JSP+Struts: Handle session timeout in AJAX calls - ajax

I am making ajax calls from my JS methods to invoke the action class's methods in the following manner:
$.getJSON("treeDemo_!getRootNode?appId=" + applicationId, function () {
}).success(function (e) {
}).error(function (jqXHR, textStatus, errorThrown) {
alert(textStatus);
}).complete(function () {
});
Session configuration in my web.xml looks like this
<session-config>
<session-timeout>1</session-timeout>
</session-config>
Now when the session expires after 1 minute, the ajax call returns error (without calling the action method). The error says
textStatus = parsererror
errorThrown = SyntaxError: JSON.parse: unexpected character
But this looks like a generic error. I want to catch the session timeout exception and redirect the user to the login.jsp page in case this exception occurs.
I even tried handling it by doing this. But it didn't work for me.
Can you please suggest how should I solve it?

There's no " session timeout exception ".
Your Ajax call is expecting to get JSON back, nothing in your app sends JSON back if there's a session timeout. Use a filter or interceptor as in the link, check for session timeout, handle normally if it's a normal request, but if it's an Ajax request send back an HTTP error code.
Handle this error code in your JavaScript callbacks.

Related

POST request doesn't get response from server in chrome but work in postman

I'am making a POST request to spring boot endpoint and wanna get data return from server.With testing my API in Postman,it works good.but when testing it in
chrome,it doesn't even get a response and chrome NETWORK bar even did't have record.
so code is simple,I can't find any problem,RestController
#PostMapping("/signup")
public User signup(#RequestBody ModelUser user){
//fetch data from DTO and craft a user
User userData=user.adapter();
//...code here omit for sake of brevity
return userData;
}
it indeed get data from ajax,when I use logger(slf4j) to debug.
and ajax:
$("#sign-up").submit(function () {
var userInfo={}
userInfo["phone"]=$("#phone").val()
userInfo["password"]=$("#password").val()
$.ajax({
//ajax successful send to spring boot endpoint
type:"POST",
contentType:"application/json",
url:"http://localhost:8080/signup",
data:JSON.stringify(userInfo)
}).then(
function(){
//this doesn't print in console
console.log("Hello Callback is executed")
}
)
})
weird as it is,I never encounter this when I use GET request,since ajax callback is successfully called when I use GET to test a GetMapping endpoint.
oh,with lots of similar questions
AJAX POST request working in POSTMAN but not in Chrome
Angular 4 POST call to php API fails, but GET request work and POST requests work from Postman
POST response arrives in Postman, but not via Ajax?
I don't get any response status code in chrome and completely not involved CORS in question
Have you tried adding a consumes and produces media type of Json in the Java
#PostMapping(path="/signup", consumes=MediaType.APPLICATION_JSON_VALUE, produces=MediaType.APPLICATION_JSON_VALUE)
And explicitly set the Accept header in the javascript
$.ajax({
//ajax successful send to spring boot endpoint
type:"POST",
headers: {Accept : "application/json"},
contentType:"application/json",
url:"http://localhost:8080/signup",
data:JSON.stringify(userInfo)
})
I'am sorry for my poor front end skill,the main reason is that I don't understand Javascript event.
$("#sign-up").submit(function (e) {
//e.preventDefault();
var user={};
user["phone"]="187308";
user["name"]="icywater";
$.ajax({
type:'POST',
contentType:'application/json',
data:JSON.stringify(user),
url:"http://localhost:8080/test"
}).done(function(data){
console.log("Hello Callback is executed");
console.log(data)
});
});
here when I click submit It actually already submit the form and don't wait ajax code to be executed,so I should use e.preventDefault()to suppress default behavior.It's nothing
related about POST or postman ,it is about the form submit default behavior,ahh,Oolong event.
I got it when I found this page

React js AJAX sends sometimes GET instead of POST and getting 304 strange

I've got a problem and I have no idea why it appears. The circumstances of its appearance are very strange for me...
I've got a POST REST service /login. It expects json {"email":email,"password":password}. I am using ajax and everything works correctly... except for the case when email (is in real format) contains '#' sign and some letters before and after( I know it is strange but only in this case such error appears). When I pass email i.e "mum#mum.com" then few things are happening:
I see that browser sends GET request instead of POST and obtains 304 http status
In the browser console I see infomation "The development server has disconnected. Refresh the page if necessary" and page refreshes automatically
The above things happen only when email is in format I described above.When I pass "aaa" or "aaa#" as email everything works correctly(browser sends POST request and I don't get error in console).
I honestly have no idea why this happens... would be extremely grateful for your help and I will answer all your questions concerning this.
PS.
When I use REST web service tool in IntellJ everything always works fine.
handleLogin() {
const input = {
email: this.state.email,
password: this.state.password
};
$.ajax({
url: CONST.USER_SERVICE + "/login",
type: "POST",
data: JSON.stringify(input),
contentType: "jsonp"
})
.fail(function () {
alert("Wrong data");
})
.always(function (arg1, arg2, arg3) {
if (arg3.status === 200) {
alert("ok!");
}
}.bind(this));
}
Try making the ajax request like data: input without stringify. Ajax expects an object.

Using ajax to GET a token from external site returns empty response

I have two sites right now. One that has a token and one that is supposed to allow a user to do stuff with the token.
When I visit the first site that has the token, mySite.local/services/session/token it shows it: OTV4Gu9VQfjIo2ioQ0thajdEJ6nEINoxsLuwgT_6S0w
When I am on the page that is supposed to GET this token, I get an empty response and the error for the ajax function is thrown.
The weird part is that when investigating the issue with firebug, I can see the response for the ajax request is 43B - the same size as the token. So for some reason the page with the token is being hit properly, but the response is not coming through.
Here is a screenshot of the firebug response:
And here is the JQuery with the ajax request:
var nid; //global node id variable
$('html').click(function(){
try {
$.ajax({
url:"http://mySite.local/services/session/token",
type:"get",
dataType:"text",
error:function (jqXHR, textStatus, errorThrown) {
alert('error thrown - ' + errorThrown);
console.log(JSON.stringify(jqXHR));
console.log(JSON.stringify(textStatus));
console.log(JSON.stringify(errorThrown));
},
success: function (token) {
//Do some stuff now that token is received
}
});
}
catch (error) {
alert("page_dashboard - " + error);
}
});
Your running into the Same Origin Policy which essentially states any request done by client side/browser language like Javascript must be on the same port, with the same domain name and the same protocol. In your case http://mysitemobile.local does not equal http://mysite.local so you're request is being blocked. Firebug's way of displaying that is no response with 43 bytes.
There are two ways to work around this, Cross-origin resource sharing (CORS) or JSONP. CORS is a HTTP header that is added to the server you are requesting to and provides a whitelist of acceptable domains that are allowed break the same origin policy. Most recent browsers support this header.
The other option is JSONP, wraps a JSON object into a Javascript function that is called using <script> tags normally. If the other server returns {status: 0} and you have a function called parseStatus() in your code that the remote server would wrap into parseStatus({status:0}); thus calling your function without having to worry about the same origin policy.

Status of ajax or post request

status - contains the status of the request like
("success", "notmodified", "error", "timeout", or "parsererror") /ajax or post
I know what is success,not modified,error meant here but I am unable to find out how to handle this errors. If the call back is success then update my div, if there is any error not modified, error, time out, parse error then let me alert a pop up some error occurred.
What would be the cause for each type of error? I mean the situations where not modified,timeout,error and parseerror occurs.
If it results success, then does it mean my post request has successfully worked?
My local-server xampp never results any error, the status is always success. I guess, since its limited to my system but when I put my website online there exists several issues like traffic on server.
So how do I find out, whether my post request to some sample.php page was successfully sent and else pop out an alert to user if something went wrong?
The error types are a little self-explanatory. They simply provide a string for you to easily handle the different errors.
error callback option is invoked, if the request fails. It receives the jqXHR, a string indicating the error type, and an exception object if applicable. Some built-in errors will provide a string as the exception object: "abort", "timeout", "No Transport".
Source: jQuery.Ajax documentation
Codes Explained:
Error: Any of the HTTP response codes, like the well-know 404 (not found) or other internal server errors.
Notmodified: Compares the cached version of the browser with the server's version. If they are the same, the server responds with a 304
Timeout: Ajax requests are time-limited, so errors can be caught and handled to provide a better user experience. Request timeouts are usually either left at their default or set as a global default using $.ajaxSetup() rather than being overridden for specific requests with the timeout option.
Parse Error: The jQuery data (JSON) cannot be parsed (usually due to syntax errors)
Handling these error codes:
Here is some example of handling the errors
$(function() {
$.ajaxSetup({
error: function(jqXHR, exception) {
if (jqXHR.status === 0) {
alert('Not connect.\n Verify Network.');
} else if (jqXHR.status == 404) {
alert('Requested page not found. [404]');
} else if (jqXHR.status == 500) {
alert('Internal Server Error [500].');
} else if (exception === 'parsererror') {
alert('Requested JSON parse failed.');
} else if (exception === 'timeout') {
alert('Time out error.');
} else if (exception === 'abort') {
alert('Ajax request aborted.');
} else {
alert('Uncaught Error.\n' + jqXHR.responseText);
}
}
});
});
Source: Blog Post - jQuery Error Handling
Success
Response code is between 200-299 or is 304 Not Modified.
Not Modified
Response code is 304. If you employ caching, the browser can tell the server which version it currently has, and the server compares this with its version and if there has been no change, it can send a 304 Not Modified response, to indicate to the client that their version is up to date. In jQuery ajax, a 304 Not Modified response will still fire the success handler.
Error
Response code is between 400-599. This could be for example 404 not found, 403 forbidden, 500 internal server error etc.
Parse Error
This is a jQuery internal, not actually a HTTP response. This will happen if jQuery is trying to parse JSON or XML that is not in the valid format or has syntax errors.
Timeout
Again, this isn't a HTTP response. The ajax request has a timeout which if is exceeded before the server responds, will abort the request.
If you control the server side, in your example a PHP script, and you never change the response code using header() then your ajax will always receive 200 OK responses unless there is an unhandled exception in the PHP which will trigger a 500 internal server error.
It is acceptable to always send 200 OK response codes. For example, if the server outputs a JSON object which contains its own success/error flag then any errors can be handled by looking at the flag.
As far as I know
not modified: Server sends a Not Modified(304) response status
timeout: the server has not responded within the time period specified by the timeout property
error: server response with a error status like 4xx or 5xx
parseerror: there was an client side error when processing server response like an invalid json format/xml format

ajax json request , always returning error

Hello i've got a problem with ajax json request. Im always getting an error, even if the requests are succeeded. At the moment i have this code:
function sumbitLoginForm(user, pass) {
if (user.trim() == '' || pass.trim() == '') {
alert("You must enter username and password!");
} else {
$.ajax({
type : 'POST',
url : 'https://url.php',
dataType : 'json',
data : {
userlogin : user,
userpass : pass
},
contentType: "application/json;",
success : function(data) {
$("#images").html("uspeshno");
},
error : function(data) {
$("#images").html("greshka");
}
});
}
return false;
}
$(document).ready(function() {
clearPageInputs();
$("#submitButton").click(function() {
sumbitLoginForm($("#username").val(), $("#password").val());
});
});
Im always getting an error , no matter what username and password i type . But the status of request is changing , if i type correct user and pass i get status 302 Moved temporarly , but when i type wrong user or pass i get status 200 OK . What am i doing wrong ?
PRG Pattern and Ajax
It looks like your server returns a HTTP 200 status code when the userid and password will not validate. This is proper behavior, as HTTP error codes not meant for application errors, but for HTTP protocol errors.
When the userid and password are matched succesfully, you are redirected to another page. This is also normal behavior, e.g. to prevent other people to re-use your login credentials using the back key.
This is called the Post/Redirect/Get pattern.
See: http://en.wikipedia.org/wiki/Post/Redirect/Get
The problem is that the PRG pattern does not play nice with Ajax applications. The redirect should be handled by the browser. It is therefore transparent for the jQuery code. The Ajax html response will be the page that is mentioned in the Location header of the 302. Your Ajax application will not be able to see that it is being redirected. So your are stuck.
In one of my projects I solved this on the server side. If I detected an Ajax call, I would not send a redirect but a normal 200 response. This only works if you have access to the server code.
If you cannot change the redirect for your Ajax calls, then you can parse the response headers or the html to see if you were being redirected and act accordingly. Probably the login will set a cookie, so you might try and look for the presence of that cookie.

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