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The Programmatic Access Library (PAL) SDK for Roku enables publishers with direct VAST call (DVC) approval to monetize DVC-based Roku applications. The PAL SDK allows you to request nonces, which are encrypted strings, from Google, so that you can sign DVC requests. Each new stream request must be accompanied by a newly generated nonce. However, you can reuse the same nonce for multiple ad requests within the same stream.

This guide explains an example of how to incorporate the PAL SDK into a Roku application, request a nonce, and register ad impressions.

Prerequisites

Before starting this guide, you need to following:

  • A Roku development environment — see the Roku Developer environment setup guide for more information.
  • A project folder with the following structure:

    ./
      components/
        MainScene.xml
        PALInterface.xml
        SampleVideoPlayer.xml
      images/
        icon_focus_hd.png
        icon_focus_sd.png
        icon_side_hd.png
        icon_side_sd.png
        splash_fhd.png
        splash_hd.png
        splash_sd.png
      source/
        main.brs
      manifest
    

Set up your project

Before you integrate the PAL SDK, you need to configure your project files.

manifest

title=PAL for Roku Sample
subtitle=As seen in the PAL for Roku Get Started Guide
major_version=1
minor_version=0
build_version=00001

mm_icon_focus_hd=pkg:/images/icon_focus_hd.png
mm_icon_side_hd=pkg:/images/icon_side_hd.png
mm_icon_focus_sd=pkg:/images/icon_focus_sd.png
mm_icon_side_sd=pkg:/images/icon_side_sd.png

splash_screen_sd=pkg:/images/splash_sd.jpg
splash_screen_hd=pkg:/images/splash_hd.jpg
splash_screen_fhd=pkg:/images/splash_fhd.jpg
splash_color=#000000
splash_min_time=1000
ui_resolutions=hd

source/main.brs

sub Main()
    showChannelSGScreen()
end sub

sub showChannelSGScreen()
  screen = CreateObject("roSGScreen")
  m.port = CreateObject("roMessagePort")

  screen.setMessagePort(m.port)
  m.scene = screen.CreateScene("MainScene")
  screen.show()

  while(true)
    msg = wait(0, m.port)
    msgType = type(msg)
    if msgType = "roSGScreenEvent"
      if msg.isScreenClosed() then return
    end if
  end while
end sub

Create a sample video player

The SampleVideoPlayer component simply wraps a video component to capture remote control presses. Override onKeyEvent so that once the remote's focus is transferred to the video/ad player any further key presses (up, down, left, right, click, etc), are captured and bubbled up to PAL.

components/SampleVideoPlayer.xml

<?xml version="1.0" encoding="utf-8" ?>

<component name="SampleVideoPlayer" extends="Video">
  <interface>
    <field id="pressedKey" type="String" />
  </interface>
  <script type="text/brightscript">
    <![CDATA[

      Function onKeyEvent(key as String, press as Boolean) as Boolean
        If press
          m.top.pressedKey = key
        End If
        return True
      End Function

    ]]>
  </script>

  <children>
    <Label text="VIDEO" color="0xFFFFFFFF" font="font:MediumBoldSystemFont" horizAlign="center" vertAlign="center" width="720" height="480" />
  </children>

</component>

Create a test interface

Implements a scene with buttons to do the following:

  • Request a nonce.
  • Send an ad click.
  • Send a playback-started event.
  • Send a playback-ended event.
  • Transfer focus to the video button.

components/MainScene.xml

<?xml version="1.0" encoding="utf-8" ?>
<component name="MainScene" extends="Scene" initialFocus="requestNonceButton">
<children>
  <ButtonGroup>
    <button text="Request Nonce" id="requestNonceButton" />
    <button text="Send Ad Click" id="sendAdClickButton" />
    <button text="Send Playback Start" id="sendPlaybackStartButton" />
    <button text="Send Playback End" id="sendPlaybackEndButton" />
    <button text="Transfer Focus to Video" id="transferFocusToVideoButton" />
  </ButtonGroup>
  <SampleVideoPlayer id="YourVideoPlayer" width="720" height="480" focusable="true" />
</children>
</component>

Create an SDK interface component

To communicate between the main scene and the PAL SDK, you need a component that contains asynchronous code. This is necessary because the PAL SDK makes external network requests, which cannot occur on the main thread in a Roku application. To send data to this component, you need an interface that defines what data the component sends and receives.

components/PALInterface.xml

<?xml version="1.0" encoding="utf-8" ?>
<component name="PALInterface" extends="Task">
<interface>
  <!--Commands-->
  <field id="requestNonce" type="Boolean" />
  <field id="sendAdClick" type="Boolean" />
  <field id="sendAdTouchKey" type="String" />
  <field id="sendPlaybackStart" type="Boolean" />
  <field id="sendPlaybackEnd" type="Boolean" />
  <field id="endThread" type="Boolean" />
  <!--Responses-->
  <field id="errors" type="stringarray" />
  <field id="nonce" type="String" />
</interface>
</component>

Import the IMA SDK

To use the PAL library, you need to require the IMA SDK for Roku in your app manifest and import it into the PALInterface component.

manifest

...
splash_color=#000000
splash_min_time=1000
ui_resolutions=hd
bs_libs_required=googleima3

components/PALInterface.xml

<?xml version = "1.0" encoding = "utf-8" ?>

<component name="PALInterface" extends="Task">
<interface>
  <!-- commands -->
  <field id="requestNonce" type="Boolean" />
  <field id="sendAdClick" type="Boolean" />
  <field id="sendAdTouchKey" type="String" />
  <field id="sendPlaybackStart" type="Boolean" />
  <field id="sendPlaybackEnd" type="Boolean" />
  <field id="endThread" type="Boolean" />
  <!-- responses -->
  <field id="errors" type="stringarray" />
  <field id="nonce" type="String" />
</interface>
<script type = "text/brightscript">
<![CDATA[
  Library "IMA3.brs"
]]>
</script>
</component>

Trigger interface component from scene

Next, add the BrightScript code that listens for user interactions and triggers changes in the interface component:

  • To receive output from the interface component, implement field observers on the interface fields associated with those outputs, and attach them to callback functions in the main component. Do this when the component is first registered.

  • To send user interactions to the interface component, implement field observers on the buttons that you created earlier to trigger changes in the interface fields associated with those commands.

components/MainScene.xml

<?xml version="1.0" encoding="utf-8" ?>
<component name="MainScene" extends="Scene" initialFocus="requestNonceButton">
<children>
  <ButtonGroup>
    <button text="Request Nonce" id="requestNonceButton" />
    <button text="Send Ad Click" id="sendAdClickButton" />
    <button text="Send Ad Touch" id="sendAdTouchButton" />
    <button text="Send Playback Start" id="sendPlaybackStartButton" />
    <button text="Send Playback End" id="sendPlaybackEndButton" />
  </ButtonGroup>
  <Video id="YourVideoPlayer" width="720" height="480" focusable="true" />
</children>
<script type="text/brightscript">
<![CDATA[
  Function init()
    requestNonceButton = m.top.findNode("requestNonceButton")
    requestNonceButton.observeField("buttonSelected", "requestNonce")

    sendAdClickButton = m.top.findNode("sendAdClickButton")
    sendAdClickButton.observeField("buttonSelected", "sendAdClick")
    sendPlaybackStart = m.top.findNode("sendPlaybackStartButton")
    sendPlaybackStart.observeField("buttonSelected", "sendPlaybackStart")
    sendPlaybackEnd = m.top.findNode("sendPlaybackEndButton")
    sendPlaybackEnd.observeField("buttonSelected", "sendPlaybackEnd")

    loadImaSdk()
  End Function

  ' Initialize SDK Interface component and attach callbacks to field observers.
  Function loadImaSdk() as Void
    m.sdkTask = createObject("roSGNode", "PALInterface")
    m.sdkTask.observeField("errors", "onSdkLoadedError")
    m.sdkTask.observeField("nonce", "onNonceLoaded")
    print "Running load IMA task."
    m.sdkTask.control = "RUN"
  End Function

  Sub onSdkLoadedError(message as Object)
    print "----- errors in the sdk loading process --- ";message.getData()
  End Sub

  ' Callback triggered when Nonce is loaded.
  Sub onNonceLoaded(message as Object)
    nonce = m.sdkTask.nonce
    print "onNonceLoaded ";nonce
  End Sub

  Function requestNonceButtonPressed() As Void
    print "Request Nonce"
    ' Inform the SDK interface component to request a nonce.
    m.sdkTask.requestNonce = True
  End Function

  ' Action triggered on player start, either from user action or autoplay.
  Function sendPlaybackStart() As Void
    m.sdkTask.sendPlaybackStart = True
  End Function

  ' Action triggered on player end, either when content ends or the user exits
  ' playback of this content.
  Function sendPlaybackEnd() As Void
    m.sdkTask.sendPlaybackEnd = True
  End Function
]]>
</script>
</component>

Add methods to transfer focus

Next, capture user key presses to transfer focus to and from your video element.

components/MainScene.xml

...

<script type="text/brightscript">
<![CDATA[
  Function init()

    ...

    m.sendPlaybackStart = m.top.findNode("sendPlaybackStartButton")
    m.sendPlaybackStart.observeField("buttonSelected", "sendPlaybackStart")
    m.sendPlaybackEnd = m.top.findNode("sendPlaybackEndButton")
    m.sendPlaybackEnd.observeField("buttonSelected", "sendPlaybackEnd")

    m.transferFocusToVideoButton = m.top.findNode("transferFocusToVideoButton")
    m.transferFocusToVideoButton.observeField("buttonSelected", "transferFocusToVideo")

    ' Your video player set up to handle key press events.
    m.video = m.top.findNode("YourVideoPlayer")
    m.video.observeField("pressedKey", "onVideoKeyPress")

    loadImaSdk()
  End Function

  ...

  ' Action triggered on player end, either when content ends or the user exits
  ' playback of this content.
  Function sendPlaybackEnd() As Void
    m.sdkTask.sendPlaybackEnd = True
  End Function

  Function transferFocusToVideo() As Void
    m.video.setFocus(true)
  End Function

  Function onVideoKeyPress() As Void
    key = m.video.pressedKey
    If key = ""
      Return
    End If
    m.sdkTask.sendAdTouchKey = key

    ' If back or up is pressed, transfer focus back up to the buttons.
    If key = "back" or key = "up"
      m.transferFocusToVideoButton.setFocus(true)
    End If

    ' Reset so that we get the next key press, even if it's a repeat of the last
    ' key.
    m.video.pressedKey = ""
  End Function
]]>
</script>
</component>

Initialize the PAL SDK and create a nonceLoader

Now you can start building out the core logic of the PAL SDK implementation. First, initialize the SDK from a separate thread.

components/PALInterface.xml

...
<script type = "text/brightscript">
<![CDATA[
  Library "IMA3.brs"

  Sub init()
    ' It is not possible to access roUrlTransfer on the main thread. Setting
    ' functionName to a function and then setting control to "RUN" causes that
    'function to run on a separate thread.
    m.top.functionName = "runPalThread"

    ' Loads the SDK on the current thread if it is not yet loaded.
    ' This blocks execution of other functions on this thread until the SDK is loaded.
    If m.sdk = Invalid
      m.sdk = new_imaSdk()
    End If

    m.nonceLoader = m.sdk.CreateNonceLoader()
  End Sub

  ' Starts the player event loop. This loop only terminates when "endThread" is sent.
  Function runPalThread() as Void
    ' Used for the player life cycle loop.
    m.top.endThread = False
    port = CreateObject("roMessagePort")

  End Function
]]>
</script>
</component>

Process nonce requests

Once the nonceLoader is created, you need to handle nonce requests by attaching an observer to the requestNonce field. By attaching this observer only after the nonceLoader is initialized, you can ensure that nonce requests are handled in the SDK thread, and that a nonce request can only be made if there is a valid nonceLoader.

components/PALInterface.xml

...

  ' Starts the player event loop. This loop only terminates when "endThread" is sent.
  Function runPalThread() as Void
    ' Used for the player life cycle loop.
    m.top.endThread = False
    port = CreateObject("roMessagePort")

    ' Now that the nonceLoader exists, begin listening for nonce requests.
    m.top.observeField("requestNonce", m.port)

  End Function

  ' Requests a nonce from the PAL SDK.
  Function requestNonce() as Void
    nonceRequest = m.sdk.CreateNonceRequest()
    m.nonceManager = m.nonceLoader.loadNonceManager(nonceRequest)
    m.top.nonce = nonceManager.getNonce()
  End Function
]]>
</script>
</component>

Listen for player life cycle signals

To allow your PAL integration to properly send signals, you need to set up a loop to listen for your player's life cycle signals.

components/PALInterface.xml

...

    ' Now that the nonceLoader exists, begin listening for nonce requests.
    m.top.observeField("requestNonce", m.port)

    m.top.observeField("sendAdClick", m.port)
    m.top.observeField("sendAdTouchKey", m.port)
    m.top.observeField("sendPlaybackStart", m.port)
    m.top.observeField("sendPlaybackEnd", m.port)

    ' Setting endThread to true causes the while loop to exit.
    m.top.observeField("endThread", m.port)

    While Not m.top.endThread
      message = m.port.waitMessage(1000)
      If message = Invalid
        pollManager()
      Else If message.getField() = "requestNonce" And m.top.requestNonce = True
        requestNonce()
        m.top.requestNonce = False
      Else If message.getField() = "sendAdClick" And m.top.sendAdClick = True
        sendAdClick()
        m.top.sendAdClick = False
      Else If message.getField() = "sendAdTouchKey" And m.top.sendAdTouchKey <> ""
        sendAdTouch(m.top.sendAdTouchKey)
        m.top.sendAdTouchKey = ""
      Else If message.getField() = "sendPlaybackStart" And m.top.sendPlaybackStart = True
        sendPlaybackStart()
        m.top.sendPlaybackStart = False
      Else If message.getField() = "sendPlaybackEnd" And m.top.sendPlaybackEnd = True
        sendPlaybackEnd()
        m.top.sendPlaybackEnd = False
      End If
    End While
  End Function

  Function pollManager() as Void
    If m.nonceManager <> Invalid
      m.nonceManager.poll()
    End If
  End Function

  ' Requests a nonce from the PAL SDK.
  Function requestNonce() as Void
    nonceRequest = m.sdk.CreateNonceRequest()
    m.nonceManager = m.nonceLoader.loadNonceManager(nonceRequest)
    m.top.nonce = nonceManager.getNonce()
  End Function
]]>
</script>
</component>

Register listeners for sendPlaybackStart, sendPlaybackEnd, sendAdClick, and sendAdTouch

Next, call sendPlaybackStart on "video player start". This method starts asynchronous calls to Google servers to collect the signal needed for IVT monitoring and detection. Call sendPlaybackEnd when playback ends. Call sendAdClick in response to ad clickthrough. Then, call sendAdTouch for non-clickthrough user touch or click events.

components/PALInterface.xml

...

  ' Requests a nonce from the IMA SDK.
  Function requestNonce() as Void
    nonceRequest = m.sdk.CreateNonceRequest()
    m.nonceManager = m.nonceLoader.loadNonceManager(nonceRequest)
    m.top.nonce = nonceManager.getNonce()
  End Function

  ' Registers an ad click using the IMA SDK.
  Function sendAdClick() as Void
    If m.nonceManager <> Invalid
      m.nonceManager.sendAdClick()
    End If
  End Function

  ' Registers an ad touch event using the IMA SDK.
  Function sendAdTouch(touch as String) as Void
    If m.nonceManager <> Invalid
      m.nonceManager.sendAdTouch(touch)
    End If
  End Function

  ' Registers the start of playback using the IMA SDK.
  Function sendPlaybackStart() as Void
    If m.nonceManager <> Invalid
      m.nonceManager.sendPlaybackStart()
    End If
  End Function

  ' Registers the end of playback using the IMA SDK.
  Function sendPlaybackEnd() as Void
    If m.nonceManager <> Invalid
      m.nonceManager.sendPlaybackEnd()
    End If
  End Function
]]>
</script>
</component>

Attach the nonce to the ad requests

To use the nonce you receive from the PAL library in a production application, initiate your ad requests only after the nonce has been generated. Then, append the nonce to the ad tag using the u_paln parameter.

components/MainScene.xml

...

  ' Callback triggered when Nonce is loaded.
  Sub onNonceLoaded(message as Object)
    nonce = m.sdkTask.nonce
    print "onNonceLoaded ";nonce
    makeAdRequest(nonce)
  End Sub

  Sub makeAdRequest(nonce)
    ' Sample ad tag URL used in this sample. Your apps method of getting this
    ' URL will likely be different.
    adTag = "https://pubads.g.doubleclick.net/gampad/ads?iu=/124319096/external/single_ad_samples"

    preparedTag = adTag + "&u_paln=" + nonce

    ' Implement custom ad request logic here.
    Print "ad tag with nonce ";preparedTag
  End Sub
...

That's it! You now have a Roku app that can request a PAL nonce and register playback session events with the PAL SDK.