Figure 1 shows a simplified network topology in which clients use a browser to access back-end TCP-based services using a full-duplex HTML5 WebSocket connection. However, in real environments, lots of network traffic is routed through intermediary servers.Ī picture is worth a thousand words. Without any intermediary servers (proxy or reverse proxy servers, firewalls, load-balancing routers and so on) between the browser and the WebSocket server, a WebSocket connection can be established smoothly, as long as both the server and the client understand the Web Socket protocol. WebSocket connections use standard HTTP ports (80 and 443), which has prompted many to call it a "proxy server and firewall-friendly protocol." Therefore, HTML5 Web Sockets do not require new hardware to be installed, or new ports to be opened on corporate networks-two things that would stop the adoption of any new protocol dead in its tracks. Let's take a look at how HTML5 Web Sockets work with proxy servers. Additionally, proxy servers may also buffer unencrypted HTTP responses, thereby introducing unpredictable latency during HTTP response streaming.
This behavior is a problem with long-lived connections such as Web Sockets. The problem with proxy servers for web applications that have a long-lived connection (for example, Comet HTTP streaming or HTML5 Web Sockets) is clear: HTTP proxy servers - which were originally designed for document transfer - may choose to close streaming or idle WebSocket connections, because they appear to be trying to connect with an unresponsive HTTP server. Proxy servers can monitor traffic and close a connection if it has been is open for too long. Typically, a proxy server is set up between a private network and the Internet.
Proxy servers are commonly used for content caching, Internet connectivity, security, and enterprise content filtering. Proxy ServersĪ proxy server is a server that acts as an intermediary between a client and another server (for example, a web server on the Internet).
A WebSocket connection is established by upgrading from the HTTP protocol to the Web Socket protocol during the initial handshake between the client and the server, over the same underlying TCP/IP connection. The specification defines a ws:// and a wss:// scheme to indicate WebSocket and WebSocket Secure connections, respectively. To use HTML5 Web Sockets to connect from a Web client to a remote end-point, you create a new WebSocket instance and provide it with the URL that represents the end-point to which you want to connect. Stuck trying to diagnose connectivity or performance issues? Learn howto quickly get to the root cause of traffic and network problems. This delivers an enormous reduction in unnecessary network traffic and latency compared to legacy polling and long-polling (Comet) solutions that are often used to push real-time data to clients or even simulate a full-duplex connection by maintaining two HTTP connections. HTML5 Web Sockets effectively provide a socket connection over the Web with minimal overhead. It introduces the WebSocket interface and defines a full-duplex communication channel that operates through a single socket over the Web. The HTML5 Web Sockets specification defines the Web Sockets API that enables web pages to use the Web Socket protocol for full-duplex communication with a remote host. Let's start with some basic concepts: what exactly are HTML5 Web Sockets and proxy servers? HTML5 Web Sockets About HTML5 Web Sockets and Proxy Servers Additionally, I’ll explain how Kaazing WebSocket Gateway and its Web Socket emulation can add additional value. Will proxy servers automatically kill WebSocket connections? Do HTML5 Web Sockets handle firewalls and proxy server issues better than Comet? Are Web Sockets the silver bullet in seamless proxy server traversal? In this article, I’ll explain how HTML5 Web Sockets interact with proxy servers, load balancing routers, and firewalls. With the recent explosion of WebSocket server implementations, a lot of questions have come up about how HTML5 Web Sockets deal with proxy servers, firewalls, and load-balancing routers.