transport.go

package dmsghttp

import (
	"bufio"
	"context"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"strings"

	"github.com/SkycoinProject/dmsg"
	"github.com/SkycoinProject/dmsg/cipher"
)

// Transport holds information about client who is initiating communication.
type Transport struct {
	DmsgClient *dmsg.Client
}

// RoundTrip implements golang's http package support for alternative transport protocols.
// In this case dmsg is used instead of TCP to initiate the communication with the server.
func (t Transport) RoundTrip(req *http.Request) (*http.Response, error) {
	// process remote pub key and port from dmsg-addr request header
	addrSplit := strings.Split(req.Host, ":")
	if len(addrSplit) != 2 {
		return nil, errors.New("invalid server Pub Key or Port")
	}
	var pk cipher.PubKey
	if err := pk.Set(addrSplit[0]); err != nil {
		return nil, err
	}

	rPort, err := strconv.Atoi(addrSplit[1])
	if err != nil {
		return nil, fmt.Errorf("invalid port: %v", err)
	}
	port := uint16(rPort)

	serverAddress := dmsg.Addr{PK: pk, Port: port}

	var (
		stream    *dmsg.Stream
		streamErr error
	)

	stream, streamErr = t.DmsgClient.DialStream(context.Background(), serverAddress)
	if streamErr != nil {
		return nil, streamErr
	}
	defer stream.Close() //nolint:errcheck

	if err := req.Write(stream); err != nil {
		return nil, err
	}

	return http.ReadResponse(bufio.NewReader(stream), req)
}