/transaction/{dbname}/start:
  post:
    tags:
      - data
    summary: Starts a transaction on a path
    description: Starts a transaction on a path in the database by returning its current value, locking it until the _finish_ endpoint is called. NOTE this API endpoint is also available through the websocket connection, which is the preferred method. This API endpoint is provided for clients not supporting websockets, and those that don't have a websocket connection by choice or because of network limitations.
    parameters:
      - name: dbname
        in: path
        description: name of the database
        required: true
        schema:
          type: string
          example: mydb
      - name: AceBase-Context
        in: header
        description: Contextual info about the database operation (must be valid JSON). This info is included in event notifications sent to clients watching data at this or child paths
        schema:
          type: string
          example: {}
    requestBody:
      description: path to start the transaction on
      content:
        'application/json':
          schema:
            type: object
            properties:
              path:
                type: string
                description: database path
            example:
              path: collection/child/property
    responses:
      200:
        description: returns an object with the transaction id, and the current (serialized) value of the given path
        content:
          'application/json':
            schema:
              type: object
              properties:
                id:
                  type: string
                  description: transaction id
                  example: jld2cjxh0000qzrmn831i7rn
                value:
                  $ref: '#/components/schemas/SerializedValue'
      403:
        description: Returns a "403 Forbidden" if the signed in user is not allowed to write to the target path
        content:
          'application/json':
            schema:
              $ref: '#/components/schemas/Error'
      500:
        description: An unexpected error occurred
        content:
          'application/json':
            schema:
              $ref: '#/components/schemas/UnexpectedError'