Crate io_jmap 

io-jmap

I/O-free JMAP client coroutines built on io-http: every network exchange is a resumable state machine emitting read and write requests instead of performing I/O itself. The caller owns the socket and pumps the coroutine with the bytes it read, whatever the runtime (blocking, async, in-memory tests). The client feature ships a ready-made std-blocking pump for callers who just want a working client.

Layout: one folder per RFC

The source tree mirrors how the JMAP specification itself is split, one module per RFC. rfc8620 implements the core protocol: the session, request and response objects, the generic Foo/get, Foo/set, Foo/query, Foo/changes and Foo/queryChanges coroutines every data type builds on, the blob upload and download coroutines, plus the two push channels (PushSubscription and the SSE-based Event Source). rfc8621 covers JMAP for Mail: Mailbox, Thread, Email, Identity, EmailSubmission and VacationResponse, each folder wrapping the generic core coroutines with the mail capability and its own data types. rfc9610 covers JMAP for Contacts: AddressBook and ContactCard, where the JSContact payload stays raw JSON, converting it being out of scope.

Two modules span the RFC modules and therefore live at the crate root: coroutine defines the coroutine contract every state machine implements, and the optional client module (client feature) is the std-blocking pump: a light client wrapping any stream you opened yourself, or a full client opening the TCP/TLS connection itself when one of the TLS features is enabled.

The coroutine contract

Every coroutine implements coroutine::JmapCoroutine: a resume method taking the bytes read since the last step and returning either an intermediate yield or a terminal completion. Standard coroutines yield the shared read/write requests of coroutine::JmapYield; richer coroutines declare their own yield type, like the redirect-aware session and blob coroutines surfacing 3xx responses to the caller instead of following them, or the streaming Event Source coroutine yielding one push frame at a time. Completion carries a per-coroutine output or error; the jmap_try macro chains an inner coroutine step inside an outer resume, re-yielding and short-circuiting like the question mark operator.

Conventions

The crate is no_std with alloc; std only enters behind the client feature. Every public item carries the bare Jmap prefix, the protocol not being version-scoped. Logging follows the library rules: state changes at debug level, in-process steps and data dumps at trace level.

Modules

clientclient

Standard, blocking JMAP client.

coroutine

Generator-shape coroutine contract.

rfc8620

RFC 8620: The JSON Meta Application Protocol (JMAP).

rfc8621

RFC 8621: JMAP for Mail.

rfc9610

RFC 9610: JMAP for Contacts.

Macros

jmap_try

Coroutine ?: forwards Yielded (via Into), short-circuits on Err (via Into), evaluates to the inner Ok value.