/**
* Provides a mechanism to fetch remote resources and
* insert them into a document
* @module get
* @requires yahoo
*/
/**
* Fetches and inserts one or more script or link nodes into the document
* @namespace YAHOO.util
* @class YAHOO.util.Get
*/
YAHOO.util.Get = function() {
/**
* hash of queues to manage multiple requests
* @property queues
* @private
*/
var queues={},
/**
* queue index used to generate transaction ids
* @property qidx
* @type int
* @private
*/
qidx=0,
/**
* node index used to generate unique node ids
* @property nidx
* @type int
* @private
*/
nidx=0,
// ridx=0,
// sandboxFrame=null,
/**
* interal property used to prevent multiple simultaneous purge
* processes
* @property purging
* @type boolean
* @private
*/
purging=false,
ua=YAHOO.env.ua,
lang=YAHOO.lang;
/**
* Generates an HTML element, this is not appended to a document
* @method _node
* @param type {string} the type of element
* @param attr {string} the attributes
* @param win {Window} optional window to create the element in
* @return {HTMLElement} the generated node
* @private
*/
var _node = function(type, attr, win) {
var w = win || window, d=w.document, n=d.createElement(type);
for (var i in attr) {
if (attr[i] && YAHOO.lang.hasOwnProperty(attr, i)) {
n.setAttribute(i, attr[i]);
}
}
return n;
};
/**
* Generates a link node
* @method _linkNode
* @param url {string} the url for the css file
* @param win {Window} optional window to create the node in
* @return {HTMLElement} the generated node
* @private
*/
var _linkNode = function(url, win, charset) {
var c = charset || "utf-8";
return _node("link", {
"id": "yui__dyn_" + (nidx++),
"type": "text/css",
"charset": c,
"rel": "stylesheet",
"href": url
}, win);
};
/**
* Generates a script node
* @method _scriptNode
* @param url {string} the url for the script file
* @param win {Window} optional window to create the node in
* @return {HTMLElement} the generated node
* @private
*/
var _scriptNode = function(url, win, charset) {
var c = charset || "utf-8";
return _node("script", {
"id": "yui__dyn_" + (nidx++),
"type": "text/javascript",
"charset": c,
"src": url
}, win);
};
/**
* Returns the data payload for callback functions
* @method _returnData
* @private
*/
var _returnData = function(q, msg) {
return {
tId: q.tId,
win: q.win,
data: q.data,
nodes: q.nodes,
msg: msg,
purge: function() {
_purge(this.tId);
}
};
};
var _get = function(nId, tId) {
var q = queues[tId],
n = (lang.isString(nId)) ? q.win.document.getElementById(nId) : nId;
if (!n) {
_fail(tId, "target node not found: " + nId);
}
return n;
};
/*
* The request failed, execute fail handler with whatever
* was accomplished. There isn't a failure case at the
* moment unless you count aborted transactions
* @method _fail
* @param id {string} the id of the request
* @private
*/
var _fail = function(id, msg) {
YAHOO.log("get failure: " + msg, "warn", "Get");
var q = queues[id];
// execute failure callback
if (q.onFailure) {
var sc=q.scope || q.win;
q.onFailure.call(sc, _returnData(q, msg));
}
};
/**
* The request is complete, so executing the requester's callback
* @method _finish
* @param id {string} the id of the request
* @private
*/
var _finish = function(id) {
YAHOO.log("Finishing transaction " + id);
var q = queues[id];
q.finished = true;
if (q.aborted) {
var msg = "transaction " + id + " was aborted";
_fail(id, msg);
return;
}
// execute success callback
if (q.onSuccess) {
var sc=q.scope || q.win;
q.onSuccess.call(sc, _returnData(q));
}
};
/**
* Loads the next item for a given request
* @method _next
* @param id {string} the id of the request
* @param loaded {string} the url that was just loaded, if any
* @private
*/
var _next = function(id, loaded) {
YAHOO.log("_next: " + id + ", loaded: " + loaded, "info", "Get");
var q = queues[id];
if (q.aborted) {
var msg = "transaction " + id + " was aborted";
_fail(id, msg);
return;
}
if (loaded) {
q.url.shift();
if (q.varName) {
q.varName.shift();
}
} else {
// This is the first pass: make sure the url is an array
q.url = (lang.isString(q.url)) ? [q.url] : q.url;
if (q.varName) {
q.varName = (lang.isString(q.varName)) ? [q.varName] : q.varName;
}
}
var w=q.win, d=w.document, h=d.getElementsByTagName("head")[0], n;
if (q.url.length === 0) {
// Safari 2.x workaround - There is no way to know when
// a script is ready in versions of Safari prior to 3.x.
// Adding an extra node reduces the problem, but doesn't
// eliminate it completely because the browser executes
// them asynchronously.
if (q.type === "script" && ua.webkit && ua.webkit < 420 &&
!q.finalpass && !q.varName) {
// Add another script node. This does not guarantee that the
// scripts will execute in order, but it does appear to fix the
// problem on fast connections more effectively than using an
// arbitrary timeout. It is possible that the browser does
// block subsequent script execution in this case for a limited
// time.
var extra = _scriptNode(null, q.win, q.charset);
extra.innerHTML='YAHOO.util.Get._finalize("' + id + '");';
q.nodes.push(extra); h.appendChild(extra);
} else {
_finish(id);
}
return;
}
var url = q.url[0];
YAHOO.log("attempting to load " + url, "info", "Get");
if (q.type === "script") {
n = _scriptNode(url, w, q.charset);
} else {
n = _linkNode(url, w, q.charset);
}
// track this node's load progress
_track(q.type, n, id, url, w, q.url.length);
// add the node to the queue so we can return it to the user supplied callback
q.nodes.push(n);
// add it to the head or insert it before 'insertBefore'
if (q.insertBefore) {
var s = _get(q.insertBefore, id);
if (s) {
s.parentNode.insertBefore(n, s);
}
} else {
h.appendChild(n);
}
YAHOO.log("Appending node: " + url, "info", "Get");
// FireFox does not support the onload event for link nodes, so there is
// no way to make the css requests synchronous. This means that the css
// rules in multiple files could be applied out of order in this browser
// if a later request returns before an earlier one. Safari too.
if ((ua.webkit || ua.gecko) && q.type === "css") {
_next(id, url);
}
};
/**
* Removes processed queues and corresponding nodes
* @method _autoPurge
* @private
*/
var _autoPurge = function() {
if (purging) {
return;
}
purging = true;
for (var i in queues) {
var q = queues[i];
if (q.autopurge && q.finished) {
_purge(q.tId);
delete queues[i];
}
}
purging = false;
};
/**
* Removes the nodes for the specified queue
* @method _purge
* @private
*/
var _purge = function(tId) {
var q=queues[tId];
if (q) {
var n=q.nodes, l=n.length, d=q.win.document,
h=d.getElementsByTagName("head")[0];
if (q.insertBefore) {
var s = _get(q.insertBefore, tId);
if (s) {
h = s.parentNode;
}
}
for (var i=0; i<l; i=i+1) {
h.removeChild(n[i]);
}
}
q.nodes = [];
};
/**
* Saves the state for the request and begins loading
* the requested urls
* @method queue
* @param type {string} the type of node to insert
* @param url {string} the url to load
* @param opts the hash of options for this request
* @private
*/
var _queue = function(type, url, opts) {
var id = "q" + (qidx++);
opts = opts || {};
if (qidx % YAHOO.util.Get.PURGE_THRESH === 0) {
_autoPurge();
}
queues[id] = lang.merge(opts, {
tId: id,
type: type,
url: url,
finished: false,
nodes: []
});
var q = queues[id];
q.win = q.win || window;
q.scope = q.scope || q.win;
q.autopurge = ("autopurge" in q) ? q.autopurge :
(type === "script") ? true : false;
lang.later(0, q, _next, id);
return {
tId: id
};
};
/**
* Detects when a node has been loaded. In the case of
* script nodes, this does not guarantee that contained
* script is ready to use.
* @method _track
* @param type {string} the type of node to track
* @param n {HTMLElement} the node to track
* @param id {string} the id of the request
* @param url {string} the url that is being loaded
* @param win {Window} the targeted window
* @param qlength the number of remaining items in the queue,
* including this one
* @param trackfn {Function} function to execute when finished
* the default is _next
* @private
*/
var _track = function(type, n, id, url, win, qlength, trackfn) {
var f = trackfn || _next;
// IE supports the readystatechange event for script and css nodes
if (ua.ie) {
n.onreadystatechange = function() {
var rs = this.readyState;
if ("loaded" === rs || "complete" === rs) {
YAHOO.log(id + " onload " + url, "info", "Get");
f(id, url);
}
};
// webkit prior to 3.x is problemmatic
} else if (ua.webkit) {
if (type === "script") {
// Safari 3.x supports the load event for script nodes (DOM2)
if (ua.webkit >= 420) {
n.addEventListener("load", function() {
YAHOO.log(id + " DOM2 onload " + url, "info", "Get");
f(id, url);
});
// Nothing can be done with Safari < 3.x except to pause and hope
// for the best, particularly after last script is inserted. The
// scripts will always execute in the order they arrive, not
// necessarily the order in which they were inserted. To support
// script nodes with complete reliability in these browsers, script
// nodes either need to invoke a function in the window once they
// are loaded or the implementer needs to provide a well-known
// property that the utility can poll for.
} else {
// Poll for the existence of the named variable, if it
// was supplied.
var q = queues[id];
if (q.varName) {
var freq=YAHOO.util.Get.POLL_FREQ;
YAHOO.log("Polling for " + q.varName[0]);
q.maxattempts = YAHOO.util.Get.TIMEOUT/freq;
q.attempts = 0;
q._cache = q.varName[0].split(".");
q.timer = lang.later(freq, q, function(o) {
var a=this._cache, l=a.length, w=this.win, i;
for (i=0; i<l; i=i+1) {
w = w[a[i]];
if (!w) {
// if we have exausted our attempts, give up
this.attempts++;
if (this.attempts++ > this.maxattempts) {
var msg = "Over retry limit, giving up";
q.timer.cancel();
_fail(id, msg);
} else {
YAHOO.log(a[i] + " failed, retrying");
}
return;
}
}
YAHOO.log("Safari poll complete");
q.timer.cancel();
f(id, url);
}, null, true);
} else {
lang.later(YAHOO.util.Get.POLL_FREQ, null, f, [id, url]);
}
}
}
// FireFox and Opera support onload (but not DOM2 in FF) handlers for
// script nodes. Opera, but not FF, supports the onload event for link
// nodes.
} else {
n.onload = function() {
YAHOO.log(id + " onload " + url, "info", "Get");
f(id, url);
};
}
};
return {
/**
* The default poll freqency in ms, when needed
* @property POLL_FREQ
* @static
* @type int
* @default 10
*/
POLL_FREQ: 10,
/**
* The number of request required before an automatic purge.
* property PURGE_THRESH
* @static
* @type int
* @default 20
*/
PURGE_THRESH: 20,
/**
* The length time to poll for varName when loading a script in
* Safari 2.x before the transaction fails.
* property TIMEOUT
* @static
* @type int
* @default 2000
*/
TIMEOUT: 2000,
/**
* Called by the the helper for detecting script load in Safari
* @method _finalize
* @param id {string} the transaction id
* @private
*/
_finalize: function(id) {
YAHOO.log(id + " finalized ", "info", "Get");
lang.later(0, null, _finish, id);
},
/**
* Abort a transaction
* @method abort
* @param {string|object} either the tId or the object returned from
* script() or css()
*/
abort: function(o) {
var id = (lang.isString(o)) ? o : o.tId;
var q = queues[id];
if (q) {
YAHOO.log("Aborting " + id, "info", "Get");
q.aborted = true;
}
},
/**
* Fetches and inserts one or more script nodes into the head
* of the current document or the document in a specified window.
*
* @method script
* @static
* @param url {string|string[]} the url or urls to the script(s)
* @param opts {object} Options:
* <dl>
* <dt>onSuccess</dt>
* <dd>
* callback to execute when the script(s) are finished loading
* The callback receives an object back with the following
* data:
* <dl>
* <dt>win</dt>
* <dd>the window the script(s) were inserted into</dd>
* <dt>data</dt>
* <dd>the data object passed in when the request was made</dd>
* <dt>nodes</dt>
* <dd>An array containing references to the nodes that were
* inserted</dd>
* <dt>purge</dt>
* <dd>A function that, when executed, will remove the nodes
* that were inserted</dd>
* <dt>
* </dl>
* </dd>
* <dt>onFailure</dt>
* <dd>
* callback to execute when the script load operation fails
* The callback receives an object back with the following
* data:
* <dl>
* <dt>win</dt>
* <dd>the window the script(s) were inserted into</dd>
* <dt>data</dt>
* <dd>the data object passed in when the request was made</dd>
* <dt>nodes</dt>
* <dd>An array containing references to the nodes that were
* inserted successfully</dd>
* <dt>purge</dt>
* <dd>A function that, when executed, will remove any nodes
* that were inserted</dd>
* <dt>
* </dl>
* </dd>
* <dt>scope</dt>
* <dd>the execution context for the callbacks</dd>
* <dt>win</dt>
* <dd>a window other than the one the utility occupies</dd>
* <dt>autopurge</dt>
* <dd>
* setting to true will let the utilities cleanup routine purge
* the script once loaded
* </dd>
* <dt>data</dt>
* <dd>
* data that is supplied to the callback when the script(s) are
* loaded.
* </dd>
* <dt>varName</dt>
* <dd>
* variable that should be available when a script is finished
* loading. Used to help Safari 2.x and below with script load
* detection. The type of this property should match what was
* passed into the url parameter: if loading a single url, a
* string can be supplied. If loading multiple scripts, you
* must supply an array that contains the variable name for
* each script.
* </dd>
* <dt>insertBefore</dt>
* <dd>node or node id that will become the new node's nextSibling</dd>
* </dl>
* <dt>charset</dt>
* <dd>Node charset, default utf-8</dd>
* <pre>
* // assumes yahoo, dom, and event are already on the page
* YAHOO.util.Get.script(
* ["http://yui.yahooapis.com/2.3.1/build/dragdrop/dragdrop-min.js",
* "http://yui.yahooapis.com/2.3.1/build/animation/animation-min.js"], {
* onSuccess: function(o) {
* YAHOO.log(o.data); // foo
* new YAHOO.util.DDProxy("dd1"); // also new o.reference("dd1"); would work
* this.log("won't cause error because YAHOO is the scope");
* this.log(o.nodes.length === 2) // true
* // o.purge(); // optionally remove the script nodes immediately
* },
* onFailure: function(o) {
* YAHOO.log("transaction failed");
* },
* data: "foo",
* scope: YAHOO,
* // win: otherframe // target another window/frame
* autopurge: true // allow the utility to choose when to remove the nodes
* });
* </pre>
* @return {tId: string} an object containing info about the transaction
*/
script: function(url, opts) { return _queue("script", url, opts); },
/**
* Fetches and inserts one or more css link nodes into the
* head of the current document or the document in a specified
* window.
* @method css
* @static
* @param url {string} the url or urls to the css file(s)
* @param opts Options:
* <dl>
* <dt>onSuccess</dt>
* <dd>
* callback to execute when the css file(s) are finished loading
* The callback receives an object back with the following
* data:
* <dl>win</dl>
* <dd>the window the link nodes(s) were inserted into</dd>
* <dt>data</dt>
* <dd>the data object passed in when the request was made</dd>
* <dt>nodes</dt>
* <dd>An array containing references to the nodes that were
* inserted</dd>
* <dt>purge</dt>
* <dd>A function that, when executed, will remove the nodes
* that were inserted</dd>
* <dt>
* </dl>
* </dd>
* <dt>scope</dt>
* <dd>the execution context for the callbacks</dd>
* <dt>win</dt>
* <dd>a window other than the one the utility occupies</dd>
* <dt>data</dt>
* <dd>
* data that is supplied to the callbacks when the nodes(s) are
* loaded.
* </dd>
* <dt>insertBefore</dt>
* <dd>node or node id that will become the new node's nextSibling</dd>
* <dt>charset</dt>
* <dd>Node charset, default utf-8</dd>
* </dl>
* <pre>
* YAHOO.util.Get.css("http://yui.yahooapis.com/2.3.1/build/menu/assets/skins/sam/menu.css");
* </pre>
* <pre>
* YAHOO.util.Get.css(["http://yui.yahooapis.com/2.3.1/build/menu/assets/skins/sam/menu.css",
* "http://yui.yahooapis.com/2.3.1/build/logger/assets/skins/sam/logger.css"]);
* </pre>
* @return {tId: string} an object containing info about the transaction
*/
css: function(url, opts) {
return _queue("css", url, opts);
}
};
}();