com.vaadin.flow.server

Class DevModeHandler

java.lang.Object

com.vaadin.flow.server.DevModeHandler

All Implemented Interfaces:

Serializable

public class DevModeHandler
extends Object
implements Serializable

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

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.
boolean	isDevModeRequest(javax.servlet.http.HttpServletRequest request) Returns true if it's a request that should be handled by webpack.
boolean	serveDevModeRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Serve a file by proxying to webpack.
static DevModeHandler	start(VaadinContext context, DeploymentConfiguration configuration, File npmFolder) Start the dev mode handler if none has been started yet.
void	stop() Stops the 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(VaadinContext context,
                                   DeploymentConfiguration configuration,
                                   File npmFolder)

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

Parameters:

context - VaadinContext where to store the DevModePort on which Webpack is listening.

configuration - deployment configuration

npmFolder - folder with npm configuration files

Returns:

the instance in case everything is alright, null otherwise

stop

public void stop()

Stops the dev server.

getDevModeHandler

public static DevModeHandler getDevModeHandler()

Get the instantiated DevModeHandler.

Returns:

devModeHandler or null if not started

isDevModeRequest

public boolean isDevModeRequest(javax.servlet.http.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(javax.servlet.http.HttpServletRequest request,
                                   javax.servlet.http.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.

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

getFailedOutput

public String getFailedOutput()

Return webpack console output when a compilation error happened.

Returns:

console output if error or null otherwise.