August 2019 Summaries

Accessibility in computer applications, particularly chat-based applications, is often overlooked, but it is crucial for inclusivity, especially for users with disabilities such as visual impairments. This blog post explores how developers can enhance accessibility by integrating text-to-speech capabilities in chat applications using PubNub and Amazon Polly. By leveraging cloud-based services like Amazon Polly, developers can create real-time speech-enabled chat clients that convert incoming text messages to speech, making the content accessible to blind users. The implementation involves setting up PubNub's serverless Functions for backend support and configuring AWS Polly to generate natural speech streams. The process includes creating API keys, setting up IAM users on AWS, and using HTML5 audio tags to play speech. While the primary focus is on accessibility, this feature also presents opportunities for broader applications, such as generating voice prompts for various events or creating voice commands from predefined text messages.

PubNub Signals is a new feature within the PubNub Publish-Subscribe (Pub/Sub) API designed for sending real-time data between devices with cost efficiency, particularly suitable for high-frequency, small-sized, non-critical messages like IoT sensor updates, GPS streams in ride-share apps, and chat app typing indicators. While similar to standard Publishes with a payload of up to 32KB, Signals are limited to 64 bytes and do not store history or trigger external mobile push notifications, but they maintain the same reliability and latency. Signals are ideal for scenarios where the flow of data matters more than the content of individual messages, reducing costs and unnecessary overhead associated with global replication and history storage in high-volume data streams. A demo illustrates the use of PubNub Signals in a chat application, highlighting the simplicity and affordability of implementing typing indicators at scale, and emphasizes the need for users to obtain their own PubNub API keys for integration.

PubNub Functions offers a serverless environment for managing real-time message routing, filtering, and transformation over the PubNub Data Stream Network, allowing users to control message processes without additional server complexity. This tutorial demonstrates using Functions to implement debouncing in a Smart Doorbell app built with React Native, preventing repeated mobile push notifications by removing push notification keys from messages sent within 30 seconds of each other. Functions execute JavaScript event handlers on in-transit messages or via RESTful APIs, facilitating secure API calls, reducing latency, and enabling global message translation and audience interaction. By utilizing PubNub's edge-based processing capabilities, developers can focus on product development without managing infrastructure, reducing time to market and costs. Users are guided to create a PubNub-powered IoT smart button and React Native app, and to set up a "Push-Filter" function that ensures messages are only sent once every 30 seconds, demonstrating the effectiveness of Functions in enhancing app functionality while maintaining simplicity.

The tutorial outlines the process of developing a chat application in Rust using Pub/Sub messaging with the PubNub API, which facilitates real-time communication across multiple devices or servers. It begins with setting up a Rust environment and integrating necessary crates for functionalities such as sending HTTP requests, handling JSON data, and creating a terminal user interface (TUI) using Cursive. The guide details the implementation of a multithreaded application where one thread handles incoming messages and another manages the user interface. The subscription function retrieves messages from a specified channel, while the publish function sends messages. Both functions utilize the REST API provided by PubNub to communicate with the server. The chat application's user interface is built to allow users to input a username and channel, with messages displayed in real-time. By following this tutorial, users can understand how to leverage Rust's capabilities in developing applications that require efficient real-time data processing and communication.

Layer announced the cessation of all chat operations by October 30, 2019, prompting customers to migrate to alternative providers like PubNub, which offers a highly customizable and scalable real-time network for chat applications. Unlike Layer's end-to-end chat solution which included backend infrastructure and rigid UI/UX elements, PubNub allows for extensive app flexibility and innovation over time. While both services offer basic chat features such as messaging and user management, PubNub stands out with advanced extensibility, serverless functions, and a superior infrastructure scale with a 99.999% SLA compared to Layer's 99.9%. PubNub supports thousands of participants in a single channel, offers robust security through its Access Manager, and allows large message sizes up to 32 KB, providing a more adaptable and feature-rich platform for developers transitioning from Layer.

The tutorial series provides a comprehensive guide on building a feature-rich Android chat application using PubNub and Java, aimed at showcasing the ease of developing real-time applications with these tools. By the end of the series, participants will have created an Android app capable of real-time messaging, presence tracking, and multiplexing across multiple channels. The series highlights the advantages of using PubNub, a global real-time data stream network, which simplifies the creation of scalable applications with low-latency message delivery, as opposed to building and managing an intricate network infrastructure independently. The tutorial is designed for use with Android Studio and involves setting up the PubNub Android SDK, integrating publish/subscribe keys, and utilizing features like real-time messaging and channel groups. The series is structured in four parts, guiding developers through the initial setup, message handling, user presence management, and scaling with channel groups, ensuring the final application meets modern expectations for instant updates and dynamic data presentation.