multiple xhr.get s with dojo - ajax

how do I do two xhr.gets one after the other using dojo ?
I have ....
require(["dojo/_base/xhr", "dojo/dom", "dojo/domReady!"],
function(xhr, dom) {
// Using xhr.get, as very little information is being sent
xhr.get({
// The URL of the request
url: "inc/etl2json.php?item=Execs",
// The success callback with result from server
load: function(execContent) {
dom.byId("Execs").innerHTML = execContent;
},
// The error handler
error: function() {
// Do nothing -- keep old content there
}
});
});
I would like to do another xhr.get to "inc/etl2json.php?item=Execs" and assign it to dom.byId("Elapsed").innerHTML = elapsedContent;

just call again xhr.get() inside the load function, well that if the content is supposed to change, else you could just use the same data retrieved the first time:
xhr.get({
load:function(data){
//use the first data you retrieved
xhr.get({
load: function(data2){
//do what you like with the nuew data
}
});
}
});

Although nesting is a straightforward solution it almost always leads to unreadable code, so I would do the same as #Ricardo did, but use the advantage of Dojo's Deferred (+ here) and employ chaining:
var requestUrl = "inc/etl2json.php?item=Execs";
xhr.get({ url: requestUrl})
.then(function(results) {
dom.byId("execs").innerHTML = results;
})
.then(function(results) {
return xhr.get({ url: requestUrl});
})
.then(function(results) {
dom.byId("elapsed").innerHTML = results;
})
See it in action at jsFiddle: http://jsfiddle.net/phusick/73X88/

I think you should add another xhr call for the elapsedContent. I don't see any relation between the two calls so you should make them separate. Nesting one in another is not necessary.
just add
xhr.get({
// The URL of the request
url: "inc/etl2json.php?item=Execs",
// The success callback with result from server
load: function(elapsedContent) {
dom.byId("Elapsed").innerHTML = elapsedContent;
},
// The error handler
error: function() {
// Do nothing -- keep old content there
}
});

Related

Pass DataTable reference to the callback function on load

My current code is:
var CommissionLogs = $("#CommissionLogs").DataTable({
ajax: {
url: ajaxurl + '?action=pos&post_action=get_commissions'
},
'initComplete': function (settings, json){
//possible to access 'this'
this.api().columns(1);
}
});
I improved the code above as below with help :
var CommissionLogs = $("#CommissionLogs").DataTable({
ajax: {
url: ajaxurl + '?action=pos&post_action=get_commissions'
},
'initComplete': function(settings, json){
callbackFunction(settings);
}
});
function callbackFunction(settings){
var api = new $.fn.dataTable.Api( settings );
// api is accessible here.
}
Update :
Now I can access api from callback function. But I want use same callback with load() as below code.
CommissionLogs.ajax.url( newAjaxURL ).load( callbackFunction(), true);
But settings param is not accessible in load function.
I can clear and destroy datatable and re initialize always. But what will be the right way.
I think you need settings:
https://datatables.net/reference/type/DataTables.Settings
$('#example').dataTable( {
"initComplete": function(settings, json) {
myFunction(settings);
}
});
function myFunction(settings){
var api = new $.fn.dataTable.Api( settings );
// Output the data for the visible rows to the browser's console
// You might do something more useful with it!
console.log( api.rows( {page:'current'} ).data() );
}
Other option is re-use your var CommissionLogs variable throughout the code without using this, I recommend strongly this last option.
The dataTable.ajax.url().load() has not access to settings.
So can not call a callback function with settings.
But possible to use callback function without settings.
So here is an alternative way to use settings.
CommissionLogs.clear();// clear the table
CommissionLogs.destroy();// destroy the table
CommissionLogs = $("#CommissionLogs").DataTable({
ajax: {
url: newAjaxUrl
},
'initComplete': function (settings, json){
callbackDatatableFunciton(settings);
}
});

How to deal with async requests in Marionette?

I am trying to fill in an ItemView in Marionette with the combined results of 2 API requests.
this.standings = App.request('collection:currentStandings');
this.userInfo = App.request('model:userInfo');
this.standings.each(function(s) {
if (s.currentUser) {
s.set('alias', this.userInfo.alias);
s.set('imageURL', this.userInfo.imageURL);
}
});
userInfoView = new LeagueBar.UserInfo({ collection: this.standings });
The problem is, the combination never happens because the requests have not been fulfilled before I try to combine them.
I know I probably need to add a promise for each request, but I haven't been able to find a clean way to do it. I could make 'collection:currentStandings' and 'model:userInfo' return promises, however, they are currently used in many other parts of the code, so I would have to go back and add .then()s and .done()s all over the code base where they weren't required before.
Any ideas or suggestions?
EDIT:
I have currently solved this in a less-than-ideal way: I created a template/view for the alias and a template/view for the imageURL and kept the template/view for the standings info. This doesn't seem like the best way and I'm interested to know the right way to solve this problem.
here are the two requests I am trying to combine:
Models.CurrentStandings = App.Collection.extend({
model: Models.PlayerStandings,
url: function() { return 'leagues/' + App.state.currentLeague + '/standings'; },
parse: function(standings) {
return _.map(standings, function(s) {
if (s.memberId == App.user.id)
s.currentUser = true;
return s;
});
}
});
App.reqres.setHandler('collection:currentStandings', function() {
weekStandings = new Models.CurrentStandings();
weekStandings.fetch({ success: function(data){ console.log(data); }});
return weekStandings;
});
Models.UserInfo = App.Model.extend({
url: 'users/me'
});
App.reqres.setHandler('model:userInfo', function(options) {
myuser = new Models.UserInfo();
myuser.fetch(options);
return myuser;
});
There are 2 solutions which based on your dependencies among views can be selected:
You can create views which are handling 'change' event of Models.UserInfo and when the data is ready (Change/Reset event raised) re-render the content. It is probably your solution.
If you are looking for a solution which should not create instance of LeageBar.UserInfo until both Models.CurrentStanding and Models.UserInfo are ready, you have to return the result of fetch function, so you may remove calling fetch from setHandlers and use them as following:
this.standings = App.request('collection:currentStandings');
this.userInfo = App.request('model:userInfo');
var that=this;
that.standings.fetch().done(function(){
that.userInfo.fetch().done(function(){
that.standings.each(function(s) {
if (s.currentUser) {
//....
}
});
userInfoView = new LeagueBar.UserInfo({ collection: that.standings });
});

Deferred Promises with AJAX in Angular

I'm trying to send data to my view from an AJAX call to my API. I am able to successfully hit my API and get data, but I was having problems with the view rendering before the AJAX call came back.
I'm trying to wrap my AJAX call in a Promise but it's not working. Here's my layout
Controller
.controller('DashCtrl', function($scope, Tweets) {
$scope.tweets = Tweets.all()
})
Factory doing ajax call
.factory('Tweets', function($http) {
$http.get('http://localhost:3000/tweets')
.success(function(data) {
var tweets = data
debugger
})
return {
all: function() {
//should return the results of the AJAX call when it's complete
}
}
});
I've tried making wrapping the ajax call into a function and using .then(function(payload){ return payload.data }) - Payload.data has my data but its never returned when I call the function. I'm new to angular, so I would appreciate any help or insight.
You should define your factory as
.factory('Tweets', function($http) {
return {
all: function() {
return $http.get('http://localhost:3000/tweets')
.then(function(response) {
return reponse.data;
})
}
}
});
Then change your controller to
.controller('DashCtrl', function($scope, Tweets) {
Tweets.all().then(function(data) {
$scope.tweets = data;
});
})
Use the $resource service. The docs don't mention it, but comments in the source do.
$resolved: true after first server interaction is completed (either with success or rejection), false before that.
So in the controller:
$scope.tweets = $resource('/tweets').query()
And in the view:
<div ng-if="tweets.$resolved">
Loading data with ngResource or from factory promise callback are viable options, but there's one more way nobody mentioned yet: resolve data to controller via route definition. This approach allows to write simplistic controllers that don't know how to load data at all. In most cases it will be more than enough if you don't need to load data dynamically, like pagination or infinite scroll.
You will need to define route and resolve function:
angular
.module('app', ['ngRoute'])
.config(function ($routeProvider) {
$routeProvider
.when('/', {
controller: 'ctrl',
controllerAs: 'view',
templateUrl: 'view.html',
resolve: {
tweets: function (Tweets) {
return Tweets.all();
}
}
})
})
The tweets property on resolve will inject loaded data into controller as tweets, all you have to do is just assign received data:
.controller('ctrl', function (tweets) {
this.tweets = tweets;
});
In addition, here's how Tweets service might look like:
.factory('Tweets', function ($timeout) {
function all () {
return $timeout(function () {
return ["hey", "there"];
});
}
return {
all: all
};
})
Basically, it exposes methods that return promise, returning some data ($timeout returns promise too, so I've used it instead of $http for example purpose).
Full example on JS Bin.

jQuery wait for an AJAX request to be completed before refreshing the page

I've got the following jQuery:
$("#delete_products").click(function() {
$(":checkbox:checked").each(function() {
var pid = $(this).val();
$.get('delete_product.php',{pid: pid});
});
location.reload();
});
There is a problem with this since the page doesn't wait for the AJAX request to be completed (MULTIPLE AJAX REQUESTS), and refreshes the page immediately and makes the AJAX request to not run and fail.
How can I do that the page will only refresh when it done loading?
I've been given this code:
$("#delete_products").click(function () {
var promises = [];
$(":checkbox:checked").each(function () {
var pid = $(this).val();
promises.push($.get('delete_product.php', {
pid: pid
}));
});
$.when.apply($, promises).done(function () {
location.reload();
});
return false;
});
But this solution just doesn't work.
any suggestions?
your code seems like it should work, but i would recommend to delete all products with one call by passing array of ids.
less work for the browser, less work for the server, faster results.
UPDATED ANSWER
$("#delete_products").click(function () {
var ids = [];
$(":checkbox:checked").each(function () {
ids.push($(this).val());
});
$.post('delete.php', { 'ids': ids } }).done(function() {
alert('hells yeah!');
});
return false;
});
and as for the server side:
$commaSeperatedIds = explode(',', $_POST['ids']);
mysql_query('DELETE FROM products WHERE id IN('.mysql_real_escape_string($commaSeperatedIds).')');
Use "success" parameter of "get"
EDIT: add counter of requests.
total_requests = $(":checkbox:checked").length;
total_success = 0;
...
$.get('delete_product.php',{pid: pid}, function (data, status, xx) {
...
total_success++;
if (total_success >= total_requests) {
location.reload();
}
});
...
Possible Solution #1:
The async parameter could help. Set it to false.
Since you`re using the $.get() function, this is done with:
$.ajaxSetup({
async: false
});
 
With the $.ajax() function, you'd simply set it like:
$.ajax({
url: ...,
async: false,
success: function(data) {}
});
More info on this can be found here.
 
Possible Solution #2:
Use the .success() callback hook OR .complete() if you want to refresh the page no mather if the request failed or not.
$.get('delete_product.php',{pid: pid}).success(function(response)
{
location.reload();
});
 
Happy coding!
 
Edit:
The questioner seems to prever sUP's answer. I'd like to provide an example of how to achieve the desired functionality with jQuery:
$("#delete_products").click(function()
{
var products = [];
$(":checkbox:checked").each(function()
{
var pid = $(this).val();
products.push(pid);
});
$.post('delete_products.php', {'products': products}).done(function()
{
location.reload();
});
});
 
If you prefer to use JSON for the post data, try:
$('#delete_products').click(function()
{
var products = [];
$(':checkbox:checked').each(function()
{
products.push($(this).val());
});
// Convert the products array into JSON
products = JSON.stringify(products);
$.post('delete_products.php', {'products': products}).done(function()
{
location.reload();
});
});
In PHP you need to parse the json string as follows:
<?php
// This creates an associative array from the JSON string
$delete_products = json_decode($_POST['products'], true);
// Use explode to make a comma separated string from the array
// for use in a SQL SELECT query:
$delete_products = explode(',', $delete_products);
Info about json_decode can be found in the PHP Manual.
JSON.stringify is not supported in older browsers. Include JSON-js if you need cross browser support.
I too believe that the desired result can probably be achieved best by collecting the product IDs and then sending a single Ajax call to take care of them all.
But since the OP put the interesting question forward of how to handle multiple Ajax requests and wait for them all to be finished I have looked at the when() method again and it seems to me that the original syntax is still faulty.
According to the jQuery manual when() is a method and therefore requires to be called with one or more argument(s) in parentheses. I have not worked with promises yet and I have not tested anything but I assume that something like the following might bring at least a different result:
$("#delete_products").click(function () {
var promises = [];
$(":checkbox:checked").each(function () {
var pid = $(this).val();
promises.push($.get('delete_product.php', {
pid: pid
}));
});
$.when(promises).done(function () {
location.reload();
});
return false;
});
As I said before, I still have not quite grasped the promises mechanisms/syntax yet ...
In the original version $.when does not have any meaningful context to work on, The apply() method does provide context but only after when has done its (unseccessful) work already.

Backbone fetching data using a callback cursor

How would I use Backbones fetch to deal with callback results that contain a cursor? I'm going to use this simple example of a book that is fetching pages.
var Book = Backbone.Collection.extend({
model: Page,
recursiveFetch: function(cursor) {
this.fetch({
url: 'book/pages',
data: {
cursor: {cursor here};
},
success: function(response) {
if (response.cursor) {
this.recursiveFetch(response.cursor);
}
}
});
}
})
I need to be able to use fetch to keep fetching until the response doesn't contain a cursor. It should keep adding page models, but not replacing and overwriting them. It needs to do something like the example above, though I'm not sure of the best way to implement it.
I think that all you need to do is add in a {remove: false} into your fetch options. Its also worth mentioning that the this context of your success function may not be the collection, so you might want to pass it into the success function as a parameter. The end result would be:
recursiveFetch: function(cursor) {
this.fetch({
remove:false, // prevents removal of existing models
url: 'book/pages',
success: function(collection, response) {
if (response.cursor) {
collection.recursiveFetch(response.cursor);
}
}
});
}
The fix is very simple: add cursor to the parameters only when it's present. In other cases (i.e. the first time) make a normal request with the rest of the parameters.
var CursorCollection = Backbone.Collection.extend({
fetchAll: function(cursor) {
var params = {
// if you have some other request parameters...
};
// if we have a cursor from the previous call, add it to the parameters
if (cursor) { params.cursor = cursor; }
this.fetch({
remove: false,
data: params,
success: function(collection, response) {
if (response.cursor) {
return collection.fetchAll(response.cursor);
}
}
});
}
});
Then the first time you call it collection.fetchAll() and it recurses until it gets a response without a cursor.
Note, that the remove: false parameter is very important to accumulate the results as pointed out by #dcarson.

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