in this series we’re looking at using the amber language to write scripts that transpile into bash. so far we’ve covered using shell commands and handling error cases. in this installment, we’ll be looking at control structures: loops and ifs, basically.
writing shell scripts is zero fun. the bash syntax is a mess, error handling is difficult, and any script longer than a hundred lines is basically unreadable. but we keep writing bash scripts because they’re the right tool for the job and the job must be done.
amber aims to fix this pain by being a language that gives us a sane, readable syntax that transpiles into messy bash so we don’t have to write messy bash ourselves.
this post is a three-parter that will go over the basic features of amber from the perspective of those of us who actually want to use it. we’ll start with calling shell commands and handling errors, then look at loops and if statements, and finally investigate functions.
knowing the geolocation of your site’s users is handy thing. maybe you want to force your canadian users into a degraded, second-rate version of your ecommerce site, or maybe you want to redirect people from brazil to a frontend you ran through google translate, or maybe you just want to block the netherlands because you hate the dutch. there are reasons.
traditionally, this gets done by calling a third-party geolocation api. you gotta fiddle with api keys and manage rate limits and write a bunch of code. or… we could just let nginx do it all for us.
in this post we’re going to go over how to do ip geolocation for country and city in nginx and get that data into our web app where we can use it. all of this was written for ubuntu-like systems runing nginx 1.18.0.
recursion has a bad reputation amongst programmers; it’s convoluted and complicated and difficult to debug, a real footgun. it’s something you do at school (if you went to school for that sort of thing) and then never touch again if you can avoid it. which is a drag, because there’s a lot of use cases for recursion. data structures of arbitrary depth are everywhere: file systems, dom trees, that 32kb json packet your integration partner just shovelled into your api.
in this post we’re going to over two features of php that help make recursion easier: the RecursiveIterator interface, which provides us with methods and features that make writing recursive functions easier, and the dreadfully-named RecursiveIteratorIterator class which we can use to flatten down arbitrarily-deep data structures.
we’ll be building a recursive function using RecursiveArrayIterator, starting with a simple loop and working up to the full function. then we’ll look at how leverage RecursiveIteratorIterator to smash that nested array into a single level so we can extract data, either with a simple loop or a more-complex-but-powerful call to iterator_apply.
