isCloudEvent Function

[grant]

Describe the Bug

Is there an easy way to determine if a HTTP request is a CloudEvent or not?

It would be great if there was a isCloudEvent function or something similar. Maybe just documentation if we can re-use existing functions together to achieve this.

Steps to Reproduce

• Try to find a function to determine if a HTTP request is a valid CE

Expected Behavior

• Documentation in the main README for how to determine if a HTTP req is a CE

[lance]

We do not have that in this module, although I can see it being useful. For a current project I am working on, we do this before trying to parse the event.

https://github.com/boson-project/faas-js-runtime/blob/master/lib/event-handler.js#L32-L48

[grant]

@lance What do you think about this logic?

https://github.com/cloudevents/sdk-javascript/blob/master/src/event/cloudevent.ts

• static CloudEvent#isBinary
  • True if HTTP request has 4 required CE headers, otherwise false

[lance]

Hmm - I don't think that it makes sense for a static isBinary method on CloudEvent because a CloudEvent itself is neither binary or structured. Those are just transport representations and really only make sense in the context of an incoming request over a transport protocol.

This would make more sense as a standalone function in cloudevents/transport/http. The logic for an isCloudEvent (distinct from isBinary) method should be something like this:

• if the content-type header is set to an event format media type return true (it's a structured event)
• if the ce-id, ce-type, ce-source and ce-specversion headers exist return true (it's a binary event)
• else return false

[grant]

Yup, adding the method to the HTTP transport files instead of CloudEvent files makes sense.