Understanding SignalR
In the early days of the Web in the 1990s, browsers had to make a full-page HTTP GET request to the web server to get fresh information to show to the visitor.
In late 1999, Microsoft released Internet Explorer 5.0 with a component named XMLHttpRequest that could make asynchronous HTTP calls in the background. This alongside dynamic HTML (DHTML) allowed parts of the web page to be updated with fresh data smoothly.
The benefits of this technique were obvious and soon all browsers added the same component. Google took maximum advantage of this capability to build clever web applications such as Google Maps and Gmail. A few years later, the technique became popularly known as Asynchronous JavaScript and XML (AJAX).
AJAX still uses HTTP to communicate, however, and that has limitations. First, HTTP is a request-response communication protocol, meaning that the server cannot push data to the client. It must wait for the client to make a request. Second, HTTP...