Do you currently use websockets in your applications? Do you want to learn more about what websockets can do for your apps? Continue reading to learn everything you need to know about using websockets with Delphi, as well as a rundown of some of the available component sets that take the guesswork out of making the magic happen.

What are WebSockets?

A websocket implementation has two sides: the client side and the server side. A websocket server is, at its most basic, an application that listens for TCP traffic. Websocket clients are one or more applications or web pages that connect to the websocket server via a “handshake” request and, if successful, establish a continuous connection between the server and the client.

Are websockets just a special type of HTML?

The short answer to that question is no, websockets use the TCP communication protocol – not the much more heavyweight HTTP. The websockets server is not a web server, although it can be implemented on one. The websockets TCP traffic, the data sent back and forth between the client and server, is not the familiar “200 OK” and “HTTP/2.0 a bunch of HTML” type text data. The websockets protocol is very lightweight and as a result, very fast.

Websockets are also designed to be used in situations where there are prolonged and ‘constantly-on’ connections to the server by multiple clients. Compare that to HTML where the interaction is typically client makes a page request, the web server sends back its response and that’s end of interaction until the next web resource request. Websockets are more like a ‘push’ technology where the server can send updates without being asked. This push ability is more similar to the notifications on your mobile phone.

Are websockets secure?

The websocket protocol provides for both non-secure and secure connections. The secure protocol uses TLS/SSL.

Why would I want to use websockets in my app?

Websockets are really useful for applications which need to update small amounts of data frequently and on a schedule which is not predictable. You can use websockets to provide a highly efficient way of communicating that data without the overhead of things like REST which relies on HTML and therefore has all the added baggage of HTML request/response codes, headers and MIME types. Your applications cut out all that extra noise using websockets while providing a near real-time response without needing to implement things like the server or client polling for any requests or updates.

This makes your app super-responsive and lightweight.

What sort of applications can I write?

The most common example you see given for websockets is in real-time “chat” programs which emulate popular apps like Slack, Discourse and Messenger. There are a whole host of other uses too:

• “Feed” type usage – like a Twitter tweet feed or an “as it happens” time and status update print-out from something like a temperature monitoring hardware control.
• Two-way updates between two client applications. For example, two users are both updating a shared resource like a set of notes or different parts of a patient record. Using websockets you could implement an update mechanism where both users could see the other’s changes in near-real time rather than having to hit a refresh or reload button.
• Real time location monitoring. By using websockets in your Delphi app you could have an interactive map which updates the display in real-time when it gets changed, rather than when you ‘poll’ the server.
• In/Out board. Websockets would allow you to write a client/server application which showed a live, real-time and constantly up-to-date view of employee’s in/out or available/unavailable status in the office without having to constantly run database queries to get that data or poll the server for the information on a timing loop.

What websocket libraries are available for Delphi?

The “RAD” in RAD Studio Delphi is, of course, all about Rapid Application Development which means we use someone else’s hard work to make our lives easier. Luckily there is a solid stack of excellent Delphi websocket components available. This is a list of some of the more popular websocket component libraries available for Delphi. There are plenty of others so add a comment below if I’ve missed any you think should be on the list.

Commercial/paid websockets libraries for Delphi

Web-based components for Delphi

Free websockets libraries for Delphi

So, are you ready to use real-time streaming WebSockets in your Delphi programs? Try our IDE Software and make the most of it. Request a Free Trial here.