Asset::getContents() + support assets from the svg() Twig function

resolves #2838

CHANGELOG-v3.md

@@ -2,10 +2,14 @@
 
 ## Unreleased
 
+### Added
+- Added `craft\elements\Asset::getContents()`.
+
 ### Changed
 - Edit User pages will now warn editors when leaving the page with unsaved changes. ([#2832](https://github.com/craftcms/cms/issues/2832))
 - Modules are once again loaded before plugins, so they have a chance to register Twig initialization events before a plugin initializes Twig. ([#2831](https://github.com/craftcms/cms/issues/2831))
 - `craft\helpers\FileHelper::isSvg()` now returns `true` for files with an `image/svg` MIME type (missing the `+xml`). ([#2837](https://github.com/craftcms/cms/pull/2837))
+- The `svg()` Twig function now accepts assets to be passed directly into it. ([#2838](https://github.com/craftcms/cms/pull/2838))
 
 ### Fixed
 - Fixed an error that could occur in the Plugin Store.

src/elements/Asset.php

@@ -22,6 +22,7 @@
 use craft\elements\actions\ReplaceFile;
 use craft\elements\db\AssetQuery;
 use craft\elements\db\ElementQueryInterface;
+use craft\errors\AssetException;
 use craft\errors\AssetTransformException;
 use craft\errors\FileException;
 use craft\errors\VolumeObjectNotFoundException;
@@ -893,15 +894,29 @@ public function getCopyOfFile(): string
     }
 
     /**
-     * Get a stream of the actual file.
+     * Returns a stream of the actual file.
      *
      * @return resource
+     * @throws InvalidConfigException if [[volumeId]] is missing or invalid
+     * @throws AssetException if a stream could not be created
      */
     public function getStream()
     {
         return $this->getVolume()->getFileStream($this->getPath());
     }
 
+    /**
+     * Returns the file’s contents.
+     *
+     * @return string
+     * @throws InvalidConfigException if [[volumeId]] is missing or invalid
+     * @throws AssetException if a stream could not be created
+     */
+    public function getContents(): string
+    {
+        return stream_get_contents($this->getStream());
+    }
+
     /**
      * Return whether the Asset has a URL.
      *

src/web/twig/Extension.php

@@ -9,6 +9,7 @@
 
 use Craft;
 use craft\base\MissingComponentInterface;
+use craft\elements\Asset;
 use craft\elements\db\ElementQuery;
 use craft\helpers\ArrayHelper;
 use craft\helpers\DateTimeHelper;
@@ -806,16 +807,25 @@ public function shuffleFunction($arr)
     /**
      * Returns the (sanitized) contents of a given SVG file, namespacing any of its IDs in the process.
      *
-     * @param string $svg The SVG file path or contents
+     * @param string|Asset $svg An SVG asset, a file path, or XML data
      * @param bool $sanitize Whether the file should be sanitized first
      * @return \Twig_Markup|string
      */
-    public function svgFunction(string $svg, bool $sanitize = true)
+    public function svgFunction($svg, bool $sanitize = true)
     {
-        // If we can't find an <svg> tag, it's probably a file path
-        if (stripos($svg, '<svg') === false) {
+        if ($svg instanceof Asset) {
+            try {
+                $svg = $svg->getContents();
+            } catch (\Throwable $e) {
+                Craft::error("Could not get the contents of {$svg->getPath()}: {$e->getMessage()}", __METHOD__);
+                Craft::$app->getErrorHandler()->logException($e);
+                return '';
+            }
+        } else if (stripos($svg, '<svg') === false) {
+            // No <svg> tag, so it's probably a file path
             $svg = Craft::getAlias($svg);
             if (!is_file($svg) || !FileHelper::isSvg($svg)) {
+                Craft::warning("Could not get the contents of {$svg}: The file doesn't exist", __METHOD__);
                 return '';
             }
             $svg = file_get_contents($svg);