Package com.vaadin.flow.server.frontend

Class FrontendUtils

  • public class FrontendUtils
extends Object
    A class for static methods and definitions that might be used in different locations.

    For internal use only. May be renamed or removed in a future release.

    Since:
    2.0

    • Method Detail

      • getOsName

        public static String getOsName()
        Get the Operating System name from the os.name system property.
        Returns:
        operating system name

      • isWindows

        public static boolean isWindows()
        Check if the current os is Windows.
        Returns:
        true if windows

      • streamToString

        public static String streamToString​(InputStream inputStream)
        Read a stream and copy the content into a String using system line separators for all 'carriage return' characters.
        Parameters:
        inputStream - the input stream
        Returns:
        the string

      • createProcessBuilder

        public static ProcessBuilder createProcessBuilder​(List<String> command)
        Creates a process builder for the given list of program and arguments. If the program is defined as an absolute path, then the directory that contains the program is also appended to PATH so that the it can locate related tools.
        Parameters:
        command - a list with the program and arguments
        Returns:
        a configured process builder

      • clearCachedStatsContent

        public static void clearCachedStatsContent​(VaadinService service)
        Clears the stats.json cache within this VaadinContext.
        Parameters:
        service - the vaadin service.

      • getIndexHtmlContent

        public static String getIndexHtmlContent​(VaadinService service)
                                  throws IOException
        Gets the content of the frontend/index.html file which is served by webpack-dev-server in dev-mode and read from classpath in production mode. NOTE: In dev mode, the file content file is fetched via webpack http request. So that we don't need to have a separate index.html's content watcher, auto-reloading will work automatically, like other files managed by webpack in `frontend/` folder.
        Parameters:
        service - the vaadin service
        Returns:
        the content of the index html file as a string, null if not found.
        Throws:
        IOException - on error when reading file

      • getFrontendFileFromDevModeHandler

        public static InputStream getFrontendFileFromDevModeHandler​(VaadinService service,
                                                            String path)
        Get the contents of a frontend file from the running dev server.
        Parameters:
        service - the Vaadin service.
        path - the file path.
        Returns:
        an input stream for reading the file contents; null if there is no such file or the dev server is not running.

      • resolveFrontendPath

        public static File resolveFrontendPath​(File projectRoot,
                                       String path)
        Looks up the front file at the given path. If the path starts with ./, first look in projectRoot/frontend, then in projectRoot/node_modules/@vaadin/flow-frontend. If the path does not start with ./, look in node_modules instead.
        Parameters:
        projectRoot - the project root folder.
        path - the file path.
        Returns:
        an existing File , or null if the file doesn't exist.

      • getStatsAssetsByChunkName

        public static String getStatsAssetsByChunkName​(VaadinService service)
                                        throws IOException
        Load the asset chunks from stats.json. We will only read the file until we have reached the assetsByChunkName json and return that as a json object string. Note: The stats.json is cached when external stats is enabled or stats.json is provided from the class path. To clear the cache use clearCachedStatsContent(VaadinService).
        Parameters:
        service - the Vaadin service.
        Returns:
        json for assetsByChunkName object in stats.json or null if stats.json not found or content not found.
        Throws:
        IOException - if an I/O error occurs while creating the input stream.

      • isWebpackConfigFile

        public static boolean isWebpackConfigFile​(File file)
                                   throws IOException
        Checks whether the file is a webpack configuration file with the expected content (includes a configuration generated by Flow).
        Parameters:
        file - a file to check
        Returns:
        true iff the file exists and includes a generated configuration
        Throws:
        IOException - if an I/O error occurs while reading the file

      • getUnixRelativePath

        public static String getUnixRelativePath​(Path source,
                                         Path target)
        Get relative path from a source path to a target path in Unix form. All the Windows' path separator will be replaced.
        Parameters:
        source - the source path
        target - the target path
        Returns:
        unix relative path from source to target

      • getUnixPath

        public static String getUnixPath​(Path source)
        Get path as a String in Unix form.
        Parameters:
        source - path to get
        Returns:
        path as a String in Unix form.

      • readFallbackChunk

        public static FallbackChunk readFallbackChunk​(elemental.json.JsonObject object)
        Read fallback chunk data from a json object.
        Parameters:
        object - json object to read fallback chunk data
        Returns:
        a fallback chunk data

      • parseFrontendVersion

        public static FrontendVersion parseFrontendVersion​(String versionString)
                                            throws IOException
        Parse the version number of node/npm from version output string.
        Parameters:
        versionString - string containing version output, typically produced by tool --version
        Returns:
        FrontendVersion of versionString
        Throws:
        IOException - if parsing fails

      • getVaadinHomeDirectory

        public static File getVaadinHomeDirectory()
        Gets vaadin home directory (".vaadin" folder in the user home dir).

        The directory is created if it's doesn't exist.

        Returns:
        a vaadin home directory

      • commandToString

        public static String commandToString​(String baseDir,
                                     List<String> command)
        Pretty prints a command line order. It split in lines adapting to 80 columns, and allowing copy and paste in console. It also removes the current directory to avoid security issues in log files.
        Parameters:
        baseDir - the current directory
        command - the command and it's arguments
        Returns:
        the string for printing in logs

      • getPackageVersionFromJson

        public static FrontendVersion getPackageVersionFromJson​(elemental.json.JsonObject sourceJson,
                                                        String pkg,
                                                        String versionOrigin)
        Tries to parse the given package's frontend version or if it doesn't exist, returns null. In case the value cannot be parsed, logs an error and returns null.
        Parameters:
        sourceJson - json object that has the package
        pkg - the package name
        versionOrigin - origin of the version (like a file), used in error message
        Returns:
        the frontend version the package or null

      • console

        public static void console​(String format,
                           Object message)
        Intentionally send to console instead to log, useful when executing external processes.
        Parameters:
        format - Format of the line to send to console, it must contain a `%s` outlet for the message
        message - the string to show

      • deleteNodeModules

        public static void deleteNodeModules​(File nodeModules)
                              throws IOException
        Try to remove the node_modules directory, if it exists inside the given base directory. Note that pnpm uses symlinks internally, so delete utilities that follow symlinks when deleting and/or modifying permissions may not work as intended.
        Parameters:
        nodeModules - the node_modules directory
        Throws:
        IOException - on failure to delete any one file, or if the directory name is not node_modules