Flash messages in Symfony projects give feedback to website users after an action is performed. They usually only show for one page load after the action is triggered.
Unfortunately, when caching is turned on my messages fail to appear and only the cached version of the page is returned.
In one instance a version of a page with a message was cached, meaning that the message was displayed to everyone.
Is it possible to make the cache aware of the flash messages?
There are two options, the one mentioned by benlumley:
Turn with_layout off, so that the layout is not part of the cached file. This will not prevent your problem is your rendering of the flash is inside the action template though.
Clear selected parts of the cache whenever you set and display the flash (remember to clear it after the display of the cache, otherwise you'll bump into your problem with the flash appearing to other users again. Alternatively you can choose to programmatically disable the cache once on the page that displays the flash (see the symfony docs on 'Configuring the Cache Dynamically). The last option is quite dodgy in my opinion and should be used as a last resort, since for example redirects can screw it all up.
No matter how you do it there is no optimal solution that can make your flash messages magically bypass the cache.
There is not automatic way to make symfony cope with this.
The best/most common solution is to disable with_layout for either all of your cached actions, or else just these particular actions where flash messages have to be displayed. This normally resolves the issue as most people tend to output flash messages from the layout rather than within the cached templates.
Related
It's very important for the website I'm working on to be offline-functional. I'm using a Cache Manifest to store all the files on the application cache, so that takes care of that and all is good and well.
BUT, as I read and noticed myself, the browser first shows the cached version of the site before checking for an update online. Hitting refresh reloads the cache again, with the new cached files this time (or what it had time to update for the swift refreshers).
I'm aware of this fix : http://www.html5rocks.com/en/tutorials/appcache/beginner/, where the user is told an update is available and is asked to refresh the page. Not a bad method, but still sketchy for user experience.
Is there any other way to force the browser to show the most up to date files if online? Would cache busting all files manually AND using a cache manifest fix this problem, or will it conflict with the cache manifest and cause problem to the offline functionality?
I found something that works well for me:
The URL linking to the web page contains a parameter. If there is ever a change to the page or related files, the url is changed to something like this: http:/ /www.mywebsite.com/mypage.html?v=3 where v=3 is changed depending on updates.
This is a longer fix to implement (finding every page affected by a change & changing all their cache busting links), but the pages at least show what they're supposed to on the first load and the cache manifest still load the update for offline viewing.
2 popular Wordpress plugins, Super Cache and Contact Form 7 - there are still some issues expected around _nonce AJAX calls.. How it is possible to make them work together smoothly? Definitely, there are some situations you want to keep ALL your posts (pages) super-cached, and not to be served dinamically without caching while preserving and providing contact form functionality.
When not checking the "Cache rebuild" in the settings, Super Cache will function:
standard pages will NOT enforce a new cache file to be generated (e.g. it REALLY serves an (if) existing supercache file whithout triggering a new cache file to be generated
pages with a wpcf7-form included WILL enforce/trigger the re-generation of supercache file while serving the initial on the request. I think that is the point when things go wrong.
Question: How to stop unwanted re-generation of pages with a wpcf7-form included? Based on wpcf7 plugin homepage Docs by the author, my expectation is that the wpcf7 form has evolved and been developing to meet this ajax-call requirements such _nonce calls. Any idea how to resolve this?
to be hard-coded (e.g. exclude _nonce call and/or URL parameter..) within wpcf7 form (this is against WP standards) or
settings in Super cache?
any other idea, solution or alternatives?
In this thread wpcf7 author says:
Contact Form 7 uses WP nonce as secret key. As nonce life is 24 hours by default, if cache clears less than 24 hours, the two plugins should work without problem, even if the page is cached.
I have an ASP.NET MVC web page that has a file upload control. Under rare conditions the file referenced by the user moves or is deleted on the filesystem prior to the user triggering the post to the page. In IE9 the page successfully posts but the ContentLength is zero (expected) and can be handled server-side. However in Firefox I find that the POST action never reaches the server.
Is there anyway to detect that the file reference is still valid prior to posting the page? Or a way to detect that an error occurred client-side during the POST due to the moved/deleted file?
Using just input type="file", you have no access to check whether the file actually exists until an upload attempt is made. There are some emerging functionalities like FileReader which may help as browsers mature (as it's not available in all browsers) that should make the upload process far smoother (and will make detection of this situation more simple).
If you use an Ajax style upload process, you could initiate the upload right away to help prevent the issue from occurring in the first place.
Or, a bit hacky: one idea for Firefox would be to add a setTimeout in the onsubmit event that fires after a second ... and checks to see if the upload started (by querying the server using Ajax to a JsonResult action/function that can quickly see if an upload started, etc.). It's a bit messy though as you'll need to worry about timing issues -- and may be overkill just to handle the cases where this is occurring.
I've got a web service that, like most others, uses js and css files. I use the old trick of appending a version number to the js and css file like; ?v=123 and that gets changed every time we update the service on production.
Now, this works fine on all browsers, except for Chrome. Chrome seems to prefer it's cached version over getting the new one and therefor seems to ignore the appended variable. In some cases, forcing it to refresh cache (cmd+r / ctrl+f5) wasn't enough so I had to go into options and clear out the cache for it to load up the new content.
Has anyone experienced this issue with Chrome? And if so, what was the resolution to the problem?
Chrome should certainly treat requests with varying query strings as different requests; a cached result for style.css?v=123 should never be used for style.css?v=124. If you're seeing different behavior, please file a bug at http://new.crbug.com/ and post the bug ID here.
That said, I'd first check to see whether the page was cached longer than you expected. If a new version of the page itself wasn't downloaded, then it would still be requesting ?v=123 as the HTML wouldn't have changed. If you're sending long-lived cache headers with the page, it's certainly possible that Chrome is caching it more aggressively than you expected. If that's the behavior you're seeing, please star http://crbug.com/8742 for updates.
I had also same experience
You can user Ctrl + Shift + R for cache free browsing in both Chrome + Mozilla.
I have had this experience as well.
I run a membership site which displays content such as "You must be logged in as a Gold member in order to see this content" if they are not logged in or are trying to view content not allowed by their membership level. But even if the user is logged in, the user would still see "You need to log in", due to Google Chrome's aggressive caching. In Firefox, however, it works fine as I test logging in and out of all 5 levels of membership - each displaying the proper content.
While Chrome's caching problem can be solved by clearing the cache every time the user logs in and out, it would be really annoying to take that approach.
Background
I'm building an app that links recent
web pages you've visited together.
To do this, I need to get the HTML
for recent URLs using Cocoa.
Right now, I'm using an invisible
WebView to do this.
As I understand it, if the URL isn't
in the cache for my app, this is
hitting web servers.
What I want
The chances are high that the URL I'm grabbing has already been cached by Safari as the page has already been visited.
I want my app to check Safari's cache for the URL first. If it's there, it should just use this data. If not, it should hit the web server and store the page in my app's cache.
I don't really want to have to parse the cache.db file from Safari using sqlite3 - I've no idea if this format will stay the same. I'm after something simpler and more high level.
What I've tried
I know that you can set up your own NSURLCache using the method initWithMemoryCapacity:diskCapacity:diskPath: but I don't want to try pointing this to the Safari cache in case it screws up Safari by writing to it.
Is there an easy, high level way of sharing the Safari cache?
UPDATE
Aha. I've just realised there may be a way to do this I've been missing.
I could make a new instance of NSURLCache with initWithMemoryCapacity:diskCapacity:diskPath:, point it at the Safari cache, then specify a cache policy of NSURLRequestReturnCacheDataDontLoad for the URL Request when loading the page.
When this fails, I could just try and load the page as normal. I'll try this out and update the question when I know more.
To be honest, you just can't do this.
Firstly, I'm pretty certain -[NSURLCache initWithMemoryCapacity:diskCapacity:diskPath:] won't work as you expect. It will instead blow away the old cache file to create its own; potentially highly upsetting Safari.
Secondly NSURLCache is a composite cache. That is, it caches data first in memory, and then moves it out to disk at some point. So even if you could properly access Safari's cache file (which you can't) you'd only be able to access the older cached data; not the most recent.