JMAP REST Mapping

Introduction Structured data exchange over JMAP 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.

Conventions Used In This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here. The definitions of JSON keys and datatypes in the document follow the conventions described in the core JMAP specification .

Addition to the capabilities object The capabilities object is returned as part of the JMAP Session object; see , Section 2. This document defines one additional capability URI.

urn:ietf:params:jmap:rest The capability urn:ietf:params:jmap:rest being present in the "capabilities" property represents support for the simplified JMAP REST API. The value of this property in the JMAP Session capabilities property and the account's accountCapabilities property is an empty object.

Addition to the Session Resource The JMAP Session Resource will be extended by the following property:

apiUrlRest: String The URL to use for JMAP API requests. THE URL MUST contain the variable methodCall, the name of the method to call as defined in Section 3.2. For example, Mailbox/get. One MAY specify additional variables here, also those specific to a JMAP method like using, ids or accountId. Only properties that are a subset of the types String, Number, Boolean and arrays (as defined in Section 1.1) can be referenced as variables. All values of arrays MUST also be of a type that is a subset of String, Number, Boolean or Id. For properties that are arrays, the value is a comma-separated list of values in the array. An example property of type array is the using property: using=urn%3Aietf%3Aparams%3Ajmap%3Acontacts,urn%3Aietf%3Aparams%3Ajmap%3Acore.

The required variables MAY be implemented as query parameters to avoid routing logic as a requirement.

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 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 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 ( 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 ( Section 5) to improve performance in that scenario.

Example: Endpoint supporting using and accountId as URL Parameters Example value in the Session Object: ?using=&accountId=" } ]]> For the example, we chose ContactCard/get as the method call. Request: Response:

Security considerations All security considerations of JMAP 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.

IANA considerations

JMAP Capability registration for "rest" IANA is requested to register the "rest" JMAP Capability as follows: Capability Name: urn:ietf:params:jmap:rest Specification document: this document Intended use: common Change Controller: IETF Security and privacy considerations: this document, .

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