Howto use our WebDAV Storages

1. Introduction: WebDAV

WebDAV (Web Distributed Authoring and Versioning) is an extension to the HTTP Protocol and allows users to collaboratively edit documents directly on a web server. We use the provided WebDAV storages for storing data files from within applications. More information about WebDAV can be found here.

2. Introduction: the two WebDAV Storages Clipboard and OpStore

For persisting files that can be easily accessed and modified by everyone, two WebDAV storages are provided by the Controls Infrastructure Group: the temporary "WebDAV Clipboard" and the permanent "WebDAV OpStore". It is recommended to discuss usage scenarios with APP to decide, which of them fits best to the use case. Roughly the usage scenarios are as follows:
  • Clipboard: should be used in most cases, will be wiped e.g. after a beamtime
  • OpStore: used in specific cases in agreement with Operations, used e.g. for long-term storage of measurement data

3. How to access WebDAV storages with standard Tools

3.1 Access to WebDAV from Linux

On the development cluster asl75x, you can easily use the file manager thunar (available from the menu: Applications -> File Manager). To navigate to a WebDAV directory, just copy one of the following lines to the address bar: 

        davs://clipboard.acc.gsi.de/dav/
        davs://websvcpro.acc.gsi.de/public/opstore/

Once you open a WebDAV location in thunar, you see on the left side under "Network" and can easily bookmark / create a shortcut for both WebDAVs.

3.2 Access to WebDAV from Windows

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3.3 Read-only access to WebDAV from everywhere

The simplest way of just viewing the contents of your WebDAV folder is just by using a Browser, e.g. Firefox. To access a WebDAV link, the URLs shown in 3.1. need to be modified to start with https:// instead of davs: E.g. type the following adress into your browser's navigation bar: 

        https://clipboard.acc.gsi.de/dav

4. How to use the WebDAV storages programmatically

4.1 Programmatic upload and download of a file

Simple up- and download

The simplest way of creating a folder and uploading and downloading a file looks as follows: 

        String testfolder = WebDavHelper.WebDavStorageLocation.OPSTORE.getPath() + "test/";
        String filename = "testfile" + System.currentTimeMillis() + ".txt";

        // create folder
        System.out.println("*** Creating folder " + testfolder);
        final ResourceItem folder = ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, testfolder);
        System.out.println("Creating folder successful? " + ResourceItemUtils.exists(folder) + "\n");

        // create file
        System.out.println("*** Creating file " + filename);
        ResourceItem file = ResourceItemUtils.createFile(folder, filename);
        System.out.println("Creating file successful? " + ResourceItemUtils.exists(file) + "\n");

        System.out.println("*** Writing to file " + filename);
        ResourceItemUtils.writeLinesToFile(file, List.of("Hello", "World"));
        System.out.println("Writing to file successful? " + ((ResourceItemUtils.getSize(file) > 0) ? "y" : "n") + "\n");

        // try to read the file
        System.out.println("*** File contents: ");
        List<String> contents = ResourceItemUtils.readLinesFromFile(file);
        contents.forEach(s -> System.out.println(s));

Convenience methods: automatic creation of the folder structure

In addition, we provide some convenience methods for you.

If a file shall be created by a given URI using ResourceItemUtils.createFile, all the missing folder structure in between will be automatically created for you. E.g. 

        ResourceItemUtils.createFile(ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, WebDavHelper.WebDavStorageLocation.CLIPBOARD.getPath() + "DeviceAutomator/config/test.json"));

would create the folders DeviceAutomator /config/ if they would not exist before.

Convenience methods: generated filenames

For automatic generation of filenames containing e.g. the timestamp or the hostname, we provide some convenience methods. Check out the ResourceItemUtils.createDefaultSubPathAndFilename or ResourceItemUtils.createSubPathAndFilename methods. 
        final String uriAsString = WebDavHelper.WebDavStorageLocation.CLIPBOARD.getPath() + ResourceItemUtils
                .createDefaultSubPathAndFilename(applicationTitle, categoryDirectory, "", fileNameAndExtension);
        final ResourceItem file = ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, uriAsString);
        return ResourceItemUtils.createFile(file, data);

Convenience methods: providing the file content while creating the file

All methods for creating a file are also provided in a version that directly gets the List or byte[] to be written to the file. Thus the following code lines 
        String filename = WebDavHelper.WebDavStorageLocation.CLIPBOARD.getPath() + "/myapp/test.txt";
        final ResourceItem file = ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, filename);

        ResourceItemUtils.createFile(file);
        ResourceItemUtils.writeLinesToFile(file, List.of("Hello", "World"));

can be written simpler 
        ResourceItemUtils.createFile(file, List.of("Hello", "World"));

(similarly with byte[]).

4.2 Programmatic upload of an image

For uploading images, we provide a special utility class ScreenShotUtils in common-uilib-fx, that does convert a given Image to the necessary byte[] array and uploads a file for you. 

        final ResourceItem uploadedFile = ScreenShotUtils.convertAndUploadImageAndOpenInBrowser(
                    WebDavStorageLocation.CLIPBOARD,
                    applicationName, "screenshots", true,
                    getWellFormedFileName(FILE_NAME_FRAGMENT_SEPARATOR) + FILE_NAME_FRAGMENT_SEPARATOR, true,
                    PNG_SUFFIX, null, screenShotImage);
        LOGGER.info(ScreenShotButtonResourceBundle.LANG_TEXT_SCREEN_SHOT_SUCCESS_UPLOAD,uploadedFile.getFullPathName());

Or there is even a ScreenShotButton in common-utils, that you can just use in your Application.

4.3 Upload and download by using the GSI version of the FileChooserFx that can deal with Filesystem and WebDAV resources seamlessly

The example is taken from the benno-app and has been slightly modified here: 

    @FXML
    private void exportMadX() {
        final ResourceItem initialDirectory =
                ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, WEBDAV_FOLDER + comboPattern.getValue() + "/");
        final FileChooser fileChooser = new FileChooserImpl();
        fileChooser.setTitle("Export MadX File");
        fileChooser.setWebdavDirectories(Collections.singletonList(WEBDAV_FOLDER));
        fileChooser.setInitialDirectory(initialDirectory);
        String timeString = Instant.now().atZone(TIMEZONE_ID_APP).format(DATETIME_FORMATTER_EXPORT_FILE);
        fileChooser.setInitialFileName(
                "CUSTOM_" + comboPattern.getValue().replace(" ", "_").toUpperCase() + "_" + timeString + ".opt");
        fileChooser.showSaveDialog(ApplicationBase.getPrimaryStage(), fileOptional -> {
            if (!fileOptional.isEmpty()) {
                physicsService.exportMadxStrengthFile(fileOptional.get());
            }
        });
    }
    @FXML
    private void importMadX() {
        final ResourceItem initialDirectory = ResourceItemUtils.newResourceItem(ResourceType.WEBDAV, WEBDAV_FOLDER);

        final FileChooser fileChooser = new FileChooserImpl();
        fileChooser.setTitle("Import MadX File");
        fileChooser.setWebdavDirectories(Collections.singletonList(WEBDAV_FOLDER));
        fileChooser.setInitialDirectory(initialDirectory);
        fileChooser.showOpenDialog(ApplicationBase.getPrimaryStage(), fileOptional -> {
            if (!fileOptional.isEmpty()) {
                physicsService.importMadxStrengthFile(fileOptional.get());
                updateChartThread("draw");
            }
        });
    }

-- JuttaFitzek - 24 Feb 2023

This topic: Applications > WebHome > AppHowToMain > AppHowToWebDav
Topic revision: 16 Mar 2023, JuttaFitzek
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