feat: support font URLs in GPDFAPI::add_pdf_font()

api.php

@@ -647,18 +647,21 @@ public static function get_pdf_fonts() {
 	 *   'font_name'   => 'Lato',
 	 *   'regular'     => '/full/path/to/font/Lato-Regular.ttf',
 	 *   'italics'     => '/full/path/to/font/Lato-Italic.ttf',
-	 *   'bold'        => '/full/path/to/font/Lato-Bold.ttf',
-	 *   'bolditalics' => '/full/path/to/font/Lato-BoldItalic.ttf',
+	 *   'bold'        => 'https://example.com/fonts/Lato-Bold.ttf',
+	 *   'bolditalics' => 'https://example.com/fonts/Lato-BoldItalic.ttf',
 	 * )
 	 *
 	 * Only the 'font_name' and 'regular' keys are required.
-	 * All fonts should be referenced with the full server path.
+	 * Fonts should be referenced with the full server path, or a http(s) URL that is downloaded
+	 * with wp_remote_get(). URLs must point to a .ttf file, resolve to a public address, and the
+	 * response cannot exceed 32MB.
 	 * Currently, only .ttf fonts are supported.
 	 * The font name can only contain alphanumeric characters, or a space
 	 *
 	 * @return bool|WP_Error
 	 *
 	 * @since 4.1
+	 * @since 6.17 Added support for http(s) URLs
 	 */
 	public static function add_pdf_font( $font ) {
 
@@ -683,30 +686,43 @@ public static function add_pdf_font( $font ) {
 		$request = new WP_REST_Request();
 		$request->set_param( 'label', $font['font_name'] ?? '' );
 
-		foreach ( $controller->get_font_keys() as $id ) {
-			if ( isset( $font[ $id ] ) && is_file( $font[ $id ] ) ) {
-				/* phpcs:disable WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents */
-				$_FILES[ $id ] = [
-					'file'     => file_get_contents( $font[ $id ] ),
-					'name'     => basename( $font[ $id ] ),
-					'size'     => filesize( $font[ $id ] ),
-					'tmp_name' => $font[ $id ],
-					'error'    => UPLOAD_ERR_OK,
-				];
+		$downloader = new \GFPDF\Helper\Fonts\RemoteFontDownloader();
+
+		$id   = '';
+		$path = '';
+
+		try {
+			foreach ( $controller->get_font_keys() as $id ) {
+				$path = $font[ $id ] ?? '';
+				if ( ! is_string( $path ) || $path === '' ) {
+					continue;
+				}
+
+				/* Abort on the first bad URL rather than downloading fonts this call is going to discard */
+				if ( \GFPDF\Helper\Fonts\RemoteFontDownloader::is_url( $path ) ) {
+					$_FILES[ $id ] = $downloader->download( $path );
+				} elseif ( is_file( $path ) ) {
+					$_FILES[ $id ] = [
+						'name'     => basename( $path ),
+						'tmp_name' => $path,
+						'error'    => UPLOAD_ERR_OK,
+					];
+				}
 			}
-		}
 
-		// phpcs:ignore WordPress.Security.NonceVerification.Missing -- $_FILES populated above from $font arg, not a form post.
-		$request->set_file_params( $_FILES );
-		$response = $controller->add_item( $request );
+			// phpcs:ignore WordPress.Security.NonceVerification.Missing -- $_FILES populated above from $font arg, not a form post.
+			$request->set_file_params( $_FILES );
+			$response = $controller->add_item( $request );
 
-		$_FILES = $files_backup;
+			return is_wp_error( $response ) ? $response : true;
+		} catch ( \GFPDF\Exceptions\GravityPdfFontDownloadException $e ) {
+			self::get_log_class()->error( $e->getMessage(), [ 'url' => $path ] );
 
-		if ( is_wp_error( $response ) ) {
-			return $response;
+			return new WP_Error( 'font_download_error', [ $id => $e->getMessage() ], [ 'status' => 400 ] );
+		} finally {
+			$_FILES = $files_backup;
+			$downloader->cleanup();
 		}
-
-		return true;
 	}
 
 	/**

src/Exceptions/GravityPdfFontDownloadException.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace GFPDF\Exceptions;
+
+/**
+ * @package     Gravity PDF
+ * @copyright   Copyright (c) 2026, Blue Liquid Designs
+ * @license     http://opensource.org/licenses/gpl-2.0.php GNU Public License
+ */
+
+/* Exit if accessed directly */
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * Class GravityPdfFontDownloadException
+ *
+ * @package GFPDF\Exceptions
+ *
+ * @since   6.17
+ */
+class GravityPdfFontDownloadException extends GravityPdfRuntimeException {
+}

src/Helper/Fonts/RemoteFontDownloader.php

@@ -0,0 +1,166 @@
+<?php
+
+declare( strict_types=1 );
+
+namespace GFPDF\Helper\Fonts;
+
+use GFPDF\Exceptions\GravityPdfFontDownloadException;
+
+/**
+ * @package     Gravity PDF
+ * @copyright   Copyright (c) 2026, Blue Liquid Designs
+ * @license     http://opensource.org/licenses/gpl-2.0.php GNU Public License
+ */
+
+/* Exit if accessed directly */
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * Downloads a remote TTF font to a temporary file on disk so it can be handed to the Custom Fonts controller
+ *
+ * The caller owns the temporary files and must call self::cleanup() once finished with them.
+ *
+ * @since 6.17
+ */
+class RemoteFontDownloader {
+
+	/**
+	 * The maximum size, in bytes, a remote font file is allowed to be. Generous enough for the largest CJK fonts.
+	 *
+	 * @since 6.17
+	 */
+	public const MAX_FILE_SIZE = 33554432; /* 32MB */
+
+	/**
+	 * @var string[] The temporary files created by this instance
+	 * @since 6.17
+	 */
+	protected $temp_files = [];
+
+	/**
+	 * Whether the value looks like a URL (as opposed to a path on the local filesystem)
+	 *
+	 * Any value with a scheme is treated as a URL so unsupported schemes (ftp://, file://, php://)
+	 * are rejected by self::download() instead of falling through to the local filesystem handling.
+	 *
+	 * @since 6.17
+	 */
+	public static function is_url( string $value ): bool {
+		return (bool) preg_match( '#^[a-z][a-z0-9+.\-]*://#i', $value );
+	}
+
+	/**
+	 * Download a remote TTF font to a temporary file
+	 *
+	 * @return array A synthetic $_FILES entry for the downloaded font
+	 *
+	 * @throws GravityPdfFontDownloadException
+	 *
+	 * @since 6.17
+	 */
+	public function download( string $url ): array {
+		$scheme = strtolower( (string) wp_parse_url( $url, PHP_URL_SCHEME ) );
+		if ( ! in_array( $scheme, [ 'http', 'https' ], true ) ) {
+			throw new GravityPdfFontDownloadException( esc_html__( 'Only http:// and https:// font URLs are supported.', 'gravity-pdf' ) );
+		}
+
+		/* Blocks credentials in the URL, non-standard ports, and hosts that resolve to a private/loopback IP */
+		if ( wp_http_validate_url( $url ) === false ) {
+			throw new GravityPdfFontDownloadException( esc_html__( 'The font URL is not valid, or resolves to a restricted address.', 'gravity-pdf' ) );
+		}
+
+		$filename = $this->get_filename_from_url( $url );
+
+		if ( ! function_exists( 'wp_tempnam' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/file.php';
+		}
+
+		$tmp_name           = wp_tempnam( $filename );
+		$this->temp_files[] = $tmp_name;
+
+		$response = wp_remote_get(
+			$url,
+			[
+				'timeout'             => 30,
+				/* Each redirect target is revalidated against reject_unsafe_urls by WP_Http */
+				'redirection'         => 3,
+				'reject_unsafe_urls'  => true,
+				'limit_response_size' => static::MAX_FILE_SIZE + 1,
+				'stream'              => true,
+				'filename'            => $tmp_name,
+			]
+		);
+
+		if ( is_wp_error( $response ) ) {
+			/* translators: %s: the HTTP error message */
+			throw new GravityPdfFontDownloadException( sprintf( esc_html__( 'Could not download the font: %s', 'gravity-pdf' ), esc_html( $response->get_error_message() ) ) );
+		}
+
+		$status = (int) wp_remote_retrieve_response_code( $response );
+		if ( $status !== 200 ) {
+			/* translators: %d: the HTTP status code returned by the remote server */
+			throw new GravityPdfFontDownloadException( sprintf( esc_html__( 'Could not download the font. The server responded with a %d status code.', 'gravity-pdf' ), esc_html( (string) $status ) ) );
+		}
+
+		clearstatcache( true, $tmp_name );
+		$size = (int) @filesize( $tmp_name ); /* phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged */
+
+		if ( $size === 0 ) {
+			throw new GravityPdfFontDownloadException( esc_html__( 'The downloaded font file is empty.', 'gravity-pdf' ) );
+		}
+
+		/* The response is capped at MAX_FILE_SIZE + 1 bytes, so anything larger is either oversized or truncated */
+		if ( $size > static::MAX_FILE_SIZE ) {
+			throw new GravityPdfFontDownloadException(
+				sprintf(
+					/* translators: %s: the maximum font file size e.g. 32 MB */
+					esc_html__( 'The font file exceeds the maximum size of %s.', 'gravity-pdf' ),
+					esc_html( (string) size_format( static::MAX_FILE_SIZE ) )
+				)
+			);
+		}
+
+		return [
+			'name'     => $filename,
+			'tmp_name' => $tmp_name,
+			'error'    => UPLOAD_ERR_OK,
+		];
+	}
+
+	/**
+	 * Delete any temporary files created by this instance
+	 *
+	 * @since 6.17
+	 */
+	public function cleanup(): void {
+		foreach ( $this->temp_files as $file ) {
+			if ( is_file( $file ) ) {
+				wp_delete_file( $file );
+			}
+		}
+
+		$this->temp_files = [];
+	}
+
+	/**
+	 * Derive a safe .ttf filename from the URL path
+	 *
+	 * @throws GravityPdfFontDownloadException
+	 *
+	 * @since 6.17
+	 */
+	protected function get_filename_from_url( string $url ): string {
+		$path = rawurldecode( (string) wp_parse_url( $url, PHP_URL_PATH ) );
+
+		/* basename() before sanitizing so any traversal segments in the decoded path are discarded */
+		$filename = sanitize_file_name( basename( $path ) );
+
+		if ( strtolower( (string) pathinfo( $filename, PATHINFO_EXTENSION ) ) !== 'ttf' ) {
+			throw new GravityPdfFontDownloadException( esc_html__( 'The font URL must point to a .ttf file.', 'gravity-pdf' ) );
+		}
+
+		return $filename;
+	}
+}