HTTP

Core #522 extracted the reusable xila_http package under libraries/http. It provides no_std HTTP/1 request helpers, response-head parsing, borrowed URL parsing and incremental body decoding. The default feature set does not require a heap allocator; the optional alloc feature provides URL formatting helpers.

Framing and ownership

parse_response_head::<N> borrows a caller-managed header buffer and returns an incomplete result when more bytes are needed. Its generic N header capacity contributes N × size_of::<httparse::Header>() of parser stack storage; the caller must also bound header bytes. Header names and transfer coding names are compared case-insensitively.

BodyDecoder accepts fragmented input and decodes chunked bodies in place, discarding chunk extensions and trailers. The parser also handles Content-Length, close-delimited responses, informational 1xx replies and responses that cannot carry a body (including HEAD/204/304). It detects truncated bodies when the stream ends. Protocol upgrades, pipelining and content decompression are not implemented.

HTTP/HTTPS devices

Xila's VFS HTTP and HTTPS devices now stream response data through a single 2 KiB buffer per opening, with reader backpressure instead of accumulating the entire download. Device reads return the original response headers followed by decoded body bytes: callers must not decode HTTP chunk framing a second time. Head reads may be fragmented, so read through the empty line before interpreting body bytes.

The reported native exchange peak of 2,592 bytes for both 4 KiB and 4 MiB generated downloads excludes socket storage, TLS and application buffers. HTTPS separately uses a 16 KiB + 256-byte receive record buffer and a 16 KiB send record buffer. Core #524 fixed reception of maximum-size TLS records and added optional tests against a real local TLS 1.3 server. TLS certificate policy, public-server interoperability and MCU use are not established by those tests.

Sockets are reclaimed through the Network runner after queued traffic and FIN/RST processing. Cancelled exchanges stop their worker, and abandoned shutdowns have a bounded cleanup window.

Validation and boundaries

cargo test -p xila_http --all-features
cargo test -p xila-network --test https -- --ignored --nocapture

The HTTPS integration test needs Python 3 and OpenSSL and is intentionally ignored by default. Tests cover chunking, fragmented heads, premature EOF, response variants and memory allocation behavior. For protocol sockets and control-plane integration see Network.

References

• xila_http crate — portable HTTP library Rustdoc.
• libraries/http/README.md — formats and memory bounds.
• libraries/http/src/framing.rs — incremental HTTP framing.
• drivers/shared/src/devices/http_exchange.rs — VFS stream transport.
• drivers/shared/src/devices/https_client.rs — HTTPS device.