Difference between revisions of "ClientContextLibrary"

From Gcube Wiki
Jump to: navigation, search
(→‎Portlet Example)
Line 2: Line 2:
 
=Client Context library for gCube Portlets =
 
=Client Context library for gCube Portlets =
  
−
Starting from '''gCube 4.2''', a new mechanism to retrieve the current user identifier and the current context identifier at client side has been introduced for gCube's portlets. The ''Client Context library'' allows to easily retrieve these information by relying on the ''Liferay.ThemeDisplay'' javascript object <ref>[https://www.liferay.com/it Liferay] is the portal technology adopted in the D4Science Infrastructure which is built upon the gCube software</ref>, and inject them at server side (they are transparently sent along the header of the remote requests). There you should use the PortalManager library<ref>More information about the PortalManager are reported [https://wiki.gcube-system.org/gcube/Portal_Manager here]</ref>, to retrieve and convert them automatically to the current user and gCube context.
+
Starting from '''gCube 4.2''', the current Context identifier resides client side. If your Portlet does use '''AJAX calls''' (i.e. XMLHttpRequest to exchange data with a server behind the scenes) '''you don't need this component'''. Everything is already set up for you by the gCube Portal/Gateway in which your application is running.
  
−
= The Client Context Widget =
+
If you use standard http GET or POST to exchange data with the server instead, and you need to pass to the server the current Infrastructure scope identifier (the Liferay groupId).
  
−
The Client Context has been developed as a GWT Widget. Its source code is available in the gCube SVN repository, at this [http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portal/client-context-library url]. Basically, it offers two self-explanatory methods
+
== Getting the Client Context in Javascript ==
  
−
<source lang="java">
+
var groupId = Liferay.ThemeDisplay.getScopeGroupId();
−
public static native String getCurrentContextId();
+
−
</source>
+
  
−
and
+
== Getting the Client Context in GWT (Widget) ==
−
 
+
−
<source lang="java">
+
−
public static native String getCurrentUserId();
+
−
</source>
+
  
−
This code is translated to native Javascript code, starting from pure Java code by the GWT Framework. Please note that both methods actually return a number value.
+
The Client Context has been wrapped as a GWT Widget. Its source code is available in the gCube SVN repository, at this [http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portal/client-context-library url].  
  
 
To use the widget, you need to declare the following maven dependency in your project's pom.xml
 
To use the widget, you need to declare the following maven dependency in your project's pom.xml
Line 38: Line 32:
 
</source>
 
</source>
  
−
Finally, in the ''onModuleLoad()'' method of your gwt web application, you must declare the following code line
+
then you just use the GCubeClientContext.getCurrentContextId() method:
  
 
<source lang="java">
 
<source lang="java">
−
public class ... implements EntryPoint {
+
public static native String getCurrentContextId();
−
+
−
  public void onModuleLoad() {
+
−
 
+
−
    /**
+
−
      * Inject client context to automatically pass the context id and the user id to the server side
+
−
      */
+
−
      GCubeClientContext.injectContext();
+
−
     
+
−
      ...
+
−
  }  
+
−
}
+
−
 
+
 
</source>
 
</source>
  
−
== Portlet Example ==
 
−
 
−
A portlet example's source code is available [http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portlets/user/client-context-example url]. It uses both the Client Context library and the PortalManager library, together with the UserManagement library <ref>More information about the UserManagement library are reported [https://wiki.gcube-system.org/gcube/UserManagement_Core here]</ref>, which abstracts Liferay's concepts and map them to gCube's ones. Once deployed on Liferay, the portlets looks like
 
−
 
−
[[File:Contextclientexample.png |200px]]
 
−
 
−
As you can see, the Javascript client code automatically set the user identifier and the context identifier by using the ClientContext methods reported above. By pushing on the button '''Retrieve''', a remote request that has in the header these information is sent to the server side, and the Portal Manager is used to retrieve the current user's username (given the user identifier) and the context (given the group id), as follows:
 
−
 
−
<source lang="java">
 
−
/**
 
−
* Server side implementation.
 
−
* @author Massimiliano Assante at ISTI-CNR (massimiliano.assante@isti.cnr.it)
 
−
* @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
 
−
*/
 
−
public class ClientContextExampleServlet extends RemoteServiceServlet implements GcubeContextExampleServices {
 
−
 
−
    private static final long serialVersionUID = -8208421700660483142 L;
 
−
 
−
    // Logger
 
−
    private static final org.slf4j.Logger logger = LoggerFactory.getLogger(ClientContextExampleServlet.class);
 
−
 
−
    @Override
 
−
    public String getInjectedUserid() {
 
−
 
−
        // Read user id from the request, using the PortalContext
 
−
        try {
 
−
            HttpServletRequest request = this.getThreadLocalRequest();
 
−
            return PortalContext.getConfiguration().getCurrentUser(request).getUsername();
 
−
        } catch (Exception e) {
 
−
            logger.debug("Failed to retrieve the user id", e);
 
−
        }
 
−
        return null;
 
−
    }
 
−
 
−
    @Override
 
−
    public String getInjectedContextid() {
 
−
 
−
        // Read context id from the request, using the PortalContext
 
−
        try {
 
−
            HttpServletRequest request = this.getThreadLocalRequest();
 
−
            return PortalContext.getConfiguration().getCurrentScope(request);
 
−
        } catch (Exception e) {
 
−
            logger.debug("Failed to retrieve the context id", e);
 
−
        }
 
−
        return null;
 
−
    }
 
−
 
−
}
 
−
</source>
 
  
−
The result after the methods invocation is this one
 
  
−
[[File:Contextclientexample_retrievedvalues.png|200px]]
 
  
 
== Tips for Development Environment ==
 
== Tips for Development Environment ==

Revision as of 16:43, 14 November 2016

Client Context library for gCube Portlets

Starting from gCube 4.2, the current Context identifier resides client side. If your Portlet does use AJAX calls (i.e. XMLHttpRequest to exchange data with a server behind the scenes) you don't need this component. Everything is already set up for you by the gCube Portal/Gateway in which your application is running.

If you use standard http GET or POST to exchange data with the server instead, and you need to pass to the server the current Infrastructure scope identifier (the Liferay groupId).

Getting the Client Context in Javascript

var groupId = Liferay.ThemeDisplay.getScopeGroupId();

Getting the Client Context in GWT (Widget)

The Client Context has been wrapped as a GWT Widget. Its source code is available in the gCube SVN repository, at this url.

To use the widget, you need to declare the following maven dependency in your project's pom.xml 

<dependency>
        <groupId>org.gcube.portal</groupId>
	<artifactId>client-context-library</artifactId>
	<version>[1.0.0-SNAPSHOT,)</version>
	<scope>compile</scope>
</dependency>

as well as the following line in the gwt.xml file of your gwt-portlet: 

<!--Inherit the GCubeClientContext widget code -->
<inherits name='org.gcube.portal.clientcontext.GCubeClientContext' />

then you just use the GCubeClientContext.getCurrentContextId() method: 

public static native String getCurrentContextId();



Tips for Development Environment

The client context relies on Liferay.ThemeDisplay javascript object, which obviously is not available if you run your application outside the real D4Science's portals. Moreover, the Portal Manager allows to retrieve the current context, the current user (plus some other information, such as his/her current security token) at server side. To overcome such limitation and allow developers to test their applications in Eclipse, a file like this one can be used: 

# ONLY FOR LOCAL (IDE) DEVELOPMENT - NOT FOR PRODUCTION USE!
# change the properties with your user data and desired scope / token
# Author: Massimiliano Assante, CNR-ISTI
 
# a development user 
user.username=test.user
user.name=aTestName
user.lastname=aTestLastName
user.email=testing.user@gcube-system.org
 
# a development scope (the scope must be bound to the token below)
development.scope=/gcube/devsec/devVRE
 
# a valid user token on the (above) development scope.
# you can obtain it by registering on one development VRE and using Token Generator portlet
user.token= ....


The name of the file must be gcube-dev-context.properties, and must be placed under the CATALINA_HOME system variable. The PortalManager will recognize if the application is running on a real or fake portal and, in the latter case, will retrieve and use the information written in this file.

NOTE : depending on the current implementation, the PortalManager set/doesn't set in the ThreadLocal variables the retrieved user's security Token and current Context, once it is queried for this information. Be sure to always set them in your own code, if you need them.

Retrieved from "https://wiki.gcube-system.org/index.php?title=ClientContextLibrary&oldid=27756"