RS.HTM

// ************************************************************************<BR>
// Microsoft Script Library<BR>
// Visual InterDev 6.0 Remote Scripting utilities for client<BR>
// Copyright 1998 Microsoft Corporation. All Rights Reserved.<BR>
// <B>Do not modify in design view. Switch to source view.</B><BR>
// ************************************************************************<BR>
// <SCRIPT>	
	
//*****************************************************************	
// The Remote Scripting utilities for the client consist of
// three public methods and the RSCallObject definition.
// The public methods are RSEnableRemoteScripting, RSExecute
// and RSGetASPObject. The RSCallObject is returned from any
// remote scripting call and provides status and return value.
//*****************************************************************	
	
//*****************************************************************
// function RSEnableRemoteScripting()
//	This function enables the remote scripting proxy.
//*****************************************************************
function RSEnableRemoteScripting(codebase)
{
	MSRS = new _MSRS_Object();
	if (typeof(codebase) == 'undefined')
	{	// assume applet is in _ScriptLibrary directory off the webroot
		var secondSlash, path;
		codebase = '';
		if ((secondSlash = (path = window.location.pathname).indexOf('/',1)) != -1)
			codebase = path.substring(0,secondSlash);
		codebase += '/_ScriptLibrary';
	}
	document.write('<' + 'APPLET name=RSAspProxyApplet codebase=' + codebase + ' code=RSProxy.class height=0 width=0></APPLET>');	
}

//*****************************************************************
// function RSExecute(url,method,p1 ... pn,cb,ecb,context)
//	This is the function by which remote scripting calls are made.
//	The caller provides the following :
//		url		: url to the asp file containing remote script
//		method	: name of the method to be invoked
//		p1...pn	: any parameters required by the method
//		cb		: an optional callback routine for async.
//		ecb		: an optional error callback routine for async.
//		context	: an optional user context
//*****************************************************************
function RSExecute(url,method)
{
	var cb, ecb, context;
	var params = new Array;
	var pn = 0;
	var len = RSExecute.arguments.length;
	for (var i=2; i < len; i++)
		params[pn++] = RSExecute.arguments[i];
		
	return MSRS.invokeMethod(url,method,params);
}

//*****************************************************************
// function RSGetASPObject(url)
//	This function returns a server object for an ASP file
//	described by its public_description.
//*****************************************************************
function RSGetASPObject(url)
{
	var cb, ecb, context;
	var params = new Array;
	var request = MSRS.startRequest(url,'GetServerProxy',params,cb,ecb,context);
	if (request.status == MSRS_COMPLETED)
	{
		var server = request.return_value;
		if (typeof(Function) == 'function')
		{
			for (var name in server)
				server[name] = Function('return MSRS.invokeMethod(this.location,"' +  name + '",this.' + name + '.arguments);');
		}
		else
		{	// JavaScript 1.0 does not support Function  ( IE3.0 )
			for (var name in server)
				server[name] = eval('function t(p0,p1,p2,p3,p4,p5,p6,p7,p8,p9,pA,pB,pC,pD,pE,pF) { return MSRS.invokeMethod(this.location,"' + name + '",this.' + name + '.arguments);} t');
		}
		server.location = url;
		return server;
	}
	alert('Failed to create ASP object for : ' + url);
	return null;
}

//*****************************************************************
// function RSCallObject(cb,ecb,context)
//
//	The RSCallObject is returned for every remote scripting
//	invocation. It contains the return value and status.
//
//		id				:	unique id of request
//		status			:	status of request, one of 
//								MSRS_COMPLETED
//								MSRS_FAIL
//								MSRS_PENDING
//								MSRS_PARTIAL
//		message			:	message associated with status
//		data			:	raw data returned from server
//		return_value	:	evaluated value returned from server
//		callback		:	user provided callback ( optional )
//		error_callback	:	user provided callback ( optional )
//		context			:	user provided context ( optional )
//
//*****************************************************************
function RSCallObject(cb,ecb,context)
{
	this.id = MSRS.nextRequestID++;
	this.status = MSRS_PENDING;
	this.message = '';
	this.data = '';
	this.return_value = '';
		
	this.callback = cb;
	this.error_callback = ecb;
	this.context = context;

	this.wait = RSCallObject_wait;
	this.cancel = RSCallObject_cancel;

	MSRS.requestList[this.id] = this;
}

//*****************************************************************
// function RSCallObject_wait()
//
//	The RSCallObject_wait method can be called from an asynchronous
//  request to wait for it to complete.  If the request has finished
//  this call returns immediately.
//
//		this = RSCallObject instance to wait for
//*****************************************************************
function RSCallObject_wait()
{
	if (this.status != MSRS_PENDING)
		return;
	while (true)
	{	// wait synchronously for response
		if (MSRS.rsapplet.waitForResponse())
		{
			if (MSRS.rsapplet.hasResponse())
			{
				var rid = MSRS.rsapplet.getRequestID();
				MSRS.handleResponse(rid);
				// DO NOT CHANGE THIS CODE
				// Solves Java to Script discrepancies between IE3 and Navigator
				var strrid = String(rid);
				if (strrid == null)
					strrid = rid;
				if (strrid == this.id)	
					break;				// this response completed			
			}
		}
		else
		{
			this.status = MSRS_FAIL;
			this.message = 'Request not handled.'
			break;
		}
	}
}

//*****************************************************************
// function RSCallObject_cancel()
//
//	The RSCallObject_cancel method can be called from an 
//	asynchronous request to cancel it.  If the request has 
//	finished this call returns immediately.
//
//		this = RSCallObject instance to cancel
//*****************************************************************
function RSCallObject_cancel()
{
	if (this.status == MSRS_PENDING)
	{
		MSRS.rsapplet.cancelRequest(this.id);
		this.status = MSRS_FAIL;
		this.message = 'Request cancelled.'
	}
}

//*** PRIVATE IMPLEMENTATION BELOW ********************************
//*** PRIVATE IMPLEMENTATION BELOW ********************************
//*** PRIVATE IMPLEMENTATION BELOW ********************************
//*****************************************************************
//
// Remote Scripting Object --  private implementation
//
//	The following code is private glue code that contains the
//	implementation of a JSObject to enable remote scripting
//	functionality on the client. This private object is utilized
//	by the public Remote Scripting methods defined above.
//
//*****************************************************************
//*****************************************************************

//*****************************************************************
// function _MSRS_Object
//
//	This is the JSObject that interacts with the RSAspProxy
//	applet to synchronously/asynchronously retrieve data via
//	an ASP file.
//*****************************************************************
//var MSRS = new _MSRS_Object();
function _MSRS_Object()
{
	MSRS_FAIL = -1;
	MSRS_COMPLETED = 0;
	MSRS_PENDING = 1;
	MSRS_PARTIAL = 2;

	this.REQUEST_MODE_COMPLETE = 0;
	this.POLLING_PERIOD = 100;

	this.pollID = 0;
	this.pollCount = 0;
	this.nextRequestID = 1;
	this.requestList = new Array;
	this.rsapplet = null;

	this.startRequest = _MSRS_startRequest;
	this.invokeMethod = _MSRS_invokeMethod;
	this.handleResponse = _MSRS_handleResponse;
	this.evaluateRequest = _MSRS_evaluateRequest;
	this.setRequestPoll = _MSRS_setRequestPoll;
	this.requestPollHandler = _MSRS_requestPollHandler;
	this.buildURL = _MSRS_buildURL;
}

//*****************************************************************
// function _MSRS_startRequest(url,method,args,cb,ecb,context)
//
//	This is key function for initiating a request for data.
//	The url to the ASP file is required. The callback, 
//	error_callback, and user context parameters are optional.
//*****************************************************************
function _MSRS_startRequest(url,method,args,cb,ecb,context)
{
	var request = new RSCallObject(cb,ecb,context);
	if (this.rsapplet == null)
	{
		if (typeof(document.RSAspProxyApplet) == 'object')
			this.rsapplet = document.RSAspProxyApplet;
		else if (typeof(document.thisForm) == 'object' && typeof(document.thisForm.RSAspProxyApplet) == 'object')
			this.rsapplet = document.thisForm.RSAspProxyApplet;
		else
		{
			errmsg = 'ERROR:\nCannot locate proxy which supports Remote Scripting.\nWas RSEnableRemoteScripting method invoked?';
			request.status = MSRS_FAIL;
			request.message = errmsg; 
			alert(errmsg);
		}
	}

	if (request.status != MSRS_FAIL)
	{
		url = this.buildURL(url,method,args);
		url_context = window.location.href; // May not be 'window.location.pathname'
		this.rsapplet.startRequest(request.id,url_context,url,this.REQUEST_MODE_COMPLETE);
		if (typeof(cb) == 'function')
		{
			if (this.pollCount++ == 0)
				this.setRequestPoll();
		}
		else
		{	// wait synchronously for response
			request.wait();
		}
	}
	return request;
}

//*****************************************************************
// function _MSRS_invokeMethod(url,method,args)
//	This is the function by which remote scripting calls are 
//	via a server object retrieved with the GetASPObject call.
//	The caller provides the following :
//		url		: url to the asp 
//		method	: name of the method to be invoked
//		args	: an array containing method parameters
//				  and the optional cb, ecb, context parameters
//*****************************************************************
function _MSRS_invokeMethod(url,method,args)
{
	var cb, ecb, context;
	var params = new Array;
	var pn = 0;
	var i = 0;
	for (var i=0; i < args.length; i++)
	{
		if (typeof(args[i]) == 'function')
		{
			pn = -1;	// no more params
			if (typeof(cb) == 'undefined')
				cb = args[i];
			else
				ecb = args[i];
		}
		else if (pn != -1)
		{
			params[pn++] = args[i];
		}
		else
			context = args[i];
	}

	return MSRS.startRequest(url,method,params,cb,ecb,context);
}

//*****************************************************************
// function _MSRS_handleResponse(requestid)
//
//	This function will handle the response for a given request.
//	If the response is complete or failed, then the associated
//	request object will be updated and the appropriate callback
//	invoked, if provided.
//	NOTE: incremental data retrieval is not yet supported
//*****************************************************************
function _MSRS_handleResponse(requestid)
{
	var request = this.requestList[requestid];
    if (typeof(request) == 'undefined')
	{
        alert('Unknown request id.');
		return;
	}

    request.status = this.rsapplet.getStatus();
    if (request.status == MSRS_COMPLETED)
	{
		request.data = this.rsapplet.getData();
		request.message = this.rsapplet.getMessage();
		this.evaluateRequest(request);
		if (request.status == MSRS_FAIL)
		{	
			if (typeof(request.error_callback) == 'function')
			{
				this.pollCount--;
				request.error_callback(request);
			}
			else
				alert('Remote Scripting Error\n' + request.message);
		}
		else
		{
			if (typeof(request.callback) == 'function')
			{
				this.pollCount--;
				request.callback(request);
			}
		}
		this.rsapplet.endResponse();
		this.requestList[request.id] = null;
	}
    else if (request.status == MSRS_FAIL)
	{
		request.message = this.rsapplet.getMessage();
		if (typeof(request.error_callback) == 'function')
		{
			this.pollCount--;
			request.error_callback(request);
		}
		this.rsapplet.endResponse();
		this.requestList[request.id] = null;
	}
    else if (request.status == MSRS_PARTIAL)
	{	// not handling partial data retrieval yet
	}
    else if (request.status == MSRS_PENDING)
	{	// do nothing
	}
}

//*****************************************************************
// function _MSRS_evaluateRequest(request)
//
//	This function evaluates the data returned to the request. 
//	Marshalled jscript objects are re-evaluated on the client.
//*****************************************************************
function _MSRS_evaluateRequest(request)
{
	var data = request.data;
	var start_index = 0;
	var end_index = 0;
	var start_key = '<' + 'RETURN_VALUE';
	var end_key = '<' + '/RETURN_VALUE>';

	if ((start_index = data.indexOf(start_key)) != -1)
	{
		var data_start_index = data.indexOf('>',start_index) + 1;
		end_index = data.indexOf(end_key,data_start_index);
		if (end_index == -1) 
			end_index = data.length;
		var metatag = data.substring(start_index,data_start_index);
		if (metatag.indexOf('TYPE=SIMPLE') != -1)
		{
			request.return_value = unescape(data.substring(data_start_index,end_index));
		}
		else if (metatag.indexOf('TYPE=EVAL_OBJECT') != -1)
		{
			request.return_value = data.substring(data_start_index,end_index);
			request.return_value = eval(unescape(request.return_value));
		}
		else if (metatag.indexOf('TYPE=ERROR') != -1)
		{
			request.status = MSRS_FAIL;
			request.message = unescape(data.substring(data_start_index,end_index));		
		}
	}
	else
	{
		request.status = MSRS_FAIL;
		request.message = 'REMOTE SCRIPTING ERROR: Page invoked does not support remote scripting.';			
	}
}

//*****************************************************************
// function _MSRS_setRequestPoll()
//
//	Due to limitations in calling back into JScript from a worker
//	thread of an applet, a polling mechanism is used to determine
//	when a request has been completed. This function sets up
//	a timer to kick the requestPollHandler at a later time.
//*****************************************************************
function _MSRS_setRequestPoll()
{
	this.pollID = window.setTimeout('MSRS.requestPollHandler()',this.POLLING_PERIOD,'javascript');
}

//*****************************************************************
// function _MSRS_requestPollHandler()
//
//	Due to limitations in calling back into JScript from a worker
//	thread of an applet, a polling mechanism is used to determine
//	when a request has been completed. This function is the 
//	handler which is kicked by a timer. It polls the applet to
//	see if a response to a prior request is available.
//*****************************************************************
function _MSRS_requestPollHandler()
{
    while (this.rsapplet.hasResponse())
    {
		this.handleResponse(this.rsapplet.getRequestID());
	}
    if (this.pollCount != 0)
        this.setRequestPoll();
}

//*****************************************************************
// function _MSRS_escapePlus(value)
//
//	This replaces all occurances of '+' with ''%2B' in the supplied
//  string.
//*****************************************************************
function _MSRS__escapePlus(value)
{
	for (var i = 0, newValue = ''; i < value.length; i++)
		newValue += (value.charAt(i) == '+' ? '%2B' : value.charAt(i));
	return newValue;
}

//*****************************************************************
// function _MSRS_buildURL(url,method,args)
//
//	This builds the proper url entry point into the ASP page
//	such that the intended server method with parameters gets
//	invoked.
//*****************************************************************
function _MSRS_buildURL(url,method,args)
{
	if (url == '') url = window.location.pathname;
	if (typeof(method) == 'string')
	{
		url += '?_method=' + method;
		url += '&_mtype=execute';
		var params = '&pcount=0';
		if (typeof(args) != 'undefined' && args.length)
		{	// add parameters
			params = '&pcount=' + args.length 
			for (var i = 0; i < args.length; i++) 
			{
				var arg = args[i];
				params += '&p' + i + '=' + _MSRS__escapePlus(escape(arg));
			}
		}
		url += params;
	}
	return url;
}