Context

I am working with a service that consumes CloudEvents produced by another service using the CloudEvents .NET SDK.

The issue arises with the data_base64 field in the messages produced by the second service. Specifically, this field contains the character sequence \u002B, which represents the + character. According to the specification RFC4648, the backslash character (\) is not permitted, leading to potential parsing errors.

Upon encountering this issue, I reported it to the CloudEvents C# SDK repository. In response, John Skeet clarified that the use of \u002B to represent the + character is a valid encoding method within JSON, and the + itself is indeed a valid character according to RFC4648.

This suggests that the handling or decoding of such sequences needs to be managed correctly by the consuming application or library.

Steps to reproduce

// simplified event based on jskeet input
jsonData := `{
	    "specversion": "1.0",
	    "id": "00716a6e-6063-43d3-8717-66888f060055",
	    "source": "urn:aws-global:7777",
	    "type": "updated.v1",
	    "datacontenttype": "application/octet-stream",
	    "data_base64": "\\u002B\\u002B\\u002B\\u002B"
	}`

var eventWithBase64Data cloudevents.Event
if err := json.Unmarshal([]byte(jsonData), &eventWithBase64Data); err != nil {
	slog.Error("Failed to unmarshal cloudevent JSON", err)
}

/// output:
/// ERROR Failed to unmarshal cloudevent JSON !BADKEY="illegal base64 data at input byte 0"