How to fix browser cache and notmodified respond for JSON? jQuery.ajax({ifModified:true,cache:true}) JSON request break on data respond.

[Binyamin <7raivis@…>]

How to fix browser cache and notmodified respond for JSON? jQuery.ajax({ifModified:true,cache:true}) JSON request break on data respond.

First time browser request  http://localhost/api returns status 200 OK and nexts 304 Not Modified

    $.ajax({
        type:"GET",
        url:'http://localhost/api',
        dataType:'json',
        cache:true,
        ifModified:true,
        success:function(data,textStatus,jqXHR){
            console.debug(jqXHR.status+':'+textStatus);
            console.debug(data); // On repeated request returns `undefined`
        }
    });

XHR first time returns ok:

    200:success
    Object {content="Hello!"}

but on next times returns data undefined:

    304:notmodified
    undefined

How to solve it? It seems jQuery 1.5.1 bug. Expected result:

    304:notmodified
    Object {content="Hello!"}

[jaubourg]

That's exactly how the ifModified option is supposed to work. Setting ifModified to true will have ajax set headers to issue a conditional request.

 http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html, section 10.3.5, about 304 Not Modified:

If the client has performed a conditional request and access is allowed,
but the document has not been modified, the server SHOULD respond with this
status code. The 304 response MUST NOT contain a message-body, and thus is
always terminated by the first empty line after the header fields.

If you want to receive 200 OK responses all the time, then do NOT use the ifModified option: the browser's xhr implementation will deal with 304 Not Modified responses under the hood while only presenting 200 OK responses to user code.

[Binyamin <7raivis@…>]

@jaubourg - Then how to get:

304:notmodified
    Object {content="Hello!"}

when  http://localhost/api returns 304 Not Modified?

[dmethvin]

@Binyamin: Cache it in your own code. If you need more help, ask on forum.jquery.com since this is not a bug.