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Notehub.io can support a broad range of API endpoints by utilizing the Route feature. This guide provides instructions for leveraging the General HTTP/HTTPS Request/Response Route type to invoke the Twilio API, thus enabling your Notecard applications to communicate and send alerts over SMS.

In order to follow the instructions in this guide, you'll need the following:

  • A Notecard assigned to a Notehub.io project, with data synching from the Notecard to Notehub.io.
  • A Twilio account , with at least one Verified Caller ID established. A verified caller ID is required in order to send messages from your Twilio account. Typically, this would be your personal telephone number.

To send SMS messages, the Twilio API expects form data with three key/value pairs (Body, From and To). Transforming a Note body into an HTTP body for Twilio requires some special handling. This can be achieved using a JSONata expression to massage the data into the desired form. JSONata is traditionally used to transform input data into output JSON, but it can also be used, with a couple of tricks, to craft a standard HTTP body.

In JSONata, the string "Hello, world!" is rendered as "Hello, world!", quotation marks included. This causes a problem, because the content type, application/x-www-form-urlencoded, is not expecting enclosing quotation marks. Fortunately, you can prefix a string with an ampersand (&) and JSONata will interpret the leading quotation mark (") as an empty form parameter of the same name. Likewise, an ampersand at the end of the string interprets the final quotation mark as a redefinition of the earlier dummy parameter. Upon receipt, Twilio discards the unknown parameter, and continues parsing the incoming request.

note

The complete Twilio route configuration is displayed at the bottom of the page if you want to skip ahead to the end.

  1. Navigate to the Notehub.io Route creation screen and click the Add Route button.

    Notehub.io: Route creation

  2. Select the General HTTP/HTTPS Request/Response route type.

  3. Give the route a name, and then set the URL to your Twilio Messages endpoint. For example, https://api.twilio.com/2010-04-01/Accounts/[twilio_account_sid]/Messages.json

    Be sure to replace [twilio_account_sid] with your Twilio "ACCOUNT SID".

  4. To safeguard yourself, you should update the Rate Limit dropdown, with the Limited Request Rate and set the Requests per Second to 1. This may help to prevent you from accidentally exhausting your Twilio credit.

  5. The Twilio API expects two headers with each request. Select the Additional Headers option from the HTTP Headers dropdown, and set the Authorization and Content-Type headers in the following steps.

  6. For the first header, set the name as Authorization, and set the value to Basic followed by your authorization token. This token can be generated by base 64 encoding your Twilio account SID and authentication token, with a colon separating the two (account_sid:auth_token). You can obtain the Account SID and Token from your Twilio dashboard.

    This value will end up looking something like: Basic QUMwNW...lYWE2Y2Jkw==.

    Twilio.com: Account credentials

  7. For the second header, set Content-Type as the name and application/x-www-form-urlencoded as the value. This will ensure that events are properly sent to the Twilio API as form data.

  8. Specify which Notes should be sent via SMS, by updating the Select Notefiles field to twilio.qo.

  9. From the Transform JSON dropdown, select JSONata Expression.

  10. In the JSONata Expression field, enter the expression "&Body=" & body.body & "&From=" & body.from & "&To=" & body.to & "&".

    note

    You are not limited to the body of the Note when crafting a message to send to Twilio. You may utilize hardcoded strings for testing, or any key from the associated Event JSON.

    In this example, it could be particularly useful if you wanted to know which Notecard had generated the SMS message.

  11. Lastly, ensure the route is enabled, and click Create Route.

Notehub.io: Twilio Route 1 Notehub.io: Twilio Route 2

The Notecard request required to provide the parameters consumed by the JSONata Expression provided above is fairly straight-forward.

  1. Expand the web console, and connect to your Notecard.

    Notehub.io: Web Console Button

  2. Update the configuration to minimize latency (for the sake of the demonstration).

    {
    "req": "hub.set",
    "product": "com.example.user:twilio",
    "mode": "continuous",
    "sync": true
}
    note

    Be sure to substitute your product's actual ProductUID for the example string provided above.

  3. Queue the following Note onto the twilio.qo output queue.

    {
    "req": "note.add",
    "file": "twilio.qo",
    "sync": true,
    "body": {
        "body": "Hello from Notecard!",
        "from": "+1251577xxxx",
        "to": "+1314359xxxx"
    }
}

    The from number must match your Twilio account number.

    Twilio.com: Your Twilio number

    The to number must be a number from your list of Verified Caller IDs.

    Twilio.com: Your Verified Caller IDs

    note

    The numbers provided MUST be formatted in the manner specified by the E.164 international telephone numbering plan .

Once you've created a Twilio Route in Notehub, you can verify that it is working through the Notehub Events table, Webhook.site, Twilio.com, or by looking at your phone.

Notehub.io provides a Route Log for each event. To access it, click on an individual event on the Events view, then click the "Details" link.

Then, click on the "Route Log" tab. If your Twilio Route is properly configured, the response from Twilio will be a JSON object describing the message results.

If the server returns an error, Notehub.io will display error details in the Route Log.

Since we are pushing Notehub to its limits, it can be difficult to diagnose any errors you encounter. To make it easier, we can route our event information to Webhook.site and see the actual output of our JSONata expression. Using Webhook.site is easy. To get started, navigate to https://webhook.site and get a session specific endpoint so you can route your events.

Webhook.site: Homepage

Update the Route URL of your Notehub Route to direct your events to Webhook.site.

Webhook.site: Requests

Look to the Form values section, and ensure your form data looks correct.

After messages have been received by the Twilio API, Twilio provides the Programmable Messaging Dashboard to view your messages and statistics.

Twilio.com: Programmable Messaging Dashboard

SMS Note

If you have configured everything correctly, Route verification should only be as far away as your pocket!