In modern web apps, the window.postMessage()
method is commonly used to enable secure communication between different origins. However, if not properly managed, the use of this method can lead to unintended behaviors.
Issue
The Pendo agent uses postMessage
events for communication between different origins. If your app also uses postMessage
events but doesn't properly distinguish between the postMessage
events being generated by Pendo and those generated by your app, there's a risk of processing unintended postMessage
events from the Pendo agent.
This can cause unexpected POST request errors because your application might be expecting a particular format or set of data that isn't present in the postMessage
events from Pendo.
Solution
This solution is one example approach to securing your application. Consider implementing selective processing logic within your postMessage
listener based on message origin and content.
-
Include a unique token in your messages. Modify the sending part of your application to include a unique
type
field with a value likecustomerNamespace:MessageName
. -
Validate incoming messages. Update your message event listener to check for the presence and value of this unique
type
field before processing any messages. Additionally, verify the origin and destination to ensure it matches your expected sender.
Here's an example implementation:
// Sending a message
window.postMessage({ type: 'customerNamespace:MessageName', data: yourData }, 'https://your-app.com');
// Listening for messages
window.addEventListener('message', function(event) {
// Check the origin of the message
if (event.origin !== 'https://your-app.com') return;
// Check the type of the message
if (event.data.type && event.data.type.startsWith('customerNamespace:')) {
// Process the message
handleMessage(event.data);
}
});
function handleMessage(data) {
// Your custom message handling logic
}
While this article demonstrates a basic validation method, it's essential to adapt the security measures to fit the specific needs and security requirements of your application.