2020-10-24 19:15:32 +00:00
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package gemini
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2020-09-25 23:06:56 +00:00
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import (
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2021-02-15 04:58:28 +00:00
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"context"
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2020-09-25 23:06:56 +00:00
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"crypto/tls"
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2020-11-05 20:27:12 +00:00
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"errors"
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2020-09-25 23:06:56 +00:00
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"log"
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"net"
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2021-02-15 04:58:28 +00:00
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"sync"
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2020-09-25 23:06:56 +00:00
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"time"
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)
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2021-02-14 20:50:41 +00:00
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// A Server defines parameters for running a Gemini server. The zero value for
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// Server is a valid configuration.
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2020-09-25 23:06:56 +00:00
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type Server struct {
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2021-02-14 20:50:41 +00:00
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// Addr optionally specifies the TCP address for the server to listen on,
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// in the form "host:port". If empty, ":1965" (port 1965) is used.
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// See net.Dial for details of the address format.
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2020-09-25 23:06:56 +00:00
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Addr string
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2021-02-18 01:30:59 +00:00
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// The Handler to invoke.
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Handler Handler
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2021-02-14 20:50:41 +00:00
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// ReadTimeout is the maximum duration for reading the entire
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// request.
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//
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// A ReadTimeout of zero means no timeout.
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2020-11-01 01:07:02 +00:00
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ReadTimeout time.Duration
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// WriteTimeout is the maximum duration before timing out
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// writes of the response.
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//
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// A WriteTimeout of zero means no timeout.
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2020-11-01 01:07:02 +00:00
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WriteTimeout time.Duration
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2021-02-19 23:53:06 +00:00
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// GetCertificate returns a TLS certificate based on the given
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// hostname.
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//
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// If GetCertificate is nil or returns nil, then no certificate
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// will be used and the connection will be aborted.
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2021-02-23 14:08:44 +00:00
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//
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// See the certificate submodule for a certificate store that creates
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// and rotates certificates as needed.
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2021-02-19 03:22:17 +00:00
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GetCertificate func(hostname string) (*tls.Certificate, error)
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2020-09-25 23:06:56 +00:00
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2021-02-14 20:50:41 +00:00
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// ErrorLog specifies an optional logger for errors accepting connections,
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// unexpected behavior from handlers, and underlying file system errors.
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2020-11-03 21:11:31 +00:00
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// If nil, logging is done via the log package's standard logger.
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2021-02-23 16:10:30 +00:00
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ErrorLog interface {
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Printf(format string, v ...interface{})
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}
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2020-11-03 21:11:31 +00:00
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2021-02-23 02:13:42 +00:00
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listeners map[*net.Listener]context.CancelFunc
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conns map[*net.Conn]context.CancelFunc
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closed bool // true if Closed or Shutdown called
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shutdown bool // true if Shutdown called
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doneChan chan struct{}
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mu sync.Mutex
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2020-10-11 21:53:22 +00:00
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}
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2021-02-23 02:13:42 +00:00
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func (srv *Server) isClosed() bool {
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srv.mu.Lock()
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defer srv.mu.Unlock()
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return srv.closed
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}
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// done returns a channel that's closed when the server is closed and
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// all listeners and connections are closed.
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2021-02-21 05:21:29 +00:00
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func (srv *Server) done() chan struct{} {
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srv.mu.Lock()
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defer srv.mu.Unlock()
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return srv.doneLocked()
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}
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func (srv *Server) doneLocked() chan struct{} {
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if srv.doneChan == nil {
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srv.doneChan = make(chan struct{})
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}
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return srv.doneChan
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}
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2021-02-23 02:13:42 +00:00
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// tryCloseDone closes srv.done() if the server is closed and
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// there are no active listeners or connections.
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func (srv *Server) tryCloseDone() {
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2021-02-21 05:21:29 +00:00
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srv.mu.Lock()
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defer srv.mu.Unlock()
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2021-02-23 02:13:42 +00:00
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srv.tryCloseDoneLocked()
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}
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func (srv *Server) tryCloseDoneLocked() {
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if !srv.closed {
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return
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}
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2021-02-21 05:21:29 +00:00
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if len(srv.listeners) == 0 && len(srv.conns) == 0 {
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ch := srv.doneLocked()
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select {
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2021-02-23 01:06:05 +00:00
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case <-ch:
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default:
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close(ch)
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}
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}
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}
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2021-02-23 02:33:23 +00:00
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// Close immediately closes all active net.Listeners and connections.
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// For a graceful shutdown, use Shutdown.
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func (srv *Server) Close() error {
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srv.mu.Lock()
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{
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if srv.closed {
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srv.mu.Unlock()
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return nil
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}
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srv.closed = true
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2021-02-21 05:21:29 +00:00
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2021-02-23 02:13:42 +00:00
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srv.tryCloseDoneLocked()
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2021-02-23 01:06:05 +00:00
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2021-02-23 02:13:42 +00:00
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// Close all active connections and listeners.
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for _, cancel := range srv.listeners {
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cancel()
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}
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for _, cancel := range srv.conns {
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cancel()
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}
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2021-02-21 05:21:29 +00:00
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}
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srv.mu.Unlock()
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select {
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case <-srv.done():
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return nil
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}
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}
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// Shutdown gracefully shuts down the server without interrupting any
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2021-02-23 02:27:41 +00:00
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// active connections. Shutdown works by first closing all open listeners
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// and then waiting indefinitely for connections to close.
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2021-02-21 05:21:29 +00:00
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// If the provided context expires before the shutdown is complete,
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// Shutdown returns the context's error.
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//
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// When Shutdown is called, Serve and ListenAndServe immediately
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2021-02-23 02:13:42 +00:00
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// return an error. Make sure the program doesn't exit and waits instead for
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// Shutdown to return.
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2021-02-21 05:21:29 +00:00
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//
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// Once Shutdown has been called on a server, it may not be reused;
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// future calls to methods such as Serve will return an error.
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func (srv *Server) Shutdown(ctx context.Context) error {
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srv.mu.Lock()
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{
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if srv.closed {
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srv.mu.Unlock()
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return nil
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}
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srv.closed = true
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srv.shutdown = true
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2021-02-21 05:21:29 +00:00
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2021-02-23 14:27:03 +00:00
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srv.tryCloseDoneLocked()
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2021-02-23 02:13:42 +00:00
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// Close all active listeners.
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for _, cancel := range srv.listeners {
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cancel()
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}
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}
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srv.mu.Unlock()
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2021-02-21 05:21:29 +00:00
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// Wait for active connections to finish.
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-srv.done():
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return nil
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}
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}
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2020-09-25 23:06:56 +00:00
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// ListenAndServe listens for requests at the server's configured address.
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2021-02-14 20:50:41 +00:00
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// ListenAndServe listens on the TCP network address srv.Addr and then calls
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2021-02-23 17:10:52 +00:00
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// Serve to handle requests on incoming connections. If the provided
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// context expires, ListenAndServe closes l and returns the context's error.
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2021-02-14 20:50:41 +00:00
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//
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// If srv.Addr is blank, ":1965" is used.
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//
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2021-02-23 02:13:42 +00:00
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// ListenAndServe always returns a non-nil error.
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2021-02-23 02:27:41 +00:00
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// After Shutdown or Closed, the returned error is context.Canceled.
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2021-02-21 05:21:29 +00:00
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func (srv *Server) ListenAndServe(ctx context.Context) error {
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2021-02-23 02:13:42 +00:00
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if srv.isClosed() {
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2021-02-23 02:27:41 +00:00
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return context.Canceled
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2021-02-16 01:16:32 +00:00
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}
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2021-02-14 20:50:41 +00:00
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addr := srv.Addr
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2020-09-25 23:06:56 +00:00
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if addr == "" {
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addr = ":1965"
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}
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2021-02-21 05:21:29 +00:00
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l, err := net.Listen("tcp", addr)
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2020-09-25 23:06:56 +00:00
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if err != nil {
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return err
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}
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2021-02-21 05:21:29 +00:00
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l = tls.NewListener(l, &tls.Config{
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2020-10-28 18:59:45 +00:00
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ClientAuth: tls.RequestClientCert,
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MinVersion: tls.VersionTLS12,
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2021-02-14 20:50:41 +00:00
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GetCertificate: srv.getCertificate,
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2021-02-21 05:21:29 +00:00
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})
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return srv.Serve(ctx, l)
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}
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func (srv *Server) getCertificate(h *tls.ClientHelloInfo) (*tls.Certificate, error) {
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if srv.GetCertificate == nil {
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return nil, errors.New("gemini: GetCertificate is nil")
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}
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return srv.GetCertificate(h.ServerName)
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2020-09-25 23:06:56 +00:00
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}
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2021-02-23 02:13:42 +00:00
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func (srv *Server) trackListener(l *net.Listener, cancel context.CancelFunc) bool {
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2021-02-21 21:05:08 +00:00
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srv.mu.Lock()
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defer srv.mu.Unlock()
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2021-02-23 02:13:42 +00:00
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if srv.closed {
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2021-02-23 01:06:05 +00:00
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return false
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}
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2021-02-15 04:58:28 +00:00
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if srv.listeners == nil {
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2021-02-23 02:13:42 +00:00
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srv.listeners = make(map[*net.Listener]context.CancelFunc)
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2021-02-15 04:58:28 +00:00
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}
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2021-02-23 02:13:42 +00:00
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srv.listeners[l] = cancel
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2021-02-21 16:53:15 +00:00
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return true
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2021-02-15 04:58:28 +00:00
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}
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func (srv *Server) deleteListener(l *net.Listener) {
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srv.mu.Lock()
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defer srv.mu.Unlock()
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delete(srv.listeners, l)
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}
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2021-02-14 20:50:41 +00:00
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// Serve accepts incoming connections on the Listener l, creating a new
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2021-02-23 23:45:58 +00:00
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// service goroutine for each. The service goroutines read the requests and
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// then call the appropriate Handler to reply to them. If the provided
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2021-02-23 02:33:23 +00:00
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// context expires, Serve closes l and returns the context's error.
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2021-02-14 20:50:41 +00:00
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//
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2021-02-23 02:27:41 +00:00
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// Serve always closes l and returns a non-nil error.
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// After Shutdown or Close, the returned error is context.Canceled.
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2021-02-21 05:21:29 +00:00
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func (srv *Server) Serve(ctx context.Context, l net.Listener) error {
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2021-02-15 04:58:28 +00:00
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defer l.Close()
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2021-02-23 02:13:42 +00:00
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lnctx, cancel := context.WithCancel(ctx)
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defer cancel()
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if !srv.trackListener(&l, cancel) {
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2021-02-23 02:27:41 +00:00
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return context.Canceled
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2021-02-21 16:53:15 +00:00
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}
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2021-02-23 02:13:42 +00:00
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defer srv.tryCloseDone()
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2021-02-16 01:18:08 +00:00
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defer srv.deleteListener(&l)
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2021-02-21 05:21:29 +00:00
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errch := make(chan error, 1)
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go func() {
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errch <- srv.serve(ctx, l)
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}()
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select {
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2021-02-23 02:13:42 +00:00
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case <-lnctx.Done():
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return lnctx.Err()
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2021-02-21 05:21:29 +00:00
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case err := <-errch:
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return err
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2021-02-15 04:58:28 +00:00
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}
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2021-02-21 05:21:29 +00:00
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}
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2021-02-15 04:58:28 +00:00
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2021-02-21 05:21:29 +00:00
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func (srv *Server) serve(ctx context.Context, l net.Listener) error {
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2021-02-21 16:53:15 +00:00
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var tempDelay time.Duration // how long to sleep on accept failure
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2020-09-25 23:06:56 +00:00
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for {
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rw, err := l.Accept()
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if err != nil {
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// If this is a temporary error, sleep
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if ne, ok := err.(net.Error); ok && ne.Temporary() {
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if tempDelay == 0 {
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tempDelay = 5 * time.Millisecond
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} else {
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tempDelay *= 2
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}
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if max := 1 * time.Second; tempDelay > max {
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tempDelay = max
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}
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2021-02-14 20:50:41 +00:00
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srv.logf("gemini: Accept error: %v; retrying in %v", err, tempDelay)
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2020-09-25 23:06:56 +00:00
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time.Sleep(tempDelay)
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continue
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}
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return err
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}
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tempDelay = 0
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2021-02-21 16:53:15 +00:00
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go srv.ServeConn(ctx, rw)
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2020-09-25 23:06:56 +00:00
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}
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}
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2021-02-23 02:13:42 +00:00
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func (srv *Server) trackConn(conn *net.Conn, cancel context.CancelFunc) bool {
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2021-02-21 21:05:08 +00:00
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srv.mu.Lock()
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defer srv.mu.Unlock()
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2021-02-23 02:13:42 +00:00
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if srv.closed && !srv.shutdown {
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return false
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}
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2021-02-15 04:58:28 +00:00
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if srv.conns == nil {
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2021-02-23 02:13:42 +00:00
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srv.conns = make(map[*net.Conn]context.CancelFunc)
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2021-02-15 04:58:28 +00:00
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}
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2021-02-23 02:13:42 +00:00
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srv.conns[conn] = cancel
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return true
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2021-02-15 04:58:28 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
func (srv *Server) deleteConn(conn *net.Conn) {
|
|
|
|
srv.mu.Lock()
|
|
|
|
defer srv.mu.Unlock()
|
|
|
|
delete(srv.conns, conn)
|
|
|
|
}
|
|
|
|
|
2021-02-21 16:53:15 +00:00
|
|
|
// ServeConn serves a Gemini response over the provided connection.
|
2021-02-21 05:21:29 +00:00
|
|
|
// It closes the connection when the response has been completed.
|
2021-02-23 02:33:23 +00:00
|
|
|
// If the provided context expires before the response has completed,
|
|
|
|
// ServeConn closes the connection and returns the context's error.
|
|
|
|
//
|
|
|
|
// Note that ServeConn can be used during a Shutdown.
|
2021-02-21 16:53:15 +00:00
|
|
|
func (srv *Server) ServeConn(ctx context.Context, conn net.Conn) error {
|
2020-12-18 06:41:14 +00:00
|
|
|
defer conn.Close()
|
2021-02-15 04:58:28 +00:00
|
|
|
|
2021-02-23 02:13:42 +00:00
|
|
|
ctx, cancel := context.WithCancel(ctx)
|
|
|
|
defer cancel()
|
|
|
|
|
|
|
|
if !srv.trackConn(&conn, cancel) {
|
2021-02-23 02:27:41 +00:00
|
|
|
return context.Canceled
|
2021-02-23 02:13:42 +00:00
|
|
|
}
|
|
|
|
defer srv.tryCloseDone()
|
2021-02-21 05:21:29 +00:00
|
|
|
defer srv.deleteConn(&conn)
|
|
|
|
|
2021-02-14 20:50:41 +00:00
|
|
|
if d := srv.ReadTimeout; d != 0 {
|
|
|
|
conn.SetReadDeadline(time.Now().Add(d))
|
2020-11-01 01:07:02 +00:00
|
|
|
}
|
2021-02-14 20:50:41 +00:00
|
|
|
if d := srv.WriteTimeout; d != 0 {
|
|
|
|
conn.SetWriteDeadline(time.Now().Add(d))
|
2020-11-01 01:07:02 +00:00
|
|
|
}
|
|
|
|
|
2021-02-21 16:53:15 +00:00
|
|
|
errch := make(chan error, 1)
|
2021-02-21 05:21:29 +00:00
|
|
|
go func() {
|
2021-02-21 16:53:15 +00:00
|
|
|
errch <- srv.serveConn(ctx, conn)
|
2021-02-21 05:21:29 +00:00
|
|
|
}()
|
|
|
|
|
|
|
|
select {
|
|
|
|
case <-ctx.Done():
|
2021-02-21 16:53:15 +00:00
|
|
|
return ctx.Err()
|
|
|
|
case err := <-errch:
|
|
|
|
return err
|
2021-02-21 05:21:29 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2021-02-21 16:53:15 +00:00
|
|
|
func (srv *Server) serveConn(ctx context.Context, conn net.Conn) error {
|
2021-02-23 21:06:57 +00:00
|
|
|
ctx, cancel := context.WithCancel(ctx)
|
|
|
|
done := ctx.Done()
|
|
|
|
cw := &contextWriter{
|
|
|
|
ctx: ctx,
|
|
|
|
done: done,
|
|
|
|
cancel: cancel,
|
|
|
|
wc: conn,
|
|
|
|
}
|
|
|
|
r := &contextReader{
|
|
|
|
ctx: ctx,
|
|
|
|
done: done,
|
|
|
|
cancel: cancel,
|
|
|
|
rc: conn,
|
|
|
|
}
|
|
|
|
|
2021-02-24 03:02:45 +00:00
|
|
|
w := newResponseWriter(cw)
|
2021-02-24 01:59:04 +00:00
|
|
|
w.conn = conn
|
2020-12-18 06:41:14 +00:00
|
|
|
|
2021-02-23 21:06:57 +00:00
|
|
|
req, err := ReadRequest(r)
|
2020-10-21 20:28:50 +00:00
|
|
|
if err != nil {
|
2021-02-17 18:36:16 +00:00
|
|
|
w.WriteHeader(StatusBadRequest, "Bad request")
|
2021-02-21 16:53:15 +00:00
|
|
|
return w.Flush()
|
2021-01-05 19:16:33 +00:00
|
|
|
}
|
2021-02-14 02:10:19 +00:00
|
|
|
|
2021-02-18 01:30:59 +00:00
|
|
|
h := srv.Handler
|
2021-02-15 06:15:23 +00:00
|
|
|
if h == nil {
|
2021-02-17 18:36:16 +00:00
|
|
|
w.WriteHeader(StatusNotFound, "Not found")
|
2021-02-21 16:53:15 +00:00
|
|
|
return w.Flush()
|
2020-10-21 20:28:50 +00:00
|
|
|
}
|
2021-01-05 19:16:33 +00:00
|
|
|
|
2021-02-20 20:49:07 +00:00
|
|
|
h.ServeGemini(ctx, w, req)
|
2021-02-21 16:53:15 +00:00
|
|
|
return w.Flush()
|
2021-02-20 23:52:33 +00:00
|
|
|
}
|
|
|
|
|
2021-02-14 20:50:41 +00:00
|
|
|
func (srv *Server) logf(format string, args ...interface{}) {
|
|
|
|
if srv.ErrorLog != nil {
|
|
|
|
srv.ErrorLog.Printf(format, args...)
|
2020-11-03 21:11:31 +00:00
|
|
|
} else {
|
|
|
|
log.Printf(format, args...)
|
|
|
|
}
|
|
|
|
}
|