wamp2spring is a Java implementation of the WAMP specification built on top of the WebSocket support of Spring 7.
WAMP is a WebSocket subprotocol that provides two application messaging patterns: Remote Procedure Calls and Publish / Subscribe.

Implementation

wamp2spring implements the Basic Profile with a single shared routing scope. Connections, registrations, subscriptions, and meta APIs are handled without realm-based partitioning during session establishment or routing.

Additionally wamp2spring implements a few features from the Advanced Profile:

Feature	Remark
call_canceling	Dealer-side CANCEL / INTERRUPT with skip, kill, and killnowait. Advanced cancel modes require caller negotiation; unsupported callees fall back to dealer-managed behavior.
call_timeout	Dealer-enforced CALL.Options.timeout. Timeout intent is forwarded to callees that advertise support, but timeout semantics remain enforced by the dealer.
progressive_call_results	Dealer-side negotiation and forwarding of CALL.Options.receive_progress, INVOCATION.Details.receive_progress, progressive YIELD, and progressive RESULT, while keeping the invocation open until the final YIELD or ERROR.
caller_identification	disclose_me option in the CALL message. Specification
registration_revocation	Dealer-side administrative revocation of registrations, with extended UNREGISTERED delivery to callees that advertised support.
subscriber_blackwhite_listing	Exclude and include receivers with their WAMP session id. Only eligible and exclude options are implemented. Specification.
publisher_exclusion	exclude_me option in the PUBLISH message. By default the publisher is excluded from receiving the EVENT message. Specification
publisher_identification	disclose_me option in the PUBLISH message. Specification
pattern_based_subscription	Prefix- and wildcard matching policies for subscriptions. Specification
event_retention	Specification
testament_meta_api	wamp.session.add_testament and wamp.session.flush_testaments with detached/destroyed scopes and disconnect-triggered publication order.

For Advanced RPC timeout handling, the dealer is the source of truth once a caller and the router negotiated call_timeout. If a callee also advertises timeout support, the dealer forwards the timeout value in INVOCATION.Details.timeout. If the callee does not advertise timeout support, the dealer still enforces the timeout and returns the appropriate timeout error to the caller.

WAMP-level authorization can be extended with one or more Spring beans implementing WampAuthorizer. The dealer and broker consult these authorizers for REGISTER, CALL, SUBSCRIBE, and PUBLISH before routing, and authorizers can deny an operation with wamp.error.not_authorized or wamp.error.authorization_failed.

Dataformats
wamp2spring supports JSON (wamp.2.json) and MessagePack (wamp.2.msgpack) required by the Basic Profile. In addition it supports CBOR (wamp.2.cbor) and SMILE (wamp.2.smile).

Fallback
Currently wamp2spring does not support a fallback solution when peers cannot establish WebSocket connections. autobahn-js implements a fallback with long polling. You find the description about the protocol in the specification (Section 14.5.3.3). So far I don't have a need for a fallback solution because WebSocket works fine especially when it's sent over TLS connections. But when there is a need I will try to add this fallback solution. Pull requests are always welcome.

Quickstart

See Wiki

Maven

See Wiki

Example applications

You find a collection of example applications in the wamp2spring-demo GitHub repository.

Changelog

See Wiki

More information

See Wiki

License

Code released under the Apache license.