Advent of Functional PHP: Day 7 – Larry Garfield

Advent of Functional PHP: Day 7

Advent of Code Day 7 this year is another problem that’s more about the math than about the programming, so we won’t see much in the way of new functional techniques. Still, there’s some interesting bits in there.

Today we need to calculate the fuel costs of moving a bunch of crabs in submarines all into a line. (Don’t ask. Really, don’t ask.) Essentially we want to center-align a series of points using the least “cost” possible. Crab positions are represented by a single number, as crabs can only move horizontally. (Because crabs.)

The trick for today is realizing that the crabs don’t matter; it’s a distance-cost calculation. In part 1, the cost for a crab to move one space toward whatever alignment number we want to pick is 1.

Continue reading this post on PeakD.

7 December 2021 – 3:38pm

Xdebug Update: November 2021 – Derick Rethans

Xdebug Update: November 2021

In this monthly update I explain what happened with Xdebug development in this past month. These will be published on the first Tuesday after the 5th of each month.

Patreon and GitHub supporters will get it earlier, around the first of each month.

You can become a patron or support me through GitHub Sponsors. I am currently 46% towards my $2,500 per month goal. If you are leading a team or company, then it is also possible to support Xdebug through a subscription.

In November, I worked on Xdebug directly for only about 16 hours, with funding being around 24 hours. Please become a supporter of Xdebug through Patreon or GitHub.

Xdebug 3.1 and further

Since my last report, there were no more new issues reported with either functionality or crashes, and I have prepared for the Xdebug 3.1.2 release. Although I didn’t publish that in November, I did release it on December 1st.

It addresses a few crash bugs related to PHP 8.1 fibers, a crash bug when Xdebug can’t write a profiler file, and an issue with Xdebug’s var_dump() not using the magic __debugInfo method.

The full list of changes can be found on the updates page on the Xdebug website.

So what’s next? Xdebug’s profiler needs a rewrite. There are several design and implementation issues, that can only be resolved by a rewrite. To create less overhead it can also use PHP 8’s new Observer API as well.

But this is going to take a large amount of work, and with the current low, and decreasing, funding levels, I can not put a lot of effort behind this.

Xdebug Videos

I have published more videos on how to use Xdebug on my YouTube channel.

I will continue to create more videos, and also convert some of them to tutorials.

If you would like to suggest a topic for a 5 to 15 minute long video, feel free to request them through this Google Form.

Caddy as a Secure Reverse Proxy – Matthew Weier O’Phinney

I’ve been using Caddy as a front-end reverse proxy for several years now, on the advice of Marco Pivetta.
Somewhere along the line version 2 was released, and I updated at some point, but evidently didn’t quite understand some of its configuration options, particularly around HSTS support and providing your proxied application information about how the client tried to connect.

Caddy has always had a fairly declarative syntax, and tended towards sane defaults.
The syntax is like a hybrid of YAML and HCL, for better or worse, and includes placeholders for substituting in request or block-specific values.
Fortunately, you don’t have to write much to get the most common scenarios to work correctly.
And v2 now provides a JSON syntax as well.
The JSON syntax gives full access to all configuration options, and is particularly useful to learn if you want to be able to update the configuration on the fly via Caddy 2’s configuration API.
That said, the JSON syntax is incredibly verbose, and has quite a large set of nested members; I’ve found that for the bulk of my usage, the declarative HCL-like syntax tends to be easier to read and implement.

For instance, the documented way to create a reverse proxy to a service running on port 9000 of another machine, and that uses HTTPS by default is simply: { reverse_proxy machine-running-actual-service:9000

Boom, done.

Even better: Caddy can serve local IPs and addresses over HTTPS as well.
It will generate self-signed certificates using its own root certificate, which you then install into your system trust store.
The benefit is you can test your sites locally using TLS, which can help when testing JavaScript interactions, and reduce behavior differences with production.

Securing reverse proxies

That said, I’ve run into some small issues when running reverse proxies:

  • I assumed HSTS headers were in place.
    They were not.
    (This is true of any Caddy-served site, though, and not specific to reverse proxies.)
  • I assumed things like the X-Forwarded-Host and X-Real-IP request headers were in place.
    They were not.
    That said: by default, Caddy:

    • Passes the Host header intact to the proxy.
      This is actually quite handy, as most application frameworks will prefer the Host header when present anyways.
    • Adds the X-Forwarded-Proto header; this is the one most standardly consumed by other web servers and web application frameworks.
    • Adds or updates the X-Forwarded-For header, which is used by load balancers.

Fortunately, adding configuration for these are relatively straight-forward { reverse_proxy machine-running-actual-service:9000 { header_up X-Real-IP {remote} header_down Strict-Transport-Security max-age=31536000 }

If you have quite a number of reverse proxies, you likely don’t want to copy-paste those.
Caddy to the rescue again: configuration supports snippets.
These look like your host blocks, but the name will be in parentheses.
When a configuration block can re-use it, it can import it by name.

(reverseproxyheaders) { header_up X-Real-IP {remote} header_down Strict-Transport-Security max-age=31536000
} { reverse_proxy machine-running-actual-service:9000 { import reverseproxyheaders }

With these changes, my applications now:

  • can resolve the client IP correctly
  • provide HSTS headers to the client, helping protect users from MITM attacks

My own configuration defines three reverse proxies, two subdomains that redirect elsewhere, and defines one static site.
All in a total of 34 lines of configuration.

I’ll take it.


Why use Caddy, particularly if you’re comfortable and/or knowledgable with Apache or nginx?

For me, the decision comes down to sane defaults and ease of setup.
Setting up ACME with Apache or nginx, while it has become simpler, is not turn-key.
Caddy, however, assumes TLS by default, uses ACME to marshal a TLS certificate, and redirects non-TLS requests to TLS, all without requiring any additional configuration whatsoever.
Similarly, the fact that setting up a reverse proxy can often be as simple as pointing it to the proxy, and not require remembering to pass on common headers, sets it apart from the traditional web servers.
Finally, it’s built for speed, and I’ve found that the performance overhead of running it as a reverse proxy is essentially negligible.

Truncated by Planet PHP, read more at the original (another 816 bytes)

Advent of Functional PHP: Day 6 – Larry Garfield

Advent of Functional PHP: Day 6

Day 6’s challenge is a little fishy. Given what we’ve already done so far, it’s pretty simple. The only catch is making sure you do it in an efficient way.

Specifically, we’re asked to model the growth patterns of fictional lantern fish. In this silly model, we start with a list of fish at various ages. Each fish spawns a new fish every 7 days, and a newborn fish takes an extra 2 days before it starts spawning new fish. Fish also never die. (Someone warn the AI people that we’ve found the paperclip optimizer.)

Part 1 asks us how many fish there are after 80 days, all around the world, given the start data. Let’s find out, but let’s do so efficiently.

Continue reading this post on PeakD.

6 December 2021 – 12:43pm

Advent of Functional PHP: Day 5 – Larry Garfield

Advent of Functional PHP: Day 5

Submitted by Larry on 5 December 2021 – 9:23pm

After the last two days, Day 5 of Advent of Code is almost mundane in comparison. Today we’re asked to read in the definition for a series of lines and compute how many times they intersect.

The process is much the same as the previous days: Parse the incoming data into some sort of data model, then run some computations on it. And both parts will consist primarily of `pipe()` operations, since we’re really just shuffling data from one form to another.

Our input data looks like this (albeit with a much larger range of coordinates):

Continue reading this post on PeakD.

Advent of Functional PHP: Day 4 – Larry Garfield

Advent of Functional PHP: Day 4

Submitted by Larry on 4 December 2021 – 7:41pm

Day 4 of Advent of Code has us playing bingo against a giant squid. (Don’t ask; I don’t understand it either.) More specifically, we want to take an input file that consists of a series of numbers that will get called, followed by a series of boards. We then need to compute which board will be the first to win, following the standard rules of bingo (although with no free space in the middle, the cheating squid…).

This sort of problem is inherently very stateful, and thus, frankly, not a good fit for functional code. It absolutely can be done in a functional way, but it’s not the best fit. We’re not interested in the best fit in this series, though, just how it could be done functional-style. So let’s do it functional style just to say we did. Along the way we will really exercise the function composition concept, and show a few other tricks along the way.


Advent of Functional PHP: Day 3 – Larry Garfield

Advent of Functional PHP: Day 3

Submitted by Larry on 4 December 2021 – 6:15pm

The third challenge in this year’s Advent of Code is all about bit manipulation. We’re asked to read in a series of binary numbers and interpret them in various entirely illogical ways as a form of diagnostics. (Incidentally, if you ever write a system that requires this kind of logic to debug its output, you’re fired.)

In any case, we’re given a file with a list of 12 digit binary numbers and asked to compute various values. In the first part, we are asked to find the most common bit (0 or 1) in each position, and the result is known as “gamma.” Then we have to find the least common bit in each position, and the result is known as “epsilon.” (I don’t know why you would want to do this; it’s all Greek to me.)

Advent of Functional PHP: Day 2 – Larry Garfield

Advent of Functional PHP: Day 2

Submitted by Larry on 2 December 2021 – 11:46am

In today’s challenge, we’re asked to interpret a series of basic command lines from a file and update the position of our submarine accordingly. It’s basically a graph walk of sorts, with instructions of up, down, and forward. (Apparently you cannot go backward, as in life.)

As with yesterday’s challenge, we could do it imperatively with a foreach() loop and a couple of state variables floating around, but that conflates a whole bunch of different behaviors into one blob of code. We don’t want to do that, so let’s step back and consider the problem more clearly.

Advent of Functional PHP: Day 1 – Larry Garfield

Advent of Functional PHP: Day 1

Today’s challenge asks us to interpret a list of numbers. In the first part, our goal is to determine how many elements in the list are larger than their immediate predecessor.

The imperative way would be to toss it in a `foreach()` loop and track some state along the way. But we want to be functional and avoid “track some state,” because the whole point of functional programming is to avoid tracking state, as tracking state is error prone.

When looking at a foreach-style operation that has some state, my first inclination is to look at a reduce operation. A reduce operation walks over a list and performs the same operation (function) on each item, using the output of the previous iteration as an input. That is, each step takes the output of the previous operation and the next element, and produces an output. It’s quite elegant.

1 December 2021 – 11:24am