Ok, in my application, I have extra information sent with the data, which the Sencha docs define as metadata. If there was an error retrieving data, say for a grid, i want the server to be able to tell the client to inform the user that it was unable to complete the request. But I want to do this for EVERYTHING, and not have to redefine a callback to check on every store in my application. Is there a way to do this? Or am I trying to do this all wrong? Also, how can I go about utilizing the JSON Reader without using stores or models? That way I can do the same thing, intrepting server instructions, without having to redefine it in an Ext.Ajax success callback?
For a store, you can
Ext.define('myNewCustomStore',{
constructor:function(config){
this.callParent(arguments);
this.on('load',function(store,records,e){myCustomMetaDataHandler()});
}
});
And then instead of using
Ext.create('Ext.data.Store' or Ext.define('myStore',{extends:Ext.data.Store
You create / extend myNewCustomStore
And Json without models?
Ext.Ajax.request({
url: 'page.php',
params: {
id: 1
},
success: function(response){
var text = response.responseText;
var json = Ext.JSON.decode(text);
//now do stuff
}
});
Related
I know this is a question that's been asked to death, but I still struggle with how to use callbacks. I just want to return a value from the ajax's request.done outcome. I tried to follow Felix Kling's very informative answer on using callbacks with AJAX, but can't get my code to work.
My code below submits a form with user input data to the database. I would like it to retrieve the property employeeId. I am able to alert the correct value inside the submit function, but I would like to use this value in other functions. From reading up on asynchronous functions,i think this is because submit function exits before returning the value. I would really appreciate some guidance on using callbacks to return values.
I tried to only include the code pertaining to my issue
$('#employeeForm').submit(function(event,callback){
var values = $(this).serialize(); //gather form data
var result = foo(); //callback implementation from Felix Kling's SO answer
foo(function(result){
var request = $.ajax({
url: "game.php",
type:"post",
dataType:"json",
data: values
});
function foo(response.employeeId){ //I am trying to return value response.employeeIda in the success situation
request.done(function (response,textStatus,jqXHR){
document.getElementById("submitEmployeeInfo").innerHTML=response.employeeId;
var employeeId = response.employeeId;
}
});
})
I'm working in an ASP.NET MVC4 application, and as such, all array data sent to the server over ajax must be sent using the traditional option. (no [] for POST variables).
The problem is, I also have a filter set-up which requires an AntiforgeryToken to be sent with each ajax POST.
I have fixed this using an ajaxPrefilter like this:
$.ajaxPrefilter(function (options, originalOptions) {
if (options.type.toUpperCase() == "POST") {
options.data = $.param($.extend(originalOptions.data, { __RequestVerificationToken: "antiForgeryToken" }));
}
});
This works great, and adds the __RequestVerificationToken to all POSTs.
However, it also causes my data not to be parametrized according to the traditional flag.
Does anybody know how I can modify my prefilter to account for this?
Example can be found here:
http://jsbin.com/IxoKIKA/2/edit
You forgot to pass the traditional argument to $.param(). You should write:
options.data = $.param($.extend(originalOptions.data, {
__RequestVerificationToken: "antiForgeryToken"
}), true);
I have created a Spring MVC web app.
The app makes a few calls to the controller. These calls are close/open/end game.
I make these calls using Ajax, so I can handle a response on the top of the page.
ajaxPost = function (url, action, id, onSuccess, onError) {
$.ajax({
type: "POST",
url: url + "?" + action + "=" + id,
success: function(response) {
if(onSuccess !== null) {
onSuccess(response);
}
},
error: function(e) {
if(onError !== null) {
onError(e);
}
}
});
};
The question I have is that I'm using 'POST' for the Ajax request, is that correct, or should it be 'PUT'?
My controller has a default URL, and I'm using the param attribute to decide which method to call, as I have many buttons on the page.
#RequestMapping(params = "open", method = RequestMethod.POST)
#RequestMapping(params = "close", method = RequestMethod.POST)
It doesn't sit well with me that I'm using 'POST' for these calls. Maybe it should be 'PUT'...
Any suggestions? Does it matter?
It depends on what your request should do. So there's no general rule that you should use one over the other, they have different use cases.
POST for creating a record.
PUT for updating an existing record (or putting a record at a specified location/id).
See this wikipedia article for the definitions.
One thing to note is that PUT should be idempotent, doing the same PUT request multiple times should ideally produce the same result as doing a single PUT request. However, POST is not idempotent, so doing several POST requests should (or will) create multiple new records.
So after having read this you should check what your method does, and select the corresponding request method.
Both PUT and POST may create a new record; PUT may also update/change an existing record.
The difference between POST and PUT is that PUT is expected to address the record with it's ID, so that the server knows what ID to use when creating (or updating) the record, while POST expects the server to generate an ID for the record and return it to the client after the record has been created.
Thus, a POST is addressed to the resource as a collection: POST /resource, while PUT is addressed to a single item in the collection: PUT /resource/1
Use POST. Always use POST, unless you're absolutely rock-solid certain that PUT is properly supported by your hosting system.
I have spent days working on this and really feel dumb. I have been working on demos and samples that never work when I try it locally with my own url. I have a web service that returns results back in json and am just basically trying to call it using dojo and for now just view the results. I took the search google example and just substituted the url and parameters. Now perhaps I still do not understand the basics so:
- io.script.get vs xhrGet
if using cross domain urls it is better to use io.script.get? correct?
now what is the callbackparam? is this the function that is being called in the webservice?
My webservice url is as follows:
http://xxx.xxx.x.xxx/WcfServices/WcfInstance/Service1.svc/RetrievData?query=Word
when I use the following code I get nothing displayed.
function searchGoogle() {
// Look up the node we'll stick the text under.
var targetNode = dojo.byId("rules");
// The parameters to pass to xhrGet, the url, how to handle it, and the callbacks.
var jsonpArgs = {
url: "http://xxx.xxx.x.xxx/WcfServices/WcfInstance/Service1.svc/RetrieveData?",
callbackParamName: "callback",
content: {
query:"dojowords"
},
load: function (data) {
// Set the data from the search into the viewbox in nicely formatted JSON
targetNode.innerHTML = "<pre>" + dojo.toJson(data, true) + "</pre>";
},
error: function (error) {
targetNode.innerHTML = "An unexpected error occurred: " + error;
}
};
dojo.io.script.get(jsonpArgs);
}
dojo.ready(searchGoogle);
Here is what the webservice results look like:
"{\"rules\":[{\"value\":\"AllState\"},
{\"value\":\"Cidade de Goa beach\"},{\"value\":\"Euro 2012\"},
{\"value\":\"Euro2012\"},{\"value\":\"European&Championship\"},
{\"value\":\"Holiday Inn Resort\"},
{\"value\":\"Holiday Inn Resort goa\"},
{\"value\":\"Hotel Goa\"},{\"value\":\"Hyatt Goa\"},{\"value\":\"I buy car\"},...
If I get this part correct then at least I know I have data which I can then bind to a datagrid or chart.
dojo.io.script.get is for all cross domain requests.
xhrGet is for same domain requests.
dojo.io.script.get uses a hack which expects jsonp or json padding as a result. This wraps the response of the web service call inside a self executing function. The function name is the callback name. This has to be wired before the call so it knows what already defined function to call when a response comes back.
All of the arguments are well documented http://dojotoolkit.org/reference-guide/1.7/dojo/io/script.html
My guess as to why your service isn't working is because you wrote the web service and it does not handle jsonp. It is not wrapping its response inside the callbackparamname.
your results should look something like
callback({json});
where callback is whatever you set up in callbackParamName
you can also remove the ? from your url, that should be handled for you.
I posted this earlier on wordpress.stackexchange.com. However, never got a reply. Hence, trying my luck here.
I am hereby providing a detailed description of what I need and what I have done for this issue of mine. I am open to any workable solution around what I have done or maybe new suggestions.
I need to make use of user data that is retrieved using the following:
$user_data = get_user_by('login', get_query_var('user_login'));
The above code uses the username passed as a query_var in the URL. All works until here.
I make use of the above code in several Ajax callbacks (handled by admin-ajax.php) on single page load. Since, the site is targeted as a high volume site. All these Ajax requests lead to several database query for the same data. So the obvious idea to save some database queries is to pass the data to a global variable like below:
$_GLOBALS['user_data'] = get_user_by('login', get_query_var('user_login'));
And then use the same in the Ajax callbacks. Here's problem. None of the Ajax callback functions see the global $user_data variable. Before you ask, yes I have declared the global inside callback as well.
So, the obvious answer would be: why not use wp_localize_script and pass the $user_data to the Ajax callback via javascript like bellow:
In PHP:
wp_localize_script('jquery', 'ajaxVars', array( 'ajaxurl' => admin_url('admin-ajax.php'), 'user_data' => $user_data));
In Javascript:
jQuery.ajax({
url: ajaxVars.ajaxurl,
type:'POST',
async: false,
cache: false,
timeout: 10000,
data: 'action=ajax_callback&user_data=' + ajaxVars.user_data,
success: function(value) {
alert(value);
},
error: function() {
alert(error);
}
});
However, this poses two questions:
Can an object that get_user_by('login', get_query_var('user_login')); returns be handled by wp_localize_script()?
If the answer to above question is yes, then would it not pose a security threat since the object would contain sensitive user information?
To overcome the global variable being not available to Ajax callbacks, I declared it directly in functions.php (without wrapping it inside a function). However, get_query_var('user_login') does not return any data when used directly inside functions.php making this futile exercise (You have to add it inside a function and call it via an action).
So, the question remains: how do I stop making $user_data = get_user_by('login', get_query_var('user_login')); calls for every Ajax request? Or is there a way I could get get_query_var('user_login') to work inside functions.php directly (without wrapping it inside a function) or a workaround?
Or maybe some completely new out of the box thinking?
All these Ajax requests lead to several database query for the same
data. So the obvious idea to save some database queries is to pass the
data to a global variable like below:
$_GLOBALS['user_data'] = get_user_by('login', get_query_var('user_login'));
And then use the same in the Ajax callbacks.
Each request that your application receives, AJAX or otherwise, lives completely in isolation: the code handling the requests does not share any state between them (besides whatever is persisted to a database). A global (or constant, or property, or variable, or anything) you define in one request will never be available to subsequent requests unless you store it somewhere.
There are a number of approaches to reducing the number of queries these requests are creating. One would be to retrieve the required user data on page load and pass it to subsequent requests. E.g.:
var user = 'someUser';
$.get('user-data.php?user=' + user, function(user_data) {
$.ajax('some-endpoint.php', {
type: 'POST',
data: { user: user_data },
success: function() { /* ... */ }
});
$.ajax('some-other-endpoint.php', {
type: 'POST',
data: { user: user_data },
success: function() { /* ... */ }
});
});
Alternatively, if it's the currently logged in user you're working with you can write their details to a JavaScript object on initial page load for use later.
var userData = <?php get_currentuserinfo(); echo json_encode($current_user); ?>;
Another option would be to ensure that the get_user_by results were being cached, either by Wordpress, MySQL or some other caching layer. That way it doesn't particularly matter how many times your code calls the method.
In general if lots of your endpoints are sharing functionality, you could probably stand to refactor some of that code.