Sending an email using WSO2 Gmail Connector

The Gmail connector allows you to access the Gmail REST API through WSO2 ESB and send an Email. Gmail is a free, Web-based e-mail service provided by Google. 

First download the Gmail Connector from WSO2 store. And Start the WSO2 ESB server using below steps.

• download the ESB runtime ZIP file, and then extract the ZIP file.
  The path to this folder will be referred to as <ESB_HOME> throughout the post.
• Navigate to the <PRODUCT_HOME>/bin/ directory using the Command Prompt.
• To start the server in a typical environment:
  
  • On Windows:  wso2server.bat --run
  • On Linux/Mac OS:  sh wso2server.sh
• To start the server in the background mode of Linux: sh wso2server.sh start
  To stop the server running in this mode, you will enter: sh wso2server.sh stop
• now go to https://localhost:9443/carbon and log into the management console
using  username admin and password admin

Step 1 : 

Now go to  Home -> Manage -> Connectors -> Add. 

Upload the downloaded Gmail Connector zip file. Then change the status as enabled.

Step 2 :

Then create a custom proxy service with the name as Send_email_proxy and go to the source view. 

copy and paste below source code to your source

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="Send_email_proxy"
       transports="http,https"
       statistics="disable"
       trace="disable"
       startOnLoad="true">
   <target>
      <inSequence>
         <property name="userId" expression="json-eval($.userId)"/>
         <property name="accessToken" expression="json-eval($.accessToken)"/>
         <property name="apiUrl" expression="json-eval($.apiUrl)"/>
         <property name="to" expression="json-eval($.to)"/>
         <property name="subject" expression="json-eval($.subject)"/>
         <property name="from" expression="json-eval($.from)"/>
         <property name="messageBody" expression="json-eval($.messageBody)"/>
         <gmail.init>
            <userId>{$ctx:userId}</userId>
            <accessToken>{$ctx:accessToken}</accessToken>
            <apiUrl>{$ctx:apiUrl}</apiUrl>
         </gmail.init>
         <gmail.sendMail>
            <to>{$ctx:to}</to>
            <subject>{$ctx:subject}</subject>
            <from>{$ctx:from}</from>
            <messageBody>{$ctx:messageBody}</messageBody>
         </gmail.sendMail>
         <respond/>
      </inSequence>
   </target>
   <description/>
</proxy>

Step 3:

Now you need to create an app to connect to Gmail API.The Gmail API uses OAuth2 authentication with acessToken. Go to OAuth 2.0 Playground and select the needed API s and authorize them using your gmail account. Click on Exchange authorization code for tokens in the next window and copy the access_token code from the JSON response.

Step 4:

Now we are ready to test our proxy service. We can test our proxy using Postman by sending a JSON request as follows.

I got a new email with "wso2 gmail connector" as the subject.

Reference :

[1] https://docs.wso2.com/display/ESBCONNECTORS/Gmail+Connector

[2] https://docs.wso2.com/display/ESBCONNECTORS/Configuring+Gmail+Operations