I have been trying to figure out HTML5's new AppCache, but I feel extremely limited here.
Let's assume that I have a website with four pages:
index.html
about.html
portfolio.html
contact.html
I have the above resources outlined in the manifiest, along with all of the website's resources. The manifest looks like the below:
CACHE MANIFEST
# 2013-05-23 2:33 PM
# Master Manifest
index.html
about.html
portfolio.html
contact.html
styles/reset.css
styles/styles.css
NETWORK:
*
I have added the appcache file type to the server configuration and have used the correct HTML tag attribute on each page listed above. Just for the record, the element looks like so:
<html lang="en" manifest="example.appcache">
I have tested this setup out on my mobile device, and everything works perfectly fine... Unless I don't load every page. It seems that I have to go to each page and cache it via my mobile browser, after which I may turn off DATA and go offline for my device to be able to browse the APPCACHE'd website.
But, here's my question - How do I setup AppCache to allow me to go to index.html, cache that page, and cache the rest of the resources in the manifest? Without having to visit and manually cache each resource?
If you cannot, then I would have to ask; doesn't that sort of defeat the idea behind AppCache and Offline Accessibility?
Thank you so much for the help all! :)
You shouldn't need to visit every page. I know you mentioned you've set the MIME type in Apache, but are you 100% certain it's working correctly?
You can check it by opening your manifest in a browser and checking the Response Headers in Chrome Web Inspectors's Network tab:
Content-Type should be text/cache-manifest
It's a bit hard to debug without having access to your site, but here's some instructions for how to interpret what happens in Chrome's Web Inspector with AppCache to help you debug the problem yourself:
The Resources tab will show you the contents and status of the Application Cache. It looks like this whilst it's downloading files:
The console will also log events when it's downloading:
Application Cache Progress event (0 of 48) http://cachedfile.url
Once it's done downloading it'll look like this and show you the list of cached files:
When you go back it'll log three events (assuming there aren't any changes):
Document was loaded from Application Cache with manifest http://manifest.url
Application Cache Checking event
Application Cache NoUpdate event
And then when you're offline it looks like this:
Hopefully between the console and the appcache table you'll be able to figure out what's happening.
The manifest file is correct and you do not need to visit each page to get in cache in your mobile. You could try if this is a problem with your mobile or browser and if you have defined in your server text/cache-manifest MIME type.
The appcache will only store the cache the first time it's downloaded. It's just a list of files that says, when it's downloaded the first time, cache it.
What you could do is after load in the background do an ajax call to load each of the intended resources but it's not particularly pretty.
So looks to me like it's acting how it should be.
CACHE:
This is the default section for entries. Files listed under
this header (or immediately after the CACHE MANIFEST) will be
explicitly cached after they're downloaded for the first time.
http://www.html5rocks.com/en/tutorials/appcache/beginner/
Ahmed
I get the following when visiting your site:
Creating Application Cache with manifest
http://www.iamaaron.com/appcache/example.appcache
Application Cache Checking event
Application Cache Downloading event
Application Cache Progress event (0 of 6)
http://www.iamaaron.com/appcache/styles/reset.css
Application Cache Progress event (1 of 6)
http://www.iamaaron.com/appcache/index.html
Application Cache Progress event (2 of 6)
http://www.iamaaron.com/appcache/contact.html
Application Cache Progress event (3 of 6)
http://www.iamaaron.com/appcache/attendees.html
Application Cache Progress event (4 of 6)
http://www.iamaaron.com/appcache/events.html
Application Cache Progress event (5 of 6)
http://www.iamaaron.com/appcache/styles/styles.css
Application Cache Error event: Resource fetch failed (404)
http://www.iamaaron.com/appcache/styles/styles.css
So, it looks like it's working correctly despite the Content-Type being empty, except for the CSS file which seems to be missing (the URL is wrong, it should be main.css by the looks of things).
BUT my developer tools don't show the app cache being filled and it doesn't work when it's offline.
Try and fix your 404 error with the CSS and make sure your apache it configured correctly to return the correct Content-Type, I reckon that's what's causing issues.
Related
I am working on an HTML app for a client. The entire app front end is done with 1 HTML file, 1 Javascript file, 1 CSS file (plus jquery) and a few images. There are a few php scripts sitting on the server, which are called using AJAX, but only if an internet connection is available. If no connection is available, then the site will use locally cached data (using localStorage).
To make the site available offline, I'm declaring the cache manifest in my HTML. My HTML looks like this:
<!DOCTYPE html>
<html manifest="cache.manifest.php" language="en">
...
</html>
The cache.manifest.php's output look like this:
CACHE MANIFEST
#VersionHash: 80b9345e6c39efbbe8431e394b014b4f
CACHE:
/css/ebot.css
/favicon.ico
/images/appicon.png
/images/list-arrow.png
/images/list-checkmark.png
/images/woman.png
/index.html
/js/jquery-1.8.3.min.js
/js/ebot.ls.js
NETWORK:
/emaillog.php
/getdata.php
/uploadlog.php
So far so good. Now, I access the site from a browser with the internet connection available. I get a little notification asking whether to allow the site to store information for offline use - I allow it. When I check in settings, I see that the site stores 316K of data - about right.
Now I turn off internet connection and attempt to access http://www.mysite.com/index.html - and get an error message saying "Internet connection not available" (or something to that extent) and the page is not displayed. This is happening in 3 browsers I tested on my dev machine (firefox, safari and chrome) as well as on the client's ipad (the app is eventually for consumption on an ipad).
What am I missing here? What am I doing wrong?
There could be many reasons for this.
Take a look at this articles:
http://www.fuckyeahtml5.com/2011/06/debugging-html5s-offline-web-apps
http://appcachefacts.info/
http://diveintohtml5.info/offline.html
https://developer.mozilla.org/en/docs/HTML/Using_the_application_cache
I guess that you didn't specify proper content type (MIME) for your manifest. It shoud be 'text/cache-manifest'.
Check events in console in Chrome. You should see something like this when appcache manifest is correct:
Creating Application Cache with manifest http://example.com/manifest.appcache
Application Cache Checking event
Application Cache Downloading event
Application Cache Progress event (YYY of XXX)
Application Cache Cached event
I would suggest to start from the simplest manifest to make sure that manifest is parsed. Try:
CACHE MANIFEST
NETWORK:
*
such manifest should cache only your start html page.
I am trying to store a mp4 video file (rather small ~ 2.5MB) in the local app cache.
Manifest looks like:
CACHE MANIFEST
viddy.mp4
Chrome (22.0.1229.94 m) will log the following in the console:
Creating Application Cache with manifest http://example.net/cache.manifest
Application Cache Checking event
Application Cache Downloading event
Application Cache Progress event (0 of 1) http://example.net/viddy.mp4
Application Cache Error event: Resource fetch failed (-1) http://example.net/viddy.mp4
When I click the link right next to the Error it's opening the file quite fine.
My manifest is served with the correct MIME-type (I'm using the HTML5 Boilerplate .htaccess-file) and the video is served Content-Type:video/mp4
Is my file too big? I am perfectly able to cache a 1MB image this way, so I thought filesize should not be a problem? Safari on desktop and iPad does cache the video just fine.
Remark: I have seen this question but it does not cover my problem as the solution seemed to be something Python-related.
Chrome does not allow data to be stored in Incognito Mode.
I experienced similar problem and this is how I solve it. In this case Chrome does not give any helpful information about error. I've tried to load same page in Safari (Mac, but Windows should work as well), and I got description, that response for specified resource returns 302 (Redirect) and HTML5 Application Cache cannot handle it.
In your case it might be the same, but I'd suggest you to enable the sniffer and see, what response you get from your resource. If it's different than 200 - you figured the issue.
P.S. I've cached files up to 32 MB without any problems.
I am trying create an app which has offline features. The manifest file that I have created looks like this-
CACHE MANIFEST
# version 1.0.0
CACHE:
/ShareBill.Web-Offline/
/ShareBill.Web-Offline/Groups
/ShareBill.Web-Offline/Content/Site.css
/ShareBill.Web-Offline/Content/jquery-ui.css
/ShareBill.Web-Offline/Scripts/ShareBill.js
/ShareBill.Web-Offline/Scripts/lib/jquery-1.7.2.min.js
/ShareBill.Web-Offline/Scripts/lib/jquery-ui.min.js
/ShareBill.Web-Offline/Scripts/TransactionsIndex.js
/ShareBill.Web-Offline/Content/Images/ajax-loader.gif
/ShareBill.Web-Offline/Content/Images/br_down_icon.png
NETWORK:
/ShareBill.Web-Offline/Transactions/Filters
What I expect is when I view this url /ShareBill.Web-Offline/Groups. My browser should not make any requests to the server else the whole purpose of being offline would be void.
But as I can observe using fiddler is that, the browser makes a request for the manifest file every time i refresh the page. I made sure that I see the cached resources in the Chrome dev tools.
Now when I turn my IIS off and make a request like this, I end making my AppCache status as OBSOLETE. Then on the very next page refresh, I get a 404 response. Am I missing something in terms of implementation?
I applied the Expires header to request that was asking for the Manifest file. And that worked :)
I have a special kiosk-solution with chrome where I need chrome to upon application start, load the start-url from cache, not try to fetch it online.
The reason is that this is, like I said, a kiosk-mode presentation, is is a screen standing in the public that reboots every night, and if the reboot happens while the ISP has downtime on the internet connection, chrome will only show an error page.
If I can get it to load the cached version of the page though, instead of trying to fetch it online, then the last valid version of the page will show, and through some nifty ajax-workings of mine ;) it will automatically update after a while. If THAT update fails, the currently displayed version of the page will remain until a subsequent update succeeds.
See my problem?
In a browser like firefox I could do it by starting the browser in off-line mode and after page load switch it to online-mode. Only FF doesn't work for me in the particulat project, and Chrome doesn't seem to have an off-line mode?
You could use HTML5 Offline Web Applications to accomplish that. It's probably very easy to set up in your case, just add a file like the following to your app's directory:
CACHE MANIFEST
index.html
help.html
style/default.css
images/logo.png
images/backgound.png
NETWORK:
server.cgi
This manifest should contain all the files you'll need to display some useful information and later grab current content via AJAX. There's also a NETWORK section, where you have to specify things that should not be cached (ie the script that delivers your Updates via AJAX).
You can load the manifest file by adding a manifest attribute to your tag (cache-manifest is the name of the file above):
<html manifest="cache-manifest">
Make sure your server delivers the cache manifest with a MIME-type of
text/cache-manifest MIME
Type or copy-paste the below flag setting into the chrome address bar.
chrome://flags/#enable-offline-mode
scroll down to enable offline stale mode.
Restart your browser.
If an offline version of the page is available in the system cache it will load up when you are not connected.
One thing I'm not fully grasping is if the cache manifest is also acting as a prefetch when it is online for all the files listed.
For example, lets say I'm visiting:
/page1.html
Each of the pages on my site will have the same declaration:
<html manifest="/cache.manifest">
In the cache manifest file, I have:
CACHE MANIFEST
/page2.html
/page3.html
/page4.html
So what will happen is I visit /page1.html first, and when I'm online my browser will know to cache pages 2-4 also. And when I'm disconnected and I visit pages 2-4 everything will load just fine because it was already cached.
QUESTION: If I visit /page1.html, and I'm STILL connected online, and visit /page2.html, will my browser still request /page2.html, or will it not make another request to the server and use what it cached from the /cache.manifest file? Essentially acting like the prefetch link that firefox uses?
Well, the spec says "all files," without any exceptions for html files, so I figure it works for html files just like any other, it gets taken from the cache, not the server. However, I have not done any testing to confirm this. I would do the following:
Create the following cache manifest file:
CACHE MANIFEST
/page1.html
/page2.html
/page3.html
/page4.html
Include it in each of the four cache manifest files. Then:
Visit page1.html
Edit page2.html to make it different than before you visited page1.html
Visit page2.html
See which version you get.
Make sure you try it out on all browsers. I'll be interested to see your results.
When we use cache manifest it takes the files from the cache each time you load the page.
There is a solution for this.
You have to change the version number in the manifest file, If at all you have done any changes to the HTML files. so that your manifest pulls in the latest version of the HTML from the server and Stores it in Cache.
CACHE MANIFEST
#v01
/page1.html
/page2.html
/page3.html
/page4.html
You can just Increment the V01 to 02,03... So on, this will ensure your cache will have latest version of html pages
I think it takes it from the manifest file even if you are online :). Can't you try it out by uploading a file and then navigating to the page?