I have an appcache (with NETWORK *). So now I visit my page with <html manifest="/cache.appcache">. Then the page itself is cached as all the images are. But I want the page self to not be cached. How can I do this? I thought NETWORK * would do the trick.
Regards,
Kevin
The appcache manifest always caches the master page.
If you are using Chrome check the cached files for your page here: chrome://appcache-internals
A workaround could be to put a hidden iframe somewhere on your page, which contains the appcache file to cache offline content. (take a look at "Preventing the application cache from storing masters with an iframe" here: http://labs.ft.com/2012/11/using-an-iframe-to-stop-app-cache-storing-masters/ )
A better solution could be to write your page to fetch new content from your server when it is opened - if the server cannot be reached, it can serve the last known content from the HTML5 local storage.
I have tried the iframe work around, and find it ripe with errors. Most browsers cache the data for the iframe where the page cannot get it.
Instead make the page's content load via AJAX. Basically have a blank html page with the manifest and javascript which pulls and adds its content from the server. This way only the blank html is cached, and content is always updated from the server.
Converting a page to this method can be very difficult, but it works. Making sure the appropriate javascript gets run at the correct time, probably requires some detangling. Moving around server code which won't be called when pulling from cache to the new ajax method.
Note: no need to pull conditional content from the server if the condition is in the query string, different query strings make a separate cache
Related
Currently, I am facing an issue with HTML page. So here if a user visited the site then the browser is caching the entire HTML page. So when the user hits the URL again then the browser taking that HTML from the cache instead of calling/requesting to the server for HTML contents. Here our Team member forgot to add meta tags which would force the browser to take content from Server each time. Is there any way that we could resolve the issue? Since the page request itself not reaching the server so User will not see the refresh contents of the website. If user do Ctrl+F5 then they can see updated contents. I went through many sites and stack overflow questions but I did find a solution for forcing HTML page to load contents from server using meta tags.But existing users is there any resolution that we could apply?
Problem is here the page did not call server to get contents it just loads from cache.
There's nothing you can do.
You've previously instructed the browser to cache the file (presumably for a long time) and not check for updates (via ETags or If-Modified-Since) so it is going to use the cached version until its cache expires (from the user intervening or automatically (which might be sooner than your caching instructions said)).
There's no way to provide new caching instructions to the browser without it requesting them from the server (which it won't do because of the existing rules).
I would like to know the mechanism behind reloading/ refreshing a Webpage. My questions are-
1. Does reloading/ refreshing a webpage that completely failed to load earlier always result in instant loading of the entire webpage correctly with all its contents?
2. Or does it result in delayed loading of the entire webpage?
3. Or does it result in delayed loading of the webpage with some contents (Ex. images) missing?
4. Or does it do nothing? ie., the page still fails to load because the server is down?
I know that all these scenarios are possible. But I would like to know what causes each of these above scenarios? (For Ex. is it the server being down or busy or the content not being available anymore?)
Also I would like to know what happens in these two cases-
->when content is fetched from a single server
->when content is fetched from multiple servers
Reloading does not always result in instant loading of the entire webpage correctly. There are many different reason a page may not load correctly, many of them simply reloading the page will not fix. There are so any reasons there really isn't time to explain here.
I should load with the same data it received before reloading the page. Unless something has changed in the interim.
If the server is down. Reloading the page will not result in the page loading correctly the second time.
When content is fetched from a single server the content comes from just that server. When content is served from multiple servers, say the images are being served from a CDN, they are loaded from those places.
Reloading a page does nothing different that when you first visit a page. Although in certain circumstances the local browser cache may be reset.
I have a site which has 10mb+ of images (1000+ pngs) that have to be loaded before it starts. My current approach is loading every image in a hidden tag. How can I ensure that a client that accesses the site once/month, for example, will never have to download it all again?
No way. Client may have cache disabled, or he clears it every single minute
Compressed textures/generated textures/reused textures are how you should do it. You can't cache 10mb of images for a month reliably. If you need it for the game, then simply have a loading bar beforehand.
It sounds like you want to use an application cache. This means dealing with the page and its images as an application, with a cache manifest (.appcache file) listing them and the HTML document containing an <html manifest="..."> tag. See e.g. A Beginner's Guide to Using the Application Cache.
For performance purposes, I want to have some of my web pages use resources that have been cached for offline use (images, CSS, etc.) but to not have the page itself cached as the content will be generated dynamically.
One way to do this would be to refactor my pages so that they load the dynamic content via AJAX or by looking things up in LocalStorage. Details may vary, but broadly speaking, something like that.
If it's possible, I'd prefer to find a way to simply instruct the browser to use cached resources (again, images, CSS, etc.) for the page but to not actually cache the (dynamically generated) HTML content itself.
Is there a way to do that with HTML5 offline appcache? I'm under the impression that the answer is "no" because:
Any page that includes the manifest will be cached so I can't specify the cached resources in the page itself.
There is no way to tell a previous page "use offline assets for this other page but don't actually cache the HTML on that page". You have to specify the page itself, which means the HTML will be cached.
Am I wrong about that? It seems like there is probably some tricky (or not-so-tricky) way around that. Now that I've typed it out, I wonder if including the page explicitly in the NETWORK section of the appcache manifest will do the trick.
My answer is "yes".
I have worked on a web-app where I listed all the necessary resources in the manifest, and set the NETWORK section to *.
The manifest is then included only on the main landing page. So all resources are cached the first time you visit the site and and it works a treat.
In short,
one of your pages must include the manifest and will therefore be cached.
maybe you can have the manifest loaded in a iframe and not have the whole page cached, just a thought.
list all your resources to be cached in the CACHE section
set the NETWORK section to *
I'm fairly certain that the answer to this is no.
If you use the Network section in Chrome, then it shows which resources are loaded from the cache and which are loaded from the server. I have attempted to set the appcache as described above and the resources are always loaded from the server.
Would I be correct in assuming that if the current page is not in the appcache then it wont bother to check in the appcache for any of the resources?
What I've found that is working is to list those files that you don't want cached in appcache in the NETWORK: section of the manifest. For me, that meant adding *.asp* to the network section. Now, none of the classic asp files, or aspx files are cached.
I have a situation where my page loads some information from a database, which is then modified through AJAX.
I click a link to another page, then use the 'back' button to return to the original page.
The changes to the page through AJAX I made before don't appear, because the browser has the unchanged page stored in the cache.
Is there a way of fixing this without setting the page not to cache at all?
Thanks :)
Imagine that each request to the server for information, including the initial page load and each ajax request, are distinct entities. Each one may or may not be cached anywhere between the server and the browser.
You are modifying the initial page that was served to you (and cached by the browser, in most cases) with arbitrary requests to the server and dynamic DOM manipulation. The browser has to capacity to track these changed.
You will have to maintain state, maybe using a cookie, in order to reconstruct the page. In fact, it seems to me that a dynamically generated document that you may wish to move to and from should definitely have a workflow defined that persists and retrieves it's state.
Perhaps set a cookie for each manipulated element with the key that was sent to the server to get the data?