com.vaadin.flow.server

Class VaadinServlet

java.lang.Object

HttpServlet

com.vaadin.flow.server.VaadinServlet

Direct Known Subclasses:

FrontendVaadinServlet

public class VaadinServlet
extends HttpServlet

The main servlet, which handles all incoming requests to the application.

This servlet is typically subclassed in all applications to provide servlet mappings and init parameters. Together with a web.xml file, it is also possible to use this class directly.

Internally sets up a VaadinService through createServletService(DeploymentConfiguration) and delegates handling of most requests to that.

Since:

1.0

Author:

Vaadin Ltd

Constructor Summary

Constructors

Constructor and Description
VaadinServlet()

Method Summary

Modifier and Type	Method and Description
protected DeploymentConfiguration	createDeploymentConfiguration() Creates a deployment configuration to be used for the creation of a VaadinService.
protected DeploymentConfiguration	createDeploymentConfiguration(Properties initParameters) Creates a deployment configuration to be used for the creation of a VaadinService.
protected VaadinServletService	createServletService() Creates a vaadin servlet service.
protected VaadinServletService	createServletService(DeploymentConfiguration deploymentConfiguration) Creates a vaadin servlet service.
protected StaticFileHandler	createStaticFileHandler(VaadinServletService servletService) Creates a new instance of StaticFileHandler, that is responsible to find and serve static resources.
protected VaadinServletRequest	createVaadinRequest(HttpServletRequest request) Creates a Vaadin request for a http servlet request.
void	destroy()
protected URL	getApplicationUrl(HttpServletRequest request) Deprecated. As of 1.0. Will be removed in 3.0.
static VaadinServlet	getCurrent() Gets the currently used Vaadin servlet.
protected static String	getLastPathParameter(String uri) Finds any path parameter added to the last part of the uri.
VaadinServletService	getService() Gets the Vaadin service for this servlet.
protected Optional<WebJarServer>	getWebJarServer() Gets the web jar server.
protected boolean	handleContextOrServletRootWithoutSlash(HttpServletRequest request, HttpServletResponse response) Invoked for every request to this servlet to potentially send a redirect to avoid problems with requests to the context root with no trailing slash.
void	init(ServletConfig servletConfig) Called by the servlet container to indicate to a servlet that the servlet is being placed into service.
static String	safeEscapeForHtml(String unsafe) Deprecated. As of 1.0. Will be removed in 3.0. Use Entities.escape(String) instead.
protected boolean	serveStaticOrWebJarRequest(HttpServletRequest request, HttpServletResponse response) Handles a request by serving a static file from Webpack when in npm-dev-mode, or from a WebJar when in bower-dev-mode or from the file-system when in production.
protected void	service(HttpServletRequest request, HttpServletResponse response) Receives standard HTTP requests from the public service method and dispatches them.
protected void	servletInitialized()

Methods inherited from class java.lang.Object

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

Constructor Detail

VaadinServlet

public VaadinServlet()

Method Detail

init

public void init(ServletConfig servletConfig)
          throws ServletException

Called by the servlet container to indicate to a servlet that the servlet is being placed into service.

Parameters:

servletConfig - the object containing the servlet's configuration and initialization parameters

Throws:

ServletException - if an exception has occurred that interferes with the servlet's normal operation.

createStaticFileHandler

protected StaticFileHandler createStaticFileHandler(VaadinServletService servletService)

Creates a new instance of StaticFileHandler, that is responsible to find and serve static resources. By default it returns a StaticFileServer instance.

Parameters:

servletService - the servlet service created at createServletService()

Returns:

the file server to be used by this servlet, not null

servletInitialized

protected void servletInitialized()
                           throws ServletException

Throws:

ServletException

getCurrent

public static VaadinServlet getCurrent()

Gets the currently used Vaadin servlet. The current servlet is automatically defined when initializing the servlet and when processing requests to the server (see ThreadLocal) and in VaadinSession.access(Command) and UI.access(Command). In other cases, (e.g. from background threads), the current servlet is not automatically defined.

The current servlet is derived from the current service using VaadinService.getCurrent()

Returns:

the current Vaadin servlet instance if available, otherwise null

createDeploymentConfiguration

protected DeploymentConfiguration createDeploymentConfiguration()
                                                         throws ServletException

Creates a deployment configuration to be used for the creation of a VaadinService. Intended to be used by dependency injection frameworks.

Returns:

the created deployment configuration

Throws:

ServletException

createDeploymentConfiguration

protected DeploymentConfiguration createDeploymentConfiguration(Properties initParameters)

Creates a deployment configuration to be used for the creation of a VaadinService. Override this if you want to override certain properties.

Parameters:

initParameters - the context-param and init-param values as properties

Returns:

the created deployment configuration

createServletService

protected VaadinServletService createServletService()
                                             throws ServletException,
                                                    ServiceException

Creates a vaadin servlet service. This method functions as a layer of indirection between init(ServletConfig) and createServletService(DeploymentConfiguration) so dependency injection frameworks can call createDeploymentConfiguration() when creating a vaadin servlet service lazily.

Returns:

the created vaadin servlet service

Throws:

ServletException - if creating a deployment configuration fails

ServiceException - if creating the vaadin servlet service fails

createServletService

protected VaadinServletService createServletService(DeploymentConfiguration deploymentConfiguration)
                                             throws ServiceException

Creates a vaadin servlet service.

Parameters:

deploymentConfiguration - the deployment configuration to be used

Returns:

the created vaadin servlet service

Throws:

ServiceException - if creating the vaadin servlet service fails

service

protected void service(HttpServletRequest request,
                       HttpServletResponse response)
                throws ServletException,
                       IOException

Receives standard HTTP requests from the public service method and dispatches them.

Parameters:

request - the object that contains the request the client made of the servlet.

response - the object that contains the response the servlet returns to the client.

Throws:

ServletException - if an input or output error occurs while the servlet is handling the TRACE request.

IOException - if the request for the TRACE cannot be handled.

serveStaticOrWebJarRequest

protected boolean serveStaticOrWebJarRequest(HttpServletRequest request,
                                             HttpServletResponse response)
                                      throws IOException

Handles a request by serving a static file from Webpack when in npm-dev-mode, or from a WebJar when in bower-dev-mode or from the file-system when in production. It's not done via VaadinService handlers because static requests do not need a established session.

Parameters:

request - the HTTP servlet request object that contains the request the client made of the servlet

response - the HTTP servlet response object that contains the response the servlet returns to the client

Returns:

true if the request was handled a response written; otherwise false

Throws:

IOException - if an input or output error occurs while the servlet is handling the HTTP request

handleContextOrServletRootWithoutSlash

protected boolean handleContextOrServletRootWithoutSlash(HttpServletRequest request,
                                                         HttpServletResponse response)
                                                  throws IOException

Invoked for every request to this servlet to potentially send a redirect to avoid problems with requests to the context root with no trailing slash.

Parameters:

request - the processed request

response - the processed response

Returns:

true if a redirect has been sent and the request should not be processed further; false if the request should be processed as usual

Throws:

IOException - If an input or output exception occurs

getLastPathParameter

protected static String getLastPathParameter(String uri)

Finds any path parameter added to the last part of the uri. A path parameter is any string separated by ";" from the path and ends in / or at the end of the string.

For example the uri http://myhost.com/foo;a=1/bar;b=1 contains two path parameters, a=1 related to /foo and b=1 related to /bar.

For http://myhost.com/foo;a=1/bar;b=1 this method will return ;b=1

Parameters:

uri - a URI

Returns:

the last path parameter of the uri including the semicolon or an empty string. Never null.

createVaadinRequest

protected VaadinServletRequest createVaadinRequest(HttpServletRequest request)

Creates a Vaadin request for a http servlet request. This method can be overridden if the Vaadin request should have special properties.

Parameters:

request - the original http servlet request

Returns:

a Vaadin request for the original request

getService

public VaadinServletService getService()

Gets the Vaadin service for this servlet.

Returns:

the Vaadin service

getApplicationUrl

@Deprecated
protected URL getApplicationUrl(HttpServletRequest request)
                                     throws MalformedURLException

Deprecated. As of 1.0. Will be removed in 3.0.

Gets the current application URL from request.

Parameters:

request - the HTTP request.

Returns:

current application URL

Throws:

MalformedURLException - if the application is denied access to the persistent data store represented by the given URL.

destroy

public void destroy()

safeEscapeForHtml

@Deprecated
public static String safeEscapeForHtml(String unsafe)

Deprecated. As of 1.0. Will be removed in 3.0. Use Entities.escape(String) instead.

Escapes characters to html entities. An exception is made for some "safe characters" to keep the text somewhat readable.

Parameters:

unsafe - non-escaped string

Returns:

a safe string to be added inside an html tag

getWebJarServer

protected Optional<WebJarServer> getWebJarServer()

Gets the web jar server.

Returns:

the web jar server or an empty optional if no web jar server is used