webtty: switch upward protocol to JSON

Switch the client-to-server messages from the HTML forms format to
JSON (for the webtty app).  Message numbers are sent but not yet used.

shterm.js

@@ -2,6 +2,9 @@
  * is running a shell via the webtty.js server.
  */
 
+/* The number of the next packet to send. */
+var nsend = 0;
+
 // A state machine that keeps track of polling the server.
 var ajaxstate = {
   state: 0,
@@ -169,10 +172,11 @@ function postResponseHandler() {
 
 function sendback(str) {
   /* For responding to terminal queries. */
+  var formdata = {"t": "d", "n": nsend++, "d": str};
   var datareq = new XMLHttpRequest();
   datareq.onreadystatechange = postResponseHandler;
   datareq.open('POST', '/feed', true);
-  datareq.send("keys=" + str);
+  datareq.send(JSON.stringify(formdata));
   return;
 }
 
@@ -214,10 +218,11 @@ function sendkey(ev) {
   }
   if (termemu.alive)
     ev.preventDefault();
+  var formdata = {"t": "d", "n": nsend++, "d": code};
   var datareq = new XMLHttpRequest();
   datareq.onreadystatechange = postResponseHandler;
   datareq.open('POST', '/feed', true);
-  datareq.send("keys=" + code);
+  datareq.send(JSON.stringify(formdata));
   //dkey(code);
   return;
 }
@@ -263,10 +268,11 @@ function vkey(c) {
   else
     return;
   //writeData("Sending " + keystr);
+  var formdata = {"t": "d", "n": nsend++, "d": code};
   var datareq = new XMLHttpRequest();
   datareq.onreadystatechange = postResponseHandler;
   datareq.open('POST', '/feed', true);
-  datareq.send("keys=" + keystr);
+  datareq.send(JSON.stringify(formdata));
   return;
 }
 
@@ -300,6 +306,7 @@ function togglectrl() {
 function login(h, w) {
   if (termemu.alive)
     return;
+  params = {"login": true, "h": h, "w": w};
   var req = new XMLHttpRequest();
   req.onreadystatechange = function () {
     if (req.readyState == 4 && req.status == 200) {
@@ -308,6 +315,7 @@ function login(h, w) {
         /* Success */
         termemu.resize(logindict.h, logindict.w);
         termemu.alive = true;
+        nsend = 0;
 	setTitle("Logged in");
         debug(1, "Logged in with id " + logindict.id);
         getData();
@@ -317,7 +325,8 @@ function login(h, w) {
     }
   };
   req.open('POST', '/login', true);
-  req.send("login=login&h=" + String(h) + "&w=" + String(w));
+  req.send(JSON.stringify(params));
+  //req.send("login=login&h=" + String(h) + "&w=" + String(w));
   return;
 }
 
@@ -332,7 +341,7 @@ function stop() {
     }
   };
   req.open('POST', '/feed', true);
-  req.send("quit=quit");
+  req.send(JSON.stringify({"t": "q", "n": nsend++}));
   return;
 }
 

webtty.js

@@ -144,22 +144,14 @@ function urlDec(encstr) {
 
 /* Returns the contents of a form */
 function getFormValues(formtext) {
-  var pairstrs = formtext.split("&");
-  var data = {};
-  for (var i = 0; i < pairstrs.length; i++)
-  {
-    var eqsign = pairstrs[i].indexOf("=");
-    if (eqsign > 0) {
-      rawname = pairstrs[i].slice(0, eqsign);
-      rawval = pairstrs[i].slice(eqsign + 1);
-      name = urlDec(rawname);
-      val = urlDec(rawval);
-      if (!(name in data))
-        data[name] = [];
-      data[name].push(val);
-    }
+  var jsonobj;
+  try {
+    jsonobj = JSON.parse(formtext);
+  } catch (e) {
+    if (e instanceof SyntaxError)
+      return null;
   }
-  return data;
+  return jsonobj;
 }
 
 function login(req, res, formdata) {
@@ -298,14 +290,14 @@ function handler(req, res) {
           sendError(res, 1);
           return;
         }
-        if (formdata["quit"] == "quit") {
+        if (formdata["t"] == "q") {
           /* The client wants to quit. */
           // FIXME need to send a message back to the client
           cterm.close();
         }
-        else if (formdata["keys"]) {
+        else if (formdata["t"] == "d" && typeof(formdata["d"]) == "string") {
           /* process the keys */
-          hexstr = formdata["keys"][0].replace(/[^0-9a-f]/gi, "");
+          hexstr = formdata["d"].replace(/[^0-9a-f]/gi, "");
           if (hexstr.length % 2 != 0) {
             sendError(res, 2);
             return;