In my current project we are trying to integrate a card reader into a
website. The problem is that we have to have the Windows Service
sitting on the clients machine in order for the card reader to work.
The purpose of the website is to have the client scan the card through
the card reader and have the information be sent to the database
through a web service. After the information is saved to the database
it can then be retrieved and shown on the site.
The question I have is
how can I access a .dll, that I have written, from the the asp page
sitting on the server. I know that I could use ActiveX but I am trying to
access the .dll in a way that will allow me to have the webpage be used in
as many browsers as possible.
I am thinking of using silverlight to try and access the dll. The .dll in
question is one that I have written and am trying to access. I've also looked
at trying the DLLImport but I've not been able to get it to work. I am currently using
.NET 4.0 and am writing in C#.
If your client is reading a smartcard, it might be a good idea to use the built-in windows features to use a smartcard to authenticate to IIS on the remote computer. If you're trying to read anything else from the smartcards, then it's usually better to offer the client a normal installer that registers itself as a security device, Browsers have built-in functionality to communicate to such a device. Our local bank, ABN AMRO, uses such a device which is sold by Todos AB and which comes with a driver that works in this fashion.
If you want to do anything else with the smartcard (anything other than reading a certificate or a security token, you'll probably have no other option than to offer the user with a download that I'd personally would always deny.
Related
I'm a relatively new Developer building my first app.
Right now I'm in the process of developing a UWP app and I am needing to get the Hard Drive Serial number from the PC from the Views (OnNavigatedTo), then after a few more fields are filled out, to then save all values to a SQL Server.
What I have discovered up to this point:
Grabbing some values like Hard Drive SN are not so easy with UWP.
I don't seem to have access to Registry HKLM via UWP
I can grab it very easily with PowerShell, and write it to a JSON or XML file. which I plan to do with a Service Account when PC is imaged.
I Don't know where to put the file where the App can see it.
Writing to Sql Server can only be done by creating a webservice and making HTTP / JSON calls via App. (I have this part setup but have not started accessing it via app yet)
So the part I really need help with I guess, is Where to Put JSON/XML file that App will be able to see and read from. Unless of course, someone knows of another way to get Hard Drive SN into a UWP app.
Thanks for Any Help
The recommended way to do this (if you want to go to the Windows Store) is to use a FileOpenPicker and have the user choose the file manually.
If this is for side-loading only (not going to the Windows Store) you can write the file to the user's Documents folder and then the UWP can read it using documentsLibrary capability without any user intervention. You could also use a fullTrust extension to run the PowerShell script and to put the file in the app's data folder. You can check out the Desktop Bridge docs for more info on fullTrust extensions.
I'm looking for a way to establish a simple communication between a c# web application and the operating system.
Since i'm working on Silverlight, i get everything i need to create files into any folder on the C:/ Disk. The problem is that we're going to migrate from Silverlight to Html 5 / C#
So i'd need a way to create files FROM any browser to any OS : Windows,Mac,Linux ..
I thought about using Microsoft Active X but that's not cross platforms.
I'm simply looking for a technology/plugin/software or anything that would allow me to do that, the less client interaction would be the best.
I think your need is in conflict with any common sense about security. If there was a simple way to create any file on any computer that loads your web app, just imagine how quickly all sorts of malware would spread.
But going back to your question - I think it will not be simple (btw. was it really simple in silverlight?). What I can imagine is to have some kind of service running on a client PC (the user would have to install it, or it could be corporate policy if your web app is targeted at corporate solutions). Then the service would listen on some TCP port and your web app could send requests to that port with the intent to create particular file with particular content. All the security concerns would be then implemented in mentioned service so that it doesn't get abused by hostile web apps
Do you know any cross-browser method to create and save a file with JavaScript on the client-side?
Considerations:
I can't save it on the server because the file is going to be read from a fiscal printer.
The server can't access the client. This is obvious because we are talking about a web application in the web, so the server can't access a client folder.
New ActiveXObject("Scripting.FileSystemObject"); is ONLY for Internet Explorer and even then not for all versions.
We are talking about printing on a fiscal printer, so I can't ask the cashier in the supermarket to download the text file and save it in a folder where the fiscal printer can read it.
If not JavaScript, what else can I use in my ASP, .Net 4.0, C# web application?
Basically, you said it, "we are talking about a web application." Do you know any web applications that save a file to your hard drive (besides cookies) without showing you a download prompt first?
Having said that, browsers have started to offer a persistence API that goes beyond cookies. (See, for example, this article.) But such a solution wouldn't meet your requirement of being cross-browser.
Your only options are to use persistance APIs from HTML5 or to create a browser plugin (activex control on IE, NPAPI plugin on others) that can do the file access for you. You could use FireBreath to do this, and it would be relatively simple if you know C++.
That said, it is a really dangerous idea; it is difficult to prevent people from using your plugin in other pages, so your plugin has to somehow be smart enough to keep itself from being abused by malicious sites that want to read (or even write) arbitrary data to your hard drive.
There is, after all, a reason why browsers don't natively support this. I'd look at HTML5.
you can do that by Client side Web services just make a function in web service to create a text file in your hard drive then convert the web service in to the client side service when u do that .Net framework make a client side java script then u will be able to call the server side function using Java script in client side after that your file will not be posted in the server it will remain save in your hard drive ok
we came out with a simple windows service nodejs app to be installed in the local machine.
When the web application need to create a file it just sends an API call to this app using localhost and that will write the file for it.
Cheers.
I'm a desktop application developer who is temporarily working in the web. I'm working with a client that wants me to build an app for use by locations all over the state; however, these locations have very shaky connectivity.
They really want a centralized web app and are suggesting I build a "lean" web app. I don't know what a "lean web app" means: small HTTP requests but lots of them? or large HTTP requests with few of them? I tend to favor chunky vs chatty.. but I've never had to worry about connectivity before.
Do I suggest a desktop app that replicates data when connectivity exists? If not, what's the best way to approach a web app when connectivity is shaky?
EDIT:
I must qualify my question with further information. Assuming the web option, they've disallowed the use of browser runtime technologies and anything that requires installation. Thus, Silverlight is out, Flash is out, Gears is out - only asp.net and javascript is available to me. Having state this, part of my question was whether to use a desktop app; I suppose that can be extended to "thicker technologies".
EDIT #2: Network is homogeneous - every node is Windows. This won't be changing.
You should get a definition of what the client means by "lean" so that you don't have confusion surrounding it. Maybe present them with several options of lean that you think they might mean. One thing I've found is it's no good at all to guess about client requirements. Just get clarification before you waste a bunch of time.
Shaky connectivity definitely favors a desktop application. Web apps are great for users that have always-on Internet connections, and that might be using a variety of different browsers and operating systems.
Your client probably has locations that are all using Windows, so a desktop application is an appropriate choice. One other advantage of web applications is that they make the deployment issue easy to deal with. Auto-update technologies like ClickOnce make the deployment and update of desktop applications almost as easy.
And not to knock Google Gears, but it's relatively new and would have to be considered more risky than a tried-and-true desktop application.
Update: and if you're limited to just javascript on the client side, you definitely do not want to make this a web app. Your application simply will not be available whenever the Internet connection is down. There are ways to save stuff locally in javascript using cookies and user stores and whatnot, but you just don't want to do this.
If connectivity is so bad, I would suggest that you write a WinForm app that downloads information, locally edits it and then uploads it. This way, if your connection goes down, all you have to do is retry until it works.
They seem to be suggesting a plain vanilla web app that doesn't use AJAX or rely on .NET postbacks or do anything that might make it break down horribly if your connection goes away for a bit. Instead, it should be designed so that you can hit Refresh until it works. In other words, they seem to want the closest thing to a WinForm app, only uglier.
You may consider using a framework like Google Gears to help provide functionality during network down time. This allows users to connect to the web page once (with a functioning connection) and then be able to use the web app from then on, even without a connection.
When the network is restored, the framework can sync changes back with the central database.
There is even a tutorial for using Google Gears with the .Net Framework.
Gears with other languages
You mention that connectivity is shaky at these locations, but that the app needs to be centralized. One thing you might consider is using multiple decentralized read database servers and a single centralized write server. Mysql makes this possible and affordable if your app is small.
Have the main database server at the datacenter/central office. Put up small web/db servers at each location, with your app installed. You can even run them off a user computer if the remote location is not too big. Make the local database servers connect to the centralized database server as replication slaves. As changes come in to the centralized database, the slave servers will pull down the data and make it available locally. When the connection is unavailable, your app data is still at least available, if not up to date. When the connection is available, the database handles replicating all relevant data down.
Now all you have to do is make your app use two separate database handles: reading data it uses the local database, writing data it uses the central database.
I am using Visual Studio Team System 2008, C#, .NET 3.5, IIS 7.0, and ASP.NET. I am using Silverlight 3.0 as well. I want to read the content of a USB flash disk at the client side, using the information in the USB flash disk as a user profile identifier -- just like an online bank service is using a USB key to store a client certificate (but my security requirement is not that high).
How the content of a specific file in a USB flash disk in a web application (at the client side) be read? Could we do this in Silverlight (if can not, any alternative solution to read USB flash disk content)?
BTW: I want to read the content automatically, and I do not want the user to manually select the specific file on the USB flash disk to read.
You can not do this in Silverlight. You can read a file on the user's machine, but not without user intervention. The security model built into Silverlight will not allow it.
The best you can do is to read a user-specified file is to have them browse to it with a
file-open dialog box.
You can access the USB/flash drive if you are using a console/Windows Forms/WPF application locally. You can find the drives using the DriveInfo class, then iterate over them or use a LINQ query to find the drive you want to access. See the Stack Overflow question "How to find USB drive letter?" for details. Once you have a path, you can search it for the file you want. You do not need a special API or library, the Windows OS treats the USB drive as a normal drive, same as a "permanent" HDD connected to your system, and will do all the dirty work for you at that level. Just use the .NET I/O classes. However, if you wish to access the drive in an independent manner that does not depend on any OS, then you should use a 3rd party library.
I don't think what you're asking for is possible. If it IS possible, that's scary stuff... To allow a web site to grab stuff without user intervention? Uh-Uh. No way.\
Edit - Added after reading the comment
Using only the standard framework, no. USB support is not something that comes standard. You'd think there would be some classes in the System.IO namespace for USB ports like there are for COM ports, but no such luck. However, there are some libraries that will handle this. Here are some links to get you started.
http://weblogs.asp.net/israelio/archive/2005/08/15/422637.aspx
http://www.icsharpcode.net/OpenSource/SharpUSBLib/