Is it possible to create an ApplicationUpdater in an AIR app that uses some sort of authentication (perhaps HTTP Basic) to download updates from the server? I want to enable auto-updating in a proprietary application, so it doesn't make sense to upload updates to a publicly accessible web location, since only people who already have the application should be able to get updates.
If I understand this what you wrote the right way you just use XML on your Server which will at start up read out IF OR IF NOT to update just the same way the ADOBE updater works, and with that you can use true / false etc. at least that how I did it with some of my AIR Applications! all can be enforced (visible or invisible) or just by the user done like YES / NO etc. endless options. regards aktell
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I'm working on a desktop application that uses API keys for Twitter but AFAIK, AIR applicatioons are easy to decompile. I want the processing of the API requests to be client-side, not server-sided. At most, I want to keep the dependency onto the server to as low as possible.
What I'm thinking is sending the API from the server to the AIR app on the first run. I've already seen Shared secret with API in an Ajax Adobe AIR app but my question is a bit different in that, I want to know how secure ELS is?
How does Adobe work it's way to storing stuff into the ELS? Does it go through multiple encryption sessions before finally getting stored somewhere on the computer?
Anything that an application on the user's desktop can read, can also be read by the user himself. They can get the key by using a proxy (like Charles) when you send it from or to the server; or they can read it with a debugger when AIR writes it to the ELS.
If I'm not mistaken, Twitter's API keys are public anyway (its only purpose is to track how you are using their API). Are you worried that a user might use your key for their own application? If they do that, all you have to do is get a new Twitter key.
I need an offline caching system where my app can store about 0.5 MB of data. It is preferred that there is no interaction required by the user, but small amount of user interaction might be acceptable
Currently, Microsoft's Silverlight is being used to store data offline. It is a large download for the plugin, and not installed as standard on most machines.
I have been considering cookies - but they are far too volatile. I can imagine numerous reasons someone might clear their browser cache and lose all their data.
I am not sure about HTML 5 storage, and how volatile it is in practice.
I have been looking into flash, which is installed on over 97% of windows computers. It seems I can load data from a user selected file, and save data to a user selected file.
My questions...
How big is the microsoft silverlight plugin download (in MB) for windows? (I think about 8mb, but did not get clear answer from the internet)
How can users accidentally (or deliberately without realizing the consequence) clear their HTML 5 storage on common browsers?
Is there a way to get flash to store or load data from local files without user interaction?
Is there another alternative I have not considered?
Well you could use Flash shared Object storage, which will allow between 0 and unlimited space. Check this settings panel for details of your own settings to get a better idea of what I mean.
http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html
Of course this does mean that the user will have to allow third party flash content to be stored locally, which is the default. Also the default storage space is 100KB, with the user being prompted to allow for a larger amount unless they have previously increased the default themselves. So that's a small draw back, but still workable.
I am not sure how you would access the shared object from within a silverlight app, as I have only used it via a Flash swf. I will do some digging around using javascript and get back to you on that.
Also there is another post that may help you:
Javascript bridge to Flash to store SO "cookies" within flash
It sounds like what you need is isolated storage.
I use it with all my silverlight apps and it couldn't be easier to use. With only a few calls you can store and retrieve data programatically.
Edit: I was thinking that your app is already programmed in Silverlight. What is your app programmed in? Is it simply HTML/CSS at the moment?
How do I setup the basic switching of offline storage modes (offline/online) in Web SQL? I know there's javascript
window.navigator.onLine. I can check the mode and then go through a process...
//All GET/POST performed with AJAX
//On Startup pulldown entire accessible database into offline storage (Doesn't seem secure IMO)
//if(read) pull from offline
//if(create, update, delete and online) pull from standard db, mark changes with offline expiration flag
//if(create, update, delete and offline) perform operation on offline storage, persist with POST when next online (change flag)
I'm asking if there is any OOB integration for these standard tasks?
The navigator.online property generally isn't very useful - in a desktop browser all it does is hook into the File -> Work Offline menu. It may be more useful on an iPad, I don't know because I don't have one, and I'm guessing there's not a File menu, but I would recommend you test.
A common approach to this issue is to set up two easily distinguishable files in the fallback section of your manifest. Every time you want to connect back to the server attempt to fetch the file with AJAX and, in the callback, check it to see if you got the online file or the fallback, then branch accordingly.
You shouldn't be using Web SQL as that spec was nixed a new months ago. You should be using Localstorage. Unless you are specifically coding for something like the iphone, but even then you dont know how long the spec will be in webkit.
Is it possible to build an application inside in browser? An application means:
1 Where there is connection (online mode) between the browser and an remote application server:
the application runs in typical web-based mode
the application stores necessary data in offline storage, to be used in offline mode (2)
the application sync/push data (captured during offline mode) back to the server when it is resumed from offline mode back to online mode
2 Where there is no connection (offline mode) between the browser and an remote application server:
the application will still run (javascript?)
the application will present data (which is stored offline) to user
the application can accept input from user (and store/append in offline storage)
Is this possible? If the answer is a yes, is there any (Ruby/Python/PHP) framework being built?
Thanks
Yes, that is possible.
You need to write the application in Javascript, and detect somehow whether the browser is in offline mode (simplest is to poll a server once in a while). (Edit: see comments for a better way to detect offline mode)
Make sure that your application consists of only static HTML, Js and CSS files (or set the caching policy manually in your script so that your browser will remember them in offline mode). Updates to the page are done through JS DOM manipulation, not through the server (a framework such as ExtJS http://www.extjs.com will help you here)
For storage, use a module such as PersistJS ( http://github.com/jeremydurham/persist-js ), which uses the local storage of the browser to keep track of data. When connection is restored, synchronize with the server.
You need to pre-cache images and other assets used, otherwse they will be unavailable in offline mode if you didn't use them before.
Again: the bulk of your app needs to be in javascript, a PHP/Ruby/Python framework will help you little if the server is unreachable. The server is probably kept as simple as possible, a REST-like AJAX API to store and load data.
The "Let's Take This Offline" chapter in Mark Pilgrim's (online) book Dive Into HTML5 is a very nice overview of writing offline web apps with HTML5 technologies.
Note: Since Mark Pilgrim's original Dive Into HTML5 link seems to be down.
Copies can now be found here among other places.
Jake Archibald wrote "The offline cookbook". A modern (9 December 2014) and nice approach with ServiceWorker:
http://jakearchibald.com/2014/offline-cookbook/
The answer in 2018 is to leverage the service worker, and to build a Progressive Web App:
https://developers.google.com/web/progressive-web-apps/
i was looking for this also, i found out abt HTML5 Offline Web Apps. havent tried it tho
Users of typical online Web applications are only able to use the applications while they have a connection to the Internet. When they go offline, they can no longer check their e-mail, browse their calendar appointments, or prepare presentations with their online tools. Meanwhile, native applications provide those features: e-mail clients cache folders locally, calendars store their events locally, presentation packages store their data files locally.
Have a look at Google Gears, http://code.google.com/apis/gears/. Although they have been phased out in favour of HTML5. However, it seems that what is being pushed as HTML5 is Google Gears.
Consider the following scanning procedure in a typical document handling webapp:
The user scans a document using a scanner connected to his/her computer
The scanned image is saved locally on the user's computer as a BMP/JPG/TIF/PNG file
The user hits a file upload "Browse.." button in the web application
The user is presented with a file dialog which he/she uses to locate the scanned image
The user hits "Upload image" and the scanned image is uploaded to the server where it is stored
This process is quite complicated and I'd like to reduce the number of steps in order to make the process more user friendly/fool proof. Under ideal circumstances the above steps would be replaced with only one step in which the procedure initiate document scanning, complete document scanning and upload resulting image is automatically triggered from the webapp when clicking say "Scan and upload". Unfortunely it seems like the state of "web/scanner integration" is quite poor so this might be utopia.
How would you tackle this problem? More specifically, how would you go about reducing the number steps involve in the use-case described?
Well, two years have passed, so here's an update on the state of the art for those just joining us.
Both Dynamsoft and Atalasoft have multi-browser web-scanning toolkits which are compatible with any server-side stack. Both require the user to install an ActiveX (in IE) or an NPAPI plugin (Chrome, Firefox, etc.) to get access to the scanner via the TWAIN API.
Obviously if you have the time or a limited budget, you can create your own plugin. I heartily recommend the FireBreath plugin framework, and any TWAIN library rather than writing your own TWAIN code.
Once the ActiveX or plugin is installed, the rest of the work is a combination of javascript & HTML on the client, and some kind of handler on the server to accept and process the incoming image, which can be made to look just like a multipart form submit with an attached file.
I recommend doing the image upload in javascript using AJAX, because it is then part of the same browser 'session' as the web page, and it inherits the browser's proxy settings, session cookies and server-side authentication. I don't know about Dynamsoft's control, the Atalasoft toolkit includes such AJAX uploading. The image(s) are handed from the plugin to the javascript as a base64-encoded string, so no local file is actually created.
Disclaimer: I work on Atalasoft's WingScan web-scanning toolkit.
If your target audience is running Windows and IE, and you don't mind spending a few $$, Atalasoft has some components that will do just what you're looking for.
I actually saw someone at the bank do this while setting up my account and I was totally amazed. Bank in question was using Windows and IE, I assume your in an equally controlled environment. I think the bank used a combination of a custom/ predictable scanner driver and an ActiveX control.
A page loaded which said "Open the scanner" the staff member popped the document in and hit Scan on the webpage, then the page changed to say Scanning, then it showed the scanned document on the web page for the staff member to Approve. I can only assume that the scanner driver send the image to a certain location and the active X control was polling for it to appear, once it appeared it showed the image on screen, once the staff member had approved it the active x uploaded it in the background. She opened the next page and carried on with the rest of the process.
God knows how they made all that tech work but it can be done.
Silverlight 4 is coming out soon. It is supposed to have the ability to interact with COM objects on the user's computer (provided they are running Windows). In theory you call WIA methods from your Silverlight web page.
We implemented a solution to implement Remote Deposit for a bank. It works only in IE. A winforms dll was created that interfaces with LeadTools TWAIN dll. Leadtools TWAIN dll abstracts all the TWAIN minutae. This approach is slighly better than using an ActiveX control. .NET Framework would be needed on client. The scanned images are posted back to a hidden variable on the page and are processed on the server.
Hmm, I've always wanted to look at a scanned file before I did anything with it, but I suppose that depends on your scanner and how much quality you need.
If the goal is to "automate the scanning and uploading process" as opposed to "write a web app", I'd write an AutoIt script to control the existing scanner software and a simple ftp program.
The option most likely to remove the most steps, would probably be writing a customized scan utility that the user would download and run on their local machine.
SANE or TWAIN would handle getting the scanned image. cURL could than handle uploading the image to your web app. To make things even easier for the end user, I would use something like a Comet connection to update the web page when the file was available.
If that isn't an option, you might look into seeing what options your users will likely have using their scanners software. I believe many programs now support scanning to email or ftp.
The solution I have used for an intranet app, using multifunction scanner/copiers was to scan to an SMB share that the web server had access to. The user just goes to the copier scans to the share and when they get back to their desk, they go to the new scans page which shows a list of all the new unprocessed files.
Since your audience is controlled environment, You can write your own browser extension/program based on WIA/TWAIN that does the scanning. If you choose browser extensions such as BHO/ActiveX/XPCOM, etc, you need get the user's permission to install your extension. If you choose to write a program you may need web deployment technologies like ClickOnce or Java Web Start to be launched from web.
Interfacing TWAIN is a pain on Windows. Complexity aside, you have to display some GUI written by different scanner driver developers. It may be the only way to support old scanners or features not exposed via other interfaces like full-speed multipage scans from a document feeder.
Microsoft's WIA makes interfacing with scanner much easier with a scripting object model, however scanner-specific features are not available and some old scanners do not support the interface.
After scanning you can call a web service to notify the server and the web page can refresh periodically to check new images.
We have done something similar. we used a command-line TWAIN program (http://www.burrotech.com/quickscan.php). $$ $49
1) We developed a small .Net application to run the QuickScan program as a shell command.
2) The command was assigned to the Scan button.
3) Once the user presses on the scan button, a prompt will appear to enter the file name. The user saves the transaction Id as the file name.
4) Another .Net application (or maybe the same mentioned before) will read this file and upload it into database considering that the filename is the transaction ID.
Worked like a warm knife in butter!
You can try displaying the transaction ID into IE, user to select the ID then presses Scan. Your application will read the SELECTED text and save the file using the SELECTED text as the file name. We havne't tried it but it should work.
It is only utopia if you think that web applications are limited to web browsers, in fact, web applications can include a lot of different technologies, besides HTML and Javascript.
The cool way of solving that problem -- in fact, I already used that for some usbserial devices -- is to implement your application using SOAP+XMPP. You can do that in Perl by using XML::CompileX::Transport::SOAPXMPP, Catalyst::Engine::XMPP2, Catalyst::Controller::SOAP and Catalyst::Model::SOAP.
The interesting thing about using XMPP is that it simplifies the management of addressing, since you use the JID (Jabber ID) to look for the software agent, not some host+port addressing schema. The second interesting part of using XMPP is to more easily support the server pushing information to the client.
But if you don't want to handle XMPP you still can do the same thing with a lightweight embedded http server -- HTTP::Server::Simple, in Perl -- and somehow register the current scanner address in the server so it can call back.
And a last option, which is not so cute, is to have the software agent polling the server to see when there is a "scan document and upload" order for that specific machine and realize that operation when that is present.
In summary, having a local software agent to interact with the local hardware doesn't make your webapp less "web", as long as you use web standards -- like XML, SOAP and others -- to perform that communication.
You can put a Java applet in your website. This can access the scanner and send the data via REST to your web server.