I am in a bit of a pickle right now. I am building a web page that will get data from a CGI backend. I have no control over the CGI backend, nor the server (so no mod_headers or mod_expires). Also, because of the parameters to the script, I cannot append a unique value (like '&089u0af0d98) to each request. The requests are AJAX using the XmlHttpRequest object. I have tried to set the 'If-Modified-Since' and 'Cache-Control' request headers unsuccessfully. Does anybody have any other ideas for how I can prevent the AJAX response from being cached by the browser?
You can send random parameters using POST, while sending the important vars using GET if you need to.
If you have problems with IE, I know that sending something with POST makes it to stop caching server responses
I use this javascript function ( which in turn uses jquery.ajax function )
the cache: false would do the trick.
This works perfectly for me , may be you can give it a try
function ajax_call(urlString)
{
ret_val="";
$.ajax
(
{
type: "GET",
url: urlString,
async:false,
cache:false,
dataType: 'html',
success: function(msg)
{
ret_val=msg;
},
error:function (xhr, textStatus, thrownError)
{
ret_val=xhr.readyState;
alert("status=" +xhr.status);
}
}
);
return ret_val;
}
I used $.ajaxSetup({ cache: false }); somewhere in my base html-page (default.aspx) in a non-frequent web-system and it worked fine. No pain-in-the-neck caching problems anymore.
I ran into this today, and found that if you want to keep to using get, you can add a hidden form element to the page and have JS set it's value to the current timestamp before submitting the query to ajax.
I add a form element something like this:
<input type="hidden" name="ie_sucks" id="ie_sucks", value="1" />
Then, in the function to submit the form via AJAX I set this hidden input to the current timestamp with something like this:
$('#ie_sucks').val(new Date().getTime());
The above code uses JQuery, so in pure JS it would be something like:
document.getElementById('ie_sucks').value = new Date().getTime();
This is not a pretty solution, but it does work.
I know jQuery's .ajax() call has a parameter called 'cache' which, if set to false, will force requested pages not to be cached by the browser. It's probably worth checking the jQuery source to see how they do it.
(I'm checking it now and will update if I find anything, but posting this answer early in case you or anybody else has better luck finding it.)
Related
I was searching for a similar issue for a while now, but none of the solutions worked for me (and I couldn't find exactly the same issue).
First of all, the website I'm working on is running on Zend Framework. I suspect that it has something to do with the issue.
I want to make a pretty basic AJAX functionality, but for some reason my response always equals the html of the current page. I don't need any of Zend's functionality, the functions I need to implement could (and I'd prefer them to) work separately from the framework.
For testing purposes I made it as simple as I could and yet I fail to find the error. I have a page "test.php" which only has a link that triggers the ajax call. Here's how this call looks:
$('.quiz-link').click(function(e){
e.preventDefault();
$.ajax({
URL: "/quiz_api.php",
type: "POST",
cache: false,
data: {
'test': 'test'
},
success: function(resp){
console.log(resp);
},
error: function(resp){
console.log("Error: " + reps);
}
});
});
And this quiz_api.php is just:
<?php
echo "This is a test";
?>
When I click on the link I get the entire HTML of the current page. "This is a test" can't be found there. I'm also getting an error: "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/."
I reckon it has to do with the JS files that are included into this HTML response, but I've also tried setting "async: true" and it didn't help.
I would like to avoid using Zend Framework functions for this task, because I'm not well familiar with it and even making a simple controller sounds rather painful. Instead I want to find out what's causing such behavior and see if it can be changed.
PS: I've also tried moving quiz_api.php to another domain, but it didn't change anything.
I know that it might be an older code but it works, simple and very adaptable. Here's what I came up with. Hope it works for you.
//Here is the html
Link Test
<div id="test_div"></div>
function test(){
// Create our XMLHttpRequest object
var hr = new XMLHttpRequest();
// This is the php file link
var url = "quiz_api.php";
// Attaches the variables to the url ie:var1=1&var2=2 etc...
var vars = '';
hr.open("POST", url, true);
//Set content type header information for sending url encoded variables in the request
hr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
// Access the onreadystatechange event for the XMLHttpRequest object
hr.onreadystatechange =
function(){
if(hr.readyState == 4 && hr.status == 200){
var return_data = hr.responseText;
console.log(return_data);
document.getElementById('test_div').innerHTML = return_data;
}else{
document.getElementById('test_div').innerHTML = "XMLHttpRequest failed";
}
}
//Send the data to PHP now... and wait for response to update the login_error div
hr.send(vars); // Actually execute the request
}
you can change the whole page with a document.write instead of changing individual "div"s
I'm trying to make a custom page in the adminpanel of Prestashop where the shopowner can fill in his upcoming events that will appear in a column in the header.tpl page. The templates and controller are working so far, with a structure based on an answer here at Stack Overflow:
How to create a new page in prestashop admin panel?
Now I have made in the content.tpl (with the added custom JavaScript and CSS files) the form with the input fields. The next step is to send it to the controller to save it in the database. But I'm stuck this part. I can't find how I can nicely submit the form to the controller. First I tried it with an Ajax function but I couldn't find the right way. Also without Ajax no success.
$.ajax({
type: 'POST',
headers: { "cache-control": "no-cache" },
url: baseUri + '?rand=' + new Date().getTime(),
async: true,
cache: false,
dataType : "json",
data:{
processEvents: true,
ajax: 'true',
controller: 'AdminEvents',
token: static_token
},
//success: function(jsonData){
//}
});
This is an example of an Ajax function that I tried. My questions:
How does other tpl or js files receive the baseUri, where is that
variable set?
What is the function of the ?rand date and time in that line? A kind
of security token?
What is the url of the controller? Also the url when I use
I guess the processEvents : true and Ajax : true is for security
reasons and to check if the form is submitted by Ajax or not?
Why is it necessary to send the controller name?
Where does the token come from?
Questions about the controller:
Which (Prestashop default functions) can or do need to use? For
example:
if (Tools::isSubmit('name')){
etc.
if (Tools::getValue('create_account')){
etc.
Can I use that functions anywhere or maybe only in an Init function?
A lot of questions, feel free to answer only a part of it, I just need a good push in the right direction, searching and reading in the online documentation and on the internet doesn't brought me the solution and brainwashed me a little.
EDIT:
I made a little progress by myself:
Where does the token come from?
What is the url of the controller? Also the url when I use
With the tools getAdminTokenLite and the controller name I generated the controller url:
$token = '?controller=AdminEvents&token='.Tools::getAdminTokenLite('AdminEvents');
The url to post to is the token plus the domain, admin directory and index.php.
With the tool getValue I get the POST data like in PHP with $_POST["name"].
Tools::getValue('event_name')
So its working but I guess it can be better with other Presta default tools.
I know that it's very late to answer you, but for sure it will help other mates with same problem.
Here is an example about how to implement ajax calls in Prestashop 1.6 on Admin panel using ANY Controller from BackOffice (if you want also, you can use ajax.php controller, but I'm using for this AdminImportController() )
tpl part:
$('#mybtn').click(function(e) {
var data = $('#datalist').val();
// Ajax call with secure token
$.post( "{$current|escape:'html':'UTF-8'}&token= {$token|escape:'html':'UTF-8'}",
{ ajax: true, action: "MyFunction", mydata: data } );
});
And in admin controller side:
public function ajaxProcessMyFunction()
{
// Get param
$mydata = (int)Tools::getValue('mydata');
$answer = 0;
if( $mydata > 0 ) {
$this->importProfList = Db::getInstance()->executeS(
"SELECT * FROM .... LIMIT 1"
);
...
$answer = $someOperationResult;
}
// Response
die(Tools::jsonEncode(array(
'answer' => htmlspecialchars($answer)
)));
}
Tested and working like a charm.
Regards
I'm creating a webproject in pyramid where I'd like to update a table every few secondes. I already decided to use ajax, but I'm stuck on something.
On the client side I'm using the following code:
function update()
{
var variable = 'variable ';
$.ajax({
type: "POST",
url: "/diagnose_voorstel_get_data/${DosierID}",
dataType: "text",
data: variable ,
success: function (msg) {
alert(JSON.stringify(msg));
},
error: function(){
alert(msg + 'error');
}
});
}
Pyramid side:
#view_config(route_name='diagnose_voorstel_get_data', xhr=True, renderer='string')
def diagnose_voorstel_get_data(request):
dosierid = request.matchdict['dosierid']
dosieridsplit = dosierid.split
Diagnoses = DBSession.query(Diagnose).filter(and_(Diagnose.code_arg == str(dosieridsplit[0]), Diagnose.year_registr == str(dosieridsplit[1]), Diagnose.period_registr == str(dosieridsplit[2]), Diagnose.staynum == str(dosieridsplit[3]), Diagnose.order_spec == str(dosieridsplit[4])))
return {'Diagnoses ' : Diagnoses }
Now I want to put this data inside a table with zpt using the tal:repeat statement.
I know how to use put this data in the table when the page loads, but I don't know how to combine this with ajax.
Can anny1 help me with this problem ? thanks in adance.
You can do just about anything with AJAX, what do you mean "there's no possibility"? Things become much cleaner once you clearly see what runs where and in what order - as Martijn Pieters points out, there's no ZPT in the browser and there's no AJAX on the server, so the title of the question does not make much sense.
Some of the options are:
clent sends an AJAX request, server does its server-side stuff, in the AJAX call success handler the client reloads the whole page using something like window.location.search='ts=' + some_timestamp_to_invalidate_cache. The whole page will reload with the new data - although it works almost exactly like a normal form submit, not much sense using AJAX like this at all.
client sends an AJAX request, server returns an HTML fragment rendered with ZPT which client then appends to some element on your page in the AJAX success handler:
function update()
{
var variable = 'variable ';
$.post("/diagnose_voorstel_get_data/${DosierID}")
.done(function (data) {'
$('#mytable tbody').append(data);
});
}
client sends an AJAX request, server returns a JSON object which you then render on the client using one of the client-side templating engines. This probably only make sense if you render your whole application on the client and the server provides all data as JSON.
I am trying to get the URL i see on my browser after i do an ajax request but the problem is that it changes the URL with the Ajax URL.
ex.
i am on domain.com/user/username
and the ajax URL that i call is in domain.com/posts/submit
when i echo $_SERVER['REQUEST_URI'] on the posts controller in submit function it will display the second URL and not the first... how can i assure and get the first inside the ajax function that its 100% valid and not changed by the user to prevent any bad action?
Thanks
There is HTTP_REFERER but I don't know if that works for javascript requests. Another problem of this: It won't work for all browsers.
You could try the following:
1.) As the user visits domain.com/user/username the current URL is saved with a token - let's say 5299sQA332 - into the database and the token is provided through PHP to Javascript
2.) The ajax request will send this token along with the other variables needed to the controller through POST
3.) In your ajax controller you search the database for the given token 5299sQA332 and there you have your first URL and you can be damn sure, that it hasn't been manupulated
:)
If I understand you correctly, you want to make sure the ajax call is coming from the page it is supposed to be on? In that case just pass a token with the call.
In the controller function set a token variable in session;
public function username() {
$this->session->set_userdata('ajax_token', time());
}
Then in the view with the js;
$.ajax({
url: '/user/username',
type: 'post',
data: 'whatever=bob&token='+<?php echo $this->session->userdata('ajax_token'),
success: function( data ) {
},
error: function( data ) {
}
});
Then in you form validation, do a custome callback to check they are the same.
Have you looked at CodeIgniter's Input Class ?
$this->input->get('something', TRUE);
i used javascript for it and it seems to work... hope not to have any problems in the future with it...
ps: i dont get why my other answer was deleted.. thats the answer anyway.
I have a html page that I need to call another asp page to get the date/hour via an ajax call. Which method would be better or best, Post or Get?
Since I am only retrieving a few bits of data and not sending any data to the page info is one method better or proper than the other?
This is the simple ASP page.
<%#LANGUAGE="VBSCRIPT"%>
<% Option Explicit %>
<%=Weekday(Date)%>
<%=Hour(Now)%>
And this is the Ajax call to the asp page above.
jQuery.ajax({
url: '/v/timecheck.asp',
type: 'GET',
cache: false,
success: function(data){
// do something with the data
},
error: function() {
//do something on error
return false;
}
})
The reason I have to make the Ajax call to this ASP page is I cannot query the server direct from this page.
My rule of thumb when deciding either one is:
The interaction involve database, POST
The interaction involve sensitive information, POST
Requesting simple data, GET
Sending user input, POST
Sending/requesting large data, POST
Clean URL, POST
As you can see, most cases involve POST for many reason. Such as in your case, you could use GET or POST. Either way, jQuery make calling both function easy.
A simpler $.POST
$.post("/v/timecheck.asp", function (data) {
if (data.time != "") {
//retrieve success
{
else
{
//retrieve fail
};
});
or simpler $.GET
$.get("/v/timecheck.asp", function(data) {
if (data.time != "") {
//retrieve success
{
else
{
//retrieve fail
};
});
I would use POST, I think there is a secirity reason in ASP.NET to use POST, but not sure if this relates to IIS (and possibly ASP)
The W3C have a paper with guidelines on when to use GET or POST at: http://www.w3.org/2001/tag/doc/whenToUseGet-20040321#checklist
Using a GET request allows the result to be cached by the browser whereas a POST request won't be cached and the page will be re-retrieved every time.
In your code example you are not changing any data as a result of the request and are only providing the day and hour, so using a GET and setting the cache HTTP headers to 1 hour would give you the best performance and reduce load on your server.