web/xynt/xynt-http-streaming.js

   1 function http_streaming(win, cons)
   2 {
   3     this.console = cons;
   4     this.doc = win.document;
   5     this.keepalive_old = -1;
   6     this.keepalive_new = -1;
   7     this.keepalives_equal = 0;
   8     this.ifra = this.doc.createElement("iframe");
   9     this.ifra.style.visibility = "hidden";
  10     this.doc.body.appendChild(this.ifra);
  11 }
  12
  13 http_streaming.prototype = {
  14     console:           null,
  15     doc:               null,
  16     ifra:              null,
  17     page:              null,
  18     wd_handle:         null,
  19     keepalive_old:    -1,
  20     keepalive_new:    -1,
  21     keepalives_equal:  0,
  22     keepalives_eq_max: 6,
  23     watchdog_timeout: 2000,
  24     watchable: false,
  25     restart_n: 0,
  26
  27     start: function(page) {
  28         this.log("http_streaming:start restart: "+this.restart_n);
  29         this.page = page;
  30         this.ifra.contentWindow.location.href = page;
  31         this.wd_handle = setTimeout(function(obj) { obj.log("tout1"); obj.watchdog(); }, this.watchdog_timeout, this);
  32     },
  33
  34     watchdog: function () {
  35         /* +this.keepalives_equal */
  36         this.log("hs::watchdog: start, cur equal times: "+this.keepalives_equal);
  37         if (!this.watchable) {
  38             do {
  39                 if (typeof(this.ifra.contentWindow.http_streaming) == 'undefined')
  40                     break;
  41                 /*
  42                   on IE7 the the window frame scope is cleaned after the href is set, so we wait
  43                   for a well know variable value before assign this object value to it (OO is a passion)
  44                 */
  45                 if (this.ifra.contentWindow.http_streaming == "ready") {
  46                     this.ifra.contentWindow.http_streaming = this;
  47                     this.watchable = true;
  48                 }
  49             } while (false);
  50         }
  51         this.log("hs::watchdog: this.keepalive_old: "+this.keepalive_old+" this.keepalive_new: "+this.keepalive_new);
  52         if (this.keepalive_old == this.keepalive_new) {
  53             this.keepalives_equal++;
  54         }
  55         else {
  56             this.keepalive_old = this.keepalive_new;
  57             this.keepalives_equal = 0;
  58         }
  59
  60         if (this.keepalives_equal > this.keepalives_eq_max) {
  61             this.log("hs::watchdog: MAX ACHIEVED "+this.keepalives_equal);
  62             this.reload();
  63             return;
  64         }
  65         else {
  66             this.wd_handle = setTimeout(function(obj) { obj.log("tout2"); obj.watchdog(); }, this.watchdog_timeout, this);
  67         }
  68     },
  69
  70     keepalive: function () {
  71         this.log("hs::keepalive");
  72         this.keepalive_new++;
  73     },
  74
  75     abort: function () {
  76         clearTimeout(this.wd_handle);
  77         this.restart_n++;
  78         this.log("hs::reload");
  79         this.watchable = false;
  80         delete this.ifra;
  81     },
  82
  83     reload: function () {
  84         this.abort();
  85         this.keepalives_equal = 0;
  86         this.ifra = this.doc.createElement("iframe");
  87         this.ifra.style.visibility = "hidden";
  88         this.doc.body.appendChild(this.ifra);
  89         this.start(this.page);
  90     },
  91
  92     log: function (s) {
  93         if (this.console != null) {
  94             return (this.console.log(s));
  95         }
  96     }
  97 }