CPS Delta between an anchor and JSON payload API proposal

Overview

The second API proposed under the Delta feature is to generate a delta between configuration stored under an Anchor and JSON payload provided by the user. All the responses and exceptions thrown by this API will be similar to the API to generate delta between 2 anchors to maintain consistency between the API's.

Issues & Decisions

Questions/Issues	Decisions/Answers
Should the "descendants" option be provided as part of the API? The JSON payload may or may not contain all the child nodes. Hence there is always the uncertainty. So, would it be a better approach to fetch all descendants always?

HTTP response codes for Delta between Anchor and Payload API

The proposed API will be part of the CPS Data Interface. The following response codes will be returned by the API:

#

Sub Interface

Method

Scenario

HTTP Response codes

to be implemented

Notes

1

Data

Proposed API:

GET- /v2/dataspaces/{dataspace-name}/anchors/{anchor-name}/delta?anchor2={anchor-name}?xpath={xpath}&descendants={descendants}

Proposed method name: getDeltaByDataspaceAnchorAndPayload()

Generate a delta report between an anchor and JSON payload

200 (OK)
- success
400
- dataspace not found
  DataspaceNotFoundException
- anchor not found
  AnchorNotFoundException
- Data node not found
  DataNodeNotFoundException
- invalid xpath
  CpsPathException
500
- unexpected error

Request parameters:

Parameter name	In	Required	Description
dataspace-name	Path	Yes	Dataspace name
anchor1	Query	Yes	First Anchor Name/Reference Anchor
anchor2	Query	Yes	Second Anchor Name
xpath	Query	Yes	xpath of the node
descendants	Query	No	Level of descendants for delta comparison.

Response Body/Delta Report Format

Response body should contain anchors delta report (added/deleted/modified configuration) as below.

[
  {
    "action": "ADD",
    "xpath": "/bookstore/categories/[@code=3]",
    "payload": {
      "code": 3,
      "name": "kidz"
    }
  },
  {
    "action": "DELETE",
    "xpath": "/bookstore/categories/[@code=1]",
    "payload": {
      "code": 1,
      "name": "Fiction"
    }
  },
  {
    "action": "UPDATE",
    "xpath": "/bookstore/categories/[@code=2]",
    "payload": {
      "name": "Comic"
    }
  }
]

Space shortcuts

Page tree

Overview

Issues & Decisions

HTTP response codes for Delta between Anchor and Payload API

Request parameters:

Response Body/Delta Report Format

Mechanism for Delta generation between Anchor and Payload