View List of Contents in ZIP and TAR Archives using Java

We are excited to bring a major release of GroupDocs.Viewer for Java API packaging a bunch of new features, improvements, and bug fixes. In the latest release, we have added the support of viewing archives and a couple of code files as well as provided the features of working with security settings in the PDF documents. So let’s walk through the latest release of our document viewer API for Java and check out what you are going to get after upgrading to v19.11.

View ZIP and TAR Archives

The first and foremost feature of v19.11 is viewing the list of files and folders in the ZIP and TAR archives. This feature is quite handy when you want to view the list of the contents without extracting the archives.

ZIP file is used to encase multiple files or folders as a single package that is further compressed to reduce the file size. Similarly, TAR is a Unix File Archive format used to archive the files and folders. In general, both ZIP and TAR are categorized as compression file formats.

In the following sections, you will see how to view a list of contents from the ZIP or TAR archives without extracting.

View List of Contents in ZIP or TAR Archives

When rendering an archive file as HTML, GroupDocs.Viewer returns an HTML page containing the list of items that are at the root of the archive. In the case of rendering as image or PDF, the API returns one or more pages depending on the number of items. The following code sample demonstrates this feature.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create HTML or image handler
	ViewerImageHandler imageHandler = new ViewerImageHandler(config);
	String guid = "archive.zip";

	// Render document into image
	List<PageImage> pages = imageHandler.getPages(guid);
	for (PageImage page : pages)
	{
	// use page.getStream() to work with rendering result
	}

view raw ViewZIPAndTARArchive.java hosted with ❤ by GitHub

View List of Folders from ZIP or TAR

ZIP or TAR archives may contain multiple files and folders. These folders may further contain files as well as subfolders. GroupDocs.Viewer also allows viewing the folders that are located at the root of the archive. The following code sample shows how to get a list of folders from a ZIP or TAR archive.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create HTML or image handler
	ViewerHtmlHandler htmlHandler = new ViewerHtmlHandler(config);
	String guid = "archive.zip";

	// Get archive document info
	ArchiveDocumentInfoContainer documentInfoContainer = (ArchiveDocumentInfoContainer) htmlHandler.getDocumentInfo(guid);

	for (String folderName : documentInfoContainer.getFolders())
	{
	System.out.println("Folder name: " + folderName);
	}

view raw GetListOfFoldersInArchive.java hosted with ❤ by GitHub

View List of Subfolders within a Certain Folder of ZIP or TAR

There might be the case when you need to obtain the list of subfolders within a root folder in the ZIP or TAR archive. For such a case, you can specify the folder name using ArchiveOptions.setFolderName(“FolderName”) and the API will return the list of subfolders.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create HTML or image handler
	ViewerHtmlHandler htmlHandler = new ViewerHtmlHandler(config);
	String guid = "archive.zip";

	// set option to retrieve list of folders from certain folder.
	DocumentInfoOptions options = new DocumentInfoOptions();
	options.getArchiveOptions().setFolderName("FirstLevelFolder/SecondLevelFolder");
	// Get archive document info
	ArchiveDocumentInfoContainer documentInfoContainer = (ArchiveDocumentInfoContainer) htmlHandler.getDocumentInfo(guid, options);

	for (String folderName : documentInfoContainer.getFolders())
	{
	System.out.println("Folder name: " + folderName);
	}

view raw GetListOfSubFoldersInRootFolder.java hosted with ❤ by GitHub

View List of Files within a Folder in ZIP or TAR

Now, once you have got the list of folders (and the subfolders as well), you can extract and view the items from your desired folder. The following code sample shows how to view the items of a specific folder in a ZIP or TAR.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create HTML or image handler
	ViewerImageHandler imageHandler = new ViewerImageHandler(config);
	String guid = "archive.zip";

	// Set option to retrieve list of folders from certain folder.
	ImageOptions options = new ImageOptions();
	options.getArchiveOptions().setFolderName("FirstLevelFolder1");

	// Render document into image
	List<PageImage> pages = imageHandler.getPages(guid, options);
	for (PageImage page : pages)
	{
	// use page.getStream() to work with rendering result
	}

view raw RenderSpecifiedFolderInArchive.java hosted with ❤ by GitHub

For more details on rendering archives, please visit working with archives.

Working with Security Settings in PDF Documents

The PDF documents allow setting security parameters to restrict unauthorized access. The security can be enabled using:

Owner password – The password which is required to change document permissions.
User password – The password required to open the document.
PDF file permissions – The permissions to allow or deny printing, modification and data extraction.

In the latest release, we have added the feature of setting the above-mentioned security settings when rendering a file into a PDF document. The following code sample shows how to set the owner password, user password, and the permissions to deny the printing.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create image handler
	ViewerImageHandler imageHandler = new ViewerImageHandler(config);

	// Create PDF file security
	String ownerPassword = "owner password";
	String userPassword = "user password";
	int denyPrinting = PdfFilePermissions.ALL ^ PdfFilePermissions.PRINTING;
	PdfFileSecurity pdfFileSecurity = new PdfFileSecurity(ownerPassword, userPassword, denyPrinting);

	// Create options
	PdfFileOptions pdfFileOptions = new PdfFileOptions();
	pdfFileOptions.setPdfFileSecurity(pdfFileSecurity);

	String guid = "document.doc";
	FileContainer fileContainer = imageHandler.getPdfFile(guid, pdfFileOptions);

view raw RenderIntoPDFWithSecuritySettings.java hosted with ❤ by GitHub

Detecting Security Settings in PDF Document

You can also check the security settings that are applied to a particular PDF document. For example, you can check if printing of the document is allowed or not as shown in the following code sample.

	// Setup GroupDocs.Viewer config
	ViewerConfig config = new ViewerConfig();
	config.setStoragePath("c:\\storage");

	// Create image handler
	ViewerImageHandler imageHandler = new ViewerImageHandler(config);

	// Retrieve document information
	String guid = "document.pdf";
	PdfDocumentInfoContainer documentInfo = (PdfDocumentInfoContainer) imageHandler.getDocumentInfo(guid);

	boolean printingAllowed = documentInfo.getPrintingAllowed();

view raw CheckPrintRestrictionsInPDF.java hosted with ❤ by GitHub

Support for Viewing Code Files

In addition to the support of ZIP and TAR files, we have also added the feature of viewing C# (.cs) and Visual Basic (.vb) code files.

Bug Fixes

The following is the list of bugs that are fixed in v19.11.

Output extension is empty when saving HTML page into cache
Object null reference exception when rendering DWG document
The Watermark opacity is set twice when rendering as HTML
The separator is wrong for the opacity value
File is corrupted or damaged exception for presentation documents
Unable to render .xls file with exception “file is corrupted or damaged”

Improvement

We have made the following improvements in v19.11.

Improved performance for rendering PSD image format into PDF
Improved rendering Dicom, Dng and WebP formats into PDF
Extended support for CellsOptions.setTextOverflowMode option for rendering the document into image
Extended support for CellsOptions.setTextOverflowMode option for rendering into PDF
Rendering contact photo from vCard file format (VCF)
Improve output for rendering zip archives

Well, this was a brief overview of the major features as well as improvements and bug fixes. You can also visit the release notes of GroupDocs.Viewer for Java 19.11 to know about the public API changes. Visit the documentation of GroupDocs.Viewer for Java for more details and code samples of every feature. You can download/clone the source code examples from the GitHub repository.

In case you find any issue while using our API, we are always available to provide you free support on our forum.

View Contents of ZIP and TAR Archives using GroupDocs.Viewer for Java 19.11