JsonEventFormatter throws exception when charset is included

[cecilphillip]

In my AspNetCore app, calling HttpContext.Request.ToCloudEventAsync(new JsonEventFormatter()) fails when the datacontenttype property includes the charset. It throws the following exception =>

CloudEvents with a non-JSON datacontenttype can only have string data values.

The following is a sample request that was generated by Dapr.

{
  "id": "126e4073-152e-4abe-b638-d1c2c7a79348",
  "specversion": "1.0",
  "topic": "fulfill.order",
  "pubsubname": "rabbitmqbus",
  "datacontenttype": "application/json; charset=utf-8",
  "source": "website",
  "type": "com.dapr.event.sent",
  "data": {
    "stuff": "value"
  }
}

When the charset is removed, the code works fine.

UPDATE
Just digging around the source seems to be coming from here.

I don't know what the spec says about including charsets. Otherwise, maybe we can use this check instead

ContentType dataContentType = new ContentType(cloudEvent.DataContentType);
if (IsJsonMediaType(dataContentType.MediaType))

[jskeet]

Thanks, I'll have a look tomorrow.

[jskeet]

Yes, it looks like the check you've suggested is the right one - that's what we do everywhere else.