com.vaadin.flow.server.

Class DevModeHandler

  • All Implemented Interfaces:

    RequestHandler, Serializable


    public final class DevModeHandler
extends Object
implements RequestHandler

    Handles getting resources from webpack-dev-server.

    This class is meant to be used during developing time. For a production mode site webpack generates the static bundles that will be served directly from the servlet (using a default servlet if such exists) or through a stand alone static file server. By default it keeps updated npm dependencies and node imports before running webpack server

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

    Since:

    2.0

    See Also:

    Serialized Form

    • Field Detail

      • WEBPACK_SERVER

        public static final String WEBPACK_SERVER

        The local installation path of the webpack-dev-server node script.

        See Also:

        Constant Field Values

    • Method Detail

      • start

        public static DevModeHandler start(DeploymentConfiguration configuration,
                                   File npmFolder,
                                   CompletableFuture<Void> waitFor)

        Start the dev mode handler if none has been started yet.

        Parameters:

        configuration - deployment configuration

        npmFolder - folder with npm configuration files

        waitFor - a completable future whose execution result needs to be available to start the webpack dev server

        Returns:

        the instance in case everything is alright, null otherwise

      • start

        public static DevModeHandler start(int runningPort,
                                   DeploymentConfiguration configuration,
                                   File npmFolder,
                                   CompletableFuture<Void> waitFor)

        Start the dev mode handler if none has been started yet.

        Parameters:

        runningPort - port on which Webpack is listening.

        configuration - deployment configuration

        npmFolder - folder with npm configuration files

        waitFor - a completable future whose execution result needs to be available to start the webpack dev server

        Returns:

        the instance in case everything is alright, null otherwise

      • getDevModeHandler

        public static DevModeHandler getDevModeHandler()

        Get the instantiated DevModeHandler.

        Returns:

        devModeHandler or null if not started

      • handleRequest

        public boolean handleRequest(VaadinSession session,
                             VaadinRequest request,
                             VaadinResponse response)
                      throws IOException

        Description copied from interface: RequestHandler

        Called when a request needs to be handled. If a response is written, this method should return true to indicate that no more request handlers should be invoked for the request.

        Note that request handlers by default do not lock the session. If you are using VaadinSession or anything inside the VaadinSession you must ensure the session is locked. This can be done by extending SynchronizedRequestHandler or by using VaadinSession.accessSynchronously(Command) or UI.accessSynchronously(Command).

        Specified by:

        handleRequest in interface RequestHandler

        Parameters:

        session - The session for the request

        request - The request to handle

        response - The response object to which a response can be written.

        Returns:

        true if a response has been written and no further request handlers should be called, otherwise false

        Throws:

        IOException - If an IO error occurred

      • setLiveReload

        public void setLiveReload(BrowserLiveReload liveReload)

        Set the live reload service instance.

        Parameters:

        liveReload - the live reload instance

      • getLiveReload

        public BrowserLiveReload getLiveReload()

        Get the live reload service instance.

        Returns:

        the live reload instance

      • isDevModeRequest

        public boolean isDevModeRequest(HttpServletRequest request)

        Returns true if it's a request that should be handled by webpack.

        Parameters:

        request - the servlet request

        Returns:

        true if the request should be forwarded to webpack

      • serveDevModeRequest

        public boolean serveDevModeRequest(HttpServletRequest request,
                                   HttpServletResponse response)
                            throws IOException

        Serve a file by proxying to webpack.

        Note: it considers the HttpServletRequest#getPathInfo that will be the path passed to the 'webpack-dev-server' which is running in the context root folder of the application.

        Method returns false immediately if dev server failed on its startup.

        Parameters:

        request - the servlet request

        response - the servlet response

        Returns:

        false if webpack returned a not found, true otherwise

        Throws:

        IOException - in the case something went wrong like connection refused

      • prepareConnection

        public HttpURLConnection prepareConnection(String path,
                                           String method)
                                    throws IOException

        Prepare a HTTP connection against webpack-dev-server.

        Parameters:

        path - the file to request

        method - the http method to use

        Returns:

        the connection

        Throws:

        IOException - on connection error

      • getFailedOutput

        public String getFailedOutput()

        Return webpack console output when a compilation error happened.

        Returns:

        console output if error or null otherwise.

      • removeRunningDevServerPort

        public void removeRunningDevServerPort()

        Remove the running port from the vaadinContext and temporary file.

      • getPort

        public int getPort()

        Get the listening port of the 'webpack-dev-server'.

        Returns:

        the listening port of webpack

      • reuseDevServer

        public boolean reuseDevServer()

        Whether the 'webpack-dev-server' should be reused on servlet reload. Default true.

        Returns:

        true in case of reusing the server.

      • stop

        public void stop()

        Stop the webpack-dev-server.