WSO2 Governance Registry generates notifications for events triggered by various operations performed on resources and collections stored in the repository. Notifications can be consumed in a variety of formats including E-mail. Read more about Notifications and also the API-Level Access provided for subscription operations. The contents of notification E-mails can be customized by using an Axis2 Handler. WSO2 Governance Registry contains an Apache Axis2 based runtime as a part of the WSO2 Carbon Framework. We will be reusing the code of the Handler Sample in this example. This sample requires Apache Maven. See System Requirements for links on how to install it.
This sample also includes two advanced use-cases which have been included at the bottom of this page.
1. Navigate to
samples/handler/src to find the source code of the Handler Sample.
2. Add a new Java Class named
GREG_HOME/samples/handler/src/src/main/java/org/wso2/carbon/registry/samples/notifications/EmailTransformHandler.java with the following source:
In order to add HTML formatted responses in your e-mail, you need to set the content type of the outgoing e-mail messages to
text/html. This can be done as shown below.
msgContext.getOptions().setProperty(MailConstants.TRANSPORT_MAIL_CUSTOM_HEADERS, Collections.singletonMap("Content-Type", "text/html"));
3. Compile the source code by running the following command inside
mvn clean install will trigger an Apache Maven Build in your command line. This requires you having installed Apache Maven. See System Requirements for links on how to install it.
A successful run of Apache Maven will generate a report similar to the following:
4. Copy the <
org.wso2.carbon.registry.samples.handler-5.3.0.jar file into the <
5. Add the
EmailTransformHandler to the
MessageOut phase in the
axis2.xml file already includes a
phaseOrder section with the
OutFlow type. You can either replace it with the content above, or simply add the
EmailTransformHandler to the
This might be useful if you have already defined any other handlers in the Out Flow.
6. Configure Governance Registry to send e-mails in
7. Start the server and observe the command prompt. See Running the Product for more information.
8. Navigate to the /collection of the Resource Browser and add an E-mail subscription for Update events.
9. Click on the E-mail Address verification link that you will receive via E-mail.
In this example, John Smith uses a Gmail account.
10. Make some update to the Root collection like adding a new property. Read Properties to learn how to add a new property.
11. You should now receive a Notification E-mail which contains the following text:
Advanced Use-case 1
This sample can be improved to include a clickable link in the E-mail body, making it possible for users to easily navigate to the resources in which changes have been made. The following modification can be made to the code segment to achieve this:
In this example, John Smith uses a Gmail account. Gmail automatically converts URLs into clickable links. This might not be the case if you are using a traditional E-mail client. In such situations, you might have to embed HTML syntax to convert your URL into a clickable link.
In here, the link that we have used requires the user to sign-in to the management console to browse the resource. Such notifications are useful for approvals. However, there can be situations where those who approve do not need to sing-in to the management console. Such situations can be addressed by providing a clickable link that directs the user to a web service hosted on Governance Registry which does not require authentication. Learn more on how to add web services to Governance Registry by following the Endpoint Look-up Sample.
Please be informed that this might introduce a security risk unless necessary precautions have been taken. As a precaution, for example, a token can be generated at the point of notifying the user, which will also appear on the URL within the E-mail. The web service logic can validate the presence of this token to prevent fraudulent access.
Advanced Use-case 2
This sample can be improved to restrict which users will receive an E-mail notification. For example, it might be required to get an approval from a particular group of users before moving from one state to another. However, this E-mail might not make sense to be delivered to John Smith or Joe Bloggs. The following modification can be made to the code segment to restrict the recipients such that John Doe will receive this E-mail though John Smith or Joe Bloggs would not.
In this example we have used the default
ServiceLifeCycle. We have made the restriction in the code above for the event triggered by checking of the
Smoke Test Passed checklist item of the
Testing state. We have assumed that the
Promote button which takes you to the
Production state will be restricted to the role to which John Doe belongs. Note that the Transition Permissions must be properly set.
We have also assumed that the
Smoke Test Passed checklist item will be the last to be checked in the
Testing state and that the immediate next step would be the promotion to the
Production state. Because only some users belonging to a particular role (such as John Doe in this case) will get the option to promote, it is required to keep the corresponding users informed, but not spam the others. This can be done by subscribing all users and blacklisting the ones who do not require receiving the E-mails. See below to learn how to subscribe all users for the
Check LC Item event.
For this to work, each user on Governance Registry should fill out their User Profile.
In here, we have enumerated a list of E-mail addresses that would be treated as blacklisted. However, in a real-world scenario it might be cumbersome to hard-code all E-mail addresses. In such situations the User Management APIs of Governance Registry can be used. The
UserRealm can be obtained from the The RegistryService Interface. This provides operations for managing users and roles. The E-mail address for a particular user can be obtained using claims.
An Axis2 Handler must implement the
org.apache.axis2.engine.Handler interface and can optionally extend the
org.apache.axis2.handlers.AbstractHandler class. Read more about Axis2 Handlers to get a better understanding of their uses.