Implement HTTP response parsing and reader

TODO: Handle Transfer-Encoding and Content-Length properly

cmd/http/main.ha

@@ -1,5 +1,5 @@
-use fmt;
 use io;
+use log;
 use net::dial;
 use net::http;
 use net::uri;
@@ -13,19 +13,28 @@ export fn main() void = {
 	case let u: uri::uri =>
 		yield u;
 	case uri::invalid =>
-		fmt::fatal("Invalid URI");
+		log::fatal("Invalid URI");
 	};
 	defer uri::finish(&target);
 
 	const req = http::get(&client, &target);
 	const resp = match (http::do(&client, &req)) {
 	case let err: http::error =>
-		fmt::fatal("HTTP error:", http::strerror(err));
+		log::fatal("HTTP error:", http::strerror(err));
 	case let resp: http::response =>
 		yield resp;
 	};
+	defer http::request_finish(&req);
 
-	// XXX TEMP
-	const body = resp.body as io::handle;
+	log::printfln("HTTP/{}.{}: {} {}",
+		resp.version.0, resp.version.1,
+		resp.status, resp.reason);
+
+	for (let i = 0z; i < len(resp.header); i += 1) {
+		const (name, val) = resp.header[i];
+		log::printfln("{}: {}", name, val);
+	};
+
+	const body = resp.body as *http::reader;
 	io::copy(os::stdout, body)!;
 };

net/http/README

@@ -6,3 +6,9 @@ Caveats:
   are valid according to the HTTP grammar; such cases will fail when rejected by
   the other party.
 - Details indicated by RFC 7230 et al as "obsolete" are not implemented
+- Max header length including "name: value" is 4KiB
+
+TODO:
+
+- Server stuff
+- TLS

net/http/do.ha

@@ -1,10 +1,13 @@
 use bufio;
+use encoding::utf8;
 use fmt;
 use io;
 use net::dial;
 use net::uri;
 use net;
 use os;
+use strconv;
+use strings;
 
 // Performs an HTTP [[request]] with the given [[client]]. The request is
 // performed synchronously; this function blocks until the server has returned
@@ -32,20 +35,61 @@ export fn do(client: *client, req: *request) (response | error) = {
 	bufio::flush(&file)?;
 
 	match (req.body) {
-	case void =>
-		yield;
 	case let body: io::handle =>
 		// Copy to conn directly so we can use sendfile(2) if
 		// appropriate
 		io::copy(conn, body)?;
+	case void =>
+		yield;
 	};
 
-	// Switch buffer to read mode
-	file = bufio::buffered(conn, buf, []);
+	// TODO: Improve error handling
+	let resp = response { ... };
+	const scan = bufio::newscanner_static(conn, buf);
+	read_statusline(&resp, &scan)?;
+	read_header(&resp.header, &scan)?;
 
-	// TODO: Parse resposne
-	return response {
-		body = conn,
+	const remain = bufio::scan_buffer(&scan);
+	const rd = alloc(reader {
+		vtable = &reader_vtable,
+		conn = conn,
 		...
+	});
+	rd.buffer[..len(remain)] = remain[..];
+	rd.pending = len(remain);
+	resp.body = rd;
+	return resp;
 };
+
+fn read_statusline(
+	resp: *response,
+	scan: *bufio::scanner,
+) (void | io::error) = {
+	const status = match (bufio::scan_string(scan, "\r\n")) {
+	case let line: const str =>
+		yield line;
+	case let err: io::error =>
+		return err;
+	case utf8::invalid =>
+		abort(); // TODO
+	case io::EOF =>
+		abort(); // TODO
+	};
+
+	// TODO: Error handling
+	const tok = strings::tokenize(status, " ");
+	const version = strings::next_token(&tok) as str;
+	const status = strings::next_token(&tok) as str;
+	const reason = strings::next_token(&tok) as str;
+
+	assert(version == "HTTP/1.1"); // TODO
+	const (_, version) = strings::cut(version, "/");
+	const (major, minor) = strings::cut(version, ".");
+
+	resp.version = (
+		strconv::stou(major)!,
+		strconv::stou(minor)!,
+	);
+	resp.status = strconv::stou(status)!;
+	resp.reason = strings::dup(reason);
 };

net/http/header.ha

@@ -1,19 +1,20 @@
+use bufio;
+use encoding::utf8;
 use fmt;
 use io;
 use strings;
 
 // List of HTTP headers.
+// TODO: [](str, []str)
 export type header = [](str, str);
 
-// Adds a given HTTP header, which may be added more than once. The value is
-// duplicated, but the name is borrowed from the caller. The name should be
-// canonicalized by the caller.
+// Adds a given HTTP header, which may be added more than once. The name should
+// be canonicalized by the caller.
 export fn add_header(head: *header, name: str, val: str) void = {
-	append(head, (name, strings::dup(val)));
+	append(head, (strings::dup(name), strings::dup(val)));
 };
 
-// Sets the value of a given HTTP header, removing any previous values. The
-// value is duplicated, but the name is borrowed from the caller. The name
+// Sets the value of a given HTTP header, removing any previous values. The name
 // should be canonicalized by the caller.
 export fn set_header(head: *header, name: str, val: str) void = {
 	del_header(head, name);
@@ -25,6 +26,7 @@ export fn set_header(head: *header, name: str, val: str) void = {
 export fn del_header(head: *header, name: str) void = {
 	for (let i = 0z; i < len(head); i += 1) {
 		if (head[i].0 == name) {
+			free(head[i].0);
 			free(head[i].1);
 			delete(head[i]);
 			i -= 1;
@@ -32,6 +34,15 @@ export fn del_header(head: *header, name: str) void = {
 	};
 };
 
+// Frees state associated with an HTTP [[header]].
+export fn header_free(head: *header) void = {
+	for (let i = 0z; i < len(head); i += 1) {
+		free(head[i].0);
+		free(head[i].1);
+	};
+	free(*head);
+};
+
 // Writes a list of HTTP headers to the provided I/O handle in the HTTP wire
 // format.
 export fn write_header(sink: io::handle, head: *header) (size | io::error) = {
@@ -43,10 +54,25 @@ export fn write_header(sink: io::handle, head: *header) (size | io::error) = {
 	return z;
 };
 
-// Frees state associated with an HTTP [[header]].
-export fn header_free(head: *header) void = {
-	for (let i = 0z; i < len(head); i += 1) {
-		free(head[i].1);
+fn read_header(head: *header, scan: *bufio::scanner) (void | io::error) = {
+	for (true) {
+		const item = match (bufio::scan_string(scan, "\r\n")) {
+		case let line: const str =>
+			yield line;
+		case io::EOF =>
+			break;
+		case let err: io::error =>
+			return err;
+		case utf8::invalid =>
+			abort(); // TODO
+		};
+		if (item == "") {
+			break;
+		};
+
+		// TODO: validate field-name
+		let (name, val) = strings::cut(item, ":");
+		val = strings::trim(val);
+		add_header(head, name, val);
 	};
-	free(*head);
 };

net/http/response.ha

@@ -1,7 +1,10 @@
 use io;
+use os;
 
 // Stores state related to an HTTP response.
 export type response = struct {
+	// HTTP protocol version (major, minor)
+	version: (uint, uint),
 	// The HTTP status for this request as an integer.
 	status: uint,
 	// The HTTP status reason phrase.
@@ -9,10 +12,44 @@ export type response = struct {
 	// The HTTP headers provided by the server.
 	header: header,
 	// The response body, if any.
-	body: (io::handle | void),
+	body: nullable *reader,
 };
 
 // Frees state associated with an HTTP [[response]].
 export fn response_finish(resp: *response) void = {
 	header_free(&resp.header);
+	free(resp.reason);
+};
+
+export type reader = struct {
+	vtable: io::stream,
+	conn: io::handle,
+	buffer: [os::BUFSIZ]u8,
+	pending: size,
+};
+
+const reader_vtable = io::vtable {
+	reader = &reader_read,
+	...
+};
+
+fn reader_read(s: *io::stream, buf: []u8) (size | io::EOF | io::error) = {
+	let rd = s: *reader;
+	if (rd.pending == 0) {
+		match (io::read(rd.conn, rd.buffer)?) {
+		case let n: size =>
+			rd.pending = n;
+		case io::EOF =>
+			return io::EOF;
+		};
+	};
+
+	let n = len(buf);
+	if (n > rd.pending) {
+		n = rd.pending;
+	};
+	buf[..n] = rd.buffer[..n];
+	rd.buffer[..len(rd.buffer) - n] = rd.buffer[n..];
+	rd.pending -= n;
+	return n;
 };