org.osgi.service.http.context

Class ServletContextHelper

java.lang.Object

org.osgi.service.http.context.ServletContextHelper

@ConsumerType
public abstract class ServletContextHelper
extends Object

Helper service for a servlet context used by a Http Whiteboard implementation to serve HTTP requests.

This service defines methods that the Http Whiteboard implementation may call to get information for a request when dealing with whiteboard services.

Each ServletContextHelper is registered with a "osgi.http.whiteboard.context.name" service property containing a name to reference by servlets, servlet filters, resources, and listeners. If there is more than one ServletContextHelper registered with the same context name, the one with the highest service ranking is active, the others are inactive.

A context is registered with the "osgi.http.whiteboard.context.path" service property to define a path under which all services registered with this context are reachable. If there is more than one ServletContextHelper registered with the same path, each duplicate context path is searched by service ranking order according to ServiceReference.compareTo(Object) until a matching servlet or resource is found.

Servlets, servlet filters, resources, and listeners services may be associated with a ServletContextHelper service with the "osgi.http.whiteboard.context.select" service property. If the referenced ServletContextHelper service does not exist or is currently not active, the whiteboard services for that ServletContextHelper are not active either.

If no ServletContextHelper service is associated, that is no "osgi.http.whiteboard.context.select" service property is configured for a whiteboard service, a default ServletContextHelper is used.

Those whiteboard services that are associated with the same ServletContextHelper object will share the same ServletContext object.

The behavior of the methods on the default ServletContextHelper is defined as follows:

• getMimeType - Always returns null.
• handleSecurity - Always returns true.
• getResource - Assumes the named resource is in the bundle of the whiteboard service, addressed from the root. This method calls the whiteboard service bundle's Bundle.getEntry method, and returns the appropriate URL to access the resource. On a Java runtime environment that supports permissions, the Http Whiteboard implementation needs to be granted org.osgi.framework.AdminPermission[*,RESOURCE].
• getResourcePaths - Assumes that the resources are in the bundle of the whiteboard service. This method calls Bundle.findEntries method, and returns the found entries. On a Java runtime environment that supports permissions, the Http Whiteboard implementation needs to be granted org.osgi.framework.AdminPermission[*,RESOURCE].
• getRealPath - Always returns null.

See Also:

HttpWhiteboardConstants.HTTP_WHITEBOARD_CONTEXT_NAME, HttpWhiteboardConstants.HTTP_WHITEBOARD_CONTEXT_PATH

"ThreadSafe"

Field Summary

Fields

Modifier and Type	Field and Description
static String	AUTHENTICATION_TYPE HttpServletRequest attribute specifying the scheme used in authentication.
static String	AUTHORIZATION HttpServletRequest attribute specifying the Authorization object obtained from the org.osgi.service.useradmin.UserAdmin service.
static String	REMOTE_USER HttpServletRequest attribute specifying the name of the authenticated user.

Constructor Summary

Constructors

Constructor and Description
ServletContextHelper() Construct a new context helper.
ServletContextHelper(Bundle bundle) Construct a new context helper associated with the specified bundle.

Method Summary

Methods

Modifier and Type	Method and Description
String	getMimeType(String name) Maps a name to a MIME type.
String	getRealPath(String path) Gets the real path corresponding to the given virtual path.
URL	getResource(String name) Maps a resource name to a URL.
Set<String>	getResourcePaths(String path) Returns a directory-like listing of all the paths to resources within the web application whose longest sub-path matches the supplied path argument.
boolean	handleSecurity(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Handles security for the specified request.

Methods inherited from class java.lang.Object

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

Field Detail

REMOTE_USER

public static final String REMOTE_USER

HttpServletRequest attribute specifying the name of the authenticated user. The value of the attribute can be retrieved by HttpServletRequest.getRemoteUser.

See Also:

Constant Field Values

AUTHENTICATION_TYPE

public static final String AUTHENTICATION_TYPE

HttpServletRequest attribute specifying the scheme used in authentication. The value of the attribute can be retrieved by HttpServletRequest.getAuthType.

See Also:

Constant Field Values

AUTHORIZATION

public static final String AUTHORIZATION

HttpServletRequest attribute specifying the Authorization object obtained from the org.osgi.service.useradmin.UserAdmin service. The value of the attribute can be retrieved by HttpServletRequest.getAttribute(ServletContextHelper.AUTHORIZATION) .

See Also:

Constant Field Values

Constructor Detail

ServletContextHelper

public ServletContextHelper()

Construct a new context helper.

If needed, the subclass will have to handle the association with a specific bundle.

ServletContextHelper

public ServletContextHelper(Bundle bundle)

Construct a new context helper associated with the specified bundle.

Parameters:

bundle - The bundle to be associated with this context helper.

Method Detail

handleSecurity

public boolean handleSecurity(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response)
                       throws IOException

Handles security for the specified request.

The Http Whiteboard implementation calls this method prior to servicing the specified request. This method controls whether the request is processed in the normal manner or an error is returned.

If the request requires authentication and the Authorization header in the request is missing or not acceptable, then this method should set the WWW-Authenticate header in the response object, set the status in the response object to Unauthorized(401) and return false. See also RFC 2617: HTTP Authentication: Basic and Digest Access Authentication.

If the request requires a secure connection and the getScheme method in the request does not return 'https' or some other acceptable secure protocol, then this method should set the status in the response object to Forbidden(403) and return false.

When this method returns false, the Http Whiteboard implementation will send the response back to the client, thereby completing the request. When this method returns true, the Http Whiteboard implementation will proceed with servicing the request.

If the specified request has been authenticated, this method must set the AUTHENTICATION_TYPE request attribute to the type of authentication used, and the REMOTE_USER request attribute to the remote user (request attributes are set using the setAttribute method on the request). If this method does not perform any authentication, it must not set these attributes.

If the authenticated user is also authorized to access certain resources, this method must set the AUTHORIZATION request attribute to the Authorization object obtained from the org.osgi.service.useradmin.UserAdmin service.

The servlet responsible for servicing the specified request determines the authentication type and remote user by calling the getAuthType and getRemoteUser methods, respectively, on the request.

Parameters:

request - The HTTP request.

response - The HTTP response.

Returns:

true if the request should be serviced, false if the request should not be serviced and Http Whiteboard implementation will send the response back to the client.

Throws:

IOException - May be thrown by this method. If this occurs, the Http Whiteboard implementation will terminate the request and close the socket.

getResource

public URL getResource(String name)

Maps a resource name to a URL.

Called by the Http Whiteboard implementation to map the specified resource name to a URL. For servlets, the Http Whiteboard implementation will call this method to support the ServletContext methods getResource and getResourceAsStream. For resources, the Http Whiteboard implementation will call this method to locate the named resource.

The context can control from where resources come. For example, the resource can be mapped to a file in the bundle's persistent storage area via BundleContext.getDataFile(name).toURI().toURL() or to a resource in the context's bundle via getClass().getResource(name)

Parameters:

name - The name of the requested resource.

Returns:

A URL that a Http Whiteboard implementation can use to read the resource or null if the resource does not exist.

getMimeType

public String getMimeType(String name)

Maps a name to a MIME type.

Called by the Http Whiteboard implementation to determine the MIME type for the specified name. For whiteboard services, the Http Whiteboard implementation will call this method to support the ServletContext method getMimeType. For resource servlets, the Http Whiteboard implementation will call this method to determine the MIME type for the Content-Type header in the response.

Parameters:

name - The name for which to determine the MIME type.

Returns:

The MIME type (e.g. text/html) of the specified name or null to indicate that the Http Whiteboard implementation should determine the MIME type itself.

getResourcePaths

public Set<String> getResourcePaths(String path)

Returns a directory-like listing of all the paths to resources within the web application whose longest sub-path matches the supplied path argument.

Called by the Http Whiteboard implementation to support the ServletContext method getResourcePaths for whiteboard services.

Parameters:

path - The partial path used to match the resources, which must start with a /.

Returns:

A Set containing the directory listing, or null if there are no resources in the web application whose path begins with the supplied path.

getRealPath

public String getRealPath(String path)

Gets the real path corresponding to the given virtual path.

Called by the Http Whiteboard implementation to support the ServletContext method getRealPath for whiteboard services.

Parameters:

path - The virtual path to be translated to a real path.

Returns:

The real path, or null if the translation cannot be performed.