开始使用

借助适用于 Roku 的 Programmatic Access Library (PAL) SDK，获得直接 VAST 调用 (DVC) 批准的发布商可以通过基于 DVC 的 Roku 应用创收。借助 PAL SDK，您可以向 Google 请求 Nonce（加密字符串），以便对 DVC 请求进行签名。每个新串流请求都必须附带新生成的 Nonce。不过，您可以针对同一串流中的多个广告请求重复使用同一个 Nonce。

本指南通过示例介绍了如何将 PAL SDK 纳入 Roku 应用、请求 Nonce 并注册广告展示。

前提条件

在开始使用本指南之前，您需要完成以下操作：

  • Roku 开发环境 - 如需了解详情，请参阅 Roku 开发者环境设置指南。

  • 一个结构如下的项目文件夹：

    ./
  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

设置项目

在集成 PAL SDK 之前，您需要配置项目文件。

清单

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

创建示例视频播放器

SampleVideoPlayer 组件只是封装了视频组件，以捕获遥控器按键操作。替换 onKeyEvent，以便在遥控器的焦点转移到视频/广告播放器后，系统会捕获并向上传递任何进一步的按键操作（向上、向下、向左、向右、点击等）。

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>

创建测试接口

实现一个包含按钮的场景，以执行以下操作：

  • 请求 Nonce。
  • 发送广告点击。
  • 发送播放开始事件。
  • 发送播放结束事件。
  • 将焦点转移到视频按钮。

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>

创建 SDK 接口组件

如需在主场景和 PAL SDK 之间进行通信，您需要一个包含异步代码的组件。这是必要的，因为 PAL SDK 会发出外部网络请求，而 Roku 应用的主线程无法执行此操作。如需向此组件发送数据，您需要一个接口来定义该组件发送和接收的数据。

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>

导入 IMA SDK

如需使用 PAL 库，您需要在应用清单中声明对 IMA SDK for Roku 的要求，并将其导入 PALInterface 组件。

清单

...
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>

从场景触发界面组件

接下来，添加用于监听用户互动并触发界面组件更改的 BrightScript 代码：

  • 如需从接口组件接收输出，请在与这些输出关联的接口字段上实现字段观察器，并将其附加到主组件中的回调函数。请在组件首次注册时执行此操作。

  • 如需将用户互动发送到界面组件，请在您之前创建的按钮上实现字段观察器，以触发与这些命令关联的界面字段中的更改。

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>

添加了用于转移焦点的方法

接下来，捕获用户按键操作，以便在视频元素之间转移焦点。

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>

初始化 PAL SDK 并创建 nonceLoader

现在，您可以开始构建 PAL SDK 实现的核心逻辑了。首先，从单独的线程中初始化 SDK。

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>

处理 Nonce 请求

创建 nonceLoader 后，您需要将观察器附加到 requestNonce 字段，以处理 Nonce 请求。通过仅在 nonceLoader 初始化后附加此观察器，您可以确保在 SDK 线程中处理 Nonce 请求，并且只有在存在有效的 nonceLoader 时才能发出 Nonce 请求。

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>

NonceRequest.storageAllowed 的默认值为 true，但您在征得适当的意见后可以更改此值。getConsentToStorage() 方法是您自己用于征求用户同意的方法的占位符，您可以通过集成 CMP 或基于其他方法来处理存储权限同意。

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.isConsentToStorage = getConsentToStorage()

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

  ...

  ' Requests a nonce from the PAL SDK.
  Function requestNonce() as Void
    nonceRequest = m.sdk.CreateNonceRequest()

    ' Include changes to storage consent here.
    nonceRequest.storageAllowed = m.isConsentToStorage

    m.nonceManager = m.nonceLoader.loadNonceManager(nonceRequest)
    m.top.nonce = nonceManager.getNonce()
  End Function

监听播放器生命周期信号

为了让 PAL 集成能够正确发送信号，您需要设置一个循环来监听播放器的生命周期信号。

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>

为 sendPlaybackStart、sendPlaybackEnd、sendAdClick 和 sendAdTouch 注册监听器

接下来，在“video player start”上调用 sendPlaybackStart。此方法会开始对 Google 服务器进行异步调用，以收集 IVT 监控和检测所需的信号。在播放结束时调用 sendPlaybackEnd。调用 sendAdClick 以响应广告点击。然后，针对非点击型用户轻触或点击事件调用 sendAdTouch。

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>

将 Nonce 附加到广告请求

如需在正式版应用中使用从 PAL 库收到的 Nonce，请仅在生成 Nonce 后发起广告请求。然后，使用 u_paln 参数将 Nonce 附加到广告代码。

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
...

大功告成！现在，您的 Roku 应用可以请求 PAL Nonce 并向 PAL SDK 注册播放会话事件。

（可选）通过第三方广告服务器发送 Google Ad Manager 信号

配置第三方广告服务器向 Ad Manager 发出的请求。

配置第三方广告服务器，以便在服务器向 Ad Manager 发出的请求中添加 Nonce。以下是第三方广告服务器中配置的广告代码示例：

'https://pubads.serverside.net/gampad/ads?givn=%%custom_key_for_google_nonce%%&...'

如需了解详情，请参阅 Google Ad Manager 服务器端植入指南。

Ad Manager 会查找 givn= 以识别 Nonce 值。第三方广告服务器需要支持自己的某些宏（例如 %%custom_key_for_google_nonce%%），并将其替换为您在上一步中提供的 Nonce 查询参数。如需详细了解如何实现此目的，请参阅第三方广告服务器的文档。

大功告成！现在，您应该已将 Nonce 参数从 PAL SDK 传播到中间服务器，然后再传播到 Google Ad Manager。这样，您就可以通过 Google Ad Manager 更好地创收。