I have two functions that makes Ajax calls: getData and getMoreData. getMoreData requires a url variable that is dependent on the url variable getData. This questions continues from: String append from <select> to form new variable.
By appending an item obtained from the received from getData onto a base URL, I create a new variable (Let's call this NewDimensionURL) that I use for getMoreData url. However, NewDimensionURL will show error because the original list (from getData) has yet to be populated and will append nothing onto the base URL.
An idea that I have is to set NewDimensionalURL once getData finishes populating the combobox, so that getMoreData can run after.
JavaScript
var GetDimensions = 'SomeURL1';
//--Combines URL of GetDimensionValues with #dimensionName (the select ID)
var UrlBase = "Required URL of getMoreData";
var getElement = document.getElementById("dimensionName");
var GetDimensionValues = UrlBase + getElement.options[getElement.selectedIndex].text;
function handleResults(responseObj) {
$("#dimensionName").html(responseObj.DimensionListItem.map(function(item) {
return $('<option>').text(item.dimensionDisplayName)[0];
}));
}
function handleMoreResults (responseObj) {
$("#dimensionId").html(responseObj.DimensionValueListItem.map(function(item) {
return $('<option>').text(item.dimensionValueDisplayName)[0];
}));
}
function getData() {
debugger;
jQuery.ajax({
url: GetDimensions,
type: "GET",
dataType: "json",
async: false,
success: function (data) {
object = data;
handleResults(data);
}
});
}
function getMoreData() {
debugger;
jQuery.ajax({
url: GetDimensionValues,
type: "GET",
dataType: "json",
async: false,
success: function (data) {
object = data;
handleMoreResults (data);
}
});
}
Answered
Reordered as:
var GetDimensionValues;
function handleResults(responseObj) {
$("#dimensionName").html(responseObj.DimensionListItem.map(function(item) {
return $('<option>').text(item.dimensionDisplayName)[0];
}));
GetDimensionValues = UrlBase + getElement.options[getElement.selectedIndex].text;
}
Created onchange function Repopulate() for getMoreData() to parse and for handleMoreResults() to populate.
I'm guessing you just do getData(); getMoreData() back to back? If so, then you're running getmoreData BEFORE getData has ever gotten a response back from the server.
You'll have to chain the functions, so that getMoreData only gets executed when getData gets a response. e.g.
$.ajax($url, {
success: function(data) {
getMoreData(); // call this when the original ajax call gets a response.
}
});
Without seeing your code it's hard to say if this is the right solution, but you should try chaining the functions:
$.ajax({url: yourUrl}).then(function (data) {
// deal with the response, do another ajax call here
}).then(function () {
// or do something here
});
Related
I am working on the jquery to call a function to get the return value that I want to store for the variable email_number when I refresh on a page.
When I try this:
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
return email_number;
}
I will get the return value as 6 as only when I use alert(email_number) after the email_number = data;, but I am unable to get the value outside of a function.
Here is the full code:
var email_number = '';
// check if page refreshed or reloaded
if (performance.navigation.type == 1) {
var hash = window.location.hash;
var mailfolder = hash.split('/')[0].replace('#', '');
var emailid = 'SUJmaWg4RTFRQkViS1RlUzV3K1NPdz09';
get_emailno(emailid, mailfolder);
}
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
return email_number;
}
However, I have been researching and it stated that I would need to use callback via ajax but I have got no idea how to do this.
I have tried this and I still don't get a return value outside of the get_emailno function.
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
async: true,
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
I am getting frustrated as I am unable to find the solution so I need your help with this. What I am trying to do is I want to call on a get_emailno function to get the return value to store in the email_number variable.
Can you please show me an example how I could use a callback function on ajax to get the return value where I can be able to store the value in the email_number variable?
Thank you.
From the jquery documentation, the $.ajax() method returns a jqXHR object (this reads fully as jquery XMLHttpRequest object).
When you return data from the server in another function like this
function get_emailno(emailid, mailfolder) {
$.ajax({
// ajax settings
});
return email_number;
}
Note that $.ajax ({...}) call is asynchronous. Hence, the code within it doesn't necessarily execute before the last return statement. In other words, the $.ajax () call is deferred to execute at some time in the future, while the return statement executes immediately.
Consequently, jquery specifies that you handle (or respond to) the execution of ajax requests using callbacks and not return statements.
There are two ways you can define callbacks.
1. Define them within the jquery ajax request settings like this:
$.ajax({
// other ajax settings
success: function(data) {},
error: function() {},
complete: function() {},
});
2. Or chain the callbacks to the returned jqXHR object like this:
$.ajax({
// other ajax settings
}).done(function(data) {}).fail(function() {}).always(function() {});
The two methods are equivalent. success: is equivalent to done(), error: is equivalent to fail() and complete: is equivalent to always().
On when it is appropriate to use which function: use success: to handle the case where the returned data is what you expect; use error: if something went wrong during the request and finally use complete: when the request is finished (regardless of whether it was successful or not).
With this knowledge, you can better write your code to catch the data returned from the server at the right time.
var email_number = '';
// check if page refreshed or reloaded
if (performance.navigation.type == 1) {
var hash = window.location.hash;
var mailfolder = hash.split('/')[0].replace('#', '');
var emailid = 'SUJmaWg4RTFRQkViS1RlUzV3K1NPdz09';
get_emailno(emailid, mailfolder);
}
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
// sufficient to get returned data
email_number = data;
// use email_number here
alert(email_number); // alert it
console.log(email_number); // or log it
$('body').html(email_number); // or append to DOM
}
});
}
I'm need some help figuring out how to get back data from the second ajax call, not the first.
I have this method that calls my ajax calls
var projectWithIssues = getProjects().done(function(result) {
....
}
When I look at the results from this, I get back the results on my first ajax call(getEnt_PodType().done()). I want to get the results from the second ajax call within getProjects(). I understand the reason I'm getting the first results back is because I have the return on the first ajax call. However, If I don't have a return there. I get a undefined on the line above. How can I return the data from the second call?
function getEnt_PodType() {
var ent_PodType;
var oDataUrl = //URL to my data;
return $.ajax({
url: oDataUrl,
type: "GET",
async: true,
beforeSend: function (xhr) {
xhr.setRequestHeader("ACCEPT", accept);
},
success: function (xhr, textStatus) {
}
});
}
function getProjects() {
return getEnt_PodType().done(function (res) {
var ent_PodType;
if (res.d.results != undefined) {
ent_PodType = res.d.results[0].Ent_PodType;
}
console.log("The ent pod type value is " + ent_PodType);
var QUERY_FILTER =
"$filter=Ent_PodType eq '" + ent_PodType + "'";
var url = restUrl + QUERY_FILTER;
// I want to return the results from this ajax call
$.ajax({
url: url,
type: "GET",
async: true,
beforeSend: function (xhr) {
xhr.setRequestHeader("ACCEPT", accept);
},
success: function (xhr, textStatus) {
//projects = parseODataResultTest(xhr);
//return projects;
}
});
});
}
Thanks in advance!
Try utilizing pattern found at deferred.then
// first request
var request = $.ajax(url1),
chained = request.then(function( data ) {
console.log(data) // first request response data
// return second request
return $.ajax(url2)
});
chained.then(function( data ) {
console.log(data) // second request response data
// data retrieved from url2 as provided by the first request
});
var request = $.ajax("https://gist.githubusercontent.com/guest271314/23e61e522a14d45a35e1/raw/62775b7420f8df6b3d83244270d26495e40a1e9d/ticker.json"), // first request , `html` document
chained = request.then(function( data ) {
console.log(data) // `["abc"]`
// return `data` from second request
return $.ajax("https://gist.githubusercontent.com/guest271314/6a76aa9d2921350c9d53/raw/49fbc054731540fa68b565e398d3574fde7366e9/abc.txt")
});
chained.then(function( data ) {
console.log(data) // `abc123`
// data retrieved from url2 as provided by the first request
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Use .then instead of .done, it allows better chaining of functions.
Break your code apart so that the two AJAX calls are in separate functions, and have both those functions return the result of their $.ajax call. You can then use:
func1().then(func2).then(...);
func2 will be passed the result of the first AJAX call, and then the result of that will be passed to whatever function is in the final then.
In your case you can also put the call to parseODataResultTest in the chain and then the final function will (eventually) be called with the required data, i.e.:
getEnt_PodType().then(getProjects).then(parseODataResultTest).then(function(projects) {
// use projects here, and _only_ here because it won't
// be in scope or defined anywhere else
...
});
I have getGeneral function that calls ajax GET. When ajax recieves data (json), it creates KO model from given json and returns created KO.
When Knockout model is created and values are assigned, knockout applybindings should be called. Here is my code:
Defines GeneralModel and some related functions (inside "GeneralModel.js"):
var GeneralModel = function() {
//for now it is empty as data ar binded automatically from json
// CountryName is one of the properties that is returned with json
}
function getGeneral(pid) {
$.ajax({
url: "/api/general",
contentType: "text/json",
dataType: "json",
type: "GET",
data: { id: pid},
success: function (item) {
var p = new GeneralModel();
p = ko.mapping.fromJS(item);
return p;
},
error: function (data) {
}
});
}
This is called from another file (GeneralTabl.html), it should call get function and applyBindings to update UI:
var PortfolioGeneral = getGeneral("#Model.Id");
ko.applyBindings(PortfolioGeneral, document.getElementById("pv-portfolio-general-tab"));
However, in this scenario I am getting error (CountryName is not defined). This is because applyBindings happens before ajax returns data, so I am doing applyBindings to empty model with undefined properties.
Mapping from Json to Model happens here and is assignes values:
p = ko.mapping.fromJS(item);
I can also fill in GeneralModel with all fields, but it is not necessary (I guess):
var GeneralModel = function() {
CountryName = ko.observable();
...
}
It will still give an error "CountryName is not defined".
What is the solution?
1) Can I somehow move getGeneral inside GeneralModel, so get data would be part of GeneralModel initialization?
or
2) Maybe I should somehow do "wait for ajax results" and only then applyBindings?
or
I believe there are other options, I am just not so familiar with KO and pure JS.
Note: I fully understand that this is because Ajax is Async call, so the question is how to restructure this code taking into account that I have two seperate files and I need to call getGeneral from outside and it should return some variable.
Try using the returned promise interface:
function getGeneral(pid) {
return $.ajax({
url: "/api/general",
contentType: "text/json",
dataType: "json",
type: "GET",
data: {
id: pid
}
});
}
getGeneral("#Model.Id").done(function (item) {
var p = new GeneralModel();
p = ko.mapping.fromJS(item);
ko.applyBindings(p, document.getElementById("pv-portfolio-general-tab"));
}).fail(function () {
//handle error here
});
Alright... at 2am, this is where I draw the line. Help... before my laptop ends up going out the window. :)
I've tried using setTimer, callbacks, and everything else I can think of (along with a few other Stackoverflow hints of course). I've stripped out everything so I'm leaving just the base code.
What I'm looking to do is call parseRow() and before it saves the record at the end, I need to grab the associated Category (via AJAX); however, it blows right past it so category is always "undefined".
function parseRow(row){
var rowArray = row.trim().split(",");
var date = rowArray[0];
var checknum = rowArray[1];
var payee = rowArray[2];
var memo = rowArray[3];
var amount = rowArray[4];
//ERROR: blows right past this one and sets the category variable BEFORE ajax returns
var category = autoSelectCategory(payee);
saveRecord(date, checkNum, payee, memo, category, payment, deposit);
}
function autoSelectCategory(payee) {
var data;
$.ajax({
async: false,
url: "autoselectcategory",
dataType: "json",
data: {
string: payee
},
success: function (returnedData) {
data = returnedData;
}
});
return data;
}
AJAX stands for asynchronous. That means that in your original code, saveRecord will be executed before the client will receive the response from the server (and, depending on the $.ajax implementation, it might be before the client will send the request to the server).
Additionally, you seem to misunderstand how functions work in JS. var category = autoSelectCategory(payee); will set the category to the return value of autoSelectCategory; but the autoSelectCategory function in your code returns nothing.
From the other side, the data return value of your anonymous function could only be used by $.ajax function (and $.ajax likely ignores the success parameter return value).
Here is the code that should work:
function parseRow(row){
var rowArray = row.trim().split(",");
var date = rowArray[0];
var checknum = rowArray[1];
var payee = rowArray[2];
var memo = rowArray[3];
var amount = rowArray[4];
autoSelectCategory(payee, function (category) {
saveRecord(date, checkNum, payee, memo, category, payment, deposit);
});
}
function autoSelectCategory(payee, callback) {
$.ajax({
async: false,
url: "autoselectcategory",
dataType: "json",
data: {
string: payee
},
success: callback
});
}
Do not use async: false option. It's a pure evil (blocks all scripts in browser and even other tabs!) and it's deprecated since jQuery 1.8. You should use callbacks as it was always meant to be.
function parseRow(row) {
/* the other code */
autoSelectCategory(payee, function() {
saveRecord(date, checkNum, payee, memo, category, payment, deposit);
});
}
function autoSelectCategory(payee, callback) { // <---- note the additional arg
$.ajax({
url: "autoselectcategory",
dataType: "json",
data: {
string: payee
},
success: function(res) {
/* the other code */
callback();
}
});
}
Got some basic problem again.
I need to modify a function that previously returned a in code written object.
Im now trying to get the object from json through $.getJSON
function getEventData() {
var result = '';
$.getJSON("ajax.php?cmd=getbydate&fromdate=&todate=", function(data) {
result = data;
});
return result;
}
Problem is that result isn't set in the callback function for obvious reasons.
Do you guys have a solution for this?
Edit:
Ok i got an answer that was removed.
I just had to change it abit..
This is the answer that works:
function getEventData() {
var result = '';
url = "ajax.php?cmd=getbydate&fromdate=&todate=";
$.ajax({
url: url,
async: false,
dataType: 'json',
success: function(data) {
result = data;
}
});
return result;
}
You should program your application in an asynchronous way, which means, that you should use callback functions for you application flow, too, or continue in the getJson callback function. You can also make the request synchronously which should then be able to return the value (or at least assign it and block the function till the callback is completed), but this is not recommended at all:
function getEventData() {
var result = '';
result = $.ajax({
url: "ajax.php?cmd=getbydate&fromdate=&todate=",
async: false,
dataType: "json",
data: data,
success: function(data) {
return data;
}
});
return result;
}
Are you sure that the server returns valid json? It will be better to validate it using a tool like jsonlint. Also make sure that application/json is used as content type for the response.