api.js

GET /invoices
200 OK
{
  [
    {
      "@id": "/invoices/123",
      "status": 0,
      "total": 199.99,
      "actions": [
        { "approve": "/invoices/123/approve" }
      ]
    },
    {
      "@id": "/invoices/456",
      "status": 1,
      "total": 299.99,
      "actions": [
        { "reject": "/invoices/123/reject" }
      ]
    }
  ]
}

GET /invoices/123/approve
200 OK
{
  "fields": [
    { "name": "approver_id", "type": "number", "required": true },
    { "name": "comment", "type": "string" }
  ] 
}

POST /invoices/123/approve
{
  "approver_id" : 789
}
302 FOUND
Location: /invoices/123