Unofficial JDA (Javascript Dataflow Architecture) Wiki

This is another is_proxy wrapper which doesn't use input terminals, but traps acess to the wrapped/embedded achor element.

Demos that use it

• 43.html
• flickr_and_webshot.html
• evdb.html
• rss_feeds.html
• rss_feeds_timeline.html
• yahoosearch.html
• map.html
• multi_map.html

BLUEPRINT(
"~011A83EC1CBFAD4a3188344C9BA816DE73",
[
 [null, null, -1] // magic 
],
[
 "response_out"
],
function (Class) {

  Class.prototype._onInit = function(props) 
  {
    var a = this.dom_node.getElementsByTagName("A")[0];
    
//#ifdef __DEBUG__
    if (!a || a.rel != "rpc" || !a.href || !a.getAttribute("impl")) {
      
      throw "This is a proxy infotron: an anchor tag of the format \
<a rel=\"rpc\" href=\"URI\" impl=\"UUID\"></a> is required!";
      /***********************************************************************/
    }
    
    if (this.dom_node.getAttribute("is_proxy") != "true") {
      
      throw "This is a proxy infotron: you must specify is_proxy=\"true\"";
      /***********************************************************************/
    }
//#endif
    
    /*************************************************************************/
    this._base_url = a.href || "/";
    this._uri_suffix = props["uri_suffix"] ||  "";
    this._path_suffix = props["path_suffix"] || props["url_suffix"] || "";
    this._encoding = props["encoding"] || "json";
    this._cb_func_name = props["callback_function"] || "callback";
    this._use_plus = props["escapes_space_with_plus_sign"];
    this._add_random_qs = props["adds_randomized_query"];
  };

  Class.prototype._onMsgDelivery = function(iterm, msg) 
  {
    var o, e;
    
    if (iterm != "%startup") {
      var type;
      var url = this._createUrl(iterm, msg);

      o =__d.createElement("SCRIPT");
      o.type = "text/javascript";
      o.src = url;
      this.debug(url);
      this.dom_node.appendChild(o);
    }
  };
  
  
  Class.prototype._onResponse = function(msg)
  {    
    this.postMessage("response_out", msg);
  }

  /*************************************************************************/
  Class.prototype._createUrl = function(iterm, msg)
  {
    var args, v;
    var random_qs = "";

      if (this._encoding == "uri-form") {
	  args = ""
	  for (key in msg) {
	    v = escape(msg[key]);	    
	    if (this._use_plus) {
	      try {
		v = v.replace(/%20/g, '%2b');
	      } catch (ex) {	      
	      }
	    }

	    args += escape(key) + "=" + v + "&";
	  }
      } else {
	args = "msg=" + escape(this._toJson(msg)) + "&";
      }

    if (this._add_random_qs) {
	random_qs = "__r=" + (new Date()).valueOf() + "_" + Math.random() + "&";
    }
      return this._base_url + "/" + escape(iterm) + this._path_suffix + "?" + 
	  this._cb_func_name + "=__star.infotrons." + 
	  this.id + "._onResponse" + "&" + random_qs + args + this._uri_suffix;
  }
  
  Class.prototype._toJson = function(obj)
  {
    // modified from http://www.crockford.com/JSON/js.html
    // being used for GOOD not evil!!
    var c, i, l, s = '', v;
    
    switch (typeof(obj)) {
    case 'object':
      if (obj) {
	if (obj.constructor == Array) {
	  for (i = 0; i < obj.length; ++i) {
	    v = this._toJson(obj[i]);
	    if (s) {
	      s += ',';
	    }
			s += v;
	  }
	  return '[' + s + ']';
	} else if (obj.constructor == Date) {
	  return obj.valueOf();
	} else if (typeof obj.toString != 'undefined') {
	  for (i in obj) {
	    v = obj[i];
	    if (typeof v != 'undefined' && typeof v != 'function') {
	      v = this._toJson(v);
	      if (s) {
		s += ',';
	      }
	      s += this._toJson(i) + ':' + v;
	    }
	  }
	  return '{' + s + '}';
	}
      }
      return 'null';
    case 'number':
      return isFinite(obj) ? (new String(obj)) : 'null';
    case 'string':
      l = obj.length;
      s = '"';

      for (i = 0; i < l; i += 1) {
	c = obj.charAt(i);
	if (c >= ' ') {
	  if (c == '\\' || c == '"') {
	    s += '\\';
	  }
	  s += c;
	} else {
	  switch (c) {
	  case '\b':
	    s += '\\b';
	    break;
	  case '\f':
	    s += '\\f';
	    break;
	  case '\n':
	    s += '\\n';
	    break;
	  case '\r':
	    s += '\\r';
	    break;
	  case '\t':
	    s += '\\t';
	    break;
	  default:
	    c = c.charCodeAt();
	    s += '\\u00' + Math.floor(c / 16).toString(16) +
	      (c % 16).toString(16);
	  }
	}
      }
      return s + '"';
    case 'boolean':
      return (new String(obj));
    default:
      return 'null';
    }
  }

 }, "JSON Callback Service Proxy");