I have a web page that invokes long request on the server. The request generates an excel file and stream it back to the client when it is ready.
The request is invoked by creating form element using jQuery and invoking the submit method.
I would like during the request is being processed to display the user with progress of the task.
I thought to do it using jQuery ajax call to service I have on the server that returns status messages.
My problem is that when I am calling this service (using $.ajax) The callback is being called only when the request intiated by the form submit ended.
Any suggestions ?
The code:
<script>
function dummyFunction(){
var notificationContextId = "someid";
var url = $fdbUI.config.baseUrl() + "/Promis/GenerateExcel.aspx";
var $form = $('<form action="' + url + '" method="POST" target="_blank"></form>');
var $hidden = $("<input type='hidden' name='viewModel'/>");
$hidden.val(self.toJSON());
$hidden.appendTo($form);
var $contextId = new $("<input type='hidden' name='notifyContextId'/>").val(notificationContextId);
$contextId.appendTo($form);
$('body').append($form);
self.progressMessages([]);
$fdbUI.notificationHelper.getNotifications(notificationContextId, function (message) {
var messageText = '';
if (message.IsEnded) {
messageText = "Excel is ready to download";
} else if (message.IsError) {
messageText = "An error occured while preparing excel file. Please try again...";
} else {
messageText = message.NotifyData;
}
self.progressMessages.push(messageText);
});
$form.submit();
}
<script>
The code is using utility library that invokes the $.ajax. Its code is:
(function () {
if (!window.flowdbUI) {
throw ("missing reference to flowdb.ui.core.");
}
function NotificationHelper() {
var self = this;
this.intervalId = null;
this.getNotifications = function (contextId, fnCallback) {
if ($.isFunction(fnCallback) == false)
return;
self.intervalId = setInterval(function() {
self._startNotificationPolling(contextId, fnCallback);
}, 500);
};
this._startNotificationPolling = function (contextId, fnCallback) {
if (self._processing)
return;
self._processing = true;
self._notificationPolling(contextId, function (result) {
if (result.success) {
var message = result.retVal;
if (message == null)
return;
if (message.IsEnded || message.IsError) {
clearInterval(self.intervalId);
}
fnCallback(message);
} else {
clearInterval(self.intervalId);
fnCallback({NotifyData:null, IsEnded:false, IsError:true});
}
self._processing = false;
});
};
this._notificationPolling = function (contextId, fnCallback) {
$fdbUI.core.executeAjax("NotificationProvider", { id: contextId }, function(result) {
fnCallback(result);
});
};
return this;
}
window.flowdbUI.notificationHelper = new NotificationHelper();
})();
By default, ASP.NET will only allow a single concurrent request per session, to avoid race conditions. So the server is not responding to your status requests until after the long-polling request is complete.
One possible approach would be to make your form post return immediately, and when the status request shows completion, start up a new request to get the data that it knows is waiting for it on the server.
Or you could try changing the EnableSessionState settings to allow multiple concurrent requests, as described here.
Related
I try to create a Web App. Therefor I have to pass an Object from the backend to the HTML-Script. I tried a lot of possibilites but nothing worked.
Backend
function searchMain (allSeaVal) {
var headCon = DbSheet.getRange(1, 1, 1, DbSheet.getLastColumn()).getValues();
var bodyCon = DbSheet.getRange(valRow, typesCol, 1, DbSheet.getLastColumn()).getValues();
var Con = {
headline: headCon,
values: bodyCon
};
var tmp = HtmlService.createTemplateFromFile('page_js');
tmp.Con = Con.map(function(r){ return r; });
return tmp.evaluate();
}
HTML
<script>
function searchValues() {
var allSeaVal = {};
allSeaVal.seaType = document.getElementById('valSearchTyp').value;
allSeaVal.seaVal = document.getElementById('HSearchVal').value;
google.script.run.searchMain(allSeaVal);
Logger.log(Con);
}
<script/>
I want to use the information in "Con" in the Website. The script-code is stored in the file "page_js.
I don´t know why but I can´t pass the information into the frontend.
In your html interface you have to use the success and failure handler in your google.script.run.
Code will looks like
google.script.run
.withSuccessHandler(
function(msg) {
// Respond to success conditions here.
console.log('Execution successful.');
})
.withFailureHandler(
function(msg) {
// Respond to failure conditions here.
console.log('Execution failed: ' + msg, 'error');
})
.searchMain(allSeaVal);
Do not hesitate to check the documentation : https://developers.google.com/apps-script/guides/html/communication
Stéphane
I solved my problem with your help. Thank you so much. I struggled with this many days.
My solution is the code below.
Backend
function searchMain (allSeaVal) {
var typesCol = searchTypesCol(allSeaVal.seaType);
var valRow = searchRow(allSeaVal.seaVal, typesCol);
var headCon = DbSheet.getRange(1, 1, 1, DbSheet.getLastColumn()).getValues();
var bodyCon = DbSheet.getRange(valRow, typesCol, 1, DbSheet.getLastColumn()).getValues();
var Con = {
headline: headCon,
values: bodyCon
};
return Con;
}
HTML
function searchValues() {
var allSeaVal = {};
allSeaVal.seaType = document.getElementById('valSearchTyp').value;
allSeaVal.seaVal = document.getElementById('HSearchVal').value;
google.script.run
.withSuccessHandler(
function(Con) {
console.log(Con + 'success');
})
.withFailureHandler(
function(Con) {
console.log(Con + 'failure');
})
.searchMain(allSeaVal);
}
I am trying to send sensor data to artik cloud via node.js. (using web socket and serial port). But its sending null. Anyone knows the reason? I just copied the code from tutorial so there is no syntax error.
var webSocketUrl = "wss://api.artik.cloud/v1.1/websocket?ack=true";
var device_id = "####";
var device_token = "#####";
var isWebSocketReady = false;
var ws = null;
var serialport = require("serialport");
var portName = 'COM5';
var sp= new serialport.SerialPort(portName, {
baudRate: 9600,
parser: serialport.parsers.readline("\r\n")
});
var WebSocket = require('ws');
/**
* Gets the current time in millis
*/
function getTimeMillis(){
return parseInt(Date.now().toString());
}
/**
* Create a /websocket bi-directional connection
*/
function start() {
//Create the websocket connection
isWebSocketReady = false;
ws = new WebSocket(webSocketUrl);
ws.on('open', function() {
console.log("Websocket connection is open ....");
register();
});
ws.on('message', function(data, flags) {
console.log("Received message: " + data + '\n');
});
ws.on('close', function() {
console.log("Websocket connection is closed ....");
});
}
/**
* Sends a register message to the websocket and starts the message flooder
*/
function register(){
console.log("Registering device on the websocket connection");
try{
var registerMessage = '{"type":"register", "sdid":"'+device_id+'", "Authorization":"bearer '+device_token+'", "cid":"'+getTimeMillis()+'"}';
console.log('Sending register message ' + registerMessage + '\n');
ws.send(registerMessage, {mask: true});
isWebSocketReady = true;
}
catch (e) {
console.error('Failed to register messages. Error in registering message: ' + e.toString());
}
}
/**
* Send one message to ARTIK Cloud
*/
function sendData(temperature){
try{
// ts = ', "ts": '+getTimeMillis();
var data = {
"temp": temperature
};
var payload = '{"sdid":"'+device_id+'", "data": '+JSON.stringify(data)+', "cid":"'+getTimeMillis()+'"}';
console.log('Sending payload ' + payload);
ws.send(payload, {mask: true});
} catch (e) {
console.error('Error in sending a message: ' + e.toString());
}
}
/**
* All start here
*/
start(); // create websocket connection
sp.on("open", function () {
sp.on('data', function(data) {
if (!isWebSocketReady){
console.log("WebSocket is not ready. Skip sending data to ARTIK Cloud (data:" + data +")");
return;
}
console.log("Serial port received data:" + data);
//var parsedStrs = data.split(",");
var temperature = parseInt(data);
sendData(temperature);
});
});
If you reference our First IoT Sample:
https://developer.artik.cloud/documentation/tutorials/your-first-iot-device.html
The node.js sample sends the value from the temperature sensor. As a dependency it requires a connected Arduino, Raspberry Pi, and a DHT temperature sensor located at the right pin. If you are seeing null "before" sending the data to ARTIK Cloud, you are not getting any value from the sensor.
In particular, output and print to console the "temperature" value from the following function in case of any parsing errors:
function sendData(temperature) //...
Email us at developer#artik.cloud if you need additional information.
Thanks!
In this line:
var temperature = parseInt(data);
If you're getting empty or non numeric data (you can verify this in the previous line where you're logging the variable's content), then temperature will be NaN (not a number). Then, when you build the JSON payload for Artik Cloud, you'll end up with something like:
{
"sdid": "cbd3f844967d464da3c4f4989f80f86c",
"data": {
"temp":null
},
"cid":"1495817841624"
}
Because the JSON.stringify of:
{"temp":NaN}
would be translated to:
{"temp":null}
I want to make a demo on how to combine ASP and AJAX. I have found snippets from http://www.aspjax.com and implemented it in my project. However, the text that should be displayed cannot be output properly.
Here's the code. Basically the same as the one in the original:
In index.asp
<script language="javascript" type="text/javascript">
/** XHConn - Simple XMLHTTP Interface - bfults#gmail.com - 2005-04-08 **
** Code licensed under Creative Commons Attribution-ShareAlike License **
** http://creativecommons.org/licenses/by-sa/2.0/ **/
function XHConn()
{
var xmlhttp, bComplete = false;
try { xmlhttp = new ActiveXObject("Msxml2.XMLHTTP"); }
catch (e) { try { xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); }
catch (e) { try { xmlhttp = new XMLHttpRequest(); }
catch (e) { xmlhttp = false; }}}
if (!xmlhttp) return null;
this.connect = function(sURL, sMethod, sVars, fnDone)
{
if (!xmlhttp) return false;
bComplete = false;
sMethod = sMethod.toUpperCase();
try {
if (sMethod == "GET")
{
xmlhttp.open(sMethod, sURL+"?"+sVars, true);
sVars = "";
}
else
{
xmlhttp.open(sMethod, sURL, true);
xmlhttp.setRequestHeader("Method", "POST "+sURL+" HTTP/1.1");
xmlhttp.setRequestHeader("Content-Type",
"application/x-www-form-urlencoded");
}
xmlhttp.onreadystatechange = function(){
if (xmlhttp.readyState == 4 && !bComplete)
{
bComplete = true;
fnDone(xmlhttp);
}};
xmlhttp.send(sVars);
}
catch(z) { return false; }
return true;
};
return this;
}
// doAJAXCall : Generic AJAX Handler, used with XHConn
// Author : Bryce Christensen (www.esonica.com)
// PageURL : the server side page we are calling
// ReqType : either POST or GET, typically POST
// PostStr : parameter passed in a query string format 'param1=foo¶m2=bar'
// FunctionName : the JS function that will handle the response
var doAJAXCall = function (PageURL, ReqType, PostStr, FunctionName) {
// create the new object for doing the XMLHTTP Request
var myConn = new XHConn();
// check if the browser supports it
if (myConn) {
// XMLHTTPRequest is supported by the browser, continue with the request
myConn.connect('' + PageURL + '', '' + ReqType + '', '' + PostStr + '', FunctionName);
}
else {
// Not support by this browser, alert the user
alert("XMLHTTP not available. Try a newer/better browser, this application will not work!");
}
}
// launched from button click
var getMessage = function () {
// build up the post string when passing variables to the server side page
var PostStr = "";
// use the generic function to make the request
doAJAXCall('ajaxtest.asp', 'POST', '', showMessageResponse);
}
// The function for handling the response from the server
var showMessageResponse = function (oXML) {
// get the response text, into a variable
var response = oXML.responseText;
// update the Div to show the result from the server
document.getElementById("responseDiv").innerHTML = response;
};
</script>
<body>
<button onclick="javascript:getMessage();">Get Message From Server</button>
<div id="responseDiv">Original Text</div>
</body>
So, the code tells it to replace the Original Text in the div with the one in ajaxtest.asp
In ajaxtest.asp
<%# Language=VBScript %>
Response.Write "The Server time is " & Now()
The problem is when I click the button Get Message From Server, the stuff in ajaxtest.asp is rendered as plain text, but not in ASP. How to fix this? Is it because of the extension used is wrong?
EDIT: by plain text I mean exactly as Response.Write "The Server time is " & Now()
You probably want the contents of your ASP page to be:
<%# Language=VBScript %>
The Server time is <%=Now()%>
I am currently exploring possible methods to handle application-wide exceptions in AngularJS.
One of the things we really wanted to avoid was wrapping multiple parts of the application in nested try/catch blocks, but handle things cleanly - i.e throw an exception in response to a promise.
Has anyone covered this issue before and have any recommendations?
Any suggestions on how to pick up exceptions in services as well as controllers/directives. (See below - broadcast works ok, but only if you can attach a listener to a scope).
Progress so far
A few short design goals:
Allow exceptions from one part of the application to be handled elsewhere - or possibly multiple places (i.e. 'display error notification to user', 'disable widget').
Provide central management of common error conditions - i.e. log to server, display notification to user, redirect to login.
Allow exceptions to be thrown from controllers, directives, services etc.
Eventually allow localized messages.
The current leaning of my team is to write a service to handle exceptions, which would expose a range of simple calls:
exceptionService.warn('exception_token');
exceptionService.crit('another_exception_token');
This service would then format an 'exception' object and broadcast this from the rootscope. This would allow a default handler to watch for any broadcasts and apply default actions, as well as allow custom listeners to be set in others scopes, which could handle more specific conditions - i.e. disable a part of the UI.
var exception = {
token: 'exception_token',
severity': 'crit'
};
// broadcast exception
$rootScope.$broadcast(
'application_exception',
exception
);
I was thinking about the same recently, and it occurred to me that when it comes to a good error handling in javascript, it is irrelevant which framework you are using, Angular on something else. I wrote one such error handler recently for an AngularJS project, but I did it in a way it can be used in any framework.
Here's the complete code. You can either use it directly, or modify to your needs...
/*
Factory errorFact is to simplify error handling and reporting in other objects.
It supports detailed error output as a text string and into the browser's console.
Usage example:
A function that supports return of an error object would have the following declaration
as its very first line:
var e = errorFact.create("objectName.funcName", arguments);
- in this declaration we specify the full object + method name as the first string parameter,
- and as the second parameter we pass javascript's reserved variable called arguments, which
provides reference to all of the function's parameters for logging.
When an error occurs, the function would return:
return e.error("Error description text");
- this line will create and return a complete error context.
When a function that supports return of an error object makes a call into another
function that also supports the error context, then it can return the nested error
result by passing the embedded error to the current error object instead of the error
text.
Example:
var e = errorFact.create("objectName.funcName", arguments);
var data = callAnotherFunc(...); // calling a function that support an error object;
if(data.isError){ // If an error was triggered;
return e.error(data); // return that error from the current context;
}
The top-level code that calls an error-returning function would do verification
and if an error occurred, log all its details into console (typically).
Example:
var data = getData(...);
if(data.isError){
data.log(); // Output all the error details into the browser's console;
}
*/
"use strict";
app.factory("errorFact", function(){
return {
// creates a new error context;
create: function(method, args){
var result = {
// initiates and returns the error context;
error: function(msg){
this.info.isError = true;
if(msg.isError){
this.info.details.caller = msg;
}else{
this.info.details.msg = msg;
}
return this.info;
},
info:
{
isError: false,
details: {},
log: function(){
if(this.isError){
console.error(this.format());
}
},
// formats complete error details into a text string;
format: function(){
if(this.details.caller){
var txt = this.details.caller.format();
txt += "\nCALLER: " + this.details.method + "(" + this.formatArguments() + ")";
return txt;
}
if(this.details.method){
return "Error calling " + this.details.method + "(" + this.formatArguments() + "): " + this.details.msg;
}else{
return this.details.msg;
}
return "";
},
// formats function argument details into a text string;
formatArguments: function(){
if(!this.details.args){
return "";
}
var params = "";
for(var i = 0;i < this.details.args.length;i ++){
if(params.length > 0){
params += ",";
}
var p = this.details.args[i];
if(p === undefined){
params += "undefined";
}else{
if(p === null){
params += "null";
}else{
if(typeof(p) == "object"){
params += "Object";
}else{
params += p;
}
}
}
}
return params;
}
}
};
if(method){
result.info.details.method = method;
}
if(args){
result.info.details.args = args;
}
return result;
}
}
});
Below is a factory that shows how it is used:
"use strict";
app.factory('moduleFact', ['errorFact', function(errorFact){
return {
// Locates existing module and expands its key Id references
// into corresponding object references:
// - If 'hintGroupId' is present, property 'hints' is added from
// the corresponding hint group.
// - If 'repModules' is present, properties 'question' and 'refs'
// are added.
// On success, return the expanded module object.
// On failure, returns an error object.
//
// NOTE: Currently supports only the first value in repModules.
expandModule: function(moduleData, moduleId){
var e = errorFact.create("moduleFact.expandModule", arguments);
if(!moduleData || !moduleData.modules || !moduleId){
return e.error("Invalid parameters passed");
}
var mod = this.findModule(moduleData, moduleId);
if(mod.isError){
return e.error(mod);
}
var src = mod;
if(mod.repModules){
var repId = mod.repModules[0];
if(!repId){
return e.error("Invalid repModules encountered");
}
///////////////////////////////////////
// temporary check to throw a warning:
if(mod.repModules.length > 1){
console.warn("Multiple values in property repModules: " + JSON.stringify(mod.repModules) +
", which is not supported yet (only the first value is used)");
}
///////////////////////////////////////
src = this.findModule(moduleData, repId);
if(src.isError){
return e.error(src);
}
}
if(src.question){
mod.question = src.question;
}else{
return e.error("Question not specified");
}
if(src.refs){
mod.refs = src.refs;
}
if(src.hintGroupId){
var hg = this.findHintGroup(moduleData, src.hintGroupId);
if(hg.isError){
return e.error(hg);
}
mod.hints = hg.hints;
}
return mod; // needed extra: expand attribute repModules
},
// Expands all the modules and returns the data;
expandAllModules: function(moduleData){
var e = errorFact.create("moduleFact.expandAllModules", arguments);
if(!moduleData || !moduleData.modules){
return e.error("Invalid parameters passed");
}
for(var i = 0;i < moduleData.modules.length;i ++){
var result = this.expandModule(moduleData, moduleData.modules[i].id);
if(result.isError){
return e.error(result);
}
}
return moduleData;
},
// Locates and returns module by its Id;
findModule: function(moduleData, moduleId){
var e = errorFact.create("moduleFact.findModule", arguments);
if(!moduleData || !moduleData.modules || !moduleId){
return e.error("Invalid parameters passed");
}
for(var i = 0;i < moduleData.modules.length;i ++){
if(moduleData.modules[i].id == moduleId){
return moduleData.modules[i];
}
}
return e.error("Module with Id = " + moduleId + " not found");
},
// Locates and returns Hint Group by its Id;
findHintGroup: function(moduleData, hintGroupId){
var e = errorFact.create("moduleFact.findHintGroup", arguments);
if(!moduleData || !moduleData.hintGroups || !hintGroupId){
return e.error("Invalid parameters passed");
}
for(var i = 0;i < moduleData.hintGroups.length;i ++){
if(moduleData.hintGroups[i].id == hintGroupId){
return moduleData.hintGroups[i];
}
}
return e.error("Hint Group with Id = " + hintGroupId + " not found");
}
}
}]);
So, when you have such factory in place, your high-level code, such as in a controller would just log any issues as shown in the example below:
"use strict";
app.controller('standardsCtrl', ['$scope', 'moduleFact', function($scope, moduleFact){
var data = ...//getting data;
var mod = moduleFact.expandAllModules(data);
if(mod.isError){
mod.log(); // log all error details into the console;
}else{
// use the data
}
});
}]);
You can override the $exceptionHandler in order to pass the exceptions to your own central service for exceptions, but the $exceptionHandler seems to only receive the exceptions thrown from your controllers, directives, etc... but not for the exceptions originated from ajax calls. For those exceptions you can implement an interceptor like the one described in this page:
EDITED: Link is dead permanently.
Archive.org link
whats your opinion to create a centralized error handling function for your app
so whenever an error happened with your frontend tear (angular, API calls,...) it executed, so no need to write your error handling every time
so here is my code
(function () {
'use strict';
angular
.module('app')
.factory('$exceptionHandler', ExceptionHandler);
ExceptionHandler.$inject = ['$injector']; //for minification
function ExceptionHandler($injector) {
var $log, sweetAlert, $translate;
return function exceptionHandler(exception, cause) {
// Add DI here to prevent circular dependency
$log = $log || $injector.get('$log');
sweetAlert = sweetAlert || $injector.get('sweetAlert'); //19degrees.ngSweetAlert2
$translate = $translate || $injector.get('$translate');
// $loggerService = $loggerService || $injector.get('$loggerService');
var title, message;
title = $translate.instant('General error title');
message = $translate.instant('General error message', { exceptionMessage: exception.message });
sweetAlert.error(title, message);
$log.error(exception, cause);
// loggerService.logErrorsToBackend(exception, cause);
};
}
})();
I'm not sure if this approach considered to be a best practice but hope it helps you.
I am not able to figure out that why do I see polling log in fiddler for the server sent event I am trying to implement using HTML 5. Please find the image of my fiddler log below
If its server sent event, the message should be sent from server without system calling the method again and again to look for updates. Or i have not implemented it properly. Here my code:
<script type="text/javascript">
$(function () {
var userStatusChangeEvent = new EventSource("/events");
userStatusChangeEvent.onmessage = function (event) {
data = $.parseJSON(event.data);
for (index = 0; index < data.length; index++) {
$elem = $('#' + data[index].Id);
isOnline = data[index].IsOnline;
if (isOnline) {
$elem.addClass('is_online');
$('.loginTimestamp', $elem).html(data[index].Time);
}
else {
$elem.removeClass('is_online');
$('.loginTimestamp', $elem).html('');
}
}
};
});
</script>
public virtual ActionResult Events()
{
var userStream = new UserServerSentStatusResult();
userStream.ChangeUserStatus = new LoggedUsersViewModel().Users.Where(x => x.HasChanged).ToList();
userStream.Content = () =>
{
var serializer = new JavaScriptSerializer();
return serializer.Serialize(userStream.ChangeUserStatus);
};
userStream.ChangeUserStatus.ForEach(x =>
{
x.HasChanged = false;
x.Time = DateTime.Now.ToShortTimeString();
});
return userStream;
}
Turn on the Streaming mode in Fiddler