feat(web): support WebSocket subprotocols

[MuNeNiCK (MuNeNiCK)]

Motivation

WebSocket subprotocol negotiation is a standard part of the opening handshake. Endpoints commonly use it for application protocol selection, version negotiation, and handshake authentication, especially in browser clients that cannot attach arbitrary request headers.

ironrdp-web currently creates its WebSocket internally with only the proxy URL, so consumers cannot connect to endpoints that require one or more subprotocols.

Changes

• expose a webSocketProtocols() configuration extension from the RDP web package
• accept and validate a JavaScript string array in ironrdp-web
• open the connection with WebSocket::open_with_protocols when protocols are configured
• preserve the existing WebSocket::open path when the option is omitted or empty
• document the new configuration helper

Validation

• cargo xtask wasm check -v
• cargo xtask web check -v
• cargo xtask check fmt -v
• cargo xtask check lints -v
• cargo xtask check locks -v

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[Benoît Cortier (CBenoit)]

Hi! Thank you for the PR.

I think this is something I would like to have in the main "iron-remote-desktop" API, not as an extension. Could you change that before we merge?

Thank you!

[Benoît Cortier (CBenoit)]

question: Why json feature is necessary now?

[MuNeNiCK (MuNeNiCK)]

The json feature was required only because gloo-net::WebSocket::open_with_protocols serializes the protocol slice through Serde. I changed the implementation to construct the browser WebSocket with web_sys::WebSocket::new_with_str_sequence and then wrap it with the existing gloo WebSocket TryFrom implementation. The json, serde, and serde_json dependencies are no longer added.

[Copilot]

🟢 Approval recommended

The implementation correctly preserves the default connection path, with only a non-blocking documentation-format finding.

Pull request overview

Adds configurable WebSocket subprotocol negotiation to the RDP web backend while preserving existing behavior when none are configured.

Changes:

• Exposes webSocketProtocols() for consumers.
• Validates and forwards protocol arrays when opening WebSockets.
• Documents the configuration helper.

File summaries

File	Description
web-client/iron-remote-desktop-rdp/src/main.ts	Adds the configuration extension.
web-client/iron-remote-desktop-rdp/README.md	Documents subprotocol configuration.
crates/ironrdp-web/src/session.rs	Parses protocols and selects the appropriate WebSocket constructor.
crates/ironrdp-web/Cargo.toml	Enables required gloo-net JSON support.
Cargo.lock	Records transitive serialization dependencies.

Review details

• Files reviewed: 4/5 changed files
• Comments generated: 1
• Review effort level: Balanced

[MuNeNiCK (MuNeNiCK)]

Fixed. The documentation is now in the main iron-remote-desktop README, and each sentence is kept on one source line.

[MuNeNiCK (MuNeNiCK)]

Thank you! I moved the option into the main iron-remote-desktop API. Consumers now configure it with ConfigBuilder.withWebSocketProtocols(), and the value flows through the common SessionBuilder.webSocketProtocols() API. The RDP-specific extension was removed, while an empty list still preserves the existing connection path.