Abstract: Using blogger.com and blogger.com SignalR, in this article, you will build a basic real-time graphics chart application for the modern web. The wondrous web is evolving! It constantly changes and sometimes these changes and standards can be overwhelming enough for any web developer to ignore Jul 16, · Add new item. In the Add New Item dialog box, select the Visual C# | Web | SignalR node in the left pane, select SignalR Hub Class (v2) from the center pane, name the file blogger.com and click Add. Add new item dialog box. Replace the code in the StatisticsHub class with the following code Aug 06, · As you can see, we have a working multithreading application with updates shown in real time. If you wish to see/download the code, please click here! Summary. In today’s article, we have seen how to implement multithreading in blogger.com Core MVC application and show its updates in real-time in our web application. Hope you all liked it
Using blogger.com and blogger.com SignalR for Real-time Data Visualization | DotNetCurry
The wondrous web is evolving! It constantly changes and sometimes these changes and standards can be overwhelming enough for any web developer to ignore. In its modern incarnation, one of the hottest things that the web has delivered is the support for real-time communication. In this mode of communication, the server pushes new data to the client as soon as it is available.
This communication could be in the form of a live chat, notification, in exciting apps like Twitter, Facebook and even real-time financial data.
Another area where the web has taken big leaps is in Data Visualization. HTML5 Canvas and Scalable Vector Graphics SVG are both web technologies that enable us to create rich graphics in the browser, without the need of a plugin like Flash or Silverlight. One of the several useful cases where we need graphics in the browser is to draw some interactive charts. These charts may range from simple line charts to very sophisticated 3D graphic charts.
By combining Real-time communication with Data Visualization, we can build some real cool sites that would impress our customers. In this article, we will see how to leverage ASP. NET SignalR real-time communication and D3 JavaScript charting library to build real-time charts in browsers. There are several techniques to implement real-time communication in web applications like Interval Polling, Long Polling, Server Sent Events, Web Sockets etc.
HTML 5 Web Sockets is one of the most popular techniques amongst them. In order for Web Sockets to work, they should be supported on both the client as well as the server. In such cases, we need a polyfill that includes some fallback mechanisms.
NET SignalR provides this feature for free. SignalR abstracts all the plumbing logic needed to detect the feature supported by both communication ends and uses the best possible feature. SignalR checks and uses one of the following techniques in the order listed below:. As already mentioned, most of the modern browsers have good support for graphics because of features like: Canvas and SVG. JavaScript API on the browser enables us to talk to these components through code, and manipulate them as needed.
When we start learning these new features, the APIs seem very nice initially, but we start getting tired of them once we get into rendering graphics beyond simple drawing. This is where we need an abstraction that wraps all default browser APIs and makes it easier to get our work done. D3 is an abstraction over SVG. D3 makes it easier to work with SVG and provides APIs to create very rich graphics.
To learn more about D3, please check the official site. We are going to create a Stock Charts application. This is a simple application that maintains details of stocks of some companies and then displays a simple how to display real time forex data asp.net example chart to the users that shows the change in stock value of a company.
Values of stocks keep changing after every 10 seconds. A real-time notification is sent to all the clients with the latest value of the stock data. Charts on the client browsers are updated as soon as they receive new data from the server. Open Visual Studio and create a new Empty Web Project named StockCharts-SignalR-D3. In the project, install the following NuGet packages:. On the server side, we need Entity Framework to interact with SQL Server and Web API, SignalR to serve data to the clients.
In the database, we need two tables: Companies and StockCosts. We will use Entity Framework Code First to create our database. We need a DbContext class that defines DbSets for the above classes and tables are generated automatically for these classes when the application is executed or when the migrations are applied. Following is the context class:. The parameter passed into the base class DbContext in the above snippet is the name of the connection string. config file:.
I am using SQL Server as how to display real time forex data asp.net example data source. You can change it to SQL CE, local DB or any source of your choice. Entity Framework migrations provide an easier way to seed the database with some default data. To enable migrations, open Package Manager Console and type the following command:. The above command creates a new folder named Migrations and adds a class called Configuration to the folder.
The command is smart enough to detect the DbContext class and use it to create the Configuration class, how to display real time forex data asp.net example. The constructor of the Configuration class contains a statement that switches off the automatic migrations.
For this application, we need to enable the option. Replace the statement as:. The Seed method is executed every time we create the database using migrations. Seed method is the right place to seed some data to the database. Following is the definition of the seed method:. Open the Package Manager Console again and run the following command to create the database with the default data:. Now if you open your SQL Server, you will see a new database created with the required tables and the tables containing default data.
We need repositories to interact with the data. The StockCostRepository class should include the following functionalities:. Get last 20 costs for a specified company. If the number of records is less than 20, it should return all rows. We need a Web API endpoint to expose the list of companies. Add a new folder to the project and name it Web API. Add a new Web API controller class to this folder and name it CompaniesController. The controller needs to have just one Get method to serve the list of companies.
Following is the implementation:. The Route attribute added to the CompaniesController is a new feature added in Web API 2. asax to enable attribute routing:. NET SignalR has two mechanisms to talk to the clients: Hubs and Persistent connections. Persistent connections are useful to deal with the low-level communication protocols that SignalR wraps around. Hubs are one level above Persistent Connection and they provide API to communicate using data without worrying about underlying details.
For the Stock charts application, we will use Hubs as the communication model. We need a hub to send the initial stock data to the clients. Create a new folder for adding functionalities of SignalR and add a new Hub named StockCostsHub to this folder. Following is the code of StockCostsHub:. As we see, all Hub classes are inherited from Microsoft. Hub class. The Hub classes have an inherited property, Clients that holds information about all the clients connected.
Following are some important properties of the Clients object:, how to display real time forex data asp.net example. The initiateChart method called above has to be defined by the client. To this method, we are passing the list of stocks for the given company.
The StockMarket is a singleton class containing all the logic to be performed. It includes the following:. Run a timer that calls a method after every 10 seconds to calculate next set of stock prices and return this data to all clients. Add a new class to the SignalR folder and name it StockMarket. Following is the initial setup needed in this class:. Once we receive the first request for the stock prices, how to display real time forex data asp.net example can start the market and trigger the timer with an interval of 10 seconds.
This is done by the following method:. It uses the lock object we created above to avoid any accidental parallel insertions to the database. To get the list of currently connected clients to the StockCostHubwe need to use GlobalHost. GlobalHost how to display real time forex data asp.net example a static class that provides access to the information of the Host on which SignalR runs.
ConnectionManager provides access to the current Hub s and PersistentConnection s. Using the generic GetHubContext method of the connection manager, we can get the currently connected clients and then call a client method using the dynamic Clients object. Following is the implementation of GenerateNextStockValue method:. The page has very small amount of mark-up, later we will add a lot of JavaScript to it. Following is the mark-up inside the body tag:.
The third script library file added in the above mark-up is generated dynamically by SignalR. It contains client side proxies for all the hub methods. The initiateSignalRConnection method called above in the callback of setCompanies establishes a real-time connection with the server. It is called in the callback as it needs data returned by the Web API. The StockCost class has a property called Time, how to display real time forex data asp.net example, that holds date and time when the value of the cost was changed.
In the line chart, it makes more sense to show the relative time when the value was changed.
Real-time data update in blogger.com using blogger.com - Angular blogger.com client
, time: 11:13Displaying Real Time Data using HTML5 and blogger.com
Abstract: Using blogger.com and blogger.com SignalR, in this article, you will build a basic real-time graphics chart application for the modern web. The wondrous web is evolving! It constantly changes and sometimes these changes and standards can be overwhelming enough for any web developer to ignore Feb 01, · In the first step we will create a sample app to perform CRUD operations. In the second step we will make the app real-time with SignalR. Those who are not familiar with SignalR, visit my previous article on Overview of SignalR. Step 1: At first we need to create a database named CRUD_Sample. In sample db we have to create a table named Customers Mar 25, · 1. Load the GridView and refresh the contents every minute. (60 second intervals) 2. When the GridView is refreshed every minute I would like to append only the new records to the existing grid, rather than bringing back the entire result set with each round trip to the database. 3
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