I'm having trouble using the OutputCache attribute in Microsoft's MVC3 framework.
Please imagine the following controller action, which can be used as part of an AJAX call to get a list of products based on a particular manufacturerId:
public JsonResult GetProducts(long manufacturerId)
{
return Json(this.CreateProductList(manufacturerId), JsonRequestBehavior.AllowGet);
}
I want this result to be cached on the server to avoid making excessive database queries. I can achieve this by configuring the attribute thus:
[OutputCache(Duration = 3600, Location = OutputCacheLocation.Server, VaryByParam = "manufacturerId")]
This works as I expected - the browser makes an intitial request which causes the server to create and cache the result, subsequent requests from the same or different browser get the cached version.
But... I also want the browser to cache these results locally; if I filter first on manufacturer X, then Y then go back to X, I don't want it to make another request for X's products - I want it to just use its cached version.
I can make this happen, by changing the OutputCache to this:
[OutputCache(Duration = 3600, Location = OutputCacheLocation.Client)]
Here's the question: how do I combine these so that I can have both sets of behaviour? I tried setting the Location to ServerAndClient but this just made it behave the same as when Location was Server.
I'm sure that the problem has something to do with the "Vary: *" response header I get with ServerAndClient but I don't know how to get rid of it.
I welcome comments about the rationality of my intentions - the fact that I'm not getting the results I expect makes me think I might have some fundamental misunderstanding somewhere...
Many thanks.
PS: This is on a local dev environment, IIS Express from VS2010.
You can use OutputCacheLocation.Any which specifies
The output cache can be located on the browser client (where the
request originated), on a proxy server (or any other server)
participating in the request, or on the server where the request was
processed. This value corresponds to the HttpCacheability.Public
enumeration value.
You may want to also set Cache-control public to in the HTTP header for these requests.
Edit
It seems, depending on your .Net version of the web server you may need to include Response.Cache.SetOmitVaryStar(true); within your controller action to remove the Vary * headers as you suggest.
Details of the reason why in .Net 4 breaking changes release notes.
Related
In my XPage I have a xe:djxDataGrid (dojox.grid.datagrid) which uses xe:restService which seems to use dojox.data.JsonRestStore.
Everything works fine without proxy but my client accesses the application via a proxy because of corporate policy. After a user updates data in the DataGrid it shows old values when accessed behind the proxy.
When the REST Control/JsonRestStore sends an ajax GET request to get data, there is no Cache-Control parameter in request headers. And Domino does not place Expires parameter in the reponse headers. I believe that's why the old version of the GET request gets cached by the proxy.
We have tried to disable cache in browsers but that does not help which indicates the proxy is caching the requests.
I believe this could be solved either by:
Setting Cache-Control parameter in request headers OR
Setting Expires parameter in response headers
But I haven't found a way to set either of these. For the XPage Domino sets Expires:-1 response header but not for the ajax GET request which is:
/mypage.xsp/?$$viewid=!ddrg6o7q1z!&$$axtarget=view:_id1:_id2:callback1:restService1
This returns the JSON data to JsonRestStore and gets cached by the proxy.
One options is to try to get an exception to the proxy so requests to this site would bypass the proxy cache. But exceptions are generally not easy to get thru.
Any ideas? Thanks.
Update1
My colleque suggested that I could intercept the xhr GET requests made by dojox.data.JsonRestStore and add a time parameter to the URL to prevent cache. Here is my question about that:
Prevent cache in every Dojo xhr request on page
Update2
#SvenHasselbach has a great solution for preventing cache for all xhrs:
http://openntf.org/XSnippets.nsf/snippet.xsp?id=cache-prevention-for-dojo-xhr-requests
It seems to work perfectly, &dojo.preventCache= parameter is added to the URLs and the requests seem to return correct JSON also with this parameter. But the DataGrid stops working when I use that code. Every xhr causes this error:
Tried with Firefox and Chrome. The first page of data still loads because xhr interception is not yet in place but the subsequent pages show only "..." in each cell.
The solution is Sven Hasselbach's code in the comment section of Julian Buss's blog which needs to be slightly modified.
I changed xhrPost to xhrGet and did not place the code to dojo.addOnLoad. When placed there it was not effective in the first XHR by the DataGrid/Store.
I also removed the headers modification because it overrides existing headers. When the REST control requests data from server with xhrGet the URL is always the same and rows requested are in HTTP header like this:
Range: items=0-9
This (and other) headers disappear when the original code is used. To just add headers we would have take the existing headers from args and append to them. I didn't see a need for that because it should be enough to add the parameter in the URL. Here is the extremely simple code I'm using:
if( !(dojo._xhrGet )) {
dojo._xhrGet = dojo.xhrGet;
}
dojo.xhrGet = function (args) {
args['preventCache'] = true;
return dojo._xhrGet(args);
}
Now I'm getting all rows and all XHR Get URLs have &dojo.preventCache= parameter which is exactly what I wanted. Next we'll test in customer environment to see if this solves their problem.
Update
As Julian points out in his blog I could also use a Web Site Rule to set Expires or cache-control http response headers.
Update
The customer reports it's working now for them!
I have an ASP.NET MVC3 application setup. There is a controller that returns back images and I have added the following:
[OutputCache(Duration = 3600, VaryByParam = "id;width", Order = 1000, Location = OutputCacheLocation.Client)]
public ActionResult Get(string id, int width)
{ ... }
But when I check out the HTTP Response on these images they all have headers that say "cache-control: no-cache" and "expires: -1" which means the browser is never caching them.
I'm looking all around and I can't find anything on why the response is telling the browser not to cache them. I even tried working up my own attribute that did:
public class ContentExpiresHeader : ActionFilterAttribute
{
public override void OnResultExecuted(ResultExecutedContext filterContext)
{
var cache = filterContext.HttpContext.Response.Cache;
cache.SetExpires(DateTime.Now.AddYears(1));
cache.SetCacheability(HttpCacheability.Private);
cache.SetLastModifiedFromFileDependencies();
base.OnResultExecuted(filterContext);
}
}
but that didn't get me anywhere either.
Any help is appreciated.
UPDATE: I'm starting to think this has got to be an IIS setting somewhere that is adding the no-cache and overriding. I can't seem to find anything, though. The only odd thing is that if I take a look at the state of the cache variable after I've called the .Set...() methods the internal variables have not been updated. I would have expected something to change but they're still showing "no-cache".
UPDATE 2: I should add that the return of this method is a:
return File(...);
UPDATE 3: I also found this (http://dotnetslackers.com/articles/aspnet/ASP-NET-MVC-3-Controller-for-Serving-Images.aspx) and tried implementing it without any luck. Still getting the no-cache options on the response header for the images.
UPDATE 4: Just had to check server settings... if I bypass my controller and go straight to an image file on the server, then it DOES cache and has the correct caching settings in the response header.
UPDATE 5 (yeah, getting crazy): Created a brand new MVC3 project and just made the one controller and it cached just fine. So I've got something outside the immediate code that is adding this pragma:no-cache stuff and for the life of me I can't figure out what it'd be. =-/
Try changing the cacheability from HttpCachability.Private to HttpCachability.ServerAndPrivate. It should keep the cache-control as private and not suppress e-tags/last modified.
Found the problem! And it's the weirdest thing I've seen in a while.
I am using SocialAuth-net and somewhere during the setup I added the system.webServer module for it and set runAllManagedModulesForAllRequests=true. I thought, "huh, wonder if that's causing it somehow", as I couldn't reproduce the problem outside this particular app. Low and behold, commenting out that section of the config and my images started caching! Hoorah!
But, it gets weirder. I undid my config changes, refreshed and now I'm still getting caching. I can't tell you how many resets of the system I've done with no change but somehow temporarily removing these modules from the pipeline seems to have resolved this problem.
I can track it down to the SocialAuthHttpModule and if I remove it SocialAuth-net still seems to work but caching is restored reliably. Very weird.
I am using jqgrid in my ASP.NET MVC application. Currently I have mTYpe: 'POST' like this:
jQuery("#myGrid").jqGrid({
mtype: 'POST',
toppager: true,
footerrow: haveFooter,
userDataOnFooter: haveFooter,
But I was reading this article, and I see this paragraph:
Browsers can cache images, JavaScript, CSS files on a user's hard
drive, and it can also cache XML HTTP calls if the call is a HTTP GET.
The cache is based on the URL. If it's the same URL, and it's cached
on the computer, then the response is loaded from the cache, not from
the server when it is requested again. Basically, the browser can
cache any HTTP GET call and return cached data based on the URL. If
you make an XML HTTP call as HTTP GET and the server returns some
special header which informs the browser to cache the response, on
future calls, the response will be immediately returned from the cache
and thus saves the delay of network roundtrip and download time.
Given this is the case, should I switch my jqGrid mType all to use "GET" from "POST" for the mType? (It says XML (doesn't mention JSON). If the answer is yes, then actually what would be a situation why I would ever want to use POST for jqGrid mType as it seems to do the same thing without this caching benefit?
The problem which you describe could be in Internet Explorer, but it will be not exist in jqGrid if you use default options.
If you look at the full URL which will be used you will see parameters like
nd=1339350870256
It has the same meaning as cache: true of jQuery.ajax. jqGrid add the current timestemp to the URL to make it unique.
I personally like to use HTTP GET in jqGrid, but I don't like the usage of nd parameter. The reason I described in the old answer. It would be better to use prmNames: {nd:null} option of jqGrid which remove the usage of nd parameter in the URL. Instead of that one can control the caching on the server side. For example the setting of
Cache-Control: private, max-age=0
is my standard setting. To set the HTTP header you need just include the following line in the code of ASP.NET MVC action
HttpContext.Current.Response.Cache.SetMaxAge (new TimeSpan (0));
You can find more details in the answer.
It's important to understand, that the header Cache-Control: private, max-age=0 don't prevent the caching of data, but the data will be never used without re-validation on the server. Using other HTTP header option ETag you can make the revalidate really working. The main idea, that the value of ETag will be always changed on changing the data on the server. In the case if the previous data are already in the web browser cache the web browser automatically send If-None-Match part in the HTTP request with the value of ETag from the cached data. So if the server see that the data are not changed it can answer with HTTP response having 304 Not Modified status and empty body of the HTTP response. It allows the web browser to use local previously cached data.
In the answer and in this one you will find the code example how to use ETag approach.
If the data that the server sends changes, then you should use POST to avoid getting cached data everytime you request it.
You should not use GET for all the purposes. GET requests are supposed to use for getting data from the server not for saving or deleting operation. GET requests has some limitation since the data you are sending to the server or appended as query-strings you can't send very large data using GET requests. Also you should not use GET request to send sensitive information to the server. You should the POST request in all the other cases like adding, editing and deleting.
As far as I'm aware jqgrid appends a unique key in every GET request so you don't get any benefit from browser caching.
One way around the caching behavior is to make the GET unique each time the request is made. jQuery.ajax() does this with "cache: false" by appending a timestamp to the end of the request. You can replicate this behavior with something similar:
uri = uri + '?_=' + (new Date()).getTime(); // uri represents the URI to the endpoint
I'm using mvc-mini-profiler along with Glimpse. The problem is glimse is flooding the profiler output with glimpse requests. Is there any way to ignore all request made by glimpse ?
protected void Application_Start()
{
var ignored = MiniProfiler.Settings.IgnoredPaths.ToList();
ignored.Add("Glimpse.axd");
MiniProfiler.Settings.IgnoredPaths = ignored.ToArray();
}
Solution Posted here:
Mini MVC profiler: appears to be displaying profile times for every static resource
At the moment Glimpse will make Ajax requests if you have the Remote tab selected or when ever an Ajax request is made by your site.
This is done because when we detect that a request is made we proactively get the Glimpse data. We could probably switch this in a future release to be more lazy and only fetch the data on request.
Note, even though this will help, Glimpse will still be calling back to the server in the same way that Mini Profile does. Hence, both frameworks could probably try and ignore each other for ajax requests.
Hope this helps.
Title sums it up fairly well.
Said site has cookies, I need to post data from a textbox as a value on said site, and get one of two variables back. I was reading through some tutorials and a few Windows phone 7 books. None of them were related to what I was trying to do. They only dealt with single whole files or something that could be made into a URL. I could also do it that way if someone had a way to also use cookies and just send it as a url [but i do not know how to construct the url in such a way to make that a realistic solution].
You should be able to send cookie's using code like:
CookieContainer container = new CookieContainer();
container.Add(new Uri("http://yoursite"), new Cookie("name", "value"));
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://yoursite");
request.CookieContainer = container;
request.BeginGetResponse(new AsyncCallback(GetData), request);
Code borrowed from HttpWebRequest and Set-Cookie header in response not parsed (WP7)
If the server is expecting to use cookies (e.g. for authentication) then there is no way that you'll be able to use form variables/query parameters instead.
You need to use a tool called Fiddler to inspect the calls that the website currently makes - this will include a mixture of:
cookie variables - especially for authentication
get variables - passed within the url path
and post variables - passed within the body of the request
If you do need to do a full POST, then you will need to set variables like - request.Method and request.ContentType - and you will need to brovide a RequestStream. There are libraries you can use like HAMMOCK to help - or I've got some example code in iron7 - see the DoCodePost method at the botom of this uploader class - or take a look at lots of other projects on CodePlex and GitHub.