Improvements to websocket middleware

middleware/websockets/websocket.go

@@ -10,7 +10,7 @@ import (
 )
 
 // WebSocket represents a web socket server instance. A WebSocket
-// struct is instantiated for each new websocket request.
+// is instantiated for each new websocket request/connection.
 type WebSocket struct {
 	WSConfig
 	*http.Request
@@ -21,33 +21,40 @@ type WebSocket struct {
 // the command's stdin and stdout.
 func (ws WebSocket) Handle(conn *websocket.Conn) {
 	cmd := exec.Command(ws.Command, ws.Arguments...)
+
 	cmd.Stdin = conn
 	cmd.Stdout = conn
+	cmd.Stderr = conn // TODO: Make this configurable from the Caddyfile
 
-	err := ws.buildEnv(cmd)
+	metavars, err := ws.buildEnv(cmd.Path)
 	if err != nil {
-		// TODO
+		panic(err) // TODO
 	}
 
+	cmd.Env = metavars
+
 	err = cmd.Run()
 	if err != nil {
 		panic(err)
 	}
 }
 
-// buildEnv sets the meta-variables for the child process according
+// buildEnv creates the meta-variables for the child process according
 // to the CGI 1.1 specification: http://tools.ietf.org/html/rfc3875#section-4.1
-func (ws WebSocket) buildEnv(cmd *exec.Cmd) error {
+// cmdPath should be the path of the command being run.
+// The returned string slice can be set to the command's Env property.
+func (ws WebSocket) buildEnv(cmdPath string) (metavars []string, err error) {
 	remoteHost, remotePort, err := net.SplitHostPort(ws.RemoteAddr)
 	if err != nil {
-		return err
+		return
-	}
-	serverHost, serverPort, err := net.SplitHostPort(ws.Host)
-	if err != nil {
-		return err
 	}
 
-	cmd.Env = []string{
+	serverHost, serverPort, err := net.SplitHostPort(ws.Host)
+	if err != nil {
+		return
+	}
+
+	metavars = []string{
 		`AUTH_TYPE=`,      // Not used
 		`CONTENT_LENGTH=`, // Not used
 		`CONTENT_TYPE=`,   // Not used
@@ -62,7 +69,7 @@ func (ws WebSocket) buildEnv(cmd *exec.Cmd) error {
 		`REMOTE_USER=`, // Not used,
 		`REQUEST_METHOD=` + ws.Method,
 		`REQUEST_URI=` + ws.RequestURI,
-		`SCRIPT_NAME=`, // TODO - absolute path to program being executed?
+		`SCRIPT_NAME=` + cmdPath, // path of the program being executed
 		`SERVER_NAME=` + serverHost,
 		`SERVER_PORT=` + serverPort,
 		`SERVER_PROTOCOL=` + ws.Proto,
@@ -75,8 +82,8 @@ func (ws WebSocket) buildEnv(cmd *exec.Cmd) error {
 		header = strings.ToUpper(header)
 		header = strings.Replace(header, "-", "_", -1)
 		value = strings.Replace(value, "\n", " ", -1)
-		cmd.Env = append(cmd.Env, "HTTP_"+header+"="+value)
+		metavars = append(metavars, "HTTP_"+header+"="+value)
 	}
 
-	return nil
+	return
 }

middleware/websockets/websockets.go

@@ -17,16 +17,20 @@ type (
 	// websocket middleware generally, like a list of all the
 	// websocket endpoints.
 	WebSockets struct {
+		// Next is the next HTTP handler in the chain for when the path doesn't match
+		Next http.HandlerFunc
+
 		// Sockets holds all the web socket endpoint configurations
 		Sockets []WSConfig
 	}
 
 	// WSConfig holds the configuration for a single websocket
-	// endpoint which may serve zero or more websocket connections.
+	// endpoint which may serve multiple websocket connections.
 	WSConfig struct {
 		Path      string
 		Command   string
 		Arguments []string
+		Respawn   bool // TODO: Not used, but parser supports it until we decide on it
 	}
 )
 
@@ -42,11 +46,27 @@ func (ws WebSockets) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+
+	// Didn't match a websocket path, so pass-thru
+	ws.Next(w, r)
 }
 
 // New constructs and configures a new websockets middleware instance.
 func New(c middleware.Controller) (middleware.Middleware, error) {
 	var websocks []WSConfig
+	var respawn bool
+
+	optionalBlock := func() (hadBlock bool, err error) {
+		for c.NextBlock() {
+			hadBlock = true
+			if c.Val() == "respawn" {
+				respawn = true
+			} else {
+				return true, c.Err("Expected websocket configuration parameter in block")
+			}
+		}
+		return
+	}
 
 	for c.Next() {
 		var val, path, command string
@@ -57,38 +77,40 @@ func New(c middleware.Controller) (middleware.Middleware, error) {
 		}
 		val = c.Val()
 
-		// The rest of the arguments are the command
+		// Extra configuration may be in a block
-		if c.NextArg() {
+		hadBlock, err := optionalBlock()
-			path = val
+		if err != nil {
-			command = c.Val()
+			return nil, err
-			for c.NextArg() {
+		}
-				command += " " + c.Val()
+
+		if !hadBlock {
+			// The next argument on this line will be the command or an open curly brace
+			if c.NextArg() {
+				path = val
+				command = c.Val()
+			} else {
+				path = "/"
+				command = val
+			}
+
+			// Okay, check again for optional block
+			hadBlock, err = optionalBlock()
+			if err != nil {
+				return nil, err
 			}
-		} else {
-			path = "/"
-			command = val
 		}
 
 		// Split command into the actual command and its arguments
-		var cmd string
+		cmd, args, err := parseCommandAndArgs(command)
-		var args []string
-
-		parts, err := shlex.Split(command)
 		if err != nil {
-			return nil, errors.New("Error parsing command for websocket use: " + err.Error())
+			return nil, err
-		} else if len(parts) == 0 {
-			return nil, errors.New("No command found for use by websocket")
-		}
-
-		cmd = parts[0]
-		if len(parts) > 1 {
-			args = parts[1:]
 		}
 
 		websocks = append(websocks, WSConfig{
 			Path:      path,
 			Command:   cmd,
 			Arguments: args,
+			Respawn:   respawn,
 		})
 	}
 
@@ -96,12 +118,30 @@ func New(c middleware.Controller) (middleware.Middleware, error) {
 	ServerSoftware = envServerSoftware
 
 	return func(next http.HandlerFunc) http.HandlerFunc {
-		// We don't use next because websockets aren't HTTP,
+		return WebSockets{Next: next, Sockets: websocks}.ServeHTTP
-		// so we don't invoke other middleware after this.
-		return WebSockets{Sockets: websocks}.ServeHTTP
 	}, nil
 }
 
+// parseCommandAndArgs takes a command string and parses it
+// shell-style into the command and its separate arguments.
+func parseCommandAndArgs(command string) (cmd string, args []string, err error) {
+	parts, err := shlex.Split(command)
+	if err != nil {
+		err = errors.New("Error parsing command for websocket: " + err.Error())
+		return
+	} else if len(parts) == 0 {
+		err = errors.New("No command found for use by websocket")
+		return
+	}
+
+	cmd = parts[0]
+	if len(parts) > 1 {
+		args = parts[1:]
+	}
+
+	return
+}
+
 var (
 	// See CGI spec, 4.1.4
 	GatewayInterface string
@@ -112,5 +152,5 @@ var (
 
 const (
 	envGatewayInterface = "caddy-CGI/1.1"
-	envServerSoftware   = "caddy/0.1.0"
+	envServerSoftware   = "caddy/?.?.?" // TODO
 )