com.vaadin.flow.server

Class DevModeHandler

java.lang.Object

com.vaadin.flow.server.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 Summary

Fields

Modifier and Type	Field and Description
static String	WEBPACK_SERVER The local installation path of the webpack-dev-server node script.

Method Summary

Modifier and Type	Method and Description
static DevModeHandler	getDevModeHandler() Get the instantiated DevModeHandler.
String	getFailedOutput() Return webpack console output when a compilation error happened.
BrowserLiveReload	getLiveReload() Get the live reload service instance.
int	getPort() Get the listening port of the 'webpack-dev-server'.
boolean	handleRequest(VaadinSession session, VaadinRequest request, VaadinResponse response) Called when a request needs to be handled.
boolean	isDevModeRequest(HttpServletRequest request) Returns true if it's a request that should be handled by webpack.
HttpURLConnection	prepareConnection(String path, String method) Prepare a HTTP connection against webpack-dev-server.
void	removeRunningDevServerPort() Remove the running port from the vaadinContext and temporary file.
boolean	reuseDevServer() Whether the 'webpack-dev-server' should be reused on servlet reload.
boolean	serveDevModeRequest(HttpServletRequest request, HttpServletResponse response) Serve a file by proxying to webpack.
void	setLiveReload(BrowserLiveReload liveReload) Set the live reload service instance.
static DevModeHandler	start(DeploymentConfiguration configuration, File npmFolder, CompletableFuture<Void> waitFor) Start the dev mode handler if none has been started yet.
static DevModeHandler	start(int runningPort, DeploymentConfiguration configuration, File npmFolder, CompletableFuture<Void> waitFor) Start the dev mode handler if none has been started yet.
void	stop() Stop the webpack-dev-server.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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.