PHP namespaces grouped

Consider the following code:

<?php
namespace a\b\c;
use function is_string;
use function get_class;

class main {
    protected $string;
    public function __construct( $string ) {
        if ( is_string( $string )) {
            $this->string = $string;
        } else {
            $this->string = get_class( $this );
        }
    }
}

Nothing fancy. Just a class in a namespace using two functions from the global namespace (is_string & get_class).
Those two functions are imported from the global namespace as that will give a small performance boost.

But if you have 20-30 build in PHP functions that list will get very long….

Luckily you can merge them:

use function is_string, get_class;

For now I’m not sure I’ll always import build in PHP functions, the boost is small. And it’s annoying to keep track of.

php shorthand if

I’ve known about the shorthand if for years:

<?php echo ($username) ? $username : ''; ?>

Today If saw this which is called Ternary and has been available since 5.3 which is older than my days of coding….

<?php echo ($username) ?: ''; ?>

Update PHP7.4
When assigning value especially in an array or object you can now do the following.

<?php

$person = [ 'date_of_birth' => '1970-01-01' ];

$person['name'] = $person['name'] ?? 'John Doe'; //php7.3
$person['name'] ??= 'John Doe';                  //php7.4

var_dump( $person );

for & foreach loops performance

Today we will handle a case of “Premature Optimization Is the Root of All Evil“.
But this is my blog and I was working with a very big api set, and will only get bigger, so (premature) thinking about memory usage and execution time might be a good idea in the long run.

Before I started this I thought that a for loop was faster then a foreach loop. And I usually pick foreach because it’s easier to write and read.

A quick google lands on a stackoverflow question which concludes the opposite. So I started to test a bit.

There is a big difference in my use case here.

I need to remove array items that need to be excluded from the api results. Most examples you will find online are about editing items.

First tests where quite clear, using a foreach was in most configurations faster than for. The test array I create has 10000 items and every 3rth item should be excluded:

<?php
$test_array = array();
for ( $i = 0; $i <= 10000; $i ++ ) {
    $test_array[] = [
        'index'   => $i,
        'include' => ( $i % 3 === 0 ) ? true : false,
    ];
}

The traditional foreach loop

The way I have been filtering arrays for years.
Create a empty array and only put in the elements the need to be included.

<?php
$filtered_array = [];
foreach ( $test_array as $item ) {
    if ( true === $item['include'] ) {
        $filtered_array[] = $item;
    }
}
return $filtered_array;

Immediately delete item

Don’t use a between array, just unset the item in the parent array

<?php
foreach ( $test_array as $key => $item ) {
    if ( true === $item['include'] ) {
        unset( $test_array[ $key ] );
    }
}
return $test_array;

Traditional pass by reference

The same as before, but the $item is passed by reference.
This is the big difference, since we are not editing the $item we want to remove it from the parent array

<?php
$filtered_array = [];
foreach ( $test_array as &$item ) {
    if ( true === $item['include'] ) {
        $filtered_array[] = $item;
    }
}
return $filtered_array;

Immediately delete pass by reference

Again the same and again passed by reference

<?php
foreach ( $test_array as $key => &$item ) {
    if ( true === $item['include'] ) {
        unset( $test_array[ $key ] );
    }
}
return $test_array;

The for loop

And last the for loop I was wondering about

<?php
$length = count( $test_array );
for ( $i = 0; $i < $length; $i ++ ) {
    if ( false === $test_array[ $i ]['include'] ) {
        unset( $test_array[ $i ] );
    }
}
return $test_array;

the results

I ran each of these loops 5000 times and measured the total time that took.
This was to insure the time between results was big enough to exclude the randomness (at least enough)
The test code I ran

Speed of Loops
  1. 5.6122910976414sec Loop: foreach traditional
  2. 6.0467801094055sec Loop: foreach unset key
  3. 7.7878839969635sec Loop: foreach traditional pass by reference
  4. 7.0686309337616sec Loop: foreach unset key pass by reference
  5. 8.6388339996338sec Loop: for

The traditional foreach I’ve been using for years turned out to be the fastest.
Research hours well spend ?

Bonus edit array item

As said before most examples use editing a array.
So I also ran that scenario. Test code
I upped the loops from 5000 runs to 7500 because the difference was so small.
And still it’s close.

  1. 15.363855123523sec Loop: foreach traditional
  2. 10.987272024155sec Loop: foreach foreach edit array directly
  3. 11.358484983444sec Loop: foreach traditional by reference
  4. 14.363346099854sec Loop: for

Here the traditional is the slowest. Reference is a lot faster as most articles claim.
But editing the array directly was the fastest.

WordPress filters and anonymous functions

Anonymous functions have been around for a long time. And since WordPress now supports php 5.6 it can be safely used.
And appears to be allowed?

Personally I’m not a fan of anonymous functions in combination with WordPress actions and filters. My main concern is you can’t remove them once registered. How ever today I found a use case which was very usefull in combination with the use

My example:

<?php
/* Template name: some-template */

// Gather all data
$condition_for_title = true;
$h1_title_override = 'very heavy and complicated check';
// the H1 also needed as the <title>

add_filter( 'pre_get_document_title', function( $title ) use ($h1_title_override, $condition_for_title) {
    if ($condition_for_title) {
        return $h1_title_override;
    }
    return $title;
}, 20, 1 );

get_header();

// start body
?>
    <h1><?php echo $h1_title_override ?>

Here I pass 2 variables h1_title_override and $condition_for_title which are created outside the function. In my case these where quite complicated and heavy checks. Of course I could put those in a function and cache the result. And call that check in the filter function. But still I need to check the current template before doing the function.

More traditional Example:

in functions.php

<?php
function complicated_check() {
    // Gather all data
    $condition_for_title = true;
    $h1_title_override   = 'very heavy and complicated check';

    return [
        'condition_for_title' => $condition_for_title,
        'h1_title_override'   => $h1_title_override,
    ];
}

function title_exception_for_template( $title ) {
    if ( ! is_page_template('clean-template.php')) {
        return $title;
    }

    $template_data = complicated_check();

    if ( $template_data['condition_for_title'] ) {
        return $template_data['h1_title_override'];
    }

    return $title;
}

add_filter( 'pre_get_document_title', 'title_exception_for_template', 20, 1 );

in clean-template.php

<?php
/* Template name: clean-template */
$template_data = complicated_check();

get_header();

// start body
?>
    <h1><?php echo $template_data['h1_title_override'] ?>

Both these approaches do the same thing. But the more traditional way is a lot more code. Although it has cleaner template.
I probably won’t use this much. If the anonymous function was more complicated it will get hard to read.

But for this case I think it was neat that I could use this little feature.

php array; insert new item at specific index

The php function array_splice can be used to insert new items. At specific places.

<?php
$breadcrumbs = [
    'home',
    'year',
    'month',
    'day',
];
$new_crumb = [
    'category'
];
array_splice($breadcrumbs, 1, 0, $new_crumb);

The result is that category is inserted at the second place.

<?php
array (
    0 => 'home',
    1 => 'category',
    2 => 'year',
    3 => 'month',
    4 => 'day',
);

Running php from command line

This is one of those “I know this is possible, but don’t know how”.

php -r '$parts = [ "hello", "world" ]; echo implode( " ", $parts ) . PHP_EOL;' # hello world

Only useful for simple onelines. You’re very likely to be better of putting code in a php file and run that script like:

php ./helloworld.php

Run PHP with WordPress loaded.

Of course your good old friend wp-cli can help.
It can run code with wp fully loaded. So if you add things in the init action or even after the wp_loaded, those plugin/theme functions, posttypes and such are all available.

First off the plain php code execution, with wp eval

wp eval 'var_dump(did_action( "wp_loaded" ));'  # int(1)

Secondly we execute a file with WordPress fully loaded using wp eval-file

wp eval-file ./helloworld.php

Installing PHP7.4 on a Rapsberry Pi

Note: this post call also be used to install php7.0, php7.1, php7.2 or php7.3, just change every reference to 7.x. And skip right to “Actual install php

Default Rasbian still ships with php7.3, not that weird as at time of writing 7.4 is only released for about a month.
We will install the latest php7.4. But because this is not the default we will need to do a few extra tweaks.

Add newer source

We are going to create a new source for php. We do this with the following 3 commands

sudo wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
echo "deb https://packages.sury.org/php/ buster main" | sudo tee /etc/apt/sources.list.d/php.list
sudo apt update

Actual install php

Now we are ready to install php7.4 with all modules we need:

sudo apt install -y php7.4-common php7.4-fpm php7.4-cli php7.4-curl php7.4-json php7.4-mysql php7.4-opcache php7.4-gd php7.4-sqlite3 php7.4-mbstring php7.4-zip php7.4-readline php-pear

When done check it with php -v it should show a php 7.4.0 or higher.
Now we need to add a few fpm things for nginx to work properly.
Create a extra config file sudo nano /etc/php/7.4/fpm/conf.d/90-pi-custom.ini.
And add:

cgi.fix_pathinfo=0

upload_max_filesize=64m
post_max_size=64m
max_execution_time=600

Finally reload php

sudo service php7.4-fpm reload

Now PHP is ready to use

Extra’s

You might want to follow these instructions to install. wp-cli, composer, image compression support in php

PHP interface type hinting

In interfaces you can force the return type

<?php
interface InterfaceTest {
    function GetSingleEntity(): Entity;
    function GetEntitySet() : Entity[];
}

GetEntitySet should return a array containing Entities. But this kind of syntax is not allowed.
You could just change it to only return an array, but the forcing of the class is the most powerful.
The best is to create a wrapper class for the entities, best would be to use an Iterator.