There's a growing interest in using socket APIs directly within web browsers for various applications, both client-side and server-side. This post lists potential use-cases for outgoing and incoming socket connections, eliminating the need for proxying through web servers. Examples include email clients connecting directly to IMAP/POP3/SMTP, SSH/RDP clients, real-time communication tools like IRC and XMPP, P2P applications like BitTorrent, and direct connections to servers for various purposes like video streaming, Bitcoin, and game multiplayer functionality. For incoming connections, use-cases include hosting servers for many of the aforementioned services (IRC, BitTorrent, HTTP) directly within the browser.
In part two of this series on the failures of my first AJAX application, I discuss how my initial plan to reduce bandwidth by having the client directly access third-party web services didn't work out. Due to cross-domain scripting issues in Firefox and IE 6/7, I had to implement proxy scripts on my server. This means all client requests now go through my server, increasing my bandwidth demands. While using a proxy server offers benefits like hiding security information (like Technorati developer tokens) and enabling data manipulation/request merging, it comes with the major downside of increased bandwidth usage and the need to create/maintain proxy scripts. I hope to support cross-domain data sources in the next version to mitigate these issues but acknowledge there might still be scenarios where proxy scripts are necessary.
