Files
sx/library/modules/std/http.sx
agra 8641441fad feat: std.http read buffers grow on demand toward read_buf_cap
read_buf_cap is now the per-request LIMIT, not a preallocation: slots
start at 16K, double when full (one-step sizing when a Content-Length
declares the body), and keep their grown capacity for slot reuse. At
the limit the refusal distinguishes oversized headers (431) from an
oversized body (413). Unblocks A1: distd accepts multi-hundred-MB
artifact uploads — preallocating that per slot was never an option.
examples/1633 adds a body past the initial capacity echoing intact.
2026-06-12 21:29:13 +03:00

539 lines
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// std.http — single-worker HTTP/1.1 server core (PLAN-HTTPZ S7a).
//
// The httpz shape, one worker, handlers inline: a readiness Loop
// (std.event) multiplexes the listener and every connection, so an
// idle socket costs nothing and nothing ever blocks the loop. Timeouts
// are EVICTION, not blocking — each connection carries a monotonic
// deadline (request delivery / keepalive idle), checked between waits.
// Keep-alive is the default for HTTP/1.1; a Connection header, the
// per-connection request cap, or HTTP/1.0 turns it off.
//
// API: `Server.init(cfg, handler)` then either `run()` (the forever
// loop) or `tick(max_wait_ms)` — one bounded loop iteration, which is
// also how tests drive a live server and its client sockets in ONE
// thread. S7b adds worker counts + a handler thread pool behind this
// same surface; the epoll backend arrives with the linux target (S4).
//
// MEMORY: init captures the constructing allocator (the Repo pattern):
// connection slots and their read buffers live across ticks and are
// reused connection-to-connection (httpz's buffer-pool spirit);
// response bytes are allocated per response and freed when fully sent.
// Request views handed to the handler point into the connection's read
// buffer and are valid only during the handler call.
#import "modules/std.sx";
HttpErr :: error {
Bind, // socket/bind/listen failed for the configured port
Loop, // the readiness loop could not be created or waited on
}
// httpz-mirroring knobs (single-worker subset).
Config :: struct {
port: i64 = 8080;
backlog: i32 = 128;
max_conn: i64 = 256; // workers.max_conn
// MAXIMUM bytes one request (headers + body) may occupy. The
// per-connection buffer starts at READ_BUF_INITIAL and grows on
// demand toward this limit (a declared Content-Length sizes it in
// one step); a grown buffer is retained for slot reuse.
read_buf_cap: i64 = 1048576;
timeout_request_ms: i64 = 5000; // deliver a full request, or evicted
timeout_keepalive_ms: i64 = 5000;// idle between requests, or evicted
request_count: i64 = 100; // requests per connection, then close
}
READ_BUF_INITIAL :: 16384;
// One parsed request, viewed in place over the connection's read
// buffer — valid for the duration of the handler call only.
Request :: struct {
method: string = "";
path: string = "";
version: string = "";
headers_raw: string = ""; // the raw header block (no request line)
body: string = "";
keep_alive: bool = true;
}
// What the handler fills in; the server serializes it.
Response :: struct {
status: i64 = 200;
content_type: string = "text/plain; charset=utf-8";
extra_headers: string = ""; // preformatted "Name: value\r\n" lines
body: string = "";
}
// Case-insensitive header lookup in `headers_raw`; "" when absent.
// `name` must be lowercase.
find_header :: (req: *Request, name: string) -> string {
h := req.headers_raw;
i := 0;
while i < h.len {
// line start: try to match `name` case-insensitively, then ':'
j := 0;
while j < name.len and i + j < h.len {
c := h[i + j];
if c >= 65 and c <= 90 { c = c + 32; } // ASCII lower
if c != name[j] { break; }
j += 1;
}
if j == name.len and i + j < h.len and h[i + j] == 58 { // ':'
v := i + j + 1;
while v < h.len and h[v] == 32 { v += 1; }
e := v;
while e < h.len and h[e] != 13 { e += 1; }
return string.{ ptr = @h[v], len = e - v };
}
// skip to the next line
while i < h.len and h[i] != 10 { i += 1; } // '\n'
i += 1;
}
return "";
}
ascii_ieq :: (a: string, b_lower: string) -> bool {
if a.len != b_lower.len { return false; }
i := 0;
while i < a.len {
c := a[i];
if c >= 65 and c <= 90 { c = c + 32; }
if c != b_lower[i] { return false; }
i += 1;
}
return true;
}
reason_for :: (status: i64) -> string {
if status == 200 { return "OK"; }
if status == 201 { return "Created"; }
if status == 204 { return "No Content"; }
if status == 301 { return "Moved Permanently"; }
if status == 302 { return "Found"; }
if status == 400 { return "Bad Request"; }
if status == 401 { return "Unauthorized"; }
if status == 403 { return "Forbidden"; }
if status == 404 { return "Not Found"; }
if status == 405 { return "Method Not Allowed"; }
if status == 413 { return "Content Too Large"; }
if status == 431 { return "Request Header Fields Too Large"; }
if status == 500 { return "Internal Server Error"; }
if status == 503 { return "Service Unavailable"; }
return "Status";
}
// Connection slot states.
CONN_FREE :u8: 0;
CONN_READING :u8: 1; // awaiting a complete request (deadline: request)
CONN_WRITING :u8: 2; // response partially sent (deadline: request)
CONN_KEEPALIVE :u8: 3; // between requests (deadline: keepalive)
Conn :: struct {
fd: i32 = -1;
state: u8 = 0;
read_buf: [*]u8 = null; // grows toward config.read_buf_cap, reused across connections
read_cap: i64 = 0;
read_len: i64 = 0;
out_buf: [*]u8 = null; // per-response allocation, freed when sent
out_len: i64 = 0;
out_sent: i64 = 0;
deadline: i64 = 0;
served: i64 = 0;
close_after: bool = false;
write_armed: bool = false;
}
// The listener's udata; connection udata is the slot index.
LISTENER_UDATA :usize: 0xFFFFFFFF;
Server :: struct {
cfg: Config;
loop: event.Loop;
lfd: i32 = -1;
conns: [*]Conn = null;
own_alloc: Allocator;
// The handler's third argument is `ctx`, an opaque word the app
// gave init — typically a pointer to its own state (store handle,
// config), since the server owns the call site.
handler: (*Request, *Response, usize) -> void;
ctx: usize = 0;
init :: (cfg: Config, handler: (*Request, *Response, usize) -> void, ctx: usize) -> (Server, !HttpErr) {
lfd := socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0);
if lfd < 0 { raise error.Bind; }
one : i32 = 1;
socket.setsockopt(lfd, socket.SOL_SOCKET, socket.SO_REUSEADDR, @one, 4);
addr : socket.SockAddr = .{
sin_len = 16, sin_family = xx socket.AF_INET,
sin_port = socket.htons(cfg.port), sin_addr = 0, // INADDR_ANY
};
if socket.bind(lfd, @addr, 16) != 0 { socket.close(lfd); raise error.Bind; }
if socket.listen(lfd, cfg.backlog) != 0 { socket.close(lfd); raise error.Bind; }
if !socket.set_nonblocking(lfd) { socket.close(lfd); raise error.Bind; }
lp, le := event.Loop.init();
if le { socket.close(lfd); raise error.Loop; }
are := false;
lp.add_read(lfd, LISTENER_UDATA) catch { are = true; };
if are { socket.close(lfd); raise error.Loop; }
oa := context.allocator;
slots : [*]Conn = xx oa.alloc_bytes(cfg.max_conn * size_of(Conn));
i : i64 = 0;
while i < cfg.max_conn {
slots[i] = Conn.{};
i += 1;
}
return Server.{
cfg = cfg, loop = lp, lfd = lfd, conns = slots,
own_alloc = oa, handler = handler, ctx = ctx,
};
}
close :: (self: *Server) {
i : i64 = 0;
while i < self.cfg.max_conn {
if self.conns[i].state != CONN_FREE { self.conn_close(i); }
i += 1;
}
if self.lfd >= 0 { socket.close(self.lfd); }
self.lfd = -1;
self.loop.close();
}
// ── slot management ──────────────────────────────────────────────
free_slot :: (self: *Server) -> i64 {
i : i64 = 0;
while i < self.cfg.max_conn {
if self.conns[i].state == CONN_FREE { return i; }
i += 1;
}
return -1;
}
conn_close :: (self: *Server, slot: i64) {
c := @self.conns[slot];
if c.fd >= 0 {
self.loop.del_read(c.fd);
if c.write_armed { self.loop.del_write(c.fd); }
socket.close(c.fd);
}
if c.out_buf != null {
self.own_alloc.dealloc_bytes(xx c.out_buf, c.out_len);
c.out_buf = null;
}
// read_buf stays allocated — reused by the next connection here.
c.fd = -1;
c.state = CONN_FREE;
c.read_len = 0;
c.out_len = 0;
c.out_sent = 0;
c.served = 0;
c.close_after = false;
c.write_armed = false;
}
// ── the tick: one bounded loop iteration ─────────────────────────
//
// Waits at most `max_wait_ms` (sooner when a connection deadline is
// nearer), services every ready fd, then evicts expired connections.
tick :: (self: *Server, max_wait_ms: i64) -> !HttpErr {
wait_ms := max_wait_ms;
i : i64 = 0;
while i < self.cfg.max_conn {
c := self.conns[i];
if c.state != CONN_FREE {
left := event.remaining_ms(c.deadline);
if left < wait_ms { wait_ms = left; }
}
i += 1;
}
evs : [64]event.Event = ---;
n, werr := self.loop.wait(.{ ptr = @evs[0], len = 64 }, wait_ms);
if werr { raise error.Loop; }
k : i64 = 0;
while k < n {
ev := evs[k];
k += 1;
if ev.udata == LISTENER_UDATA {
self.accept_ready();
continue;
}
slot : i64 = xx ev.udata;
c := @self.conns[slot];
if c.state == CONN_FREE or c.fd != ev.fd { continue; } // stale event for a recycled slot
if ev.writable and c.state == CONN_WRITING {
self.write_more(slot);
continue;
}
if ev.readable or ev.eof {
self.read_more(slot);
}
}
// Deadline eviction — after I/O, so a request that just arrived
// under the wire is served, not evicted.
i = 0;
while i < self.cfg.max_conn {
if self.conns[i].state != CONN_FREE and event.expired(self.conns[i].deadline) {
self.conn_close(i);
}
i += 1;
}
return;
}
run :: (self: *Server) {
while true {
self.tick(1000) catch {};
}
}
// ── accept ───────────────────────────────────────────────────────
accept_ready :: (self: *Server) {
while true {
fd, ae := socket.accept_nb(self.lfd);
if ae { return; } // WouldBlock = drained; Fault = nothing to do here
slot := self.free_slot();
if slot < 0 { socket.close(fd); return; } // at max_conn: shed
if !socket.set_nonblocking(fd) { socket.close(fd); return; }
c := @self.conns[slot];
if c.read_buf == null {
init_cap : i64 = READ_BUF_INITIAL;
if init_cap > self.cfg.read_buf_cap { init_cap = self.cfg.read_buf_cap; }
c.read_buf = xx self.own_alloc.alloc_bytes(init_cap);
c.read_cap = init_cap;
}
c.fd = fd;
c.state = CONN_READING;
c.read_len = 0;
c.served = 0;
c.close_after = false;
c.deadline = event.deadline_in(self.cfg.timeout_request_ms);
are := false;
self.loop.add_read(fd, xx slot) catch { are = true; };
if are { self.conn_close(slot); }
}
}
// ── read → parse → dispatch ──────────────────────────────────────
// Grow the slot's read buffer to at least `target` (0 = double),
// never past cfg.read_buf_cap. False when already at the limit.
grow_read_buf :: (self: *Server, slot: i64, target: i64) -> bool {
c := @self.conns[slot];
want := if target > 0 then target else c.read_cap * 2;
if want <= c.read_cap { return true; }
if want > self.cfg.read_buf_cap { want = self.cfg.read_buf_cap; }
if want <= c.read_cap { return false; } // already at the limit
nb : [*]u8 = xx self.own_alloc.alloc_bytes(want);
if c.read_len > 0 { memcpy(nb, c.read_buf, xx c.read_len); }
self.own_alloc.dealloc_bytes(xx c.read_buf, c.read_cap);
c.read_buf = nb;
c.read_cap = want;
return true;
}
read_more :: (self: *Server, slot: i64) {
c := @self.conns[slot];
if c.state == CONN_KEEPALIVE {
c.state = CONN_READING;
c.deadline = event.deadline_in(self.cfg.timeout_request_ms);
}
while true {
if c.read_len == c.read_cap {
if !self.grow_read_buf(slot, 0) {
// over the limit: oversized headers (431) or body (413)
hdr_done := false;
i : i64 = 0;
while i + 3 < c.read_len {
if c.read_buf[i] == 13 and c.read_buf[i+1] == 10 and c.read_buf[i+2] == 13 and c.read_buf[i+3] == 10 { hdr_done = true; break; }
i += 1;
}
self.respond_error_close(slot, if hdr_done then 413 else 431);
return;
}
}
nq, re := socket.read_nb(c.fd, @c.read_buf[c.read_len], xx (c.read_cap - c.read_len));
if re == error.WouldBlock { break; }
if re { // Closed or Fault
self.conn_close(slot);
return;
}
c.read_len += nq;
}
self.serve_buffered(slot);
}
// Serve every complete request sitting in the buffer (a keep-alive
// client may pipeline; each response must finish sending before the
// next parse — a pending partial write pauses the drain and
// write_more resumes it).
serve_buffered :: (self: *Server, slot: i64) {
while self.conns[slot].state == CONN_READING {
if !self.try_serve_one(slot) { return; }
}
}
// Parse one request off the front of the buffer; false = incomplete
// (need more bytes) or the connection left the READING state.
try_serve_one :: (self: *Server, slot: i64) -> bool {
c := @self.conns[slot];
buf := string.{ ptr = c.read_buf, len = xx c.read_len };
// headers complete?
he := -1;
i := 0;
while i + 3 < buf.len {
if buf[i] == 13 and buf[i+1] == 10 and buf[i+2] == 13 and buf[i+3] == 10 { he = i; break; }
i += 1;
}
if he < 0 { return false; }
// request line: METHOD SP PATH SP VERSION CRLF
req : Request = .{};
p := 0;
while p < he and buf[p] != 32 { p += 1; }
req.method = string.{ ptr = c.read_buf, len = p };
p += 1;
ps := p;
while p < he and buf[p] != 32 { p += 1; }
req.path = string.{ ptr = @c.read_buf[ps], len = p - ps };
p += 1;
vs := p;
while p < he and buf[p] != 13 { p += 1; }
req.version = string.{ ptr = @c.read_buf[vs], len = p - vs };
hdr_start := p + 2;
if req.method.len == 0 or req.path.len == 0 or hdr_start > he {
self.respond_error_close(slot, 400);
return false;
}
req.headers_raw = string.{ ptr = @c.read_buf[hdr_start], len = he - hdr_start + 2 };
// body per Content-Length
clen : i64 = 0;
clv := find_header(@req, "content-length");
j := 0;
while j < clv.len {
d := clv[j];
if d < 48 or d > 57 { self.respond_error_close(slot, 400); return false; }
clen = clen * 10 + (d - 48);
j += 1;
}
total := xx he + 4 + clen;
if total > self.cfg.read_buf_cap { self.respond_error_close(slot, 413); return false; }
if c.read_len < total {
// size the buffer for the declared body in one step
self.grow_read_buf(slot, total);
return false;
}
req.body = string.{ ptr = @c.read_buf[he + 4], len = xx clen };
// keep-alive: 1.1 default on, 1.0 default off, header overrides
req.keep_alive = !ascii_ieq(req.version, "http/1.0");
cnv := find_header(@req, "connection");
if ascii_ieq(cnv, "close") { req.keep_alive = false; }
if ascii_ieq(cnv, "keep-alive") { req.keep_alive = true; }
// dispatch (the field must be loaded — `self.handler(...)` would
// be parsed as a dot-call on a function named `handler`)
h := self.handler;
resp : Response = .{};
h(@req, @resp, self.ctx);
c.served += 1;
keep := req.keep_alive and c.served < self.cfg.request_count;
// Serialize while the request views are still valid (the body
// may reference the read buffer), THEN drop the served bytes —
// write_more's pipelining check must see only the remainder —
// and only then start sending. Overlapping copy: dst < src, so
// forward byte-wise is safe.
self.serialize_response(slot, @resp, keep);
rest := c.read_len - total;
m : i64 = 0;
while m < rest {
c.read_buf[m] = c.read_buf[total + m];
m += 1;
}
c.read_len = rest;
self.write_more(slot);
return true;
}
// ── response serialization + write continuation ──────────────────
// Build the response bytes into the slot's out buffer. Does NOT
// start sending — try_serve_one compacts the read buffer between
// serialization and the first write (see the ordering note there).
serialize_response :: (self: *Server, slot: i64, resp: *Response, keep: bool) {
head := concat("HTTP/1.1 ", concat(int_to_string(resp.status), concat(" ", reason_for(resp.status))));
head = concat(head, concat("\r\nContent-Length: ", int_to_string(resp.body.len)));
head = concat(head, concat("\r\nContent-Type: ", resp.content_type));
head = concat(head, if keep then "\r\nConnection: keep-alive\r\n" else "\r\nConnection: close\r\n");
if resp.extra_headers.len > 0 { head = concat(head, resp.extra_headers); }
head = concat(head, "\r\n");
c := @self.conns[slot];
c.out_len = xx (head.len + resp.body.len);
c.out_buf = xx self.own_alloc.alloc_bytes(xx c.out_len);
memcpy(c.out_buf, head.ptr, head.len);
if resp.body.len > 0 { memcpy(@c.out_buf[head.len], resp.body.ptr, resp.body.len); }
c.out_sent = 0;
c.close_after = !keep;
}
write_more :: (self: *Server, slot: i64) {
c := @self.conns[slot];
while c.out_sent < c.out_len {
nq, we := socket.write_nb(c.fd, @c.out_buf[c.out_sent], xx (c.out_len - c.out_sent));
if we == error.WouldBlock {
if !c.write_armed {
awe := false;
self.loop.add_write(c.fd, xx slot) catch { awe = true; };
if awe { self.conn_close(slot); return; }
c.write_armed = true;
}
c.state = CONN_WRITING;
return;
}
if we { self.conn_close(slot); return; }
c.out_sent += nq;
}
// fully sent
if c.write_armed {
self.loop.del_write(c.fd);
c.write_armed = false;
}
self.own_alloc.dealloc_bytes(xx c.out_buf, c.out_len);
c.out_buf = null;
c.out_len = 0;
c.out_sent = 0;
if c.close_after {
self.conn_close(slot);
return;
}
if c.read_len > 0 {
// pipelined bytes already buffered: keep serving
c.state = CONN_READING;
c.deadline = event.deadline_in(self.cfg.timeout_request_ms);
self.serve_buffered(slot);
return;
}
c.state = CONN_KEEPALIVE;
c.deadline = event.deadline_in(self.cfg.timeout_keepalive_ms);
}
// A terminal error response: serialize, send, close when done.
respond_error_close :: (self: *Server, slot: i64, status: i64) {
resp : Response = .{ status = status, body = reason_for(status) };
self.conns[slot].read_len = 0;
self.serialize_response(slot, @resp, false);
self.write_more(slot);
}
}