I decided to give it a try, and now you get to hear about that.
Letsencrypt.org has just entered its public beta period. This means that you can get ssl certificates really easily and for free. Letsencrypt’s certificates are up to modern specs and fully accepted by all browsers, so you no longer have any excuse not to have SSL on all your domains.
This post will hold your hand through the process of moving your Nginx site from http to https.
A short post to say that I’ve just launched a new project called Unpythonic. It’s a collection of articles introducing various concepts and techniques for functional programming in Python.
I love the Clojure language, but I don’t think there’s any use pretending that the combination of expressiveness, power, and repl-driven development can result in some staggeringly dense code. Everyone that writes Clojure is guilty of this at one time...
I have a small weakness for silly text games like Candy Box and A Dark Room, and most recently Kittens Game (“a Dark Souls of incremental gaming”). The common feature of these games is that, for the most part, the UI is just numbers on a web page, and you perform certain actions to increase those numbers to purchase upgrades that further your ability to increase the numbers.
One of the great things about this style of game is that the barrier to entry is very low (which is probably why there are approximately a brazilian of these things around), and the games in the genre are differentiated almost solely by the quality of their mechanics (without silly things like “art” to get in the way). You, the reader, might even be interested in dipping your toe in the world of incremental games. If you want to add one to the pile, I recommend you use React to do it.
Circular.io is a clone of Buffer, or at least the Buffer of about 5 years ago. Back then, all buffer did was let you schedule posts to Twitter, to be sent at regular intervals throughout the day. It was on HN about 3 years back, and has been running...
I’ve used friend to provide auth in my projects a few times, and considered it many more before resorting to my own hand-rolled business. Most of the reason for this is that is just seems so complicated. Workflows? Credentials? I just want to check a password and stash a user object in the session, end of story. After I did some investigating, though, it turns out that you can usefully deploy friend for even very simple workflows, if you understand how it works.
This weekend I made http://worldclassifiedlist.com on a whim. Past experience suggests that I’m not likely to derive any value from the site itself, so before it’s completely forgotten, overlooked by an indifferent world and relegated to an unnoticed screenshot on my portfolio page, I thought I might wring a few ideas out of the making-of.
Besides the post scheduling, the main reason people come to http://www.redditlater.com/ is the subreddit analysis feature. This lets folks enter in a subreddit and tells them when the best time to post on a given subreddit is.
Little do they know, it tells me about them, too.
When boot first appeared in my usual rotation of clojure news, I must confess that I didn’t really see what the fuss was about. It seemed like someone had taken leiningen and broken out all its parts into functions, which you could then use to get your dependencies, build your project, and so forth. Don’t you see! Leiningen is just a build tool, but boot could be anything. It could even be a build tool!
The way we make websites has changed a lot since I started doing it, and it’s important to keep up-to-date on new tools and techniques. That said, I’ve been noticing that I’ve not spent as much time churning through new frameworks and whatnot as I used to – in fact, I’ve picked out a few tools that I’ve been using for years.
Frege is a strongly-typed functional language for the JVM. Its goal is to mirror Haskell as closely as is possible on the platform, and as far as I can tell it does a pretty decent job. It seems performant enough, and more importantly grants access to a Haskell-esque type system. This makes it a pretty good complement to Clojure for those problems where a strong typing system is important.
The downside to Frege is that, even though documentation exists (and is actually quite expansive given the language’s limited adoption), it’s still hard to find straightforward how-tos by googling. So here’s some much-needed frege-related blogspam to fill out those results.
In Clojure (and many other languages), a multimethod is an implementation of multiple dispatch as an alternative to single dispatch.
Traditionally, if you define several methods with the same name on
different classes, the type/class of the first argument (in Python, self, in
many other languages implicit) is used to pick which method to call. This is
called “single dispatch” because the decision of which method to call is left
up to the inferred type of a single argument.
Multimethods take the approach of leaving the dispatch up to the user; you can dispatch on any value at all. You just need to supply a function that returns the value on which you wish to dispatch, and a method for each possible value. For certain cases, this is a lot more flexible than single dispatch.
Functional programming is often described in terms of its contrast with object-oriented programs; that is, you write functions that act on data instead of objects that wrap data and use methods to act on themselves. Functional programming wonks (like me) will tell you that writing code this way is generally better than OO, but I don’t want to do that (right now).
However, in this post, I’m not here to argue either side. Today, I’m just going to demonstrate a few equivalent approaches to the same problem: validating data.
One of my favorite genres of article to write are the ones that involve refactoring some code to make it more functional, and (hopefully) improve it on the way. With that in mind, I’ve decided to embark on a tour of some of the things users of other popular dynamic languages can take away from the ideas behind Clojure, even if they never use it themselves. Today, I’ll be taking an old Python library I wrote and refactoring it to fit a few ground rules.