Support extracting dimensions for single URLs

includes/utils/class-amp-image-dimension-extractor.php

@@ -5,13 +5,27 @@ class AMP_Image_Dimension_Extractor {
 	const STATUS_FAILED_LAST_ATTEMPT = 'failed';
 	const STATUS_IMAGE_EXTRACTION_FAILED = 'failed';
 
-	static public function extract( $urls ) {
+	/**
+	 * Extract dimensions from image URLs.
+	 *
+	 * @since 0.2
+	 *
+	 * @param array|string $urls Array of URLs to extract dimensions from, or a single URL string.
+	 * @return array|string Extracted dimensions keyed by original URL, or else the single set of dimensions if one URL string is passed.
+	 */
+	public static function extract( $urls ) {
 		if ( ! self::$callbacks_registered ) {
 			self::register_callbacks();
 		}
 
 		$return_dimensions = array();
 
+		// Back-compat for users calling this method directly.
+		$is_single = is_string( $urls );
+		if ( $is_single ) {
+			$urls = array( $urls );
+		}
+
 		// Normalize URLs and also track a map of normalized-to-original as we'll need it to reformat things when returning the data.
 		$url_map = array();
 		$normalized_urls = array();
@@ -22,6 +36,7 @@ static public function extract( $urls ) {
 				$normalized_urls[] = $normalized_url;
 			} else {
 				// This is not a URL we can extract dimensions from, so default to false.
+				$url_map[ $original_url ]           = $original_url;
 				$return_dimensions[ $original_url ] = false;
 			}
 		}
@@ -35,6 +50,11 @@ static public function extract( $urls ) {
 			$return_dimensions[ $original_url ] = $dimension;
 		}
 
+		// Back-compat: just return the dimensions, not the full mapped array.
+		if ( $is_single ) {
+			return current( $return_dimensions );
+		}
+
 		return $return_dimensions;
 	}
 

tests/test-amp-image-dimension-extractor.php

@@ -36,6 +36,35 @@ public function disable_downloads() {
 		remove_all_filters( 'amp_extract_image_dimensions_batch' );
 	}
 
+	/**
+	 * Test single url returns expected dimensions.
+	 *
+	 * @covers \AMP_Image_Dimension_Extractor::extract()
+	 */
+	public function test__single_url() {
+		add_action(
+			'amp_extract_image_dimensions_batch_callbacks_registered',
+			function() {
+				add_filter( 'amp_extract_image_dimensions_batch', function() {
+					return array(
+						'https://example.com/image.png' => array(
+							100,
+							101,
+						),
+					);
+				} );
+			},
+			9999 // Run after the `disable_downloads`.
+		);
+
+		$source_url = 'https://example.com/image.png';
+		$expected   = array( 100, 101 );
+
+		$actual = AMP_Image_Dimension_Extractor::extract( $source_url );
+
+		$this->assertEquals( $expected, $actual );
+	}
+
 	/**
 	 * Test where processed URLs should match originals.
 	 */