Improves argument handling and script loading

README.md

@@ -5,8 +5,6 @@ A [WordPress plugin](https://wordpress.org/plugins) that renders [OpenFreeMap](h
 ## Installation
 1. Upload the plugin to your `/wp-plugins/` directory
 2. Activate the plugin through the 'Plugins' menu in WordPress
-3. Go to "Settings > OpenFreemap" to configure the plugin
-
 
 ## Basic Usage
 Once activated you can render [OpenFreeMap](https://openfreemap.org) map widgets using the shortcode
@@ -21,9 +19,13 @@ The options are as follows
 - `zoom`  
    Initial zoom of the map (default: `16.5`)
 - `color`  
-   Marker color in CSS notation (default: `#ff0000`)
+   Marker color in hex notation, e.g. `#ff0000` (default: `#ff0000`)
 - `height`  
    Height of the map widget in CSS notation (default: `450px`)
+- `popup_text`  
+   HTML content shown in a popup attached to the marker (default: none)
+- `style`  
+   Map style, one of `bright`, `dark`, `fiord`, `liberty`, `positron` (default: `bright`)
 
 ## Links
 - https://openfreemap.org

assets/loader.js

@@ -0,0 +1,18 @@
+var openfreemapModuleUrl;
+var openfreemapStyleUrl;
+
+if (document.querySelector('.openfreemap') && typeof openfreemapModuleUrl === 'string') {
+  if (typeof openfreemapStyleUrl === 'string') {
+    var link = document.createElement('link');
+    link.rel = 'stylesheet';
+    link.href = openfreemapStyleUrl;
+    link.onerror = function () {
+      console.error('[OpenFreeMap] Failed to load the map stylesheet.');
+    };
+    document.head.appendChild(link);
+  }
+
+  import(openfreemapModuleUrl).catch(function (error) {
+    console.error('[OpenFreeMap] Failed to load the map library.', error);
+  });
+}

assets/openfreemap.js

@@ -1,23 +1,45 @@
 import * as maplibregl from '../vendor/maplibre-gl/maplibre-gl.mjs';
 
+const NO_WEBGL_MESSAGE =
+  'The map could not be displayed. Please enable WebGL or use a different browser.';
+
+function readNumber(value, fallback) {
+  const parsed = parseFloat(value);
+  return Number.isFinite(parsed) ? parsed : fallback;
+}
+
 document.querySelectorAll('.openfreemap').forEach((container) => {
   const center = [
-    parseFloat(container.dataset.lon),
+    readNumber(container.dataset.lon, 12.3453356),
-    parseFloat(container.dataset.lat)
+    readNumber(container.dataset.lat, 47.1092664)
   ];
-  const zoom = parseFloat(container.dataset.zoom);
+  const zoom = readNumber(container.dataset.zoom, 16.5);
-  const map = new maplibregl.Map({
+  const popupText = container.dataset.popup;
-    style: container.dataset.style,
+
-    center: center,
+  let map;
-    zoom: zoom,
+  try {
-    container: container
+    map = new maplibregl.Map({
+      style: container.dataset.style,
+      center: center,
+      zoom: zoom,
+      container: container
+    });
+  } catch (error) {
+    // MapLibre throws when WebGL is unavailable, leaving an empty box behind.
+    console.error('[OpenFreeMap] Could not initialise the map.', error);
+    container.textContent = NO_WEBGL_MESSAGE;
+    return;
+  }
+
+  map.on('error', (event) => {
+    console.warn('[OpenFreeMap]', event.error);
   });
+
   const marker = new maplibregl.Marker({
     color: container.dataset.color
   })
     .setLngLat(center)
     .addTo(map);
-  const popupText = container.dataset.popup;
   if (popupText) {
     const popup = new maplibregl.Popup({
       closeOnClick: false
@@ -27,4 +49,3 @@ document.querySelectorAll('.openfreemap').forEach((container) => {
   }
   map.addControl(new maplibregl.NavigationControl());
 });
-

openfreemap.php

@@ -2,9 +2,13 @@
 /*
 Plugin Name: OpenFreeMap
 Description: Add an OpenFreeMap widget via shortcode [openfreemap]
-Version:     0.2.0
+Version:     0.3.0
 Author:      Erwin Nindl
 Author URI:  https://nindl.net
+License:     MIT
+Requires at least: 5.9
+Requires PHP: 7.4
+Text Domain: openfreemap
 */
 
 if (!defined('ABSPATH'))
@@ -12,6 +16,79 @@ if (!defined('ABSPATH'))
   exit; // Exit if accessed directly
 }
 
+
+// Clamp a numeric shortcode attribute, falling back to $default when it is not a number
+function openfreemap_clamp_float($value, $default, $min, $max)
+{
+  if (!is_numeric($value)) {
+    return $default;
+  }
+  return max($min, min($max, (float) $value));
+}
+
+
+// Allow only plain CSS lengths so the value can be interpolated into a style attribute
+function openfreemap_sanitize_css_length($value, $default)
+{
+  $value = trim((string) $value);
+  if (preg_match('/^\d+(?:\.\d+)?(?:px|pt|em|rem|ch|%|vh|vw|vmin|vmax)$/i', $value)) {
+    return $value;
+  }
+  return $default;
+}
+
+
+// Read the release version from the plugin header, keeping the header authoritative
+function openfreemap_plugin_version()
+{
+  static $version = null;
+  if (null === $version) {
+    $header = get_file_data(__FILE__, array('Version' => 'Version'), 'plugin');
+    $version = isset($header['Version']) && $header['Version'] ? $header['Version'] : null;
+  }
+  return $version;
+}
+
+
+// Append a cache busting query argument to a bundled asset URL. Every bundled
+// asset (vendored or not) shares the plugin's Version header, so bumping that
+// header on release is what invalidates caches -- including for vendored
+// files (e.g. a new MapLibre or OpenFreeMap style release) that don't carry
+// their own version number.
+function openfreemap_versioned_url($relative_path)
+{
+  $url = plugin_dir_url(__FILE__) . $relative_path;
+  $version = openfreemap_plugin_version();
+  return $version ? add_query_arg('ver', $version, $url) : $url;
+}
+
+
+// URL of a bundled OpenFreeMap style, versioned like every other shipped asset
+function openfreemap_style_url($style)
+{
+  return openfreemap_versioned_url('vendor/openfreemap/styles/' . sanitize_key($style));
+}
+
+
+// Styles bundled under vendor/openfreemap/styles/. Kept as an explicit allow-list
+// so the shortcode can't be used to probe for arbitrary files on disk.
+function openfreemap_available_styles()
+{
+  return array('bright', 'dark', 'fiord', 'liberty', 'positron');
+}
+
+
+// Restrict the shortcode's style attribute to a known, bundled style
+function openfreemap_sanitize_style($value, $default)
+{
+  $value = sanitize_key($value);
+  if (in_array($value, openfreemap_available_styles(), true)) {
+    return $value;
+  }
+  return $default;
+}
+
+
 // Register the shortcode
 function openfreemap_handler($atts)
 {
@@ -21,16 +98,19 @@ function openfreemap_handler($atts)
     'popup_text' => '',
     'color'      => '#ff0000',
     'height'     => '450px',
-    'zoom'       => '16.5'
+    'zoom'       => '16.5',
+    'style'      => 'bright'
   ), $atts, 'openfreemap');
-  $lat = is_numeric($atts['lat']) ? (float) $atts['lat'] : 47.1092664;
+  $lat = openfreemap_clamp_float($atts['lat'], 47.1092664, -90, 90);
-  $lon = is_numeric($atts['lon']) ? (float) $atts['lon'] : 12.3453356;
+  $lon = openfreemap_clamp_float($atts['lon'], 12.3453356, -180, 180);
-  $zoom = is_numeric($atts['zoom']) ? (float) $atts['zoom'] : 16.5;
+  $zoom = openfreemap_clamp_float($atts['zoom'], 16.5, 0, 22);
   $color = sanitize_hex_color($atts['color']);
   if (!$color) {
     $color = '#ff0000';
   }
-  $height = sanitize_text_field($atts['height']);
+  $height = openfreemap_sanitize_css_length($atts['height'], '450px');
+  $popup_text = wp_kses_post($atts['popup_text']);
+  $style = openfreemap_sanitize_style($atts['style'], 'bright');
   $map_id = wp_unique_id('openfreemap-');
 
   ob_start();
@@ -43,8 +123,8 @@ function openfreemap_handler($atts)
         data-lon="<?php echo esc_attr($lon); ?>"
         data-zoom="<?php echo esc_attr($zoom); ?>"
         data-color="<?php echo esc_attr($color); ?>"
-        data-popup="<?php echo esc_attr($atts['popup_text']); ?>"
+        data-popup="<?php echo esc_attr($popup_text); ?>"
-        data-style="<?php echo esc_url(plugin_dir_url(__FILE__) . 'vendor/openfreemap/styles/bright'); ?>"
+        data-style="<?php echo esc_url(openfreemap_style_url($style)); ?>"
     ></div>
 <?php
 
@@ -53,45 +133,52 @@ function openfreemap_handler($atts)
 add_shortcode('openfreemap', 'openfreemap_handler');
 
 
-// Detect shortcode presence in post content
+// Enqueue the map stylesheet and a small loader
-function openfreemap_detect_shortcode($posts)
+function openfreemap_enqueue_assets()
 {
-  if (empty($posts) || !is_array($posts)) {
+  static $enqueued = false;
-    return $posts;
+  if ($enqueued) {
+    return;
   }
-  foreach ($posts as $post) {
+
-    if (has_shortcode($post->post_content, 'openfreemap')) {
+  // Skip entirely on singular posts/pages that have neither the shortcode
-      add_action('wp_enqueue_scripts', 'openfreemap_enqueue_shortcode_assets');
+  // in their content nor a shortcode block. Widgets, template parts, and
-      break; // Only need to enqueue once
+  // secondary loops aren't covered by this check, so it's a partial
+  // optimization, not a guarantee.
+  if (is_singular()) {
+    $post = get_post();
+    if ($post && !has_shortcode($post->post_content, 'openfreemap') && !has_block('core/shortcode', $post)) {
+      return;
     }
   }
-  return $posts;
-}
-add_filter('the_posts', 'openfreemap_detect_shortcode');
 
+  $enqueued = true;
 
-// Enqueue scripts and styles only if shortcode is used
+  // The loader is a classic script: it conditionally dynamic-imports the ES
-function openfreemap_enqueue_shortcode_assets()
+  // module below and injects the stylesheet, so both the ~1 MB of MapLibre JS
-{
+  // and its CSS are only fetched on pages that actually render a map.
-  $plugin_url = plugin_dir_url(__FILE__);
+  // Detection happens in the DOM rather than in post content, which also
-  wp_enqueue_style(
+  // covers widgets, blocks, template parts and secondary loops. The
-    'openfreemap-style',
+  // is_singular() check above is just a cheap best-effort early exit that
-    $plugin_url . 'vendor/maplibre-gl/maplibre-gl.css'
+  // skips even the tiny loader request on obviously map-free singular pages;
-  );
+  // it is not relied on for correctness.
-  $load_in_footer = false;
   wp_enqueue_script(
-    'openfreemap-script',
+    'openfreemap-loader',
-    $plugin_url . 'assets/openfreemap.js',
+    plugin_dir_url(__FILE__) . 'assets/loader.js',
     array(),
-    null,
+    openfreemap_plugin_version(),
-    $load_in_footer
+    true
   );
-  add_filter('script_loader_tag', function ($tag, $handle, $src) {
-    if ($handle === 'openfreemap-script') {
-      return '<script type="module" src="' . esc_url($src) . '"></script>';
-    }
-    return $tag;
-  }, 10, 3);
-}
-add_action('wp_enqueue_scripts', 'openfreemap_enqueue_shortcode_assets');
 
+  $module_url = openfreemap_versioned_url('assets/openfreemap.js');
+  $style_href = openfreemap_versioned_url('vendor/maplibre-gl/maplibre-gl.css');
+
+  // JSON_HEX_TAG keeps the values from terminating the inline script early.
+  wp_add_inline_script(
+    'openfreemap-loader',
+    'var openfreemapModuleUrl = ' . wp_json_encode($module_url, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES) . ';' .
+    'var openfreemapStyleUrl = ' . wp_json_encode($style_href, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES) . ';',
+    'before'
+  );
+}
+add_action('wp_enqueue_scripts', 'openfreemap_enqueue_assets');