Akhalesh Kumar (Frontend-Associate Consultant - Development)

Introduction to BrightScript

BrightScript is a scripting language specifically designed for developing applications on the Roku platform. It is a dynamically typed language, meaning you don't have to declare variable types explicitly. BrightScript is similar to Visual Basic and Python in syntax but is optimized for media streaming applications.

If you're planning to build a Roku channel or develop applications that run on Roku devices, mastering BrightScript is essential. This blog provides an overview of the language, its key features, and how you can get started with BrightScript development.

Key Features of BrightScript

1. Dynamically Typed

BrightScript does not require variable types to be declared explicitly, making it flexible and easy to use.

2. Interpreted Language

It is an interpreted language, meaning code is executed line by line, making debugging easier compared to compiled languages.

3. Optimized for Streaming Applications

BrightScript is designed specifically for Roku, offering built-in support for video playback, UI rendering, and remote control interaction.

4. Object-Oriented Approach

Although BrightScript is not a fully object-oriented language, it supports objects, associative arrays, and component-based development.

5. Extensive Roku-Specific Libraries

It provides a rich set of APIs and components to handle UI, networking, video playback, and remote input.

Setting Up a BrightScript Development Environment

To start developing with BrightScript, follow these steps:

1. Install Roku SDK and Developer Tools

• Set up a Roku developer account
• Enable Developer Mode on your Roku device
• Install the BrightScript debugger (telnet-based console) and Roku's Development Application Installer

2. Use a Code Editor

• You can write BrightScript code in any text editor, but Visual Studio Code with the BrightScript extension is highly recommended.

3. Deploy and Test

• Package your application using a ZIP file and deploy it via the Roku Developer Mode interface
• Debug using the BrightScript Debugger (BShell) to catch errors and test functionalities

Basic Syntax of BrightScript

Here's a simple BrightScript script to display a message on the Roku screen:

sub Main()
    print "Hello, Roku Developer!"
end sub

Variables and Data Types

BrightScript supports several data types, including:

• Integer: x = 10
• Float: y = 10.5
• String: name = "Roku"
• Boolean: flag = true
• Associative Arrays (similar to dictionaries in Python)

person = {name: "John", age: 30}
print person.name  ' Output: John

Working with Roku UI Components

BrightScript provides SceneGraph, a declarative XML-based UI framework to create interactive Roku applications. A basic example of a Roku SceneGraph component:

<component name="MainScene" extends="Scene">
    <script type="text/brightscript" uri="pkg:/components/MainScene.brs"/>
</component>

This component acts as the main scene in a Roku channel.

Making API Calls in BrightScript

Roku applications often fetch data from APIs. You can use the roUrlTransfer object to make HTTP requests:

url = CreateObject("roUrlTransfer")
url.SetUrl("https://api.example.com/data")
response = url.GetToString()
print response

Debugging BrightScript Code

Debugging is crucial in development. Roku provides a BrightScript Debugger (BShell) that allows developers to:

• Print debug messages using print
• Check variable values
• Step through code execution

You can access the debugger by connecting to your Roku device via telnet:

telnet <roku-ip> 8085

Best Practices for BrightScript Development

• Use Proper Logging: Print debug messages to troubleshoot issues efficiently.
• Optimize API Calls: Minimize network requests to enhance performance.
• Follow Roku UI Guidelines: Use SceneGraph components effectively to create smooth user interfaces.
• Handle Errors Gracefully: Implement error handling to prevent application crashes.

Conclusion

BrightScript is a powerful scripting language designed exclusively for Roku application development. Whether you're building a simple streaming app or a complex channel with advanced UI, learning BrightScript is a must for Roku developers.

By mastering its syntax, utilizing SceneGraph components, and following best practices, you can create high-quality applications for Roku devices. Start coding today and bring your Roku app ideas to life!

Deep Linking in Roku Channels

Deep linking enables direct navigation to specific content within your Roku channel. For example, a user searching for a movie on Roku's search interface can launch that movie directly in your channel, bypassing the home screen.

To implement deep linking, your channel must:-

1. Recognize deep link parameters (like contentId and mediaType).
2. Validate and handle these parameters.
3. Present the requested content or gracefully handle errors if the content is unavailable.

Step 1: Enable Deep Linking in the Manifest File:-

The first step is to enable deep linking in your channel's manifest file. Add the following line:

enable_deeplinking=true

Step 2: Plan Your Deep Linking Parameters:-

Define the parameters your channel will handle. Common parameters include:
1. contentId: A unique identifier for the content.
2. mediaType: The type of content, such as movie, series, episode, e

contentId=12345
mediaType=movie

Step 3: Handle Deep Link Parameters in Code
Deep linking parameters are passed to the main() function of your BrightScript application. Use the m.top.getLaunchParams() method to retrieve these parameters.

sub main()
' Retrieve deep link parameters
params = m.top.getLaunchParams()
contentId = params.lookup("contentId", invalid)
mediaType = params.lookup("mediaType", invalid)

if contentId <> invalid and mediaType <> invalid
' Handle deep linking logic
handleDeepLink(contentId, mediaType)
else
' Launch default home screen
showHomeScreen()
end if
end sub

Step 4: Implement the Deep Linking Logic
Create a function to process the deep link parameters and present the requested content.

sub handleDeepLink(contentId as String, mediaType as String)
if mediaType = "movie"
' Fetch movie details using contentId
movieDetails = fetchMovieDetails(contentId)

if movieDetails <> invalid
' Display the movie
showMovieScreen(movieDetails)
else
' Handle invalid contentId
showErrorScreen("Content not found.")
end if
else
' Handle unsupported media types
showErrorScreen("Unsupported media type.")
end if
end sub

Step 5: Fetch and Validate Content
Ensure the contentId is valid and corresponds to an available item in your database or API. Here's an example function to fetch movie details:

function fetchMovieDetails(contentId as String) as Object
' Simulate API or database lookup
movieDatabase = {
"12345": { title: "Example Movie", description: "An example movie." },
"67890": { title: "Another Movie", description: "Another example." }
}

return movieDatabase.lookup(contentId, invalid)
end function

Step 6: Submit for Certification

Roku requires proper deep linking functionality for certification. Ensure:

1.Deep links open the correct content.
2.Unsupported or invalid parameters are handled gracefully.
3.Content is consistent with search metadata.

Conclusion:-

Deep linking in Roku channels provides users with a seamless way to access specific content directly. By following the steps outlined in this guide, you can implement deep linking effectively, enhance user experience, and meet Roku's certification requirements. Happy coding!

Building an Electronic Program Guide (EPG) on Roku with BrightScript
An Electronic Program Guide (EPG) is a cornerstone of streaming applications, enabling users to explore channel schedules and program details in an organized, interactive way. On Roku, creating an EPG involves leveraging BrightScript and its powerful TimeGrid node. Here, we'll walk you through building an EPG for your Roku app while addressing layout, data handling, and common challenges.

Understanding the Layout of an EPG
Before diving into code, let's understand the basic layout of an EPG:

1.Channel List:-
Displays channel numbers or logos for easy identification.
Programs:-
2.Shows program details, including titles and scheduled start times.
3.Time Slots:-
Each time slot spans 30 minutes, giving users a clear view of program schedules.

How to Display Data on the User Interface
The TimeGrid node in BrightScript is the backbone of the EPG layout. Below is a sample function that sets up the TimeGrid with essential properties and loads data dynamically.

sub Home_screenTimegridData()
m.timeGrid = m.top.findNode("timeGrid")

' Set up TimeGrid properties
m.timeGrid.numRows = 0
m.timeGrid.maxDays = 2
m.timeGrid.translation = [95, 580]
m.timeGrid.contentStartTime = GetCurrentTimeRounded()
m.timeGrid.duration = 7200 ' Duration in seconds (2 hours)
m.timeGrid.channelNoDataText = "Loading..."
m.timeGrid.nowBarBlendColor = "0xFFFFFF"
m.timeGrid.programTitleFocusedColor = "#FFFFFF"
m.timeGrid.programTitleFont = getFont(30, "pkg:/fonts/HelveticaNeueMedium.ttf")

' Assign images for custom styling
m.timeGrid.nowBarBitmapUri = "pkg:/images/epg_timebar.png"
m.timeGrid.focusBitmapUri = "pkg:/images/epg_program_focus.png"
m.timeGrid.programBackgroundBitmapUri = "pkg:/images/epg_program.png"

' Observe user interactions
m.timeGrid.observeField("programSelected", "epgProgramSelected")
m.timeGrid.observeField("programFocused", "epgProgramFocused")
m.timeGrid.observeField("channelFocused", "epgChannelFocused")
end sub

function GetCurrentTimeRounded() as Integer
currentTime = CreateObject("roDateTime")
t = currentTime.AsSeconds()
remainder = t mod (30 * 60)
return t - remainder ' Round to the nearest 30-minute mark
end function

Challenges & Solutions

1.Getting TMS ID and Index
It's crucial to correctly fetch the program details, including the TMS ID (unique identifier for TV programs). One effective way is:
m.notdatafound = m.epg_channelList.data[m.channelIndex].program[m.programIndex]
if m.notdatafound <> invalid
m.firstElementData = m.epg_channelList.data[m.channelIndex].program[m.programIndex].TMSId
endif

2. set Utc Time. 
timestamp=item.start
num = timestamp
dateTest = CreateObject("roDateTime")
' dateTest.AsSeconds(num)
dateTest.FromSeconds(num)

dateTest.ToLocalTime()
? dateTest.asTimeStringLoc("short"),"epochtime21345"

Conclusion:-
Creating an EPG on Roku using BrightScript and nodes like TimeGrid is both rewarding and challenging. By understanding the layout, focusing on smooth data handling, and addressing common hurdles, you can deliver a user-friendly guide that elevates your streaming app's functionality.