commit 9c55ea257dc2c9014f5e82736b5337885309bbdd
Author: LandaMm <qwer.009771@gmail.com>
Date:   Tue Apr 15 18:08:52 2025 +0200

    feat: init project + server prot is ready

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..112b205
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/LandaMm/hsp-go
+
+go 1.24.1
diff --git a/hsp-go b/hsp-go
new file mode 100755
index 0000000..2f47dec
Binary files /dev/null and b/hsp-go differ
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..52f1dc1
--- /dev/null
+++ b/main.go
@@ -0,0 +1,74 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/LandaMm/hsp-go/server"
+)
+
+func FileUploadRoute(req *server.Request) *server.Response {
+	log.Println("[MAIN] File Upload request:", req)
+	bytes, err := req.ExtractBytes()
+	if err != nil {
+		return server.NewStatusResponse(server.STATUS_INTERNALERR)
+	}
+
+	filename := "received.bin"
+	err = os.WriteFile(filename, bytes, 0644)
+	if err != nil {
+		log.Fatalln("Failed to write packet payload into a file:", err)
+		return server.NewStatusResponse(server.STATUS_INTERNALERR)
+	}
+
+	log.Println("Received new request from client:", req.Conn().RemoteAddr().String())
+
+	res := server.NewTextResponse("Hello, World!")
+	res.AddHeader("filename", filename)
+
+	return res
+}
+
+func main() {
+	srv := server.NewServer("localhost:3000")
+	fmt.Printf("Server created on address: %s\n", srv.Addr)
+
+	handler := make(chan net.Conn, 1)
+
+	router := server.NewRouter()
+
+	router.AddRoute("/file-upload", FileUploadRoute)
+
+	srv.SetListener(handler)
+
+	go func() {
+		for {
+			conn := <-handler
+			if err := router.Handle(conn); err != nil {
+				log.Println("[MAIN] Error handling connection:", err.Error())
+			}
+		}
+	}()
+
+	sigs := make(chan os.Signal, 1)
+
+	go func() {
+		s := <-sigs
+		if s == syscall.SIGINT || s == syscall.SIGTERM {
+			log.Println("Gracefully shutting down the server")
+			if err := srv.Stop(); err != nil {
+				log.Fatalln("Failed to close the server:", err)
+			}
+		}
+	}()
+
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+
+	if err := srv.Start(); err != nil {
+		log.Fatalln("Failed to start server")
+	}
+}
diff --git a/received.bin b/received.bin
new file mode 100644
index 0000000..d7a7acf
--- /dev/null
+++ b/received.bin
@@ -0,0 +1,2 @@
+Hello, everyone!
+I'm a txt file
diff --git a/server/constants.go b/server/constants.go
new file mode 100644
index 0000000..89c4853
--- /dev/null
+++ b/server/constants.go
@@ -0,0 +1,40 @@
+
+package server
+
+const (
+	H_STATUS = "status"
+	H_DATA_FORMAT = "data-format"
+	H_ROUTE = "route"
+)
+
+const (
+	DF_BYTES = "bytes"
+	DF_TEXT = "text"
+	DF_JSON = "json"
+)
+
+const (
+	E_UTF8 = "utf-8"
+)
+
+const (
+	STATUS_SUCCESS = 0
+	STATUS_NOTFOUND = 69
+	STATUS_INTERNALERR = 129
+)
+
+var DATA_FORMATS map[string]string = map[string]string{
+	"bytes": DF_BYTES,
+	"text": DF_TEXT,
+	"json": DF_JSON,
+}
+
+var ENCODINGS map[string]string = map[string]string{
+	"utf-8": E_UTF8,
+}
+
+type DataFormat struct {
+	Format string
+	Encoding string
+}
+
diff --git a/server/packet.go b/server/packet.go
new file mode 100644
index 0000000..50ecd1e
--- /dev/null
+++ b/server/packet.go
@@ -0,0 +1,188 @@
+package server
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+)
+
+const (
+	Magic uint32 = 0xDEADBEEF
+)
+
+const (
+	PacketVersion int = 1
+)
+
+type RawPacket struct {
+	Magic uint32
+	Version uint8
+	Flags uint8
+	HeaderSize uint16
+	PayloadSize uint32
+	Header []byte
+	Payload []byte
+}
+
+type Packet struct {
+	Version int
+	Flags int
+	Headers map[string]string
+	Payload []byte
+}
+
+type PacketDuplex struct {
+	conn net.Conn
+}
+
+func BuildPacket(headers map[string]string, payload []byte) *Packet {
+	return &Packet{
+		Version: PacketVersion,
+		Flags: 0, // TODO:
+		Headers: headers,
+		Payload: payload,
+	}
+}
+
+func ParseHeaders(rawHeaders []byte, headers *map[string]string) error {
+	i := 0
+	for i < len(rawHeaders) {
+		if rawHeaders[i] == '\n' {
+			break
+		}
+		var key string
+		for rawHeaders[i] != ':' {
+			if rawHeaders[i] != ' ' {
+				key += string(rawHeaders[i])
+			}
+			i++
+		}
+		i++
+		var value string
+		for rawHeaders[i] != '\n' {
+			if rawHeaders[i] != ' ' {
+				value += string(rawHeaders[i])
+			}
+			i++
+		}
+		i++
+		(*headers)[key] = value
+	}
+	return nil
+}
+
+func SerializeHeaders(headers *map[string]string) []byte {
+	buf := new(bytes.Buffer)
+	for k, v := range(*headers) {
+		fmt.Fprintf(buf, "%s:%s\n", k, v)
+	}
+	fmt.Fprintf(buf, "\n")
+	return buf.Bytes()
+}
+
+func NewPacketDuplex(conn net.Conn) *PacketDuplex {
+	return &PacketDuplex{
+		conn,
+	}
+}
+
+func (r *PacketDuplex) ReadPacket() (*Packet, error) {
+	rpkt := &RawPacket{}
+
+	err := binary.Read(r.conn, binary.BigEndian, &rpkt.Magic)
+	if err != nil {
+		return nil, err
+	}
+
+	if rpkt.Magic != Magic {
+		return nil, errors.New("Magic bytes are invalid")
+	}
+
+	err = binary.Read(r.conn, binary.BigEndian, &rpkt.Version)
+	if err != nil {
+		return nil, err
+	}
+
+	err = binary.Read(r.conn, binary.BigEndian, &rpkt.Flags)
+	if err != nil {
+		return nil, err
+	}
+
+	err = binary.Read(r.conn, binary.BigEndian, &rpkt.HeaderSize)
+	if err != nil {
+		return nil, err
+	}
+
+	err = binary.Read(r.conn, binary.BigEndian, &rpkt.PayloadSize)
+	if err != nil {
+		return nil, err
+	}
+
+	rpkt.Header = make([]byte, rpkt.HeaderSize)
+	if _, err := io.ReadFull(r.conn, rpkt.Header); err != nil {
+		return nil, err
+	}
+
+	rpkt.Payload = make([]byte, rpkt.PayloadSize)
+	if _, err := io.ReadFull(r.conn, rpkt.Payload); err != nil {
+		return nil, err
+	}
+
+	pkt := &Packet{
+		Version: int(rpkt.Version),
+		Flags: int(rpkt.Flags),
+		Headers: make(map[string]string),
+		Payload: rpkt.Payload,
+	}
+
+	ParseHeaders(rpkt.Header, &pkt.Headers)
+
+	return pkt, nil
+}
+
+func (r *PacketDuplex) WritePacket(packet *Packet) (int, error) {
+	buf := new(bytes.Buffer)
+
+	if err := binary.Write(buf, binary.BigEndian, Magic); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write magic into packet: %s", err.Error()))
+	}
+
+	if err := binary.Write(buf, binary.BigEndian, uint8(packet.Version)); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write version into packet: %s", err.Error()))
+	}
+
+	if err := binary.Write(buf, binary.BigEndian, uint8(packet.Flags)); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write flags into packet: %s", err.Error()))
+	}
+
+	rawHeaders := SerializeHeaders(&packet.Headers)
+	headerSize := len(rawHeaders)
+	payloadSize := len(packet.Payload)
+
+	if err := binary.Write(buf, binary.BigEndian, uint16(headerSize)); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write header size into packet: %s", err.Error()))
+	}
+
+	if err := binary.Write(buf, binary.BigEndian, uint32(payloadSize)); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write payload size into packet: %s", err.Error()))
+	}
+	
+	if _, err := buf.Write(rawHeaders[:headerSize]); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write raw headers: %s", err.Error()))
+	}
+
+	if _, err := buf.Write(packet.Payload[:payloadSize]); err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to write payload: %s", err.Error()))
+	}
+
+	n, err := r.conn.Write(buf.Bytes())
+	if err != nil {
+		return 0, errors.New(fmt.Sprintf("Failed to send packet over connection: %s", err.Error()))
+	}
+
+	return n, nil
+}
+
diff --git a/server/request.go b/server/request.go
new file mode 100644
index 0000000..9858443
--- /dev/null
+++ b/server/request.go
@@ -0,0 +1,89 @@
+package server
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"slices"
+	"strings"
+)
+
+type Request struct {
+	conn net.Conn
+	packet *Packet
+}
+
+func NewRequest(conn net.Conn, packet *Packet) *Request {
+	return &Request{
+		conn, packet,
+	}
+}
+
+func (req *Request) Conn() net.Conn {
+	return req.conn
+}
+
+func (req *Request) GetHeader(key string) (string, bool) {
+	value, ok := req.packet.Headers[key]
+	return value, ok
+}
+
+func (req *Request) GetDataFormat() (*DataFormat, error) {
+	// TODO: use predefined header names
+	format, ok := req.packet.Headers["data-format"]
+	if !ok {
+		return nil, errors.New("Data format header is not provided in request")
+	}
+
+	parts := strings.Split(format, ":")
+	if len(parts) != 2 {
+		if format == "bytes" {
+			return &DataFormat{
+				Format: DF_BYTES,
+			}, nil
+		}
+		return nil, errors.New("Invalid data format header")
+	}
+
+	f, ok := DATA_FORMATS[parts[0]]
+	if !ok {
+		return nil, errors.New(fmt.Sprintf("Unknown data format: %s", parts[0]))
+	}
+
+	encoding, ok := ENCODINGS[parts[1]]
+	if !ok {
+		return nil, errors.New(fmt.Sprintf("Unknown payload encoding: %s", parts[1]))
+	}
+
+	return &DataFormat{
+		Format: f,
+		Encoding: encoding,
+	}, nil
+}
+
+func (req *Request) ExtractText() (string, error) {
+	df, err := req.GetDataFormat()
+	if err != nil {
+		return "", err
+	}
+
+	if !slices.Contains([]string{DF_TEXT, DF_JSON}, df.Format) {
+		return "", errors.New(fmt.Sprintf("Data format '%s' cannot be extracted as text", df.Format))
+	}
+
+	return string(req.packet.Payload), nil
+}
+
+func (req *Request) ExtractBytes() ([]byte, error) {
+	df, err := req.GetDataFormat()
+	if err != nil {
+		return nil, err
+	}
+
+	if df.Format != "bytes" {
+		return nil, errors.New(fmt.Sprintf("Data format '%s' is invalid for extracting bytes", df.Format))
+	}
+
+	return req.packet.Payload, nil
+}
+
diff --git a/server/response.go b/server/response.go
new file mode 100644
index 0000000..d40ce10
--- /dev/null
+++ b/server/response.go
@@ -0,0 +1,90 @@
+package server
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"maps"
+	"strconv"
+)
+
+type Response struct {
+	StatusCode int
+	Format DataFormat
+	Headers map[string]string
+	Payload []byte
+}
+
+func NewStatusResponse(status int) *Response {
+	return &Response{
+		StatusCode: status,
+		Headers: make(map[string]string),
+		Format: DataFormat{
+			Format: DF_BYTES,
+			Encoding: "",
+		},
+		Payload: make([]byte, 0),
+	}
+}
+
+func NewTextResponse(text string) *Response {
+	return &Response{
+		StatusCode: STATUS_SUCCESS,
+		Headers: make(map[string]string),
+		Format: DataFormat{
+			Format: DF_TEXT,
+			Encoding: E_UTF8,
+		},
+		Payload: []byte(text),
+	}
+}
+
+func NewJsonResponse(data map[string]string) (*Response, error) {
+	jsonBytes, err := json.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Response{
+		StatusCode: STATUS_SUCCESS,
+		Headers: make(map[string]string),
+		Format: DataFormat{
+			Format: DF_JSON,
+			Encoding: E_UTF8,
+		},
+		Payload: jsonBytes,
+	}, nil
+}
+
+func (res *Response) ToPacket() *Packet {
+	headers := make(map[string]string)
+
+	maps.Copy(headers, res.Headers)
+
+	headers[H_DATA_FORMAT] = fmt.Sprintf("%s:%s", res.Format.Format, res.Format.Encoding)
+	headers[H_STATUS] = strconv.Itoa(res.StatusCode)
+
+	return BuildPacket(headers, res.Payload)
+}
+
+func (res *Response) AddHeader(key, value string) {
+	if _, ok := res.Headers[key]; ok {
+		log.Printf("WARN: Rewriting already existing header: '%s'\n", key)
+	}
+	res.Headers[key] = value
+}
+
+func (res *Response) Write(p []byte) (int, error) {
+	buf := new(bytes.Buffer)
+
+	n, err := buf.Write(p)
+	if err != nil {
+		return n, err
+	}
+
+	res.Payload = buf.Bytes()
+
+	return n, err
+}
+
diff --git a/server/router.go b/server/router.go
new file mode 100644
index 0000000..1ba68fc
--- /dev/null
+++ b/server/router.go
@@ -0,0 +1,52 @@
+package server
+
+import (
+	"errors"
+	"log"
+	"net"
+)
+
+type RouteHandler func(req *Request) *Response
+
+type Router struct {
+	Routes map[string]RouteHandler
+}
+
+func NewRouter() *Router {
+	return &Router{
+		Routes: make(map[string]RouteHandler),
+	}
+}
+
+func (r *Router) AddRoute(pathname string, handler RouteHandler) {
+	if _, ok := r.Routes[pathname]; ok {
+		log.Printf("WARN: Rewriting existing route '%s'\n", pathname)
+	}
+	r.Routes[pathname] = handler
+}
+
+func (r *Router) Handle(conn net.Conn) error {
+	defer conn.Close()
+
+	log.Printf("Got new connection from %s\n", conn.RemoteAddr().String())
+
+	dupl := NewPacketDuplex(conn)
+
+	// TODO: Ability to keep connection alive
+	packet, err := dupl.ReadPacket()
+	if err != nil {
+		return err
+	}
+
+	if route, ok := packet.Headers["route"]; ok {
+		log.Printf("[ROUTER] New connection to '%s'", route)
+		if handler, ok := r.Routes[route]; ok {
+			req := NewRequest(conn, packet)
+			res := handler(req)
+			_, err := dupl.WritePacket(res.ToPacket())
+			return err
+		}
+	}
+	return errors.New("Not Found")
+}
+
diff --git a/server/server.go b/server/server.go
new file mode 100644
index 0000000..fffe599
--- /dev/null
+++ b/server/server.go
@@ -0,0 +1,86 @@
+package server
+
+import (
+	"log"
+	"net"
+	"sync"
+)
+
+type Server struct {
+	Addr string
+	Running bool
+	ConnChan chan net.Conn
+	listener net.Listener
+	mu sync.Mutex
+}
+
+func NewServer(addr string) *Server {
+	return &Server{
+		Addr: addr,
+		Running: false,
+	}
+}
+
+func (s *Server) SetListener(ln chan net.Conn) {
+	s.ConnChan = ln
+}
+
+func (s *Server) Start() error {
+	ln, err := net.Listen("tcp", ":3000")
+	if err != nil {
+		return err
+	}
+
+	s.mu.Lock()
+	s.listener = ln
+	s.Running = true
+	s.mu.Unlock()
+
+	for s.IsRunning() {
+		log.Println("DEBUG:", "Waiting for new connection to accept")
+		conn, err := ln.Accept()
+		if err != nil {
+			if !s.IsRunning() {
+				break;
+			}
+			return err
+		}
+
+		if s.ConnChan != nil {
+			s.ConnChan <- conn
+		}
+	}
+
+	log.Println("DEBUG:", "Finished listening for connections")
+
+	s.mu.Lock()
+	s.Running = false
+	s.listener = nil
+	s.mu.Unlock()
+
+	return nil
+}
+
+
+func (s *Server) Stop() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.Running = false
+	if s.listener != nil {
+		return s.listener.Close()
+	}
+	if s.ConnChan != nil {
+		close(s.ConnChan)
+	}
+	
+	return nil
+}
+
+func (s *Server) IsRunning() bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.Running
+}
+
+