scriptsrcio.js

js基本操作

/*
	Copyright (c) 2004-2006, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/community/licensing.shtml
*/

dojo.provide("dojo.io.ScriptSrcIO");
dojo.require("dojo.io.BrowserIO");
dojo.require("dojo.undo.browser");

//FIXME: should constantParams be JS object?
//FIXME: check dojo.io calls. Can we move the BrowserIO defined calls somewhere
//       else so that we don't depend on BrowserIO at all? The dependent calls
//       have to do with dealing with forms and making query params from JS object.
/**
 * See test_ScriptSrcIO.html for usage information.
 * Notes:
 * - The watchInFlight timer is set to 100 ms instead of 10ms (which is what BrowserIO.js uses).
 */
dojo.io.ScriptSrcTransport = new function(){
	this.preventCache = false; // if this is true, we'll always force GET requests to not cache
	this.maxUrlLength = 1000; //Used to calculate if script request should be multipart.
	this.inFlightTimer = null;

	this.DsrStatusCodes = {
		Continue: 100,
		Ok: 200,
		Error: 500
	};

	this.startWatchingInFlight = function(){
		//summary: Internal method to start the process of watching for in-flight requests.
		if(!this.inFlightTimer){
			this.inFlightTimer = setInterval("dojo.io.ScriptSrcTransport.watchInFlight();", 100);
		}
	}

	this.watchInFlight = function(){
		//summary: Internal method to watch for in-flight requests.
		var totalCount = 0;
		var doneCount = 0;
		for(var param in this._state){
			totalCount++;
			var currentState = this._state[param];
			if(currentState.isDone){
				doneCount++;
				delete this._state[param];
			}else if(!currentState.isFinishing){
				var listener = currentState.kwArgs;
				try{
					if(currentState.checkString && eval("typeof(" + currentState.checkString + ") != 'undefined'")){
						currentState.isFinishing = true;
						this._finish(currentState, "load");
						doneCount++;
						delete this._state[param];
					}else if(listener.timeoutSeconds && listener.timeout){
						if(currentState.startTime + (listener.timeoutSeconds * 1000) < (new Date()).getTime()){
							currentState.isFinishing = true;
							this._finish(currentState, "timeout");
							doneCount++;
							delete this._state[param];
						}
					}else if(!listener.timeoutSeconds){
						//Increment the done count if no timeout is specified, so
						//that we turn off the timer if all that is left in the state
						//list are things we can't clean up because they fail without
						//getting a callback.
						doneCount++;
					}
				}catch(e){
					currentState.isFinishing = true;
					this._finish(currentState, "error", {status: this.DsrStatusCodes.Error, response: e});
				}
			}
		}
	
		if(doneCount >= totalCount){
			clearInterval(this.inFlightTimer);
			this.inFlightTimer = null;
		}
	}

	this.canHandle = function(/*dojo.io.Request*/kwArgs){
		//summary: Tells dojo.io.bind() if this is a good transport to
		//use for the particular type of request. This type of transport can only
		//handle responses that are JavaScript or JSON that is passed to a JavaScript
		//callback. It can only do asynchronous binds, is limited to GET HTTP method
		//requests, and cannot handle formNodes. However, it has the advantage of being
		//able to do cross-domain requests.

		return dojo.lang.inArray(["text/javascript", "text/json", "application/json"], (kwArgs["mimetype"].toLowerCase()))
			&& (kwArgs["method"].toLowerCase() == "get")
			&& !(kwArgs["formNode"] && dojo.io.formHasFile(kwArgs["formNode"]))
			&& (!kwArgs["sync"] || kwArgs["sync"] == false)
			&& !kwArgs["file"]
			&& !kwArgs["multipart"];
	}

	this.removeScripts = function(){
		//summary: Removes any script tags from the DOM that may have been added by ScriptSrcTransport.
		//description: Be careful though, by removing them from the script, you may invalidate some
		//script objects that were defined by the js file that was pulled in as the
		//src of the script tag. Test carefully if you decide to call this method.
		//In MSIE 6 (and probably 5.x), if you remove the script element while 
		//part of the response script is still executing, the browser might crash.
		var scripts = document.getElementsByTagName("script");
		for(var i = 0; scripts && i < scripts.length; i++){
			var scriptTag = scripts[i];
			if(scriptTag.className == "ScriptSrcTransport"){
				var parent = scriptTag.parentNode;
				parent.removeChild(scriptTag);
				i--; //Set the index back one since we removed an item.
			}
		}
	}

	this.bind = function(/*dojo.io.Request*/kwArgs){
		//summary: function that sends the request to the server.
		//description: See the Dojo Book page on this transport for a full
		//description of supported kwArgs properties and usage:
		//http://manual.dojotoolkit.org/WikiHome/DojoDotBook/Book25

		//START duplication from BrowserIO.js (some changes made)
		var url = kwArgs.url;
		var query = "";
		
		if(kwArgs["formNode"]){
			var ta = kwArgs.formNode.getAttribute("action");
			if((ta)&&(!kwArgs["url"])){ url = ta; }
			var tp = kwArgs.formNode.getAttribute("method");
			if((tp)&&(!kwArgs["method"])){ kwArgs.method = tp; }
			query += dojo.io.encodeForm(kwArgs.formNode, kwArgs.encoding, kwArgs["formFilter"]);
		}

		if(url.indexOf("#") > -1) {
			dojo.debug("Warning: dojo.io.bind: stripping hash values from url:", url);
			url = url.split("#")[0];
		}

		//Break off the domain/path of the URL.
		var urlParts = url.split("?");
		if(urlParts && urlParts.length == 2){
			url = urlParts[0];
			query += (query ? "&" : "") + urlParts[1];
		}

		if(kwArgs["backButton"] || kwArgs["back"] || kwArgs["changeUrl"]){
			dojo.undo.browser.addToHistory(kwArgs);
		}

		//Create an ID for the request.
		var id = kwArgs["apiId"] ? kwArgs["apiId"] : "id" + this._counter++;

		//Fill out any other content pieces.
		var content = kwArgs["content"];
		var jsonpName = kwArgs.jsonParamName;
		if(kwArgs.sendTransport || jsonpName) {
			if (!content){
				content = {};
			}
			if(kwArgs.sendTransport){
				content["dojo.transport"] = "scriptsrc";
			}

			if(jsonpName){
				content[jsonpName] = "dojo.io.ScriptSrcTransport._state." + id + ".jsonpCall";
			}
		}

		if(kwArgs.postContent){
			query = kwArgs.postContent;
		}else if(content){
			query += ((query) ? "&" : "") + dojo.io.argsFromMap(content, kwArgs.encoding, jsonpName);
		}
		//END duplication from BrowserIO.js

		//START DSR

		//If an apiId is specified, then we want to make sure useRequestId is true.
		if(kwArgs["apiId"]){
			kwArgs["useRequestId"] = true;
		}

		//Set up the state for this request.
		var state = {
			"id": id,
			"idParam": "_dsrid=" + id,
			"url": url,
			"query": query,
			"kwArgs": kwArgs,
			"startTime": (new Date()).getTime(),
			"isFinishing": false
		};

		if(!url){
			//Error. An URL is needed.
			this._finish(state, "error", {status: this.DsrStatusCodes.Error, statusText: "url.none"});
			return;
		}

		//If this is a jsonp request, intercept the jsonp callback
		if(content && content[jsonpName]){
			state.jsonp = content[jsonpName];
			state.jsonpCall = function(data){
				if(data["Error"]||data["error"]){
					if(dojo["json"] && dojo["json"]["serialize"]){
						dojo.debug(dojo.json.serialize(data));
					}
					dojo.io.ScriptSrcTransport._finish(this, "error", data);
				}else{
					dojo.io.ScriptSrcTransport._finish(this, "load", data);
				}
			};
		}

		//Only store the request state on the state tracking object if a callback
		//is expected or if polling on a checkString will be done.
		if(kwArgs["useRequestId"] || kwArgs["checkString"] || state["jsonp"]){
			this._state[id] = state;
		}

		//A checkstring is a string that if evaled will not be undefined once the
		//script src loads. Used as an alternative to depending on a callback from
		//the script file. If this is set, then multipart is not assumed to be used,
		//since multipart requires a specific callback. With checkString we will be doing
		//polling.
		if(kwArgs["checkString"]){
			state.checkString = kwArgs["checkString"];
		}

		//Constant params are parameters that should always be sent with each