WP-CLI Sideload media command class, should work for images that don't have a file extension via Symfony\Component\Mime\MimeTypes

SideLoad.php

<?php
/**
 * SideLoad command class file.
 *
 * @package VendorName\ProjectName\Commands
 */

namespace VendorName\ProjectName\Commands;

use Symfony\Component\Mime\MimeTypes;
use Throwable;
use WP_CLI;

/**
 * SideLoad command class.
 */
class SideLoad {

	/**
	 * Sideload a file to the media library from a URL.
	 *
	 * ## OPTIONS
	 *
	 * <url>
	 * : URL of the file to sideload.
	 *
	 * ## EXAMPLES
	 *
	 *     wp sideload https://www.example.com/api/file/4j7bSv74Q1SvckZ5Xzqk
	 *
	 * @subcommand sideload
	 * @alias  sideload-file
	 *
	 * @since 0.1.0-dev
	 *
	 * @param mixed[] $args       Positional arguments.
	 * @param mixed[] $assoc_args Associative arguments.
	 *
	 * @return void
	 */
	public function sideload( array $args, array $assoc_args ): void {
		list( $url ) = $args;

		$temp_dir = get_temp_dir();

		/**
		 * Downloads a URL to a local temporary file using the WordPress HTTP API.
		 *
		 * Example: $tmpfname = '/var/folders/t4/7dv85j4j0mq9v2t1bzvz9ptr0000gs/T/4j7bSv74Q1SvckZ5Xzqk-IYnY3P.tmp'
		 *
		 * @var string|WP_Error $tmpfname Filename on success, WP_Error on failure.
		 */
		$tmpfname = download_url( $url );

		if ( is_wp_error( $tmpfname ) ) {
			WP_CLI::error( $tmpfname );
		}

		$mime_types = new MimeTypes();

		try {
			/**
			 * Guesses the MIME type of the file with the given path.
			 *
			 * Example: $mime_type = 'image/png'
			 *
			 * @var ?string $mime_type The MIME type on success, else null.
			 */
			$mime_type = $mime_types->guessMimeType( $tmpfname );
		} catch ( Throwable $exception ) {
			unlink( $tmpfname );
			WP_CLI::error(
				$exception
			);
		}

		// @phpstan-ignore-next-line
		if ( null === $mime_type ) {
			unlink( $tmpfname );
			WP_CLI::error(
				sprintf(
					'Unable to determine file format for URL %1$s.',
					$url
				)
			);
		}

		/**
		 * Get the extensions for the given MIME type in decreasing order of preference.
		 *
		 * Example:
		 *     $extensions = [
		 *         0 => 'png',
		 *     ];
		 *
		 * @var string[] $extensions An array of file extensions.
		 * @phpstan-ignore-next-line
		 */
		$extensions = $mime_types->getExtensions( $mime_type );

		if ( empty( $extensions ) ) {
			unlink( $tmpfname );
			WP_CLI::error(
				sprintf(
					'Unable to determine file format for URL %1$s.',
					$url
				)
			);
		}

		$extension = $extensions[0];
		$extension = '.' . $extension;

		$filename = basename( $url );

		if ( 0 !== substr_compare( $filename, $extension, - strlen( $extension ) ) ) {
			$filename .= $extension;
		}

		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
		$bits = file_get_contents( $tmpfname );

		if ( false === $bits ) {
			unlink( $tmpfname );
			WP_CLI::error(
				sprintf(
					'Unable to read file contents for URL %1$s.',
					$url
				)
			);
		}

		/**
		 * Create a file in the upload folder with given content.
		 *
		 * @var array{'file': string, 'url': string, 'type': string, 'error': string|false} $upload Information about the newly-uploaded file.
		 */
		$upload = wp_upload_bits(
			$filename,
			null,
			$bits
		);

		unlink( $tmpfname );

		if ( ! empty( $upload['error'] ) ) {
			WP_CLI::error(
				sprintf(
					'Unable to sideload image for URL %1$s. Error: %2$s.',
					$url,
					$upload['error']
				)
			);
		}

		$filename = basename( $upload['file'] );

		/**
		 * Get the filetype information that WordPress thinks.
		 *
		 * @var array{'ext': string|false, 'type': string|false} $filetype Values for the extension and mime type.
		 */
		$filetype = wp_check_filetype( $filename );

		$attachment = [
			'post_mime_type' => $filetype['type'],
			'post_parent'    => 0,
			'post_title'     => preg_replace( '/\.[^.]+$/', '', $filename ),
			'post_content'   => '',
			'post_status'    => 'inherit',
		];

		$attachment_id = wp_insert_attachment(
			$attachment,
			$upload['file'],
			0,
			true
		);

		if ( is_wp_error( $attachment_id ) ) {
			WP_CLI::error(
				$attachment_id
			);
		}

		require_once ABSPATH . 'wp-admin/includes/image.php';

		$attachment_data = wp_generate_attachment_metadata(
			$attachment_id,
			$upload['file']
		);

		wp_update_attachment_metadata( $attachment_id, $attachment_data );

		WP_CLI::success(
			sprintf(
				'Imported URL %1$s as attachment ID %2$s.',
				$url,
				$attachment_id
			)
		);
	}
}