Send a Facebook message with failover

In this example you will send a Facebook Messenger message that fails over to sending an SMS. In the Workflow object message objects can be placed in any order to suit your use case. Each message object must contain a failover object, except for the last message, as there are no more message objects to failover to.

For a step-by-step guide to this topic, you can read our tutorial Sending Facebook message with failover.

Example

Ensure the following variables are set to your required values using any convenient method:

Key	Description
`VONAGE_APPLICATION_ID`	The Vonage Application ID.
`FROM_NUMBER`	Replace with number you are sending from. E.g. `447700900002`
`TO_NUMBER`	Replace with the number you are sending to. E.g. `447700900001`
`FB_SENDER_ID`	Your Page ID. The `FB_SENDER_ID` is the same as the `to.id` value you received in the inbound messenger event on your Inbound Message Webhook URL.
`FB_RECIPIENT_ID`	The PSID of the user you want to reply to. The `FB_RECIPIENT_ID` is the PSID of the Facebook User you are messaging. This value is the `from.id` value you received in the inbound messenger event on your Inbound Message Webhook URL.

NOTE: Don't use a leading + or 00 when entering a phone number, start with the country code, for example 447700900000.

Prerequisites

If you do not have an application you can create one. Make sure you also configure your webhooks.

Write the code

Add the following to send-message-with-failover.sh:

curl -X POST https://api.nexmo.com/v0.1/dispatch \
  -H 'Authorization: Bearer '$JWT\
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json' \
  -d $'{
    "template":"failover",
    "workflow": [
      {
        "from": { "type": "messenger", "id": '$FB_SENDER_ID' },
        "to": { "type": "messenger", "id": '$FB_RECIPIENT_ID' },
        "message": {
          "content": {
            "type": "text",
            "text": "This is a Facebook Messenger Message sent via the Dispatch API"
          }
        },
        "failover":{
          "expiry_time": 600,
          "condition_status": "read"
        }
      },
      {
        "from": {"type": "sms", "number": '$FROM_NUMBER'},
        "to": { "type": "sms", "number": '$TO_NUMBER'},
        "message": {
          "content": {
            "type": "text",
            "text": "This is an SMS sent via the Dispatch API"
          }
        }
      }
    ]
  }'

View full source

Run your code

Save this file to your machine and run it:

bash send-message-with-failover.sh

Try it out

When you run the code it will attempt to send a message via Facebook Messenger. This will fail and then a message will be sent via SMS to the destination number.