Welcome!

Machine Learning Authors: Elizabeth White, Yeshim Deniz, Pat Romanski, Rene Buest, Nate Vickery

Related Topics: Machine Learning , Agile Computing

Machine Learning : Article

Instant Instant Messaging: Just Add Web Sockets

Chat requires full-duplex communication

Chat rooms and live peer-to-peer chat on the web are high on the list of stunning rich application features that can still drop jaws. Facebook recently launched an integrated web chat implementation to much fanfare. Their impressive Erlang and C++ chat infrastructure showcases real-time web techniques and live, interactive interface elements. However, following Facebook's lead is actually not that hard if you use the right approach.

The two main difficulties faced by Facebook, Google, or any other web giant that wishes to deploy a chat application are scaling out an inconceivably large messaging back end and sending real-time messages to the browser. The first problem is one that many of us would like to have, but few actually encounter. The second problem is getting much, much easier to solve. Web chat is about to go mainstream, thanks in large part to a new HTML 5 feature called Web Sockets.

Chat Is Full-Duplex; the Web Is Not
The challenges in bringing real-time messaging (chat, for example) to web applications stem from the fundamental design of the web. It is, after all, a system designed for navigating hypertext documents. The request-response model is perfect for document retrieval, but it's less perfect for an application platform. Some applications are exceptionally bad fits.

Chat requires full-duplex communication. That is, data must be able to flow bidirectionally. This is a clear necessity for chat, as messages may originate on either the server or the client and must be transmitted without delay. After all, instant messaging is of little use if it isn't instantaneous. HTTP explicitly eliminates the ability to send information over the network in either direction at will at the same time.

Since nearly anything is possible, some tenacious developers have shoehorned full-duplex communication into existing web browsers. Comet long-polling, iframe streaming, and other techniques have all been applied in pursuit of this goal. Each technique has weaknesses, however, and even Comet techniques that allow data to stream down from the server cannot avoid initiating a new request for each upstream message. While a new request might not seem like much, each HTTP action causes several hundred bytes of header data to be generated, transmitted, and parsed. Even when bandwidth and computing resources are cheap, the additional latency incurred by a full round trip hurts real-time interactivity.

Using today's browser technology for both upstream and downstream, there is significant overhead to real-time communication. Despite this, some have been willing to stomach the complexity and inefficiency to run applications like chat on the web without succumbing to the temptation of proprietary plugins.

HTML 5 Web Sockets
The HTML 5 standard specifies new APIs for storage, drawing, drag-and-drop, and other areas that have made web programming painful. Browsers have already begun incorporating parts of HTML 5 (canvas, for example) even though the specification is far from complete. The HTML 5 Communication section includes two additional connectivity features: Server-Sent Events, a standardization of HTTP push, and Web Sockets, a cross-domain safe, full-duplex connection. Server-Sent Events will make real-time updates and notifications easy, and Web Sockets provide the functionality necessary to build chat for the web without the previously required hackery.

More Stories By Frank Salim

Frank Salim is a polyglot programmer with a keen interest in making life easier for his fellow coders. He leads WebSocket development at Kaazing and is the front man for Kaazing's open source project at kaazing.org. Salim is an open source advocate and a committer in several open source projects. He is a regular author and contributor to the online tech magazine Comet Daily.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
393rocker 11/02/09 10:02:00 AM EST

do u have a source code of implementing IM? if i start from the scratch..

@CloudExpo Stories
21st International Cloud Expo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Me...
SYS-CON Events announced today that DXWorldExpo has been named “Global Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Digital Transformation is the key issue driving the global enterprise IT business. Digital Transformation is most prominent among Global 2000 enterprises and government institutions.
SYS-CON Events announced today that Datera, that offers a radically new data management architecture, has been named "Exhibitor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Datera is transforming the traditional datacenter model through modern cloud simplicity. The technology industry is at another major inflection point. The rise of mobile, the Internet of Things, data storage and Big...
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
SYS-CON Events announced today that Calligo, an innovative cloud service provider offering mid-sized companies the highest levels of data privacy and security, has been named "Bronze Sponsor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Calligo offers unparalleled application performance guarantees, commercial flexibility and a personalised support service from its globally located cloud plat...
"We focus on SAP workloads because they are among the most powerful but somewhat challenging workloads out there to take into public cloud," explained Swen Conrad, CEO of Ocean9, Inc., in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"Outscale was founded in 2010, is based in France, is a strategic partner to Dassault Systémes and has done quite a bit of work with divisions of Dassault," explained Jackie Funk, Digital Marketing exec at Outscale, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"I think DevOps is now a rambunctious teenager – it’s starting to get a mind of its own, wanting to get its own things but it still needs some adult supervision," explained Thomas Hooker, VP of marketing at CollabNet, in this SYS-CON.tv interview at DevOps Summit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We are still a relatively small software house and we are focusing on certain industries like FinTech, med tech, energy and utilities. We help our customers with their digital transformation," noted Piotr Stawinski, Founder and CEO of EARP Integration, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We've been engaging with a lot of customers including Panasonic, we've been involved with Cisco and now we're working with the U.S. government - the Department of Homeland Security," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We're here to tell the world about our cloud-scale infrastructure that we have at Juniper combined with the world-class security that we put into the cloud," explained Lisa Guess, VP of Systems Engineering at Juniper Networks, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
There is a huge demand for responsive, real-time mobile and web experiences, but current architectural patterns do not easily accommodate applications that respond to events in real time. Common solutions using message queues or HTTP long-polling quickly lead to resiliency, scalability and development velocity challenges. In his session at 21st Cloud Expo, Ryland Degnan, a Senior Software Engineer on the Netflix Edge Platform team, will discuss how by leveraging a reactive stream-based protocol,...
"With Digital Experience Monitoring what used to be a simple visit to a web page has exploded into app on phones, data from social media feeds, competitive benchmarking - these are all components that are only available because of some type of digital asset," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at DevOps Summit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, provided a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services with...
"We want to show that our solution is far less expensive with a much better total cost of ownership so we announced several key features. One is called geo-distributed erasure coding, another is support for KVM and we introduced a new capability called Multi-Part," explained Tim Desai, Senior Product Marketing Manager at Hitachi Data Systems, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"I'm here to leverage my secret sauce, which is using outsourced development and the company that I utilize is delaPlex Software and they've basically allowed me to win Fortune 500 companies," noted Justin Witz, CTO of FRA and PlanTools, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"As we've gone out into the public cloud we've seen that over time we may have lost a few things - we've lost control, we've given up cost to a certain extent, and then security, flexibility," explained Steve Conner, VP of Sales at Cloudistics,in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We are an IT services solution provider and we sell software to support those solutions. Our focus and key areas are around security, enterprise monitoring, and continuous delivery optimization," noted John Balsavage, President of A&I Solutions, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
As enterprise cloud becomes the norm, businesses and government programs must address compounded regulatory compliance related to data privacy and information protection. The most recent, Controlled Unclassified Information and the EU’s GDPR have board level implications and companies still struggle with demonstrating due diligence. Developers and DevOps leaders, as part of the pre-planning process and the associated supply chain, could benefit from updating their code libraries and design by in...
"Peak 10 is a hybrid infrastructure provider across the nation. We are in the thick of things when it comes to hybrid IT," explained Michael Fuhrman, Chief Technology Officer at Peak 10, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.