The document describes how to connect RingCentral APIs to send SMS messages using Mulesoft Mule 4. It involves creating a Mule application with a flow containing an HTTP listener, payload transformer, and HTTP request to call the RingCentral send SMS API. The flow first calls the RingCentral authorization API to get an access token, stores it in a variable, and passes it in the header when calling the send SMS API. This allows the application to authenticate and send SMS texts via the RingCentral API using Mule 4.

1. Anirban Sen Chowdhary
Mule 4 connecting RingCentral

2. RingCentral as we all familiar with, deals with different kind of APIs that
offers reliable VoIP calling, web meetings, fax, & more features over
cloud communication.
Mulesoft on other hand provides the most widely used integration
platform to help businesses connect data, applications and devices
across on-premises and cloud environment.

3. The most recent version of Mulesoft is Mule version 4 or simply called
Mule 4 which simplifies the expression language and reduces
management complexity compared to it's previous versions.
In this blog we will see a simple demo of Mule 4 connecting RingCentral
APIs. We will connect RingCentral send SMS API with Mule 4 and will
try to send SMS from Mule 4 application.

4. Mule 4 has a great improvement compared to it's previous versions
that includes many features like:
• Seamless access to data with new expression
• Repeatable streaming which is a new feature
• New error handling features
• Self-tuning capabilities like threading, exchange pattern etc
• New connectors

5. Before we start, we know that the RingCentral API for sending SMS is:
POST
https://platform.devtest.ringcentral.com/restapi/v1.0/account/accou
ntId/extension/extensionId/sms
The request for the API is in below format:

6. Let's start by creating a new application in Mule 4 as below:

7. Once the application is created, we will create a following flow with a
Http listner, a payload transformer that will transform every incoming
payload request into json mime type followed by a Http request
component which will call the external RingCentral send SMS API as
below:

8. Next step is to configure the Http request element which will consume
and call RingCentral send SMS API as below:

9. If you noticed, we have configured with RingCentral platform with Http
protocol as HTTPS and port 443.
Then we configured the flow HTTP component with RingCentral send
SMS url base path:

10. Configuring Authentication
The last step before we call the RingCentral send SMS API via Mule 4
application, we need to configure the Authentication part as every
RingCentral API is secured with Oauth.
We will design a sub flow, that will call RingCentral Authorization API
and generate the access_token (Since RingCentral Create SMS API is
secured by Oauth and access_token is needed to send the SMS) as
below:

11. Here in this sub flow also have a Http component that calls RingCentral
Authorization API and collect the access_token in a variable. This
access_token variable will be internally pass to RingCentral Create SMS
API when we call that in our main flow (SendSMS).
The Http component for Oauth token call is configured below with
RingCentral Authentication API url:

12. The input request of RingCentral Authentication API to get
access_token is as below:

13. In the main flow, we call this Oauth sub flow before we call RingCentral
send SMS API to get the access_token and send the SMS text as below
via flow reference:

14. The access_token will be passed via header in the Http component:
Once we start the application, the application will be deployed and the
first step in the flow will be the RingCentral authentication API will be
called and once the access_token is collected in the variable, it's passed
in the main RingCentral send SMS API via header and the SMS is send!
We will see the testing of this application in the next part.