Using Both STORED And DEFLATED Compression Methods With ZipOutputStream In Lucee CFML 5.3.7.47

<cfscript>

	// Zip compression method: STORED or DEFLATED.
	param name="url.method" type="string" default="DEFLATED";

	// To try out the different compression methods, I'm going to download a number of
	// images from the People section on my website and then add them, in turn, to the
	// ZIP output stream.
	imageUrls = [
		"https://bennadel-cdn.com/images/header/photos/irl_2019_old_school_staff.jpg",
		"https://bennadel-cdn.com/images/header/photos/james_murray_connor_murphy_drew_newberry_alvin_mutisya_nick_miller_jack_neil.jpg",
		"https://bennadel-cdn.com/images/header/photos/juan_agustin_moyano_2.jpg",
		"https://bennadel-cdn.com/images/header/photos/jeremiah_lee_2.jpg",
		"https://bennadel-cdn.com/images/header/photos/wissam_abirached.jpg",
		"https://bennadel-cdn.com/images/header/photos/winnie_tong.jpg",
		"https://bennadel-cdn.com/images/header/photos/sean_roberts.jpg",
		"https://bennadel-cdn.com/images/header/photos/scott_markovits.jpg",
		"https://bennadel-cdn.com/images/header/photos/sara_dunnack_3.jpg",
		"https://bennadel-cdn.com/images/header/photos/salvatore_dagostino.jpg",
		"https://bennadel-cdn.com/images/header/photos/robbie_manalo_jessica_thorp.jpg",
		"https://bennadel-cdn.com/images/header/photos/rich_armstrong.jpg"
	];

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	ZipEntryClass = createObject( "java", "java.util.zip.ZipEntry" );

	withTempDirectory(
		( imagesDirectory ) => {

			// Download the images in parallel.
			// --
			// NOTE: How cool is it that the file-IO operations in Lucee CFML will
			// seamlessly work with remote URLs? So bad-ass!
			imageUrls.each(
				( imageUrl ) => {

					fileCopy( imageUrl, "#imagesDirectory#/#getFileFromPath( imageUrl )#" );

				},
				true // Parallel processing, kablamo!
			);

			// Let's keep track of how long the various Zip METHODS take (which will
			// only include the archiving, not the downloading portion, above).
			var startedAt = getTickCount();

			// We'll generate the Zip archive in-memory, rather than writing it to disk.
			var binaryOutputStream = javaNew( "java.io.ByteArrayOutputStream" ).init();
			var zipOutputStream = javaNew( "java.util.zip.ZipOutputStream" )
				.init( binaryOutputStream )
			;

			// Now that we've downloaded the images, let's add each one to the Zip.
			for ( var imageUrl in imageUrls ) {

				var imageFilename = getFileFromPath( imageUrl );
				var imageBinary = fileReadBinary( "#imagesDirectory#/#imageFilename#" );

				var zipEntry = javaNew( "java.util.zip.ZipEntry" )
					.init( "streaming-zip/images/#imageFilename#" )
				;

				// The default method is DEFLATED, which compresses the entry as it adds
				// it to the archive. For some files, this results in wasted CPU; and, in
				// some cases, can even result in larger files (not smaller files). If we
				// just want to include the file in the archive, uncompressed, we can
				// used the STORED method. This will include the file as its raw size.
				// --
				// NOTE: As of Java 8 (where I am running this demo), a STORED file needs
				// to also set the SIZE and CRC of the entry or we get an error.
				if ( url.method == "stored" ) {

					zipEntry.setMethod( ZipEntryClass.STORED );
					zipEntry.setSize( arrayLen( imageBinary ) );
					zipEntry.setCrc( crc32( imageBinary ) );

				}

				zipOutputStream.putNextEntry( zipEntry );
				zipOutputStream.write( imageBinary );
				zipOutputStream.closeEntry();

			}

			// Finalize the Zip content.
			zipOutputStream.close();
			binaryOutputStream.close();

			// NOTE: We're baking the DURATION right into the filename.
			zipFilename = "people-#url.method#-#( getTickCount() - startedAt )#.zip";

			// Setup the response headers. By using the CFContent tag with [variable],
			// we'll implicitly reset the output buffers and use the given binary as the
			// response payload. CFContent will also terminate the request of request
			// processing (with the EXCEPTION of the FINALLY block in the method that
			// setup the temp directory).
			header
				name = "content-disposition"
				value = "attachment; filename=""#zipFilename#""; filename*=UTF-8''#urlEncodedFormat( '#zipFilename#' )#"
			;
			header
				name = "content-length"
				value = binaryOutputStream.size()
			;
			content
				type = "application/zip"
				variable = binaryOutputStream.toByteArray()
			;

		}
	); // END: withTempDirectory().

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	/**
	* I compute the CRC-32 checksum for the byte array.
	*
	* @input I am the input being checked.
	*/
	public numeric function crc32( required binary input ) {

		var checksum = createObject( "java", "java.util.zip.CRC32" ).init();
		checksum.update( input );

		return( checksum.getValue() );
	}


	/**
	* I create a Java class instance with the given class name. This is just a short-hand
	* method for the createObject() call.
	* 
	* @className I am the Java class being created.
	*/
	public any function javaNew( required string className ) {

		return( createObject( "java", className ) );

	}


	/**
	* I create a temp directory for the images and then pass the directory path to the
	* given callback. Any return value from the callback is returned-through to the
	* calling context.
	* 
	* @callback I am the callback to be invoked with the temp directory path.
	*/
	public any function withTempDirectory( required function callback ) {

		var imagesDirectory = expandPath( "./images-#createUniqueId()#" );

		directoryCreate( imagesDirectory );

		try {

			return( callback( imagesDirectory ) );

		} finally {

			directoryDelete( imagesDirectory, true ); // True = recurse.

		}

	}

</cfscript>