JMAP REST Mapping

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Table of Contents

1. Introduction

Structured data exchange over JMAP [RFC8620] usually involves processing JMAP Request JSON payloads. This might impose unnecessary requirements for certain use cases of JMAP. Likely scenarios in which this is beneficiary are situations in which portability needs to be provided due to regulatory requirements or when migrating user data away from legacy platforms.¶

For rapid development of a JMAP API, the essential properties of the Request object can instead be implemented as a URI.¶

2. Changes to structured data exchange

Clients make API Requests by issuing authenticated POST requests to the API resource, defined by the apiUrlRest property of the Session object.¶

The request typically consists of a single JSON-encoded Request object, as defined in [RFC8620] Section 3.3. Requests with a JSON body MUST be of type application/json. The response MUST be of type application/json and typically consists of a single Response object, as defined in [RFC8620] Section 3.4.¶

Properties referenced via variables in the apiUrlRest property MAY be omitted by clients in the POST request body. If all properties of a method call can be supplied as URL parameters, the methodCalls property ([RFC7540] Section 3.3) can be omitted completely in the request. Clients issuing an API request for which all properties of the request can be supplied as URL parameters MAY omit the application/json type and the whole JSON body.¶

The method call id in the Invocation object of JMAP Responses to JMAP REST requests SHOULD be set to empty string.¶

JMAP allows to batch multiple method calls in a single request by default by specifying them as multiple Invocations inside the methodCalls property. When using JMAP REST requests, this is no longer possible. Servers MAY support HTTP/2 multiplexing instead ([RFC7540] Section 5) to improve performance in that scenario.¶

3. Example: Endpoint supporting using and accountId as URL Parameters

Example value in the Session Object:¶

{
  ...
  "capabilities": {
    ...,
    "urn:ietf:params:jmap:rest": {}
  },
  "apiUrlRest": "https://jmap.me/api/<methodCall>
    ?using=<using>&accountId=<accountId>"
}

For the example, we chose ContactCard/get as the method call.¶

Request:¶

POST /api/ContactCard/get/?
 using=urn%3Aietf%3Aparams%3Ajmap%3Acontacts,
 urn%3Aietf%3Aparams%3Ajmap%3Acore&
 accountId=u7339402f
Host: jmap.me
Accept: application/json

Response:¶

HTTP/2 200 OK
Content-Type: application/json
Location:
 https://jmap.me/api/ContactCard/get/?
 using=urn%3Aietf%3Aparams%3Ajmap%3Acontacts,
 urn%3Aietf%3Aparams%3Ajmap%3Acore&
 accountId=u7339402f

{
   "methodResponses" : [
      [
         "ContactCard/get",
         {
            "accountId" : "u7339402f",
            "list" : [
               {
                "id": "123-12345",
                "addressBookId": "22294",
                ...
               }
            ],
            "notFound" : [],
            "state" : "62"
         },
         ""
      ]
   ],
   "sessionState" : ""
}

4. Security considerations

All security considerations of JMAP [RFC8620] apply to this specification.¶

The values of URL parameters SHOULD not contain sensitive data, as requested URLs are typically visible to third parties. Place sensitive data in HTTP bodies instead.¶

5. IANA considerations

6. Acknowledgements

Bron Gondwana, Neil Jenkins, Alexey Melnikov, Ken Murchison, Robert Stepanek and the JMAP working group at the IETF.¶

Authors' Addresses