Batch Operations

Processing Similar Resources

An operation that needs to process several related resources in bulk SHOULD uses a collection resource with the appropriate HTTP Request Method. When processing existing resource the request message body MUST contain the URLs of the respective resources being processed.

Example

Create Multiple Orders at Once

POST /orders
Content-Type: application/json

{
  "order": [
    {
      "itemCount": 42
    },
    {
      "itemCount": 2
    }
  ]
}

Update Multiple Orders at Once

NOTE: The self-link relation identifies the existing resource being edited.

PATCH /orders
Content-Type: application/json

{
  "order": [
    {
      "_links": {
        "self": { "href": "/order/1"}
      },
      "itemCount": 42
    },
    {
      "_links": {
        "self": { "href": "/order/2"}
      },      
      "itemCount": 2
    }
  ]
}

Results of Bulk Operation

Every bulk operation MUST be atomic and treated as any other operation.

The server must implement bulk requests as atomic. If the request is for creating ten addresses, the server should create all ten addresses before returning a successful response code. The server should not commit changes partially in the case of failures.

DO NOT USE "POST Tunneling."

Every API MUST avoid tunneling multiple HTTP Request using one POST request. Instead, provide an application-specific resource to process the batch request.

Non-atomic Bulk Operations

Non-atomic bulk operations are strongly discouraged as they bring additional burden and confusion to the client and are difficult to consume, debug, maintain and evolve over the time.

The suggestion is to split a non-atomic operation into several atomic operations. The cost of few more calls will be greatly outweighed but the cleaner design, clarity and easier maintainability.

However, in such an operation has to be provided such a non-atomic bulk operation MUST conform to the following guidelines.

1. Non-atomic bulk operation MUST return a success status code (e.g. 200 OK) only if every and all sub-operation succeeded.

2. If any single one sub-operation fails the whole non-atomic bulk operation MUST return the respective 4xx or 5xx status code.

3. In the case of a failure the response MUST contain the problem detail information about every sub-operation that has failed.

4. The client MUST be aware that the operation is non-atomic and the even the operation might have failed some sub-operations were processed successfully.

Example

Non-atomic request for creating four orders:

POST /orders
Content-Type: application/json

{
  "order": [
    {
      "itemCount": 42
    },
    {
      "itemCount": -100
    },        
    {
      "itemCount": 42
    },
    {
      "itemCount": 1.3232
    }
  ]
}

And the error response:

HTTP/1.1 400 Bad Request
Content-Type: application/problem+json

{
  "type": "https://example.net/partial_operation_failure",
  "title": "Partial Failure",
  "detail": "Some orders couldn't be created, other orders were created.",

  "errors": [
    {
      "type": "https://example.net/invalid-params",
      "instance": "/orders/1",
      "title": "Invalid Parameter",
      "detail": "itemCount must be a positive integer",
      "status": 400
    },
    {
      "type": "https://example.net/invalid-params",
      "instance": "/orders/3",
      "title": "Invalid Parameter",
      "detail": "itemCount must be a positive integer",
      "status": 400
    }
  ],

  "processed": ...
}

The processed field should contain the result of processed sub-operations as if they were returned in a 200 OK.