# YOU MUST HAVE A PUBNUB ACCOUNT TO USE THE API. http://www.pubnub.com/account ## PubNub 3.4.1 Real-time Cloud Push API - JAVASCRIPT http://www.pubnub.com - PubNub Real-time Network Push Service in the Cloud. PubNub is a blazingly fast Network providing a messaging service for building real-time web and mobile apps. Hundreds of apps and thousands of developers rely on PubNub for delivering human-perceptive real-time experiences that scale to millions of users worldwide. PubNub delivers the infrastructure needed to build amazing MMO games, social apps, business collaborative solutions, and more. ## SIMPLE EXAMPLE ```html

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``` ## HISTORY AND HERE-NOW EXAMPLE ```html Click Me for Here Now! Click Me for History! ``` ## SSL MODE ```html

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``` ## WebSocket Client Interface Optionally PubNub offers you the full RFC 6455 Support for WebSocket Client Specification. PubNub WebSockets enables any browser (modern or not) to support the HTML5 WebSocket standard APIs. Use the WebSocket Client Directly in your Browser that Now you can use `new WebSocket` anywhere! Here is a quick example: ```javascript var socket = new WebSocket('wss://pubsub.pubnub.com/PUB/SUB/CHANNEL') ``` The following example opens a `new WebSocket` in **WSS Secure Socket Mode** with full **2048 Bit SSL** Encryption. ```html ``` #### To Disable SSL WSS Secure Sockets: ```html ``` ## Using the PUBNUB init() Function Sometimes you want to use create a PubNub Instance directly in JavaScript and pass the PubNub API Keys without using a DOM element. To do this, simply follow this `init` example: ```html ``` ## Using with AES256 Encryption This client now supports AES256 encryption out of the box! And its super-easy to use! Check out the file encrypted_chat_demo.html for a working example of using encryption between this and other PubNub clients. ##### Important Highlights 1. Be sure to include the base pubnub.js, gibberish, and encryption adapter: ```html ``` 2. When instantiating your PubNub instance object, use the .secure method instead of the .init method: ```javascript var cipher_key = "enigma"; var secure_pubnub = PUBNUB.secure({ publish_key : "demo", subscribe_key : "demo", cipher_key : cipher_key }); ``` That's pretty much it. Use subscribe, publish, and history as you would normally, only the implementation is different, being that the message traffic is now encrypted. ## SUPER ADVANCED SETTINGS #### WINDOWING AND MESSAGE ORDERING PubNub JavaScript library includes a `windowing` feature that will automatically allow the PubNub Network the window time needed to bundle, compress and optimize messages for high-throughput. This means that if you specify a long window, you will be able to receive significant performance improvements and optimized performance. With high throughput applications (Apps that send many messages per second) a long enough window will benefit in performance and will allow the needed period for the PubNub Network to order the message delivery and compress the response efficiently. >**NOTE:** Windowing is a in favor of battery savings and throughput. The effect is fewer unbundled messages. ```javascript var pubnub = PUBNUB.init({ windowing : 1000, // MILLISECONDS publish_key : 'demo', subscribe_key : 'demo' }); ``` >**NOTE:** Windowing 1000ms will allow 100 messages in a second to be bundled and compressed at optimal speeds. #### KEEPALIVE >**NOTE:** The JavaScript library will automatically detect disconnects in near real-time regardless of `keepalaive`. There exists extra rare cases where `keepalives` are used to detect disconnections of the network connection; situations where a network cable was unplugged for example. Optionally you may sacrafice bandwidth and reduce battery life by lowering the `keepalive` value. By reducing the `keepalive` you receive greater precision to detect rare edge-case drops. The Default `keepalive` is *60 seconds*. **Reducing this value to 30 seconds will help detect only the rare edge-case network problems sooner under rare network disruption situations.** It is not a good idea to reduce this value lower. If you need it lower more, you must contact PubNub first. Again, the JavaScript library will automatically detect disconnects in near real-time anyway, so it is not necessary to reduce this value further. ```javascript var pubnub = PUBNUB.init({ keepalive : 30, publish_key : 'demo', subscribe_key : 'demo' }); ``` ## BEST PRACTICES #### MESSAGE DELIVERY vs. GUARANTEED MESSAGE DELIVERY The PubNub Network is a high throughput and reliable messaging services. Note however that PubNub is not a guaranteed delivery with full Read Receipt Transactions. You can however use improved designs and best practices to ensure you increase reliability. One method includes *High Windowing Length* which provides slight improvements. >**NOTE:** Higher windowing lengths allow improved message delivery. We recommend following a few best practices to achieve high frequency of message delivery. First ensure you are checking the publish response code and re-sending the publish if an error code is returned. There is an easy way to make sure you do not run into undelivered messages due to high frequency of published. Actually there are a few easy ways. The first option is to make sure you don't publish too quickly. Do this by limiting to one concurrent publish per channel. This is achievable by waiting for the publish response before sending another message. Use our Elastic Message options. You should instead send a single large message rather than segment messages into small packets you manually assemble them on the receiving client. >**NOTE:** Turn on Elastic Message Sizes in your Customer Account: https://admin.pubnub.com/ Is it possible to ensure 100% messages are delivered? **YES!** The way to do this includes a Read Receipt Design Pattern. You must allow the Receiver of a message to ACKNOWLEDGE that a message was successfully received. The Sender will continuously re-send the message; with a delay between each re-send. This continues until an ACKNOWLEDGEMENT is received from the receiver.