I am developing a web application on asp.net. there are some pages which needs to be run in offline mode also for that i have make copy database to client system in a specific folder location now i want to make connection with SQLite and Html page using javascript.
Please give me a solution for that.
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I have a webpage through which my users, using a mobile phone, can take pictures and upload them (hopefully) to the Google Cloud (I've got a JSON file, a platform project and an associated storage bucket, as well as all the login details).
However, I'm pretty new to all this and need to know how I'd get the file (coming from a standard <input file="" name="fileupload"/> ) to the Google Cloud space, and also to retrieve the URI of the file. Given that it's an asp.net webpage, I have access to Javascript and C#.
Thanks!
I have a couple of suggestions for you. We have other customers that have solutions which are similar to this architecture and so your proposed solution is good.
Google Cloud Storage (GCS) has a feature called Signed URLs. This allows you to generate a secure URL to an object in a GCS bucket. My colleague wrote the C# sample for this:
https://cloud.google.com/storage/docs/access-control#signing-code-csharp
There's a method in here that you can reuse GetSigningURL.
Each time a user requests the web page, you should generate a Signed URL and use this as the destination URL for the file upload location in your HTML.
If your HTML is generated by ASP.NET (MVC, Web Forms, Web Page), then you can make the call to GetSigningURL when the page is generated server-side. If not, you should wrap the C# code in a Web API and then you could use, e.g. jQuery ($.ajax), to call it from your client.
You may run your ASP.NET code on Google Cloud Platform using either Windows on Google Compute Engine or using Custom Runtimes on Google App Engine.
Full disclosure: I'm a Googler working in cloud as a Strategic Customer Engineer.
I am trying to build a web application to replace the functionality of an older desktop economics program. That program is essentially a calculation engine built on top of a Microsoft access database. The inputs and results are all stored on a series of tables. To offer compatibility to the legacy users, I want to have the ability for users to connect to their older, local access databases and upload them into the web app.
The approach I was contemplating was to have a page that allowed the user to select the database they wanted from their local machine and then have the schema and the data for each table sent to the web application. I don't really want to upload the whole file -- I just want to extract the relevant data.
I have done some research and I have looked into the HTML File API. One shortcoming is that the API does not expose the file path of a selected file so there does not seem to be a way to pass that to the connection string necessary to connect to the database using ODBC or ADO.
In summary my basic question is: How can I get the contents of a user's local database into a web application only using the browser?
You will have to upload the whole file to the server first. You can do your manipulations on the server to save only the relevant part and delete the rest... For security reasons Javascript is not able to read file's content from the local user's machine.
A suggestion - you can upload the file to server, read and print the relevant data as JSON or XML format, then delete the file and use all the data in your ajax response on the client's browser.
I need to ask for some advice regarding offline web applications and database sync.
Offline Scenario
We have a web site (HTML5) that needs to operate in an offline mode for extended periods of time with complex data, the product owner does not want the data put into local storage.
We have two options as I see it;
Use javascript to detect if we are offlline and if so point the urls to a local web server that replicates the stack at the data center and writes to an offline db
◦Biggest stumbling block is how, on the first load if you are offline do you get the location (URL) of the local web server? i.e. user goes to www.xyz.com, but you are offline so
Question 1: how to redirect him to localhost.xyz.com via javascript for that first call
Point all calls at the client , offline or not to a wcf service that checks offline status at the NIC and redirects every web and service call to the correct place
◦seems like a big job,
Question 2: is there any product/ opensource project you guys know off that does this?
Sync Scenario
•They want to use MS sync framework
◦But they have many clients syncing to different database, so you either need 1 sync service per client or some way to identify who the client syncing is and point them to the correct place
◦Need to minimize locking during sync as other clients are using the same tables during sync
Question 3: can the sync framework be extended to even do this
Question 4: What other options exist for database sync on MS platform?
Thanks
If the user puts the URL into their browser, they are going to go that URL. There is no javascript at that point. You would only have Javascript once a page is loaded. You will have to search for a better solution.
Here is an idea: Users ALWAYS go to the local website, and if the remote site is up, then you redirect them.
In terms of MS sync I do not know what it is, so I cannot help you there.
Re What other options exist for database sync on MS platform: there is also SQL Azure Data Sync, a windows azure web service. It is actually built upon the Microsoft Sync Framework you refer to.
There is an example in the book "Programming Microsoft SQL Server 2012" by Leonard Lobel & Andrew Brust (MS Press) - chapter 13 covers building occasionally connected systems that incorporate SQL Azure Data Sync, Windows Azure and the Windows Phone 7 development platform. In the sample solution, on the back end, an on-premise SQL Server database is kept synchronized with a public facing SQL Azure database in the cloud using SQL Azure Data Sync. The cloud database is exposed using WCF Data Services (also hosted in the cloud by deploying to Windows Azure) and consumed via OData by a mobile client application running on a Windows Phone 7 device. The sample solution detailed in the chapter demonstrates how these technologies work to keep data in sync across on-premise SQL Server, SQL Azure databases in the cloud, and local storage on Windows Phone 7 devices.
Sync Framework do not lock tables when synching.
depending on what client database you want to use on the client, you can either use Sync Framework itself which works with MS databases (SQL CE, SQL Express,LocalDB,SQL Server, SQL Azure) or you can use the Sync Framework Toolkit
whichever platform you choose, i would suggest simply writing to the local store and synching it rather than dynamically choosing which store to use when.
for example, if you went offline and you wrote to the local store. then your network monitor detects you are back online and redirects you to the online service, what would you do with the data you stored locally? or you transacted online and you suddenly went offline, how recent/updated is the local store for you to actually starting working agaisnt it?
You could use Service-Workers to make the website work while users are offline. see: Making PWAs work offline with Service workers. This allows your website to work for the users if they are offline (they need to have internet at least once every 24 hours).
Service-Workers also allows you to detect when your user is offline or online, and you can for example use the IndexedDB to store your offline changes and then synchronize them when the user is online again.
I don't know about MS Sync.
I have to create a Windows Phone 7 app as part of a research project. The app needs to:
Allow the user to login by connecting to an sql server database (stored locally for the purpose of this project)
If login successful, return a list of products associated with the user (i.e. in product table where UserID=x)
User can click on an item in the list, and then add photos for that item. This can be done offline as well (using HTML5 offline storage)
When an internet connection is available again, user can click 'Upload' (or automatically synced, but not necessary) and the images are all uploaded to the Images table with the correct ProductID as Foreign key
Since this is the first time I am doing any mobile programming, I am not sure what is the best approach. I am especially unsure of how I am going to connect to the database. I'm not really interested in learning Silverlight, so the app should use mainly HTML5 and javascript, I also am looking into JQueryMobile.
I have already installed PhoneGap and am trying it out, but my main concern is how to connect the app to the database as I am having trouble finding the 'proper' way of doing this e.g. using some kind of web service or directly through javascript (read it can be done but is not recommended). If anyone could recommend or suggest a good approach of doing this that would be great!
SqlServer is only available on the phone via LinqToSql which you need to expose via a service or a DAL. I dont think that its possible to make calls directly from Javascript to LinqToSql on the phone.
If you're not set on the idea that the DB needs to be on the phone, you can just make service calls via ajax to a server and access the db that way. I recently did a blog post exposing a db via a WCF Data service and consuming it on the phone. It doesn't cover calling it via ajax but should help get you started.
http://www.ritzcovan.com/2012/02/building-a-simple-windows-phone-apppart-4/
If you want to store data within the WP7 database, use the PhoneGap storage APIs.
I want to develop an web application that can be served without web server. I mean, via file:///... in a web browser. The application will use HTML5 and Javascript. Also , I would like to add a SQLite with the data to be presented in the application. The database will be static so a read-only access is enough. I don't want a HTML5 local storage solution because the SQLite database is already created and must be load from "server".
I don't find any solution. A pseudocode example may be the following one:
var db = load ("file:///path/to/my/database/file.sqlite");
db.execute ("SELECT * FROM DATABASE");
// Show items
load from the system files, I think this is not posible due to security reasons.
chek this online tool to manage local data storage at: http://wdbengine.sourceforge.net