com.vaadin.flow.server

Class StaticFileServer

java.lang.Object

com.vaadin.flow.server.StaticFileServer

All Implemented Interfaces:

StaticFileHandler, Serializable

public class StaticFileServer
extends Object
implements StaticFileHandler

Handles sending of resources from the WAR root (web content) or META-INF/resources in the case that VaadinServlet is mapped using "/*".

This class is primarily meant to be used during developing time. For a production mode site you should consider serving static resources directly from the servlet (using a default servlet if such exists) or through a stand alone static file server.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static Pattern	APP_THEME_PATTERN

Constructor Summary

Constructors

Constructor and Description
StaticFileServer(VaadinServletService servletService) Constructs a file server.

Method Summary

Modifier and Type	Method and Description
protected boolean	browserHasNewestVersion(HttpServletRequest request, long resourceLastModifiedTimestamp) Checks if the browser has an up to date cached version of requested resource using the "If-Modified-Since" header.
protected int	getCacheTime(String filenameWithPath) Calculates the cache lifetime for the given filename in seconds.
protected URL	getStaticResource(String path) Returns a URL to the static Web resource at the given URI or null if no file found.
boolean	isStaticResourceRequest(HttpServletRequest request) Checks if a static resource can be found for the requested path.
boolean	serveStaticResource(HttpServletRequest request, HttpServletResponse response) Serves a static resource for the requested path if a resource can be found.
protected void	writeCacheHeaders(String filenameWithPath, HttpServletResponse response) Writes cache headers for the file into the response.
protected long	writeModificationTimestamp(URL resourceUrl, HttpServletRequest request, HttpServletResponse response) Writes the modification timestamp info for the file into the response.

Methods inherited from class java.lang.Object

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

Field Detail

APP_THEME_PATTERN

protected static final Pattern APP_THEME_PATTERN

Constructor Detail

StaticFileServer

public StaticFileServer(VaadinServletService servletService)

Constructs a file server.

Parameters:

servletService - servlet service for the deployment, not null

Method Detail

isStaticResourceRequest

public boolean isStaticResourceRequest(HttpServletRequest request)

Description copied from interface: StaticFileHandler

Checks if a static resource can be found for the requested path.

Specified by:

isStaticResourceRequest in interface StaticFileHandler

Parameters:

request - the request to check

Returns:

true if a static resource exists and can be sent as a response to this request, false otherwise

serveStaticResource

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

Description copied from interface: StaticFileHandler

Serves a static resource for the requested path if a resource can be found.

Specified by:

serveStaticResource in interface StaticFileHandler

Parameters:

request - the request object to read from

response - the response object to write to

Returns:

true if a file was served and the request has been handled, false otherwise.

Throws:

IOException - if the underlying servlet container reports an exception

getStaticResource

protected URL getStaticResource(String path)

Returns a URL to the static Web resource at the given URI or null if no file found.

The resource will be exposed via HTTP (available as a static web resource). The null return value means that the resource won't be exposed as a Web resource even if it's a resource available via ServletContext.

Parameters:

path - the path for the resource

Returns:

the resource located at the named path to expose it via Web, or null if there is no resource at that path or it should not be exposed

See Also:

VaadinService.getStaticResource(String)

writeModificationTimestamp

protected long writeModificationTimestamp(URL resourceUrl,
                                          HttpServletRequest request,
                                          HttpServletResponse response)

Writes the modification timestamp info for the file into the response.

Parameters:

resourceUrl - the internal URL of the file

request - the request object

response - the response object

Returns:

the written timestamp or -1 if no timestamp was written

writeCacheHeaders

protected void writeCacheHeaders(String filenameWithPath,
                                 HttpServletResponse response)

Writes cache headers for the file into the response.

Parameters:

filenameWithPath - the name and path of the file being sent

response - the response object

getCacheTime

protected int getCacheTime(String filenameWithPath)

Calculates the cache lifetime for the given filename in seconds.

By default filenames containing ".nocache." return 0, filenames containing ".cache." return one year and all other files return 1 hour.

Parameters:

filenameWithPath - the name of the file being sent

Returns:

cache lifetime for the given filename in seconds

browserHasNewestVersion

protected boolean browserHasNewestVersion(HttpServletRequest request,
                                          long resourceLastModifiedTimestamp)

Checks if the browser has an up to date cached version of requested resource using the "If-Modified-Since" header.

Parameters:

request - The HttpServletRequest from the browser.

resourceLastModifiedTimestamp - The timestamp when the resource was last modified. -1 if the last modification time is unknown.

Returns:

true if the If-Modified-Since header tells the cached version in the browser is up to date, false otherwise