Getting randomly 302 on Ajax Request using Cakephp - php

Question

I have a system that is developed in cakephp. There I have a customer profile page that shows me different information like e.g notes, phone calls, attached files. The basic information are fetched via Cakephp other information like the above are fetched via Ajax Requests and shown as soon as the data is fetched.
Unfortunately, sometimes and very randomly (between every 10th and 100th request), I get a 302 of an Ajax Request and will logged out and redirected to the login formular (which is the basic redirection path if you are not logged in).
You can see an example from the Google network page in the pictures. The picture shows that the calls getPhonecalls, getNotes and getOutboxBook are fine, but the getFilesBackoffice call returns a 302 and afterwards triggers the login page. Also the getAllowedFiles afterwards is called fine. It is important to say, that it is always a different Ajax Call and therefore I assume, any Ajax call can cause the problem. A successful Ajax call returns a JSON.
I tried to reconstruct the problem, but it for me it seems to be mission impossible to reconstruct it. I also tried to debug that problem, and tried to check what the error might be... but no chance. Also the php Error Log gives no information.
So next, I downloaded the full "Network Information" from Chrome with "save as HAR with content". Looking at that file, it seems, like the Cookie (with its Session) is deleted.
Here is an excerpt of the HAR with the status 302:
"response": {
"status": 302,
"statusText": "Found",
"httpVersion": "HTTP/1.1",
"headers": [
{
"name": "Date",
"value": "Thu, 20 Dec 2018 09:47:27 GMT"
},
{
"name": "Server",
"value": "Apache/2.4.12 (Unix) OpenSSL/1.0.1p PHP/5.6.11 mod_perl/2.0.8-dev Perl/v5.16.3"
},
{
"name": "X-Powered-By",
"value": "PHP/5.6.11"
},
{
"name": "Content-Type",
"value": "text/html; charset=UTF-8"
},
{
"name": "Location",
"value": "http://localhost/stressfrei/HRMAppMig/Users/login"
},
{
"name": "Connection",
"value": "Keep-Alive"
},
{
"name": "Set-Cookie",
"value": "CAKEPHP=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; Max-Age=0; path=/"
},
{
"name": "Set-Cookie",
"value": "CAKEPHP=2e5gke00430jdkd8ll5jl3ini3; expires=Fri, 21-Dec-2018 09:47:28 GMT; Max-Age=86400; path=/stressfrei/HRMAppMig/; HttpOnly"
},
{
"name": "Set-Cookie",
"value": "CAKEPHP=o3udvthe0rkmjt5djrjvnt3392; expires=Fri, 21-Dec-2018 09:47:28 GMT; Max-Age=86400; path=/stressfrei/HRMAppMig/; HttpOnly"
},
{
"name": "Keep-Alive",
"value": "timeout=5, max=95"
},
{
"name": "Content-Length",
"value": "0"
}
],
"cookies": [
{
"name": "CAKEPHP",
"value": "deleted",
"path": "/",
"expires": "2018-12-20T09:47:27.127Z",
"httpOnly": false,
"secure": false
},
{
"name": "CAKEPHP",
"value": "2e5gke00430jdkd8ll5jl3ini3",
"path": "/stressfrei/HRMAppMig/",
"expires": "2018-12-21T09:47:27.127Z",
"httpOnly": true,
"secure": false
},
{
"name": "CAKEPHP",
"value": "o3udvthe0rkmjt5djrjvnt3392",
"path": "/stressfrei/HRMAppMig/",
"expires": "2018-12-21T09:47:27.127Z",
"httpOnly": true,
"secure": false
}
],
"content": {
"size": 0,
"mimeType": "text/html",
"compression": 0
},
"redirectURL": "http://localhost/stressfrei/HRMAppMig/Users/login",
"headersSize": 717,
"bodySize": 0,
"_transferSize": 717
}
Here is an excerpt of the 200
"response": {
"status": 200,
"statusText": "OK",
"httpVersion": "HTTP/1.1",
"headers": [
{
"name": "Date",
"value": "Thu, 20 Dec 2018 09:52:39 GMT"
},
{
"name": "Server",
"value": "Apache/2.4.12 (Unix) OpenSSL/1.0.1p PHP/5.6.11 mod_perl/2.0.8-dev Perl/v5.16.3"
},
{
"name": "Connection",
"value": "Keep-Alive"
},
{
"name": "X-Powered-By",
"value": "PHP/5.6.11"
},
{
"name": "Content-Length",
"value": "2239"
},
{
"name": "Keep-Alive",
"value": "timeout=5, max=97"
},
{
"name": "Content-Type",
"value": "text/html; charset=UTF-8"
}
],
"cookies": [],
"content": {
"size": 2239,
"mimeType": "text/html",
"compression": 0,
"text": "HERE IS SOME JSON"
},
"redirectURL": "",
"headersSize": 287,
"bodySize": 2239,
"_transferSize": 2526
},
Here is an example of my ajax call.
this.ajaxCall = function(offset) {
var class_prefixTemp = this.class_prefix;
var self = this;
$.ajax({
//ajax options
type: "POST",
url: self.ajaxUrl,
data: {"offset": offset, "elements_per_page": this.elements_per_page, "conditions": this.conditions, "recursive": this.recursive},
dataType: 'json',
//handling return
success: function(result) {
//print out the data from the result
}
});
}
Do you have any idea, how I can find out what my problem is to finally solve it?

Answer 1

Finally the problem was the setting of the Session in the core.php.
In the core.php of CakePhp it is possible to set for the session autoRegenrate to true. This caused the problem that a new session is generated when a new page is loaded. This can cause that long Ajax Requests are working with a wrong session id because it was renewed and therefore the session id didn't fit anymore. This caused a logout.
Finally I had to disable the renewing of the session by setting autoRegenerate to false!