subject-malformed

• Routes: write-events, read-events, observe-events, and read-subjects
• Description: subject is malformed: expected a slash-separated path such as '/books/42'
• Details: value, the subject as the request gave it. When writing events, also event or precondition, the place of the event or the precondition in its list, counting from 0. When reading or observing events, also option, which is fromLatestEvent where the subject is the one of that option; without it, the subject is the one to read or observe.

Why It Happens#

A subject is a path that starts with a slash, with segments separated by slashes, each made of letters, digits, underscores, and hyphens only. A subject without its leading slash, such as books/42, or with a space, a dot, or another character, such as /books/42.json, is refused.

When reading or observing events, the subject can be the one to read or the one of fromLatestEvent; the details tell them apart by option, which only the second has.

How to Fix It#

Send the subject as a slash-separated path, such as /books/42. If you build subjects from values such as names or file names, replace the characters that a subject does not allow.

Example#

To read the events of books/42, without the leading slash, EventSourcingDB answers with this error, as a line of the stream, and then ends the stream with its end item:

{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/subject-malformed",
    "description": "subject is malformed: expected a slash-separated path such as '/books/42'",
    "details": {
      "value": "books/42"
    }
  }
}