It's about making changes in design (css-files and images) on a website which is already online and in use. I wonder what is the best-practice to make sure that visitors see the changes without clearing there browser's cache manually. Things that came in my mind:
change meta-tag - dismissed because I do not want the site to be ALWAYS loaded from the server
include the css-file with a parameter (like timestamp) after made a change
change the names of included images so that they are reloaded - means also change names in the files where images are included
?
What else could achieve the loading from server? Did I forget some advantages/disadvantages?
Possible duplicate of this post: How to control web page caching, across all browsers?
My favoured solution is to set a random number after you call the file e.g.
css/styles.ccs?628454548
images/sprite.gif?8356484894
You could use javascript/php or whatever to set those random numbers every time the page is called to the browser.
Related
I have made some "select and checkboxes - like mac and so on..." with custom images and styles with jquery, i want them not to be reloaded each time i do full postback.
Images are normally cached in the browser without much intervention. unless you are using dynamic names or something like that the browser will load them once then pull them from the cache on following requests.
I have lots of views which don't change very often, and enjoy the benefit of caching. But I have 1 view which is used to display a random quote in a block in my sidebar, which I do not want cached. Is there a way to disable caching for this particular view? Specifically, I want to see a different quote every time I refresh the page.
UPDATE: I have Caching Mode set to Normal in my site's Performance settings, and I've tried going into the View and setting Caching = None (as well as in Block settings: Caching = Do not cache), and going into the Views tools page, and selecting "Disable views data caching", and it works when I'm logged in, but as soon as I logout, the quote stays the same after refreshing.
UPDATE: I'm beginning to think that if you have enabled page caching in Drupal, then all other cache settings are ignored (i.e. View and Block caching). Can anyone confirm this?
In the Views UI under the Basic settings of a particular display you have an option called Caching make that as none. And your view won't be cached. So you get random
quote everytime. :)
EDIT : Oops how did I miss what you were telling :(
Use Cache Exclude module to disable caching on the particular page. If your random block is on many pages, you may need to dig deeper to find an alternate solutions. All the best ;)
Suggestion: Randomize on the client side. Load 'em all up into a javascript array and write a quick function to select the random quote on page load. Unless there are hundreds of possible quotes it shouldn't weigh the page down too much, & you could exclude this one little sidebar feature from consideration when working on your caching strategy.
In fact even if there are hundreds of random quotes, you could use a combination of the two approaches. Grab 50 random lines w/ your module and them let javascript pick from there. To an end user it would be nearly identical.
The block may be being cached. Did you try to http://drupal.org/project/blockcache_alter ?
You can also directly change a block's cache setting in the database with something like:
update blocks set cache=-1 where bid=<blockbid>;
Setting this cache entry to -1 means the block will not be cached.
In addition, setting cache to 1 will cache the block per role, 2 will cache the block per user, 4 will cache the block per page, and 8 will cache the block exactly once (the same for all users, pages, etc).
The task is relatively straightforward:
A Drupal website displays a list of articles with thumbnails. Some visitors would like to view it without images by clicking on a button/link and have that preference saved.
e.g. http://patterntap.com/collections/index/
The problem is all visitors are anonymous and given certain traffic, page cache is enabled.
My idea was to use some simple JavaScript to set a cookie, refresh the page and depending on the cookie values (or its presence/absence) display or hide the images.
Except Drupal serves cached pages quite early and the only quick way to modify the cached version that I could find is by hacking includes/bootstrap.inc and add a custom class to the body classes then hide the images with css.
A very wrong approach, I know. But I wonder if there is a way to save different versions of a page and serve the correct version?
Edit:
need to keep the same uri
the js to show/hide the images without reload and set the cookie is already in place
hook_boot() is not really called for cached pages, so can't do it via custom module
.htaccess mods?
Edit/solution:
In the end went with Rimian's suggestion. But it is possible to accomplish the task using our own cache.inc implementation as seen in the Mobile Tools module. Specifically, by extending cache.inc and updating settings.php to include
$conf['page_cache_fastpath'] = FALSE;
$conf['cache_inc'] = 'path/to/my/module/my_module_cache.inc';
So let me get this right. You wanna hide some images on a cached page if the user chooses to?
Why don't you write some jQuery or javascript and load that into your cached page with all the rest of the document?
Then, the client/browser would decide to run your script and hide images depending on some parameters you passed along with the request to that page or in the cookie? The script gets cached and only runs when you call it.
If you were hacking the bootstrap for something like that you'd really need to be rethinking what you were doing. Crazy! :)
Also take a look at cache_get and cache_set:
http://api.drupal.org/api/drupal/includes--cache.inc/6
I'm not sure I 100% understand what you are trying to do but here are my thoughts. One of your root problems is that you are trying to access what is essentially different content at the same uri.
If this is truly what you want to do, then Rimian's suggestion of checking out chache_get and chache_set may be worthwhile.
Personally, it seems cleaner to me to have your "with thumbnails" and "without thumbnails" be accessed via different uri's. Depending on exactly what you are wanting to accomplish, a GET variable my be an even better way to go. With either of these two options you would hide or show your thumbnails at the theme layer. Pages with different paths or get variables would get cached separately.
If you want the visitor to be able to switch views without a page reload, then jQuery and a cookie would probably suite your needs. This wouldn't require a page reload and switching back and forth would be quite simple.
When doing webpages, the client/browser decides if it updates a file like an image or .css or .js or if it takes that from the Cache.
In case of .aspx page it is the server who decides.
Sure, on IIS level or also using some HttpModule techniques I can change the headers of requests to tell the client if and how long a file should be cached.
Now, I do have a website where the .aspx goes hand-in-hand with a corresponding .js. So, perhaps I have some jQuery code in the .js which accesses an element in the .aspx. If I remove that element from the .aspx I would also adapt the .js. If the user goes to my page he will get the new .aspx but he might still get the old .js, leading to funny effects.
My site uses lots of scripts and lots of images. For performance reasons I configured in the IIS that those files "never" expire.
Now, from time to time a file DOES change and I want to make sure that users get the update files.
In the beginning I helped myself by renaming the files. So, I had SkriptV1.js and SkriptV2.js and so on. That's about the worst option since the repository history is broken and I need to adapt both the references and the file name.
Now, I improved here and change only the references by using Skript.js?v=1 or Skript.js?v=2.
That forces the client to refresh the files. It works fine, but still I have to adapt the references.
Now, there is a further improvement here like this:
<script type='text/javascript' src='../scripts/<%# GetScriptLastModified("MyScript.js") %>'></script>
So, the "GetScriptLastModified" will append the ?v= parameter like this:
protected string GetScriptLastModified(string FileName)
{
string File4Info = System.Threading.Thread.GetDomain().BaseDirectory + #"scripts\" + FileName;
System.IO.FileInfo fileInfo = new System.IO.FileInfo(File4Info);
return FileName + "?v=" + fileInfo.LastWriteTime.GetHashCode().ToString();
}
So, the rendered .js-Link would look like this to the client:
<script type='text/javascript' src='/scripts/GamesCharts.js?v=1377815076'></script>
The link will change every time, when I upload a new version and I can be sure that the user immediately gets a new script or image when I change it.
Now, two questions:
a) Is there a more elegant way to achieve this?
b) If not: Has someone a guess how big the performance overhead on the server would be? There can be easily 50 versioned elements on one page, so for one .aspx the GetScriptLastModified would be invoked 50 times.
Looking forward to a discussion :)
There are a few different answers to this question.
First of all, if you have files which only change every once in a while, set the Expires and Cache-Control headers to expire in one year. Only if the files truly never expire should you say that they never expire. You're seeing the issues with saying "never expire" right now.
Also, if you are having performance issues on your site from serving up lots of images and JavaScript, the commonly accepted solution is to use a CDN (Content Delivery Network). There are many different providers and I'm sure that you can find one that meets your budget. You'll also save money in the long run as the CDN will offload a great deal of I/O and CPU time from IIS. It's astounding how big of a difference it can make.
Lastly, one way to make sure that users are getting the latest for your files which almost never change is to implement some sort of versioning scheme in your assets URLs to make cache busting happen. There are many different ways to do this, but one (very naive) way to do it is to have a version number that increases every time you deploy to your site.
E.g. all your asset URLs will look like /static/123/img/dog_and_pony.jpg
Then, next time you deploy to your site, you increase the version number so that it's "124". You would need some way to keep track of the version, dynamically injecting it into asset URLs, as well as making sure that the version number changes every time you deploy. The idea being that anything referencing this asset should automatically know the new version number.
In terms of performance, it's an admirable goal to never need the user to refresh or have to download the same thing twice. But sometimes it's just a lot less hassle, and if users are only refreshing everything periodically, that's probably okay for most websites.
Hope this helps.
Whenever we make changes to the CSS, it generally takes 24 hours to reflect those changes on my site. I have tried clearing the server cache and browser cache but it doesn't help too. Is there any other way to make the CSS changes reflect immediately after updation?
it happens in all the browsers... when i check it in the browser , i can access my css file with two paths eg : i store my css in folder named "Cssfolder" and my css name is say 135.css
So when i access the folder paths, Cssfolder/135.css & cssfolder/135.css, one of the path shows me latest css whereas other one shows me old css.Notice the "c" is captital in one path whereas small in other path.
Thanks.
I've found this to be a pretty common problem in a lot of my projects. I would suggest two things...
If it's just an app that you are working on you can use the CSS Cachebuster during development.
Following the idea behind the Cachebuster I have found that often adding the timestamp of the CSS file as a query string off of the CSS link will help in telling the browser that the file is different... something like... whatever.css?12212009035543
You might want to use a monitoring tool, like Live Http Headers for Firefox, to see the requests and responses to and from the server. This usually solves a lot of problems for me. Take a look at the "Expire" headers and conditional requests (like: "If-modified-since"). This said, take a look at server and client local times and timezones - it might be that they differ significantly and conditional GET requests "seem to be" handled correctly, because of future or otherwise mangled timestamps.
You can force to load the current css directly from the server with appending a random unique value to the url, like http://example.com/Cssfolder/135.css?983274928374 and http://example.com/cssfolder/134.css?08973249827. There's no way that this would ever get cached unless you use the same random value twice.
This way you learn where to look further for the solution to your problem: At the server, the ISP/a proxy or your browser.
You really need to see whether this is server side or client side. If the server is still serving the old CSS then clearly you've got no chance on the client side.
I've occasionally seen times where I've had to show the CSS in the browser, and then next time I've been to the real page, it's used that new CSS. Usually just hitting refresh does it.
Do you have any web caches like Akamai involved anywhere?
If you try to go to the CSS page from a computer which has never seen the old version, which version does it show?
EDIT: Changed answer to reflect edits in question.
I have been dealing with this issue in the past, and ended up writing a httpmodule to deal with it.
It's pretty simple, it just finds all script/css links in head tag (they now need to have runat=server) and appends the assembly version number to the link, in the same way as Tim K describes. This way im sure my clients always fetches the newest css/scripts when my app is updated in production, and never have to deal with this issue again.
Maybe Internet Service Provider cache, as in this case?
I was perplexed by this issue then someone said Ctrl+F5. Worked for me :)
When I am developing and I need to be sure that I am seeing changes as I work, I stick the css in the page ie
<style type="text/css">
/* your css */
</style>
Or you could constantly change the name of the css file itself, not very useful in a production environment, but perhaps okay while developing.
I know it doesn't solve the problem, but for developing it is okay.