# Payloads for the Todo application interop scenario

This document lists the request and response payloads for each of the API requests in the Todo interop scenario.

## Version history
* 2024-09-23: moved all non-`type`/`id` fields in `subject` and `resource` into the respective `properties` field, to make the payloads compliant with AuthZEN 1.0-01 (Implementer's Draft). Also added documentation for the `evaluations` call which leverages AuthZEN 1.1.
* 2024-08-13: added `id` keys to all `subject` and `resource` fields to make them compliant with AuthZEN 1.0-00.
* 2024-02-15: initial draft.

## Overview of the scenario

The Todo application manages a shared todo list between a set of users.

There are 5 actions that the Todo application supports, each with a permission associated with it:

| Action | Permission |
| -------- | -------- |
| View a user's information | `can_read_user` |
| View all Todos | `can_read_todos` |
| Create a Todo | `can_create_todo` |
| (Un)complete a Todo | `can_update_todo` |
| Delete a Todo | `can_delete_todo` |

There are four roles defined:
* `viewer` - able to view the shared todo list (`can_read_todos`), as well as information about each of the owners of a Todo (notably, their picture) (`can_read_user`)
* `editor` - `viewer` + the ability to create new Todos (`can_create_todo`), as well as edit and delete Todos *that are owned by that user*
* `admin` - `editor` + the ability to delete any Todos (`can_delete_todo`)
* `evil_genius` - `editor` + the ability to edit Todos that don't belong to the user (`can_update_todo`)

There are 5 users defined (based on the "Rick & Morty" cartoon), each with one (or more) roles, defined below in the Subjects section.

## Component description

The interop consists of the following components:
- a simple React frontend that manages Todo lists.
- a Node.JS backend that serves 5 routes that the frontend talks to.
- external PDPs provided by the interop participants, which the Node.JS backend calls using the AuthZEN API to issue authorization decisions.

The URIs listed in the document below are the contracts between the React app and the Node.JS backend.

The Node.JS backend will take two environment variables - **AUTHZEN_PDP_URL** and **AUTHZEN_PDP_API_KEY** - and use the **AUTHZEN_PDP_URL** to formulate the REST API call to the PDP, using the **AUTHZEN_PDP_API_KEY** as the Authorization header.

The payloads listed below are the contract between the Node.JS backend and the PDP.

The node.js backend is the PEP.

## Subjects

Note: in every request payload, the subject indicated by `<subject_from_jwt>` is one of the following strings:

| User | PID |
| -------- | -------- |
| Rick Sanchez | CiRmZDA2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs |
| Morty Smith | CiRmZDE2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs |
| Summer Smith | CiRmZDI2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs |
| Beth Smith | CiRmZDM2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs |
| Jerry Smith | CiRmZDQ2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs |

This will be extracted from the `sub` claim in the JWT passed in as a bearer token in the Authorization header of each request, and passed into the AuthZEN request.

## Attributes associated with users (expected to come from PIP)

These are noted below in JSON format, with the key being the PID string from the table above, and the value being a set of attributes associated with the user.

{
  "CiRmZDA2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs": {
    "id": "[e-mail]",
    "name": "Rick Sanchez",
    "email": "[e-mail]",
    "roles": ["admin", "evil_genius"],
    "picture": "https://www.topaz.sh/assets/templates/citadel/img/Rick%20Sanchez.jpg"
  },
  "CiRmZDM2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs": {
    "id": "[e-mail]",
    "name": "Beth Smith",
    "email": "[e-mail]",
    "roles": ["viewer"],
    "picture": "https://www.topaz.sh/assets/templates/citadel/img/Beth%20Smith.jpg"
  },
  "CiRmZDE2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs": {
    "id": "[e-mail]",
    "name": "Morty Smith",
    "email": "[e-mail]",
    "roles": ["editor"],
    "picture": "https://www.topaz.sh/assets/templates/citadel/img/Morty%20Smith.jpg"
  },
  "CiRmZDI2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs": {
    "id": "[e-mail]",
    "name": "Summer Smith",
    "email": "[e-mail]",
    "roles": ["editor"],
    "picture": "https://www.topaz.sh/assets/templates/citadel/img/Summer%20Smith.jpg"
  },
  "CiRmZDQ2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs": {
    "id": "[e-mail]",
    "name": "Jerry Smith",
    "email": "[e-mail]",
    "roles": ["viewer"],
    "picture": "https://www.topaz.sh/assets/templates/citadel/img/Jerry%20Smith.jpg"
  }
}

The PIP can, of course, express this in any way they desire. The policy for each implementation has its own contract with its PIP, and this contract is outside of the scope of the PEP-PDP interop scenario.

## Requests and payloads

Unless otherwise noted, these are payloads for the `evaluation` API, and are meant to be sent using the following HTTP(S) request:

POST /access/v1/evaluation HTTP/1.1
Host: mypdp.com
[Authorization: Bearer <token>]

### `GET /users/{userID}`

Get information (e.g. email, picture) associated with a user. This is used by the backend to render the picture of the user that owns each todo.

For simplicity, the policy always returns `true`.

#### Request payload

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_read_user"
  },
  "resource": {
    "type": "user",
    "id": "<email_OR_subject>"
  },
  "context": {
  }
}

> Notes:
> 1. to make the payload structure interoperable with the original implementation, `subject.identity` is still specified in the payload, even though it is redundant with `subject.type` + `subject.id`.
> 2. likewise, `resource.userID` is still specified, even though it is redundant with `resource.id`.

#### Response payload

For every subject and resource combination:

{
  "decision": true
}

### `GET /todos`

Get the list of todos.

> Note: For the 1.0 Implementer's Draft version of the interop, this call utilizes only the `evaluation` API. The 1.1-preview version of the interop also utilizes the `evaluations` API. See more below.

#### Evaluation API payload

For simplicity, the policy always returns `true` for every user.

##### Evaluation API Request payload

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_read_todos"
  },
  "resource": {
    "type": "todo",
    "id": "todo-1"
  },
  "context": {
  }
}

> Notes:
> 1. `subject.identity` has been removed.
> 2. `resource.type` continues to be `todo`, and `resource.id` is specified as a fixed / stable identifier.

##### Evaluation API Response payload

For every subject and resource combination:

{
  "decision": true
}

#### AuthZEN 1.1-preview semantics

AuthZEN 1.1 provides an `evaluations` API which enables a PEP to "boxcar" a number of authorization requests in a single round-trip.

The Todo Application uses this facility to determine which Todos a user is able to complete, and sends this information to the React front-end to help in rendering Todos that are not completable by the users as "disabled".

##### Evaluations API Request payload

> Note: this payload is intended for the `evaluations` (note plural) endpoint of a 1.1-compliant PDP.

POST /access/v1/evaluations HTTP/1.1
Host: mypdp.com
[Authorization: Bearer <token>]

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_update_todo"
  },
  "resource": {
  },
  "context": {
  },
  "evaluations": [
    {
      "resource": {
        "type": "todo",
        "id": "<uuid-of-the-todo>",
        "properties": {
          "ownerID": "<email_of_owner>"    
        }
      }
    },
    {
      "resource": {
        "type": "todo",
        "id": "<uuid-of-the-todo>",
        "properties": {
          "ownerID": "<email_of_owner>"    
        }
      }
    }    
  ]
}

##### Evaluations API Response payload

The `evaluations` array contains the result of each evaluation request sent in the request payload. For example, for the user Morty, using the following request payload:

{
  "subject": {
    "type": "user",
    "id": "CiRmZDE2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs"
  },
  "action": {
    "name": "can_update_todo"
  },
  "resource": {
  },
  "context": {
  },
  "evaluations": [
    {
      "resource": {
        "type": "todo",
        "id": "7240d0db-8ff0-41ec-98b2-34a096273b9f",
        "properties": {
          "ownerID": "[e-mail]"    
        }
      }
    },
    {
      "resource": {
        "type": "todo",
        "id": "7240d0db-8ff0-41ec-98b2-34a096273b9e",
        "properties": {
          "ownerID": "[e-mail]"    
        }
      }
    }    
  ]
}

The response payload will be:

{
  "evaluations": [
    {
      "decision": false
    },
    {
      "decision": true
    }
  ]
}

This is because Morty cannot update Rick's todo, but can update his own todo.

### `POST /todos`

Create a new todo.

The policy evaluates the subject's `roles` attribute to determine whether the user can create a new todo.

#### Request payload

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_create_todo"
  },
  "resource": {
    "type": "todo",
    "id": "todo-1"
  },
  "context": {
  }
}

> Notes:
> 1. `subject.identity` has been removed.
> 2. `resource.type` continues to be `todo`, and `resource.id` is specified as a fixed / stable identifier.

#### Response payload

Only users with a `roles` attribute that contains `admin` or `editor` return a `true` decision. In the user set above, this includes Rick, Morty, and Summer.

{
  "decision": true
}

For the other two users, Beth and Jerry, the decision is `false`.

{
  "decision": false
}

### `PUT /todos/{id}`

Edit (complete) a todo.

The policy allows the operation if the subject's `roles` attribute contains the `evil_genius` role, OR if the subject's `roles` contains the `editor` role AND the subject is the owner of the todo.

The `resource` contains an attribute called `ownerID` which contains the `id` of the owner (which is defined in the "Attributes" section above, and is the email address of the owner).

#### Request payload

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_update_todo"
  },
  "resource": {
    "type": "todo",
    "id": "<uuid-of-the-todo>",
    "properties": {
      "ownerID": "<email_of_owner>"    
    }
  },
  "context": {
  }
}

> Notes:
> 1. `subject.identity` has been removed.
> 2. `resource.id` is a UUID representing the Todo, but since the PDPs are not assumed to be stateful, `ownerID` continues to be passed in as a way to designate a Todo's owner.
> 3. `resource.ownerID` has been moved to `resource.properties.ownerID`, to make it compliant with AuthZEN 1.0 Implementers Draft.
>
#### Response payload

Only users with a `roles` attribute that contains `evil_genius` (Rick), OR the owner of the todo, return a `true` decision.

For the user Morty, the following request will return a `true` decision:

{
  "subject": {
    "type": "user",
    "id": "CiRmZDE2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs"
  },
  "action": {
    "name": "can_update_todo"
  },
  "resource": {
    "type": "todo",
    "id": "7240d0db-8ff0-41ec-98b2-34a096273b9f",
    "properties": {
      "ownerID": "[e-mail]"    
    }
  },
  "context": {
  }
}

{
  "decision": true
}

For a different value of `ownerID`, the decision will be `false`:

{
  "decision": false
}

### `DELETE /todos/{id}`

Delete a todo.

The policy allows the operation if the subject's `roles` attribute contains the `admin` role, OR if the subject's `roles` contains the `editor` role AND the subject is the owner of the todo.

The `resource` contains an attribute called `ownerID` which contains the `id` of the owner (which is defined in the "Attributes" section above, and is the email address of the owner).

#### Request payload

{
  "subject": {
    "type": "user",
    "id": "<subject_from_jwt>"
  },
  "action": {
    "name": "can_delete_todo"
  },
  "resource": {
    "type": "todo",
    "id": "<uuid-of-the-todo>",
    "properties": {
      "ownerID": "<email_of_owner>"    
    }
  },
  "context": {
  }
}

> Notes:
> 1. `subject.identity` has been removed.
> 2. `resource.id` is a UUID representing the Todo, but since the PDPs are not assumed to be stateful, `ownerID` continues to be passed in as a way to designate a Todo's owner.
> 3. `resource.ownerID` has been moved to `resource.properties.ownerID`, to make it compliant with AuthZEN 1.0 Implementers Draft.

#### Response payload

Only users with a `roles` attribute that contains `admin` (Rick), OR the owner of the todo, return a `true` decision.

For the user Morty, the following request will return a `true` decision:

{
  "subject": {
    "type": "user",
    "id": "CiRmZDE2MTRkMy1jMzlhLTQ3ODEtYjdiZC04Yjk2ZjVhNTEwMGQSBWxvY2Fs"
  },
  "action": {
    "name": "can_delete_todo"
  },
  "resource": {
    "type": "todo",
    "id": "7240d0db-8ff0-41ec-98b2-34a096273b9f",
    "properties": {
      "ownerID": "[e-mail]"    
    }
  },
  "context": {
  }
}

{
  "decision": true
}

For a different value of `ownerID`, the decision will be `false`:

{
  "decision": false
}