Adding a very naive in-memory cache to my Haskell web app

How I added very naive in-memory caching to my haskell webapp

vados

28 minute read

tl;dr - I added some caching to an app I’m writing in Haskell using Servant. The implementation is pretty naive, but I’ve seen some speedups (as one would expect from skipping a database access), and am glad I was able to build such a simple solution in a language as expressive as haskell. Skip to the end TLDR section to see all the code laid out! FAIR WARNING - this will is NOT an interesting article about caching algorithms or a quirk in GHC or optimization strategies.

Adding Sqlite Powered Fts Search To A Servant Powered Haskell App

Adding light and easy Full Text Search with SQLite3 to my servant-powered web app

vados

17 minute read

tl;dr - You may not need a big robust beautifully crafted DB like Postgres every time you build an app. Sometimes SQlite is probably enough. SQLite even provides Full Text Search addons in the way of FTS3/4 and FTS5, so that’s cool too – skim through the article for code snippets on the why/how I’m using SQLite + FTS3/4. If you’re unfamiliar with SQLite, it’s a pretty awesome light-weight SQL-compliant RDBMS.

Within seconds of using Pingdom I got email spam

This just happened, and I wonder how often it happens

vados

3 minute read

tl;dr - I do a web speed test on this site, get spam from a firm that does website speed consulting, I rant a little bit about it, then share a little bit about a startup idea I had at the end. I’ll be back to regular “exploring Kubernetes” related posts tomorrow! So this just happened (<5 minutes ago), but within seconds of heading over to Pingdom’s Speed test (I was really trying to test Piwik tracking on this blog), I got an email from some firm called SpeedUpgency that I’ve never heard of:

Setting Up SSL Certs on Kubernetes

Setting up SSL for Kubernetes with ployst/docker-letsencrypt

vados

6 minute read

tl;dr - letsencrypt is awesome, ployst/docker-letsencrypt makes it easy to use with Kubernetes (feel free to check out the blog post that describes it). There are even easier ways to do it these days that I haven’t tried: kube-lego which looks pretty amazing. After going through figuring out how to run HTTP applications on Kubernetes, as well as how to run databases on Kubernetes, the next natural step is to figure out how to gear up to running HTTPS applications on Kubernetes.

Stop Using React

BSD + PATENTS.md != F/OSS. Stop using React.

vados

6 minute read

tl;dr The BSD + PATENTS.md pattern is not F/OSS. Facebook is trying to goad you into entering a mutually assured destruction patent stalemate, but you don’t have nukes. They do. Stop using React, there are other better alternatives. Before you get into my thoughts, maybe you’ll want to look at some other debate from other strangers on the internet: Discussion of Facebook’s explanation on HN Discussion on Apache Foundation banning use of React on Reddit

Adding A Merge Patch Content Type To Servant

How to add a content type for HTTP spec compliant merge-patching in Servant

vados

6 minute read

*tl;dr See the code at the end Very often when developing a web application I run into the age-old problem of how to do partial updates. Doing the “U” (Update) in CRUD is actually a little more complicated than just accepting PUTs at some endpoint if you dont’ want to replace the object as a whole. I’ve often worked around this while maintaining somewhere-near spec complicance by just using the catch-all that is POST, and taking whatever object represented the update and doing whatever needed to be done.

Research Idea: Maintaining A Write Ahead Log For Application Runtime State

Exploring the stepladder of features that lead to well-engineered backends

vados

13 minute read

tl;dr:What if there was a write-ahead-logging layer above/outside the database? Then you could get CQRS+ES capabilities and assurnaces from your database without rewriting, and even abstract out the database as a whole, going as far as to create your own DSL for application-level changes, ADD_USER instead of INSERT … INTO USERS …* I spend a bunch of time thinking about how I can waste less time writing applications. Over time I’ve worked on various protoypes, with varying levels of completeness, but as I move across languages, frameworks, databases, and stacks, I always find myself solving the same problems, and having the same worries.

Case Study: Building A URL Bouncer

Building a URL bouncer for a servant-powered web application

vados

19 minute read

tl;dr - Building a simple URL bouncer with Servant isn’t that hard, and the usual warm fuzzies you get from well-typed functions, interfaces, and code still apply If you’re not familiar with Haskell or Servant, the former is a programming language that focuses on pure functional concepts and the latter is one of the most interesting/popular frameworks for it that specializes in exposing your API as a type itself. A brief taste of both of these things is below:

vados

5 minute read

Getting started with servant, part 2 tldr; Use enter to inject database information, monads and monad transformers rear their ugly heads but not for long. Multi-part blog post alert This is a multi-part blog-post! Part 1 - Getting Started with servant Part 2 - Getting Started with servant, Part 2 What are the ways to pass database information into an application using servant? From what I can tell, there are 3 main approaches to getting the database management object (whatever that is) into the app:

Getting started with servant (Part 1)

Adventures in functional programming and simple web API servers

vados

12 minute read

Getting started with Servant tldr; Haskell cool, Servant is awesome, and is a really interesting way to represent APIs in a way blessed by Haskell’s enormously powerful type system. Starting with it can be kind of difficult, but it’s a good kind of mind-bending. Multi-part blog post alert This is a multi-part blog-post! Part 1 - Getting Started with servant Part 2 - Getting Started with servant, Part 2 Background Recently I’ve been working on a project called The Start, which is meant to be a job board targeting some niches job markets in Tokyo/Japan.