Package com.vaadin.flow.server.communication

Class JavaScriptBootstrapHandler

java.lang.Object

com.vaadin.flow.server.SynchronizedRequestHandler

com.vaadin.flow.server.BootstrapHandler

com.vaadin.flow.server.communication.JavaScriptBootstrapHandler

All Implemented Interfaces:

RequestHandler, Serializable

Direct Known Subclasses:

IndexHtmlRequestHandler

public class JavaScriptBootstrapHandler
extends BootstrapHandler

Processes a 'start' request type from the client to initialize server session and UI. It returns a JSON response with everything needed to bootstrap flow views.

The handler is for client driven projects where `index.html` does not contain bootstrap data. Bootstrapping is the responsibility of the `@vaadin/flow` client that is able to ask the server side to create the vaadin session and do the bootstrapping lazily.

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

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	JavaScriptBootstrapHandler.JavaScriptBootstrapContext	Custom BootstrapContext for JavaScriptBootstrapHandler.

Nested classes/interfaces inherited from class com.vaadin.flow.server.BootstrapHandler

BootstrapHandler.BootstrapContext, BootstrapHandler.BootstrapPageBuilder, BootstrapHandler.BootstrapUriResolver, BootstrapHandler.PageBuilder

Field Summary

Fields inherited from class com.vaadin.flow.server.BootstrapHandler

SCRIPT_TAG, SCRIPT_TEMPLATE_FOR_STYLESHEET_LINK_TAG, SERVICE_WORKER_HEADER

Constructor Summary

Constructors

Constructor	Description
JavaScriptBootstrapHandler()	Creates a new bootstrap handler with default page builder.

Method Summary

Modifier and Type	Method	Description
protected boolean	canHandleRequest(VaadinRequest request)	Check whether a request may be handled by this handler.
protected BootstrapHandler.BootstrapContext	createAndInitUI(Class<? extends UI> uiClass, VaadinRequest request, VaadinResponse response, VaadinSession session)
protected BootstrapHandler.BootstrapContext	createBootstrapContext(VaadinRequest request, VaadinResponse response, UI ui, Function<VaadinRequest,String> callback)	Creates a new instance of BootstrapHandler.BootstrapContext for given request, response and ui.
protected elemental.json.JsonObject	getInitialJson(VaadinRequest request, VaadinResponse response, VaadinSession session)	Returns the JSON object with the application config and UIDL info that can be used in the bootstrapper to embed that info in the initial page.
protected String	getRequestUrl(VaadinRequest request)
protected static String	getServiceUrl(VaadinRequest vaadinRequest)	Gets the service URL as a URL relative to the request URI.
protected void	initializeUIWithRouter(BootstrapHandler.BootstrapContext context, UI ui)
boolean	synchronizedHandleRequest(VaadinSession session, VaadinRequest request, VaadinResponse response)	Identical to SynchronizedRequestHandler.handleRequest(VaadinSession, VaadinRequest, VaadinResponse) except the VaadinSession is locked before this is called and unlocked after this has completed.

Methods inherited from class com.vaadin.flow.server.BootstrapHandler

getInitialUidl, getPageBuilder, getPushScript, getStatsJson, getStylesheetLinks, getStylesheetTags, getUIClass, isFrameworkInternalRequest, isRequestForHtml, isVaadinStaticFileRequest, readResource, resolvePageTitle, setupErrorDialogs, setupHiddenElement, setupPushConnectionFactory, setupPwa, writeErrorCodeIfRequestLocationIsInvalid

Methods inherited from class com.vaadin.flow.server.SynchronizedRequestHandler

handleRequest

Methods inherited from class java.lang.Object

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

Constructor Details

JavaScriptBootstrapHandler

public JavaScriptBootstrapHandler()

Creates a new bootstrap handler with default page builder.

Method Details

canHandleRequest

protected boolean canHandleRequest(VaadinRequest request)

Description copied from class: SynchronizedRequestHandler

Check whether a request may be handled by this handler. This can be used as an optimization to avoid locking the session just to investigate some method property. The default implementation just returns true which means that all requests will be handled by calling SynchronizedRequestHandler.synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse) with the session locked.

Overrides:

canHandleRequest in class BootstrapHandler

Parameters:

request - the request to handle

Returns:

true if the request handling should continue once the session has been locked; false if there's no need to lock the session since the request would still not be handled.

getRequestUrl

protected String getRequestUrl(VaadinRequest request)

createAndInitUI

protected BootstrapHandler.BootstrapContext createAndInitUI(Class<? extends UI> uiClass,
 VaadinRequest request,
 VaadinResponse response,
 VaadinSession session)

Overrides:

createAndInitUI in class BootstrapHandler

initializeUIWithRouter

protected void initializeUIWithRouter(BootstrapHandler.BootstrapContext context,
 UI ui)

Overrides:

initializeUIWithRouter in class BootstrapHandler

createBootstrapContext

protected BootstrapHandler.BootstrapContext createBootstrapContext(VaadinRequest request,
 VaadinResponse response,
 UI ui,
 Function<VaadinRequest,String> callback)

Description copied from class: BootstrapHandler

Creates a new instance of BootstrapHandler.BootstrapContext for given request, response and ui.

Overrides:

createBootstrapContext in class BootstrapHandler

Parameters:

request - the request object

response - the response object

ui - the UI object

Returns:

a new bootstrap context instance

synchronizedHandleRequest

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

Description copied from class: SynchronizedRequestHandler

Identical to SynchronizedRequestHandler.handleRequest(VaadinSession, VaadinRequest, VaadinResponse) except the VaadinSession is locked before this is called and unlocked after this has completed.

Overrides:

synchronizedHandleRequest in class BootstrapHandler

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

See Also:

• SynchronizedRequestHandler.handleRequest(VaadinSession, VaadinRequest, VaadinResponse)

getServiceUrl

protected static String getServiceUrl(VaadinRequest vaadinRequest)

Gets the service URL as a URL relative to the request URI.

Parameters:

vaadinRequest - the request

Returns:

the relative service URL

getInitialJson

protected elemental.json.JsonObject getInitialJson(VaadinRequest request,
 VaadinResponse response,
 VaadinSession session)

Returns the JSON object with the application config and UIDL info that can be used in the bootstrapper to embed that info in the initial page.

Parameters:

request - the vaadin request.

response - the response.

session - the vaadin session.

Returns:

the initial application JSON.