Add sample image in template header in whatsapp cloud API

I am doing a project using WhatsApp cloud API. I need to create a template with a media header. I have created a template with a media header without a sample image and it gets rejected. So I want to create a template with a sample image in Node.js.

Template with a media header:

Add sample image for a template:

curl -X POST "https://graph.facebook.com/v14.0/{whatsapp-business-account-ID}/message_templates
  ?name={template-name}
  &language=en_US
  &category=TRANSACTIONAL,
  &components=[{
       type:BODY, 
       text:{message-text}
     }, 
     {
       type:HEADER, 
       format:IMAGE, 
       example:{header_handle:[{uploaded-image-file-url}]}
     }],
  &access_token={system-user-access-token}"

I want to add a sample image using Node.js (not manually like the second picture).

header_handle requires a encrypted file upload provided by facebook.

This can be done by calling 2 apis.

First, We have to create a session for the file to be uploaded. For creating session refer this

After creating session, we will get session id to upload the original file to it.Response will look something like this:

{"id":"upload:MTphdHRhY2htZW50Ojlk2mJiZxUwLWV6MDUtNDIwMy05yTA3LWQ4ZDPmZGFkNTM0NT8=?sig=ARZqkGCA_uQMxC8nHKI"}

Second,We have to upload the file to https://graph.facebook.com/v14.0/{above_id}

This will give a response something similar to

{"h":"2:c2FtcGxlLm1wNA==:image/jpeg:GKAj0gAUCZmJ1voFADip2iIAAAAAbugbAAAA:e:1472075513:ARZ_3ybzrQqEaluMUdI"}

Finally,

{header_handle:["2:c2FtcGxlLm1wNA==:image/jpeg:GKAj0gAUCZmJ1voFADip2iIAAAAAbugbAAAA:e:1472075513:ARZ_3ybzrQqEaluMUdI"]}

Should be added during the request to create template.

It worked for me.

See this for better understanding on how to do it.