I've read in a few places that file upload progress is not supported in IE9.
However I notice that gmail has some sort of solution for it. I've read articles from a couple of years ago that it is a flash-based solution but when I got the inspector tool out, I couldn't see any flash objects. I'm wondering whether anything has changed in that time.
Is anybody able to describe how gmail has solved the 'file upload progress' problem in IE9?
I do not know how gmail does it, but one possible solution is to start the upload asynchronously (javascript, iframe, whatever) and then poll the upload progress regularly from the server.
Assuming you have some kind of session identifying the user, the upload is sent to the server which updates some progress variable in the user's session while the file is being transferred. At the same time, the client polls the progress variable once a second via separate AJAX calls to the server.
Related
I am able to load and display files using the HTMLLoader class. http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/html/HTMLLoader.html
Problem is, when a user navigates to a download link or an upload button, nothing happens. I heard somewhere that any downloads get sent over to the user's main document folder. Anyway to intercept this and get some details? Someone in my browsing history suggested to somehow get it using the Socket class to fetch it's data and control where it would go using the File class. I couldn't make out the demonstration.
Bonus question...what properties do I have to set to make Google understand that this browser is not a bot? I get this in plain text when trying to navgiate to http://www.google.com . It's other services work completely fine though.
Google
Sorry...
We're sorry...
... but your computer or network may be sending automated queries. To protect our users, we can't process your request right now.
I'm developing a Windows Phone 8.1 (non silverlight) project and i'm very new to the platform.
I'm having a really hard time trying to access a pdf file from the web and saving it to the phone. First, i searched for how to display the pdf file inside the app without saving it, and learned that it can't be done.
Then i searched for a way to download the file and save it localy. Every example i found ended it up in a dead end; i tried with WebClient, and found out that i must switch to HttpClient, i tried with IsolateStorageFile and found that i must use ApplicationDataContainer.
It's becoming really frustrating searching for simple things for hours and hours without any result.
Can someone point me to an example, or anything else ?
Downloading a file for the user means that you have to take care of a variety of things:
1) The app must stay responsive while the user waits for the download to complete.
2) You have to provide some kind of status information.
3) The download should continue if your app gets suspended (e.g.: the user hits the home button).
That's why big /unknown size or slow file downloads should be load off to a background task.
This article will provide you with a working example:
http://www.informit.com/articles/article.aspx?p=2229233&seqNum=6
I've developed an iPad web app that uses the appcache. It's not intended to be a fully offline app but I use the appcache to store large image files so that they're not sent over 3G. Problem is when the manifest is updated the appcache updates whether the iPad is on wifi or 3G, which could be expensive.
Is it possible to have the user decide if the appcache can be updated or not? From what I've seen, this isn't possible, it all happens automatically, you just get events. But perhaps there's some trickery like writing the manifest on the fly or similar.
Using PHP on the server side if that helps. Thanks.
Connection Type: Theory & Future
There is a draft spec of Network Information API on W3C that provides the information of the connection type (ethernet wifi 2g 3g 4g etc.), but it hasn't been implemented on any browser yet apart from:
the stock Android browser on Android 2.2+ (not the Google Chrome browser)
navigator.connection.type // Based on W3C draft, (Implemented on stock Android browser)
and PhoneGap which is not exactly a browser
navigator.network.connection.type // on PhoneGap
Having that information in the future you could detect if the user has cellular data, then temporarily remove the src of the images and ask the user through a confirmation dialog.
You will also probably have to cancel the app cache update using:
window.applicationCache.abort() (documentation)
Reality
Unfortunately, the Net Info API is not available (at least not widespread) at the moment, but certainly will help in the future.
Long shot
There is a database that includes network speed (DIAL = dial up, DSL = broadband/cable, COMP = company/T1), but I haven't used it and I doubt it will help.
Dynamic App Cache
While checking into this, I tried to generate the html tag along with the manifest declaration on the fly, in order to combine it with the Network Info API but the AppCache manifest is loaded before javascript execution and is not affected afterwards.
So altering the manifest file on the fly through Javascript is not possible and data URI is not an option.
Alternative solution
HTML5 application cache is an untamed beast at the moment and there are talks to improve it. Until it changes to support more complex configurations (bandwidth level flag would be awesome), you could change perspective on the solution, although App Cache may be the best you have at the moment.
Depending on how big your images are you could rely on the normal browser cache. You could combine localStorage and far-future expiration HTTP headers. LocalStorage in order to keep track of the loaded/cached images.
First add a far in the future date for expiration on your images HTTP headers
On page load, remove all src from imgs
Loop the images and check localStorage if each image was loaded in the past
If there are images that were not loaded in the past, display a dialog confirming for the downloading of those images
If the image was loaded in the past, then put back the src on the img
For every image that is downloaded, save its URL on localStorage
I don't know what the status of indexedDB is on the iPad, but this could be an alternative solution.
In short: Indexeddb is a clientside database. Data is stored in object stores which are key/value pairs. The maximum storage capacity is in theory the maximum of your disk space. For more information about indexeddb:
Specification
My blog
What you could do with the indexeddb:
When someone navigates to a page:
Check every image tag if it is present in the indexeddb
if present
Get the image from the indexeddb and put it in the image tag
if not present
Download it
store it in the indexeddb
put the image in the image tag.
As extra (in the future) you can do as discribed by Sev: check the connetion type and only download the image when working on a fast internet connection.
I have 'invented' a working solution developing a webapp on the iPad (iOS 6.0.x) that may answer your question.
The idea is first to check if a localstorage variable is set/defined or not yet (I use the title of the page, thus the webapp name.)
If this localstorage variable exists, then assume (in webapp sandbox context) that its the first time the app is being run. At this point I populate a UUID in conjunction with $PHP_SESSION($uuid) to avoid 'cross app contamination' in server-side PHP land.
In addition to this I have a dynamic manifest.appcache.php which includes in the CACHE section a list of files to add to the manifest. Thus;
<?
echo $manifest_file_list[0]."\n";
?>
Using the JS appcache manifest event listeners I then monitor the progress to something like $('#manifestappcache').html(result);
From my experiences so far, I've concluded that the HTML5 Manifest scheme was really terribly designed.
My site serves a manifest file when a user is logged in. Unfortunately, when they log out, they can still access the cached protected materials. Can anyone think of a way to fix this?
A manifest file is designed to take a website offline and still be able to navigate. It essentially just tells the browser to download and keep that stuff in cache. If your adding secret stuff to the manifest and the user goes offline, he needs to be able to still access it - or whats the point of having a special logged-in-manifest-file if he has to be loggedin (therefor online)?
You could add javascript that checks if the user is online again and if he is, tries to validate the "login state" and redirects or removes the secret stuff from localstorage (if you would use localstorage to save the "secret" stuff and javascript to display it instead of a manifest file )
Lets say the secret stuff is an image and you are not using a manifest file, but just displaying images when the user is logged in and its crusial, the user cant view that image after logout, you would need to set the http headers to no-cache and cache-expire to some random date of the past, so that a normal user would see it anymore. Problem then is, that the image is downloaded everytime somebody visits the website..
You need to approach the HTML5 Application Cache in a different way. It is not useful for caching server-side dynamically generated pages, especially those that require a login to reach. The Application Cache has no concept of logins, nor securing a page from somebody with a different/no login.
It is much more appropriate for an AJAX-based site, where all HTML/CSS/JavaScript is static and registered in the Application Cache, and data is instead fetched via AJAX then used to populate pages. If you need to cache data in the application for offline use, then use one of the offline data storage mechanisms such as Local Storage/Session Storage, or IndexedDB, for data.
You can then make your own judgement on how much data you want to cache offline, since there's no way to validate a login without making a call to the server that is naturally inaccessable whilst offline.
What if when the user logs out or is not logged in they get a manifest with only network:*
I'd like to try my hand at some Chrome Extension Development. The most I have done with extensions is writing some small Greasemonkey scripts in the past.
I would like to use localStorage to store some data and then reveal the data on a extension button click later on. (Its seems like this would be done with a popup page)
How do I run a script everytime a page from lets say http://www.facebook.com/* is loaded?
How do I get access to the page? I think based off my localStorage requirement I would have to go down the background_page route (correct?) Can the background page and popup page communicate across the localStorage?
UPDATE:
I'm actually looking to learn the "Chrome way". I'm not really looking to run an existing Greasemonkey script
Google actually has some pretty good documentation on creating extensions. I recommend thoroughly reading the following two articles if you haven't already done so:
http://code.google.com/chrome/extensions/getstarted.html
http://code.google.com/chrome/extensions/overview.html
If you want to give your extension access when the user browses to Facebook, you'll need to declare that in the extension's manifest.
Unless you're wanting to save data beyond the life of the browser process, you probably don't need to use local storage. In-memory data can just be stored as part of the background page.
Content scripts (which run when you load a page) and background pages (which exist for the duration of the browser process) can communicate via message passing, which is described here:
http://code.google.com/chrome/extensions/messaging.html
Overall, I'd suggest spending some time browsing the Developer's Guide and becoming familiar with the concepts and examples.
Chrome has a feature to automatically convert greasemonkey scripts to extensions!