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|
package gemini
import (
"bufio"
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"strconv"
"strings"
"sync"
"tildegit.org/tjp/gus"
"tildegit.org/tjp/gus/logging"
)
type titanRequestBodyKey struct{}
// TitanRequestBody is the key set in a handler's context for titan requests.
//
// When this key is present in the context (request.URL.Scheme will be "titan"), the
// corresponding value is a *bufio.Reader from which the request body can be read.
var TitanRequestBody = titanRequestBodyKey{}
type server struct {
ctx context.Context
errorLog logging.Logger
network string
address string
cancel context.CancelFunc
wg *sync.WaitGroup
listener net.Listener
handler gus.Handler
}
// NewServer builds a gemini server.
func NewServer(
ctx context.Context,
errorLog logging.Logger,
tlsConfig *tls.Config,
network string,
address string,
handler gus.Handler,
) (gus.Server, error) {
listener, err := net.Listen(network, address)
if err != nil {
return nil, err
}
addr := listener.Addr()
s := &server{
ctx: ctx,
errorLog: errorLog,
network: addr.Network(),
address: addr.String(),
wg: &sync.WaitGroup{},
listener: tls.NewListener(listener, tlsConfig),
handler: handler,
}
return s, nil
}
// Serve starts the server and blocks until it is closed.
//
// This function will allocate resources which are not cleaned up until
// Close() is called.
//
// It will respect cancellation of the context the server was created with,
// but be aware that Close() must still be called in that case to avoid
// dangling goroutines.
//
// On titan protocol requests it sets a key/value pair in the context. The
// key is TitanRequestBody, and the value is a *bufio.Reader from which the
// request body can be read.
func (s *server) Serve() error {
s.wg.Add(1)
defer s.wg.Done()
s.ctx, s.cancel = context.WithCancel(s.ctx)
s.wg.Add(1)
s.propagateCancel()
for {
conn, err := s.listener.Accept()
if err != nil {
if s.Closed() {
err = nil
} else {
_ = s.errorLog.Log("msg", "accept error", "error", err)
}
return err
}
s.wg.Add(1)
go s.handleConn(conn)
}
}
func (s *server) Close() {
s.cancel()
s.wg.Wait()
}
func (s *server) Network() string {
return s.network
}
func (s *server) Address() string {
return s.address
}
func (s *server) Hostname() string {
host, _, _ := net.SplitHostPort(s.address)
return host
}
func (s *server) Port() string {
_, portStr, _ := net.SplitHostPort(s.address)
return portStr
}
func (s *server) handleConn(conn net.Conn) {
defer s.wg.Done()
defer conn.Close()
buf := bufio.NewReader(conn)
var response *gus.Response
req, err := ParseRequest(buf)
if err != nil {
response = BadRequest(err.Error())
} else {
req.Server = s
req.RemoteAddr = conn.RemoteAddr()
if tlsconn, ok := conn.(*tls.Conn); ok {
state := tlsconn.ConnectionState()
req.TLSState = &state
}
ctx := s.ctx
if req.Scheme == "titan" {
len, err := sizeParam(req.Path)
if err == nil {
ctx = context.WithValue(
ctx,
TitanRequestBody,
io.LimitReader(buf, int64(len)),
)
}
}
defer func() {
if r := recover(); r != nil {
err := fmt.Errorf("%s", r)
_ = s.errorLog.Log("msg", "panic in handler", "err", err)
_, _ = io.Copy(conn, NewResponseReader(Failure(err)))
}
}()
response = s.handler(ctx, req)
if response == nil {
response = NotFound("Resource does not exist.")
}
}
defer response.Close()
_, _ = io.Copy(conn, NewResponseReader(response))
}
func (s *server) propagateCancel() {
go func() {
defer s.wg.Done()
<-s.ctx.Done()
_ = s.listener.Close()
}()
}
func (s *server) Closed() bool {
select {
case <-s.ctx.Done():
return true
default:
return false
}
}
func sizeParam(path string) (int, error) {
_, rest, found := strings.Cut(path, ";")
if !found {
return 0, errors.New("no params in path")
}
for _, piece := range strings.Split(rest, ";") {
key, val, _ := strings.Cut(piece, "=")
if key == "size" {
return strconv.Atoi(val)
}
}
return 0, errors.New("no size param found")
}
|
