Files
zits/src/server/message_parser.zig
2026-01-02 19:53:53 +00:00

789 lines
27 KiB
Zig

const std = @import("std");
pub const MessageType = enum {
info,
connect,
@"pub",
hpub,
sub,
unsub,
msg,
hmsg,
ping,
pong,
@"+ok",
@"-err",
fn parseMemEql(input: []const u8) ?MessageType {
// if (std.mem.eql(u8, "INFO", input)) return .info;
if (std.mem.eql(u8, "CONNECT", input)) return .connect;
if (std.mem.eql(u8, "PUB", input)) return .@"pub";
if (std.mem.eql(u8, "HPUB", input)) return .hpub;
if (std.mem.eql(u8, "SUB", input)) return .sub;
if (std.mem.eql(u8, "UNSUB", input)) return .unsub;
// if (std.mem.eql(u8, "MSG", input)) return .msg;
// if (std.mem.eql(u8, "HMSG", input)) return .hmsg;
if (std.mem.eql(u8, "PING", input)) return .ping;
if (std.mem.eql(u8, "PONG", input)) return .pong;
// if (std.mem.eql(u8, "@"+OK"", input)) return .@"+ok";
// if (std.mem.eql(u8, "@"-ERR"", input)) return .@"-err";
return error.InvalidMessageType;
}
};
pub const Message = union(MessageType) {
info: ServerInfo,
connect: Connect,
@"pub": Pub,
hpub: HPub,
sub: Sub,
unsub: Unsub,
msg: Msg,
hmsg: HMsg,
ping,
pong,
@"+ok": void,
@"-err": []const u8,
pub const ServerInfo = struct {
/// The unique identifier of the NATS server.
server_id: []const u8,
/// The name of the NATS server.
server_name: []const u8,
/// The version of NATS.
version: []const u8,
/// The version of golang the NATS server was built with.
go: []const u8 = "0.0.0",
/// The IP address used to start the NATS server,
/// by default this will be 0.0.0.0 and can be
/// configured with -client_advertise host:port.
host: []const u8 = "0.0.0.0",
/// The port number the NATS server is configured
/// to listen on.
port: u16 = 4222,
/// Whether the server supports headers.
headers: bool = false,
/// Maximum payload size, in bytes, that the server
/// will accept from the client.
max_payload: u64,
/// An integer indicating the protocol version of
/// the server. The server version 1.2.0 sets this
/// to 1 to indicate that it supports the "Echo"
/// feature.
proto: u32 = 1,
};
pub const Connect = struct {
verbose: bool = false,
pedantic: bool = false,
tls_required: bool = false,
auth_token: ?[]const u8 = null,
user: ?[]const u8 = null,
pass: ?[]const u8 = null,
name: ?[]const u8 = null,
lang: []const u8,
version: []const u8,
protocol: u32,
echo: ?bool = null,
sig: ?[]const u8 = null,
jwt: ?[]const u8 = null,
no_responders: ?bool = null,
headers: ?bool = null,
nkey: ?[]const u8 = null,
pub fn deinit(self: Connect, alloc: std.mem.Allocator) void {
if (self.auth_token) |a| alloc.free(a);
if (self.user) |u| alloc.free(u);
if (self.pass) |p| alloc.free(p);
if (self.name) |n| alloc.free(n);
alloc.free(self.lang);
alloc.free(self.version);
if (self.sig) |s| alloc.free(s);
if (self.jwt) |j| alloc.free(j);
if (self.nkey) |n| alloc.free(n);
}
pub fn dupe(self: Connect, alloc: std.mem.Allocator) !Connect {
var res = self;
res.auth_token = if (self.auth_token) |a| try alloc.dupe(u8, a) else null;
errdefer if (res.auth_token) |a| alloc.free(a);
res.user = if (self.user) |u| try alloc.dupe(u8, u) else null;
errdefer if (res.user) |u| alloc.free(u);
res.pass = if (self.pass) |p| try alloc.dupe(u8, p) else null;
errdefer if (res.pass) |p| alloc.free(p);
res.name = if (self.name) |n| try alloc.dupe(u8, n) else null;
errdefer if (res.name) |n| alloc.free(n);
res.lang = try alloc.dupe(u8, self.lang);
errdefer alloc.free(res.lang);
res.version = try alloc.dupe(u8, self.version);
errdefer alloc.free(res.version);
res.sig = if (self.sig) |s| try alloc.dupe(u8, s) else null;
errdefer if (res.sig) |s| alloc.free(s);
res.jwt = if (self.jwt) |j| try alloc.dupe(u8, j) else null;
errdefer if (res.jwt) |j| alloc.free(j);
res.nkey = if (self.nkey) |n| try alloc.dupe(u8, n) else null;
errdefer if (res.nkey) |n| alloc.free(n);
return res;
}
};
pub const Pub = struct {
/// The destination subject to publish to.
subject: []const u8,
/// The reply subject that subscribers can use to send a response back to the publisher/requestor.
reply_to: ?[]const u8 = null,
/// The message payload data.
payload: []const u8,
pub fn deinit(self: Pub, alloc: std.mem.Allocator) void {
alloc.free(self.subject);
alloc.free(self.payload);
if (self.reply_to) |r| alloc.free(r);
}
pub fn toMsg(self: Pub, alloc: std.mem.Allocator, sid: []const u8) !Msg {
const res: Msg = .{
.subject = self.subject,
.sid = sid,
.reply_to = self.reply_to,
.payload = self.payload,
};
return res.dupe(alloc);
}
};
pub const HPub = struct {
header_bytes: usize,
@"pub": Pub,
pub fn deinit(self: HPub, alloc: std.mem.Allocator) void {
self.@"pub".deinit(alloc);
}
pub fn toHMsg(self: HPub, alloc: std.mem.Allocator, sid: []const u8) !HMsg {
return .{
.header_bytes = self.header_bytes,
.msg = try self.@"pub".toMsg(alloc, sid),
};
}
};
pub const HMsg = struct {
header_bytes: usize,
msg: Msg,
pub fn deinit(self: HMsg, alloc: std.mem.Allocator) void {
self.msg.deinit(alloc);
}
pub fn dupe(self: HMsg, alloc: std.mem.Allocator) !HMsg {
var res = self;
res.msg = try self.msg.dupe(alloc);
return res;
}
};
pub const Sub = struct {
/// The subject name to subscribe to.
subject: []const u8,
/// If specified, the subscriber will join this queue group.
queue_group: ?[]const u8,
/// A unique alphanumeric subscription ID, generated by the client.
sid: []const u8,
pub fn deinit(self: Sub, alloc: std.mem.Allocator) void {
alloc.free(self.subject);
alloc.free(self.sid);
if (self.queue_group) |q| alloc.free(q);
}
};
pub const Unsub = struct {
/// The unique alphanumeric subscription ID of the subject to unsubscribe from.
sid: []const u8,
/// A number of messages to wait for before automatically unsubscribing.
max_msgs: ?usize = null,
};
pub const Msg = struct {
subject: []const u8,
sid: []const u8,
reply_to: ?[]const u8,
payload: []const u8,
pub fn deinit(self: Msg, alloc: std.mem.Allocator) void {
alloc.free(self.subject);
alloc.free(self.sid);
if (self.reply_to) |r| alloc.free(r);
alloc.free(self.payload);
}
pub fn dupe(self: Msg, alloc: std.mem.Allocator) !Msg {
var res: Msg = undefined;
res.subject = try alloc.dupe(u8, self.subject);
errdefer alloc.free(res.subject);
res.sid = try alloc.dupe(u8, self.sid);
errdefer alloc.free(res.sid);
res.reply_to = if (self.reply_to) |r| try alloc.dupe(u8, r) else null;
errdefer if (res.reply_to) |r| alloc.free(r);
res.payload = try alloc.dupe(u8, self.payload);
errdefer alloc.free(res.payload);
return res;
}
};
const client_types = std.StaticStringMap(MessageType).initComptime(
.{
// {"INFO", .info},
.{ "CONNECT", .connect },
.{ "PUB", .@"pub" },
.{ "HPUB", .hpub },
.{ "SUB", .sub },
.{ "UNSUB", .unsub },
// {"MSG", .msg},
// {"HMSG", .hmsg},
.{ "PING", .ping },
.{ "PONG", .pong },
// {"+OK", .@"+ok"},
// {"-ERR", .@"-err"},
},
);
fn parseStaticStringMap(input: []const u8) ?MessageType {
return client_types.get(input);
}
pub const parse = parseStaticStringMap;
/// An error should be handled by cleaning up this connection.
pub fn next(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
var operation_string: std.ArrayList(u8) = blk: {
var buf: ["CONTINUE".len + 1]u8 = undefined;
break :blk .initBuffer(&buf);
};
while (in.peekByte()) |byte| {
if (std.ascii.isUpper(byte)) {
try operation_string.appendBounded(byte);
in.toss(1);
} else break;
} else |err| return err;
const operation = parse(operation_string.items) orelse {
return error.InvalidOperation;
};
switch (operation) {
.connect => {
// for storing the json string
var connect_string_writer_allocating: std.Io.Writer.Allocating = .init(alloc);
defer connect_string_writer_allocating.deinit();
var connect_string_writer = connect_string_writer_allocating.writer;
// for parsing the json string
var connect_arena_allocator: std.heap.ArenaAllocator = .init(alloc);
defer connect_arena_allocator.deinit();
const connect_allocator = connect_arena_allocator.allocator();
try in.discardAll(1); // throw away space
// Should read the next JSON object to the fixed buffer writer.
_ = try in.streamDelimiter(&connect_string_writer, '}');
try connect_string_writer.writeByte('}');
try expectStreamBytes(in, "}\r\n"); // discard '}\r\n'
// TODO: should be CONNECTION allocator
const res = try std.json.parseFromSliceLeaky(
Connect,
connect_allocator,
connect_string_writer.buffered(),
.{ .allocate = .alloc_always },
);
return .{ .connect = try res.dupe(alloc) };
},
.@"pub" => {
return parsePub(alloc, in);
},
.hpub => {
return parseHPub(alloc, in);
},
.ping => {
try expectStreamBytes(in, "\r\n");
return .ping;
},
.pong => {
try expectStreamBytes(in, "\r\n");
return .pong;
},
.sub => {
if (!std.ascii.isWhitespace(try in.takeByte())) {
@branchHint(.unlikely);
return error.InvalidStream;
}
const subject = try readSubject(alloc, in);
errdefer alloc.free(subject);
const second = blk: {
// Drop whitespace
while (in.peekByte()) |byte| {
if (std.ascii.isWhitespace(byte)) {
in.toss(1);
} else break;
} else |err| return err;
var acc: std.ArrayList(u8) = .empty;
errdefer acc.deinit(alloc);
while (in.peekByte()) |byte| {
if (std.ascii.isWhitespace(byte)) break;
try acc.append(alloc, byte);
in.toss(1);
} else |err| return err;
break :blk try acc.toOwnedSlice(alloc);
};
errdefer alloc.free(second);
const queue_group = if ((try in.peekByte()) != '\r') second else null;
// We do not need an errdefer free for queue group, because it will only be second (already has errdefer free) or null.
const sid = if (queue_group) |_| try alloc.dupe(u8, try in.takeDelimiterExclusive('\r')) else second;
// if queue_group is null, that means sid is second, and already has an errdefer free.
errdefer if (queue_group) |_| alloc.free(sid);
try expectStreamBytes(in, "\r\n");
return .{
.sub = .{
.subject = subject,
.queue_group = queue_group,
.sid = sid,
},
};
},
.unsub => {
if (!std.ascii.isWhitespace(try in.takeByte())) {
@branchHint(.unlikely);
return error.InvalidStream;
}
// Parse sid
const sid = blk: {
var acc: std.ArrayList(u8) = .empty;
errdefer acc.deinit(alloc);
while (in.peekByte()) |byte| {
if (std.ascii.isWhitespace(byte)) break;
try acc.append(alloc, byte);
in.toss(1);
} else |err| return err;
break :blk try acc.toOwnedSlice(alloc);
};
errdefer alloc.free(sid);
if ((try in.peekByte()) == '\r') {
try expectStreamBytes(in, "\r\n");
return .{
.unsub = .{
.sid = sid,
},
};
} else if (std.ascii.isWhitespace(try in.peekByte())) {
in.toss(1);
const max_msgs = blk: {
var max_msgs_list: std.ArrayList(u8) = .empty;
errdefer max_msgs_list.deinit(alloc);
while (in.peekByte()) |byte| {
if (std.ascii.isWhitespace(byte)) {
try expectStreamBytes(in, "\r\n");
break;
}
if (std.ascii.isDigit(byte)) {
try max_msgs_list.append(alloc, byte);
} else {
return error.InvalidStream;
}
} else |err| return err;
break :blk try std.fmt.parseUnsigned(usize, max_msgs_list.items, 10);
};
return .{
.unsub = .{
.sid = sid,
.max_msgs = max_msgs,
},
};
} else return error.InvalidStream;
},
else => |msg| std.debug.panic("Not implemented: {}\n", .{msg}),
}
}
};
fn parsePub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
try in.discardAll(1); // throw away space
// Parse subject
const subject: []const u8 = try readSubject(alloc, in);
errdefer alloc.free(subject);
const States = enum {
before_second,
in_second,
after_second,
in_third,
in_end,
};
var second: std.ArrayList(u8) = .empty;
defer second.deinit(alloc);
var third: ?std.ArrayList(u8) = null;
defer if (third) |*t| t.deinit(alloc);
var payload: std.Io.Writer.Allocating = .init(alloc);
sw: switch (@as(States, .before_second)) {
.before_second => {
// Drop whitespace
const byte = try in.peekByte();
if (std.ascii.isWhitespace(byte)) {
in.toss(1);
continue :sw .before_second;
}
continue :sw .in_second;
},
.in_second => {
const byte = try in.peekByte();
if (!std.ascii.isWhitespace(byte)) {
try second.append(alloc, byte);
in.toss(1);
continue :sw .in_second;
}
continue :sw .after_second;
},
.after_second => {
const byte = try in.peekByte();
if (byte == '\r') {
continue :sw .in_end;
} else if (std.ascii.isWhitespace(byte)) {
in.toss(1);
continue :sw .after_second;
}
third = .empty;
continue :sw .in_third;
},
.in_third => {
const byte = try in.peekByte();
if (byte == '\r') {
continue :sw .in_end;
} else if (std.ascii.isDigit(byte)) {
try third.?.append(alloc, byte);
in.toss(1);
continue :sw .in_third;
}
return error.InvalidStream;
},
.in_end => {
try expectStreamBytes(in, "\r\n");
},
}
const reply_to: ?[]const u8, const bytes: usize =
if (third) |t| .{
try alloc.dupe(u8, second.items),
try std.fmt.parseUnsigned(usize, t.items, 10),
} else .{
null,
try std.fmt.parseUnsigned(usize, second.items, 10),
};
try in.streamExact(&payload.writer, bytes);
try expectStreamBytes(in, "\r\n");
return .{
.@"pub" = .{
.subject = subject,
.payload = try payload.toOwnedSlice(),
.reply_to = reply_to,
},
};
}
test parsePub {
{
var in: std.Io.Reader = .fixed(" foo 3\r\nbar\r\n");
var res = try parsePub(std.testing.allocator, &in);
defer res.@"pub".deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{ .@"pub" = .{
.subject = "foo",
.reply_to = null,
.payload = "bar",
} },
res,
);
}
{
var in: std.Io.Reader = .fixed(" foo reply.to 3\r\nbar\r\n");
var res = try parsePub(std.testing.allocator, &in);
defer res.@"pub".deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{ .@"pub" = .{
.subject = "foo",
.reply_to = "reply.to",
.payload = "bar",
} },
res,
);
}
// numeric reply subject
{
var in: std.Io.Reader = .fixed(" foo 5 3\r\nbar\r\n");
var res = try parsePub(std.testing.allocator, &in);
defer res.@"pub".deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{ .@"pub" = .{
.subject = "foo",
.reply_to = "5",
.payload = "bar",
} },
res,
);
}
}
fn parseHPub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
try in.discardAll(1); // throw away space
// Parse subject
const subject: []const u8 = try readSubject(alloc, in);
errdefer alloc.free(subject);
const States = enum {
before_second,
in_second,
after_second,
in_third,
after_third,
in_fourth,
in_end,
};
var second: std.ArrayList(u8) = .empty;
defer second.deinit(alloc);
var third: std.ArrayList(u8) = .empty;
defer third.deinit(alloc);
var fourth: ?std.ArrayList(u8) = null;
defer if (fourth) |*f| f.deinit(alloc);
var payload: std.Io.Writer.Allocating = .init(alloc);
sw: switch (@as(States, .before_second)) {
.before_second => {
// Drop whitespace
const byte = try in.peekByte();
if (std.ascii.isWhitespace(byte)) {
in.toss(1);
continue :sw .before_second;
}
continue :sw .in_second;
},
.in_second => {
const byte = try in.peekByte();
if (!std.ascii.isWhitespace(byte)) {
try second.append(alloc, byte);
in.toss(1);
continue :sw .in_second;
}
continue :sw .after_second;
},
.after_second => {
const byte = try in.peekByte();
if (byte == '\r') {
continue :sw .in_end;
} else if (std.ascii.isWhitespace(byte)) {
in.toss(1);
continue :sw .after_second;
}
third = .empty;
continue :sw .in_third;
},
.in_third => {
const byte = try in.peekByte();
if (!std.ascii.isWhitespace(byte)) {
try third.append(alloc, byte);
in.toss(1);
continue :sw .in_third;
}
continue :sw .after_third;
},
.after_third => {
const byte = try in.peekByte();
if (byte == '\r') {
continue :sw .in_end;
} else if (std.ascii.isWhitespace(byte)) {
in.toss(1);
continue :sw .after_third;
}
fourth = .empty;
continue :sw .in_fourth;
},
.in_fourth => {
const byte = try in.peekByte();
if (byte == '\r') {
continue :sw .in_end;
} else if (std.ascii.isDigit(byte)) {
try fourth.?.append(alloc, byte);
in.toss(1);
continue :sw .in_fourth;
}
return error.InvalidStream;
},
.in_end => {
try expectStreamBytes(in, "\r\n");
},
}
const reply_to: ?[]const u8, const header_bytes: usize, const total_bytes: usize =
if (fourth) |f| .{
try alloc.dupe(u8, second.items),
try std.fmt.parseUnsigned(usize, third.items, 10),
try std.fmt.parseUnsigned(usize, f.items, 10),
} else .{
null,
try std.fmt.parseUnsigned(usize, second.items, 10),
try std.fmt.parseUnsigned(usize, third.items, 10),
};
try in.streamExact(&payload.writer, total_bytes);
try expectStreamBytes(in, "\r\n");
return .{
.hpub = .{
.header_bytes = header_bytes,
.@"pub" = .{
.subject = subject,
.payload = try payload.toOwnedSlice(),
.reply_to = reply_to,
},
},
};
}
test parseHPub {
{
var in: std.Io.Reader = .fixed(" foo 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
var res = try parseHPub(std.testing.allocator, &in);
defer res.hpub.deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{
.hpub = .{
.header_bytes = 22,
.@"pub" = .{
.subject = "foo",
.reply_to = null,
.payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
},
},
},
res,
);
}
{
var in: std.Io.Reader = .fixed(" foo reply.to 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
var res = try parseHPub(std.testing.allocator, &in);
defer res.hpub.deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{
.hpub = .{
.header_bytes = 22,
.@"pub" = .{
.subject = "foo",
.reply_to = "reply.to",
.payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
},
},
},
res,
);
}
{
var in: std.Io.Reader = .fixed(" foo 6 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
var res = try parseHPub(std.testing.allocator, &in);
defer res.hpub.deinit(std.testing.allocator);
try std.testing.expectEqualDeep(
Message{
.hpub = .{
.header_bytes = 22,
.@"pub" = .{
.subject = "foo",
.reply_to = "6",
.payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
},
},
},
res,
);
}
}
fn readSubject(alloc: std.mem.Allocator, in: *std.Io.Reader) ![]const u8 {
var subject_list: std.ArrayList(u8) = .empty;
errdefer subject_list.deinit(alloc);
// Handle the first character
{
const byte = try in.takeByte();
if (std.ascii.isWhitespace(byte) or byte == '.')
return error.InvalidStream;
try subject_list.append(alloc, byte);
}
while (in.takeByte()) |byte| {
if (std.ascii.isWhitespace(byte)) break;
if (std.ascii.isAscii(byte)) {
if (byte == '.') {
const next_byte = try in.peekByte();
if (next_byte == '.' or std.ascii.isWhitespace(next_byte))
return error.InvalidSubject;
}
try subject_list.append(alloc, byte);
}
} else |err| return err;
return subject_list.toOwnedSlice(alloc);
}
inline fn expectStreamBytes(reader: *std.Io.Reader, expected: []const u8) !void {
if (!std.mem.eql(u8, try reader.take(expected.len), expected)) {
@branchHint(.unlikely);
return error.InvalidStream;
}
}
test "parsing a stream" {
const input = "CONNECT {\"verbose\":false,\"pedantic\":false,\"tls_required\":fa" ++
"lse,\"name\":\"NATS CLI Version v0.2.4\",\"lang\":\"go\",\"version\":\"1.43" ++
".0\",\"protocol\":1,\"echo\":true,\"headers\":true,\"no_responders\":true}\r" ++
"\nPUB hi 3\r\nfoo\r\n";
var reader: std.Io.Reader = .fixed(input);
var arena: std.heap.ArenaAllocator = .init(std.testing.allocator);
defer arena.deinit();
const gpa = arena.allocator();
{
const msg: Message = try Message.next(gpa, &reader);
const expected: Message = .{ .connect = .{
.verbose = false,
.pedantic = false,
.tls_required = false,
.name = "NATS CLI Version v0.2.4",
.lang = "go",
.version = "1.43.0",
.protocol = 1,
.echo = true,
.headers = true,
.no_responders = true,
} };
try std.testing.expectEqualDeep(expected, msg);
}
{
const msg: Message = try Message.next(gpa, &reader);
const expected: Message = .{ .@"pub" = .{
.subject = "hi",
.payload = "foo",
} };
try std.testing.expectEqualDeep(expected, msg);
}
}