CLI PHP script to merge a (large) number of SVG files into 1 svg sprite

svg2sprite.php

<?php
/**
 * Created by PhpStorm.
 * User: maartenvandervelde
 * Date: 16/01/17
 * Time: 08:23
 */

/*
 * First, optionally, use SVGO to compress all SVG's:
 *
 *
 * BASH: *
 * for f in ../sprite/*.svg; do svgo  --input="$f"  --enable=removeStyleElement --enable=transformsWithOnePath  --enable=mergePath --pretty; done
 *
 */

// File content
$sprite = [];

// Get source
$dir = "";
if (isset($argv) && isset($argv[1])){
  $dir = $argv[1];
}

// Get destination
$dest = "svgmap.svg";
if (isset($argv) && isset($argv[2])){
  $dest= $argv[2];
}

// Start filling the file array
$sprite[] = '<svg xmlns="http://www.w3.org/2000/svg">';


foreach (glob("$dir*.svg") as $filename) {
  // Read SVG as XML object
  $xml = simplexml_load_file($filename);

  // Get and calculate attributes
  $viewBox = $xml->attributes()['viewBox'];
  $id = basename($filename,".svg");
  $id_seo = seoUrl($id);

  // Write out symbol and content of the SVG-tag
  $sprite[] = "<symbol id='$id_seo' viewBox='$viewBox'>";
  $sprite[] = "<title>$id_seo</title>";

  foreach($xml as $element){
    $sprite[] = $element->asXML();
  }

  $sprite[] = "</symbol>";
}

// Close SVG tag
$sprite[] = '</svg>';

// Write the array to a file
file_put_contents($dest, implode($sprite));


// From: http://stackoverflow.com/a/11330527/3010027
function seoUrl($string) {
  //Lower case everything
  $string = strtolower($string);
  //Make alphanumeric (removes all other characters)
  $string = preg_replace("/[^a-z0-9_\s-]/", "", $string);
  //Clean up multiple dashes or whitespaces
  $string = preg_replace("/[\s-]+/", " ", $string);
  //Convert whitespaces and underscore to dash
  $string = preg_replace("/[\s_]/", "-", $string);
  return $string;
}