Emailer app

The "Emailer" application provides a basic web form for filling in basic email details for submitting messages:

• email from which the message is submitted
• name of the sender
• recipient email address
• subject of the message
• text (the message itself)

Flow

1. A user fills the email details and submits the message
2. The html form is passed to the RESTfull backend application
3. The backend recieves the details as parameters and builds a "Request" prototype object
4. According to the current (at run-time) active email provider, the application formats the request object and creates a body, which is applicable to the respective 3rd party email provider's API
5. The backend sends a client request, containing the data previously received by the user and receives a response from the provider
6. The response from the mail provider is validated and if it contains "error" a failover is executed, switching the processing to the alternative mail provider
7. Another request is sent, this time to the newly activated provider. If it fails an error message is returned to the user
8. Message submission status is returned to the user.

FE validations

The fields for sender and recipient email are bundled with syntax validation upon exiting the HTML field focus - should follow the john@foobar.com template. They are also "required" so that the user cannot even submit the form without values in it.

Technology stack choice

I've chosen to write the back-end application in Java and have it compiled with Maven as war file, because thisway provides easy method for integrating different libraries (including such as the ones provided by the email engine providers) I have developed it locally, running it in JBoss 7.1 container server as this is the web server I have most experience with. I think JBoss can provide scaling and customization of the running application, including environment specific configuration management.

List of used technology

• Java - jdk1.6.0_43
• Maven - 2.2.1
• TestNG - 6.8.5
• Jboss 71

Dependencies:

• org.codehaus.jackson libraries for structured data binding and parsing
• org.jboss.resteasy.resteasy-jaxrs library for RESTful interface implementation (as it is suitable for the preferred deployment platform mentioned above)

Services

/emailer/home - email form /emailer/provider - return the currently actrive mail provider

#Personal notes: The main web service in the back end (POST /message/submit) is designed to always try with the alternative mail provider if the first request fails. I've tried to make the back-end application as much moduled as possible in order to make integrating a new mail provider easier.

How to deploy

1. Build - mvn clean install
2. Download Jboss standalone server and unzip it: http://jbossas.jboss.org/downloads/
3. Change the Jboss/bin conf files for JAVA_HOME variable to point to your local JDK installation
4. Start the JBoss standalone server
5. Copy the emailer artifact to jboss/standalone/deployments directory
6. localhost:8080/emailer/home