Allow processing of HTTP headers at WS creation

backend/localcommand/factory.go

@@ -37,12 +37,12 @@ func (factory *Factory) Name() string {
 	return "local command"
 }
 
-func (factory *Factory) New(params map[string][]string) (server.Slave, error) {
+func (factory *Factory) New(params map[string][]string, headers map[string][]string) (server.Slave, error) {
 	argv := make([]string, len(factory.argv))
 	copy(argv, factory.argv)
 	if params["arg"] != nil && len(params["arg"]) > 0 {
 		argv = append(argv, params["arg"]...)
 	}
 
-	return New(factory.command, argv, factory.opts...)
+	return New(factory.command, argv, headers, factory.opts...)
 }

backend/localcommand/local_command.go

@@ -3,6 +3,7 @@ package localcommand
 import (
 	"os"
 	"os/exec"
+	"strings"
 	"syscall"
 	"time"
 
@@ -27,11 +28,22 @@ type LocalCommand struct {
 	ptyClosed chan struct{}
 }
 
-func New(command string, argv []string, options ...Option) (*LocalCommand, error) {
+func New(command string, argv []string, headers map[string][]string, options ...Option) (*LocalCommand, error) {
 	cmd := exec.Command(command, argv...)
 
 	cmd.Env = append(os.Environ(), "TERM=xterm-256color")
 
+	// Combine headers into key=value pairs to set as env vars
+	// Prefix the headers with "http_" so we don't overwrite any other env vars
+	// which potentially has the same name and to bring these closer to what
+	// a (F)CGI server would proxy to a backend service
+	// Replace hyphen with underscore and make them all upper case
+	for key, values := range headers {
+		h := "HTTP_" + strings.Replace(strings.ToUpper(key), "-", "_", -1) + "=" + strings.Join(values, ",")
+		// log.Printf("Adding header: %s", h)
+		cmd.Env = append(cmd.Env, h)
+	}
+
 	pty, err := pty.Start(cmd)
 	if err != nil {
 		// todo close cmd?

backend/localcommand/local_command_test.go

@@ -23,7 +23,7 @@ func TestNewFactory(t *testing.T) {
 		t.Errorf("factory.options = %v, expected %v", factory.options, &Options{})
 	}
 
-	slave, _ := factory.New(nil)
+	slave, _ := factory.New(nil, nil)
 	lcmd := slave.(*LocalCommand)
 	if lcmd.closeSignal != 123 {
 		t.Errorf("lcmd.closeSignal = %v, expected %v", lcmd.closeSignal, 123)
@@ -40,7 +40,7 @@ func TestFactoryNew(t *testing.T) {
 		return
 	}
 
-	slave, err := factory.New(nil)
+	slave, err := factory.New(nil, nil)
 	if err != nil {
 		t.Errorf("factory.New() returned error")
 		return

server/handlers.go

@@ -72,7 +72,7 @@ func (server *Server) generateHandleWS(ctx context.Context, cancel context.Cance
 		}
 		defer conn.Close()
 
-		err = server.processWSConn(ctx, conn)
+		err = server.processWSConn(ctx, conn, r.Header)
 
 		switch err {
 		case ctx.Err():
@@ -87,7 +87,7 @@ func (server *Server) generateHandleWS(ctx context.Context, cancel context.Cance
 	}
 }
 
-func (server *Server) processWSConn(ctx context.Context, conn *websocket.Conn) error {
+func (server *Server) processWSConn(ctx context.Context, conn *websocket.Conn, headers map[string][]string) error {
 	typ, initLine, err := conn.ReadMessage()
 	if err != nil {
 		return errors.Wrapf(err, "failed to authenticate websocket connection")
@@ -116,7 +116,7 @@ func (server *Server) processWSConn(ctx context.Context, conn *websocket.Conn) e
 	}
 	params := query.Query()
 	var slave Slave
-	slave, err = server.factory.New(params)
+	slave, err = server.factory.New(params, headers)
 	if err != nil {
 		return errors.Wrapf(err, "failed to create backend")
 	}

server/slave.go

@@ -13,5 +13,5 @@ type Slave interface {
 
 type Factory interface {
 	Name() string
-	New(params map[string][]string) (Slave, error)
+	New(params map[string][]string, headers map[string][]string) (Slave, error)
 }