feat: add support for specifying custom querystring arguments

This allows folks to implement token-based authentication for websocket access.

Closes #82

README.md

@@ -75,6 +75,7 @@ By default, GoTTY starts a web server at port 8080. Open the URL on your web bro
    --width value                 Static width of the screen, 0(default) means dynamically resize (default: 0) [$GOTTY_WIDTH]
    --height value                Static height of the screen, 0(default) means dynamically resize (default: 0) [$GOTTY_HEIGHT]
    --ws-origin value             A regular expression that matches origin URLs to be accepted by WebSocket. No cross origin requests are acceptable by default [$GOTTY_WS_ORIGIN]
+   --ws-query-args value         Querystring arguments to append to the websocket instantiation [$GOTTY_WS_QUERY_ARGS]
    --enable-webgl                Enable WebGL renderer (default: true) [$GOTTY_ENABLE_WEBGL]
    --close-signal value          Signal sent to the command process when gotty close it (default: SIGHUP) (default: 1) [$GOTTY_CLOSE_SIGNAL]
    --close-timeout value         Time in seconds to force kill process after client is disconnected (default: -1) (default: -1) [$GOTTY_CLOSE_TIMEOUT]

js/src/main.ts

@@ -1,10 +1,11 @@
-import { OurXterm } from "./xterm";
-import { Terminal, WebTTY, protocols } from "./webtty";
 import { ConnectionFactory } from "./websocket";
+import { Terminal, WebTTY, protocols } from "./webtty";
+import { OurXterm } from "./xterm";
 
 // @TODO remove these
 declare var gotty_auth_token: string;
 declare var gotty_term: string;
+declare var gotty_ws_query_args: string;
 
 const elem = document.getElementById("terminal")
 
@@ -13,7 +14,8 @@ if (elem !== null) {
     term = new OurXterm(elem);
 
     const httpsEnabled = window.location.protocol == "https:";
-    const url = (httpsEnabled ? 'wss://' : 'ws://') + window.location.host + window.location.pathname + 'ws';
+    const queryArgs = (gotty_ws_query_args === "") ? "" : "?" + gotty_ws_query_args;
+    const url = (httpsEnabled ? 'wss://' : 'ws://') + window.location.host + window.location.pathname + 'ws' + queryArgs;
     const args = window.location.search;
     const factory = new ConnectionFactory(url, protocols);
     const wt = new WebTTY(term, factory, args, gotty_auth_token);

server/handlers.go

@@ -8,6 +8,7 @@ import (
 	"log"
 	"net/http"
 	"net/url"
+	"strings"
 	"sync/atomic"
 
 	"github.com/gorilla/websocket"
@@ -233,7 +234,12 @@ func (server *Server) handleAuthToken(w http.ResponseWriter, r *http.Request) {
 
 func (server *Server) handleConfig(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/javascript")
-	w.Write([]byte("var gotty_term = 'xterm';"))
+	lines := []string{
+		"var gotty_term = 'xterm';",
+		"var gotty_ws_query_args = '" + server.options.WSQueryArgs + "';",
+	}
+
+	w.Write([]byte(strings.Join(lines, "\n")))
 }
 
 // titleVariables merges maps in a specified order.

server/options.go

@@ -30,6 +30,7 @@ type Options struct {
 	Width               int    `hcl:"width" flagName:"width" flagDescribe:"Static width of the screen, 0(default) means dynamically resize" default:"0"`
 	Height              int    `hcl:"height" flagName:"height" flagDescribe:"Static height of the screen, 0(default) means dynamically resize" default:"0"`
 	WSOrigin            string `hcl:"ws_origin" flagName:"ws-origin" flagDescribe:"A regular expression that matches origin URLs to be accepted by WebSocket. No cross origin requests are acceptable by default" default:""`
+	WSQueryArgs         string `hcl:"ws_query_args" flagName:"ws-query-args" flagDescribe:"Querystring arguments to append to the websocket instantiation" default:""`
 	EnableWebGL         bool   `hcl:"enable_webgl" flagName:"enable-webgl" flagDescribe:"Enable WebGL renderer" default:"true"`
 	Quiet               bool   `hcl:"quiet" flagName:"quiet" flagDescribe:"Don't log" default:"false"`