feat: add WebSocket transport support by decofe · Pull Request #146 · tempoxyz/mpp-rs

decofe · 2026-03-24T07:46:53Z

Changes

Adds WebSocket transport for bidirectional session payments (TOOLS-323).

Transport trait abstraction

server::transport::Transport — abstracts credential extraction, challenge response, and receipt attachment (HTTP impl included)
client::transport::Transport — abstracts payment detection, challenge extraction, and credential attachment (HTTP impl included)

WebSocket transport

server::ws / client::ws — WebSocket transport with JSON message protocol (credential, challenge, message, needVoucher, receipt, error)
server::ws_session — metered streaming over generic Sink/Stream (framework-agnostic equivalent of SSE metering)
ws feature flag gating tokio-tungstenite + futures-util

Example & tests

examples/ws/ — working server + client example using mock charge method (runs locally out of the box)
tests/integration_ws.rs — e2e tests over real WS connections

Testing

cargo test --features ws ws
cargo test --features integration-ws --test integration_ws

Co-Authored-By: grandizzy 38490174+grandizzy@users.noreply.github.com

Prompted by: georgen

github-actions · 2026-03-24T07:47:54Z

Tempo Lint Results

Summary

Found 710 issue(s) across 45 file(s)

Severity	Count
Errors	0
Warnings	710
Hints	0

Issues by Rule Type

no-unwrap-in-lib (696 occurrences)

/home/runner/work/mpp-rs/mpp-rs/src/body_digest.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/ws.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/ws.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/ws.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.
/home/runner/work/mpp-rs/mpp-rs/src/client/fetch.rs:1 - Avoid .unwrap() in library code. Use proper error handling with ? or .expect() with context.

... and 686 more

no-leading-whitespace-strings (10 occurrences)

/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/headers.rs:1 - String literals should not start with leading whitespace. Found: ' now'
/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/headers.rs:1 - String literals should not start with leading whitespace. Found: ' now'
/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/headers.rs:1 - String literals should not start with leading whitespace. Found: ' now'
/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/types.rs:1 - String literals should not start with leading whitespace. Found: ' and backslashes '
/home/runner/work/mpp-rs/mpp-rs/src/proxy/service.rs:1 - String literals should not start with leading whitespace. Found: ' — '
/home/runner/work/mpp-rs/mpp-rs/src/error.rs:1 - String literals should not start with leading whitespace. Found: ' for '
/home/runner/work/mpp-rs/mpp-rs/src/error.rs:1 - String literals should not start with leading whitespace. Found: ' ({})'
/home/runner/work/mpp-rs/mpp-rs/src/error.rs:1 - String literals should not start with leading whitespace. Found: ' is invalid.'
/home/runner/work/mpp-rs/mpp-rs/src/error.rs:1 - String literals should not start with leading whitespace. Found: ' is invalid: already used.'
/home/runner/work/mpp-rs/mpp-rs/src/error.rs:1 - String literals should not start with leading whitespace. Found: ' (Premium access).'

unsafe-needs-safety-comment (4 occurrences)

/home/runner/work/mpp-rs/mpp-rs/src/server/mpp.rs:1 - Unsafe block requires a SAFETY comment explaining why this is safe.
/home/runner/work/mpp-rs/mpp-rs/src/server/mpp.rs:1 - Unsafe block requires a SAFETY comment explaining why this is safe.
/home/runner/work/mpp-rs/mpp-rs/src/server/mpp.rs:1 - Unsafe block requires a SAFETY comment explaining why this is safe.
/home/runner/work/mpp-rs/mpp-rs/src/server/mpp.rs:1 - Unsafe block requires a SAFETY comment explaining why this is safe.

Issues by File

View grouped by file

/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/challenge.rs (85 issues)

Line 1: [warning] no-unwrap-in-lib
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... and 80 more

/home/runner/work/mpp-rs/mpp-rs/src/client/tempo/session/mod.rs (58 issues)

Line 1: [warning] no-unwrap-in-lib
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... and 53 more

/home/runner/work/mpp-rs/mpp-rs/src/client/tempo/signing/mod.rs (54 issues)

Line 1: [warning] no-unwrap-in-lib
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/home/runner/work/mpp-rs/mpp-rs/src/server/mpp.rs (53 issues)

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... and 48 more

/home/runner/work/mpp-rs/mpp-rs/src/protocol/methods/tempo/session_method.rs (39 issues)

Line 1: [warning] no-unwrap-in-lib
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/home/runner/work/mpp-rs/mpp-rs/src/client/tempo/session/channel_ops.rs (38 issues)

Line 1: [warning] no-unwrap-in-lib
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/home/runner/work/mpp-rs/mpp-rs/src/protocol/methods/tempo/method.rs (35 issues)

Line 1: [warning] no-unwrap-in-lib
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/home/runner/work/mpp-rs/mpp-rs/src/protocol/core/headers.rs (34 issues)

Line 1: [warning] no-unwrap-in-lib
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/home/runner/work/mpp-rs/mpp-rs/src/server/middleware.rs (27 issues)

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/home/runner/work/mpp-rs/mpp-rs/src/mcp.rs (25 issues)

Line 1: [warning] no-unwrap-in-lib
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... and 20 more

Showing 10 of 45 files

Posted by https://github.com/tempoxyz/lints

Foundation for WebSocket support (TOOLS-323). Adds transport traits matching mppx's Transport interface: - server::transport::Transport — get_credential, respond_challenge, respond_receipt with associated Input/Output types - server::transport::HttpTransport — HTTP impl using http crate types - client::transport::Transport — is_payment_required, get_challenge, set_credential with associated Request/Response types - client::transport::HttpTransport — reqwest impl Existing HTTP logic (fetch.rs, axum.rs, middleware.rs) is unchanged; the traits provide a parallel abstraction that WebSocket/MCP transports will implement in follow-up PRs. Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

Server-side WS transport implementing the Transport trait with JSON message protocol: - WsMessage (client→server): credential, data variants - WsResponse (server→client): challenge, message, needVoucher, receipt, error variants - WsTransport implements get_credential, respond_challenge, respond_receipt for WS frames - ws feature flag gating tokio-tungstenite + futures-util deps Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

Client-side WS transport implementing the Transport trait: - WsClientMessage (client→server): credential, data variants - WsServerMessage (server→client): challenge, message, needVoucher, receipt, error variants (mirrors server::ws types) - WsTransport implements is_payment_required, get_challenge, set_credential for WS frames Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

axum_ws module handles the full WS payment flow: 1. Client connects → server sends challenge frame 2. Client sends credential → server verifies 3. On success, streams application data as message frames 4. Sends final receipt frame before close Uses axum dev-dependency with ws feature. Gated behind cfg(test, ws, axum) until axum becomes a proper optional dep. Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

E2e tests over real WebSocket connections: - Full challenge → credential → data/error flow - Message type serialization over the wire - NeedVoucher roundtrip Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

examples/ws/ with server + client binaries: - ws-server: axum WS endpoint that sends challenge, verifies credential, streams fortunes, sends receipt - ws-client: tokio-tungstenite client handling the full flow Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

ws_session module implements the SSE-equivalent metering loop over WS: - ws_session(): deducts tick_cost per value, sends needVoucher when exhausted, waits for channel store update, resumes, emits session receipt on completion - process_incoming_vouchers(): runs on the receiver half, parses voucher credentials from WS frames, calls verify_session() which updates ChannelStore and wakes the sender Usage: split WS into sender/receiver, run ws_session + process_incoming_vouchers concurrently via tokio::select!/join!. Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

- HttpTransport::get_credential() no longer double-prepends 'Payment ' (extract_payment_scheme already returns the full fragment) - axum_ws handler now verifies credential.challenge.id matches the issued challenge before calling verify_payment (prevents replay) - Fix doc: need-voucher → needVoucher (matches serde camelCase output) - Add test for valid Payment header parsing Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

- test_ws_challenge_id_mismatch_rejected: credential with wrong challenge ID is rejected (never succeeds as data/receipt) - test_server_client_wire_type_compat: serialize with server types, deserialize with client types and vice versa (all 7 message variants) Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

Co-authored-by: Amp <amp@ampcode.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

…em helpers Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d23a5-8821-747b-bfa0-9ae8abc12fa6

decofe assigned grandizzy Mar 24, 2026

decofe force-pushed the georgen/transport-trait branch from 8a4d1e4 to aceb75d Compare March 24, 2026 07:49

decofe and others added 2 commits March 24, 2026 07:54

decofe force-pushed the georgen/transport-trait branch from db91654 to 808989b Compare March 24, 2026 07:58

decofe and others added 3 commits March 24, 2026 08:22

test: add WebSocket integration tests

7846e9a

E2e tests over real WebSocket connections: - Full challenge → credential → data/error flow - Message type serialization over the wire - NeedVoucher roundtrip Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

decofe changed the title ~~feat: add Transport trait abstraction for server and client~~ feat: add WebSocket transport support Mar 24, 2026

docs: add ws feature to README

218a77c

Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

decofe force-pushed the georgen/transport-trait branch from 5c252a2 to 218a77c Compare March 24, 2026 08:37

decofe and others added 6 commits March 24, 2026 08:41

ci: run WebSocket integration tests

697bdf0

Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com>

fix: use mock charge method in ws example for working local demo

1a67a7c

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

refactor: extract send_error helper in axum_ws

c39a0fc

Co-authored-by: Amp <amp@ampcode.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8

grandizzy force-pushed the georgen/transport-trait branch from 9cec0af to c39a0fc Compare March 24, 2026 10:22

grandizzy and others added 6 commits March 24, 2026 12:34

feat: promote axum to optional dep, ungating axum_ws from test-only

31f8104

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

remove unused axum_ws module, revert axum to axum-core dep

9f52c3b

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

refactor: gate ws_session module on tempo feature at mod level

575c8f2

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

refactor: remove redundant client feature gates from client/transport.rs

42cf613

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

refactor: clean up ws_session imports, remove now_iso8601 and next_it…

c33170c

…em helpers Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

refactor: use let-else early returns across WS code

e2c7163

Amp-Thread-ID: https://ampcode.com/threads/T-019d1f49-ad9f-74a8-9268-37d860491bb8 Co-authored-by: Amp <amp@ampcode.com>

grandizzy marked this pull request as ready for review March 24, 2026 11:22

grandizzy requested review from Slokh, mattsse and onbjerg as code owners March 24, 2026 11:22

grandizzy requested a review from brendanjryan as a code owner March 24, 2026 11:22

merge: resolve conflicts with main (ws + stripe)

cd1ebbd

Co-Authored-By: grandizzy <38490174+grandizzy@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d23a5-8821-747b-bfa0-9ae8abc12fa6

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feat: add WebSocket transport support#146

feat: add WebSocket transport support#146
decofe wants to merge 20 commits intomainfrom
georgen/transport-trait

decofe commented Mar 24, 2026 •

edited by grandizzy

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Changes

Transport trait abstraction

WebSocket transport

Example & tests

Testing

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Tempo Lint Results

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decofe commented Mar 24, 2026 •

edited by grandizzy

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