Add support to addDocumentStartJavaScript

Author: CrisBarreiro

app/src/androidTest/java/com/duckduckgo/app/browser/BrowserWebViewClientTest.kt

@@ -61,7 +61,6 @@ import com.duckduckgo.app.browser.trafficquality.AndroidFeaturesHeaderPlugin
 import com.duckduckgo.app.browser.trafficquality.CustomHeaderAllowedChecker
 import com.duckduckgo.app.browser.trafficquality.remote.AndroidFeaturesHeaderProvider
 import com.duckduckgo.app.browser.uriloaded.UriLoadedManager
-import com.duckduckgo.app.global.model.Site
 import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
 import com.duckduckgo.app.statistics.pixels.Pixel
 import com.duckduckgo.autoconsent.api.Autoconsent
@@ -1194,6 +1193,12 @@ class BrowserWebViewClientTest {
         var countFinished = 0
         var countStarted = 0
 
+        override fun onInit(
+            webView: WebView,
+            activeExperiments: List<Toggle>,
+        ) {
+        }
+
         override fun onPageStarted(
             webView: WebView,
             url: String?,
@@ -1203,7 +1208,11 @@ class BrowserWebViewClientTest {
             countStarted++
         }
 
-        override fun onPageFinished(webView: WebView, url: String?, site: Site?) {
+        override fun onPageFinished(
+            webView: WebView,
+            url: String?,
+            activeExperiments: List<Toggle>,
+        ) {
             countFinished++
         }
     }

app/src/main/java/com/duckduckgo/app/browser/BrowserTabFragment.kt

@@ -3006,6 +3006,7 @@ class BrowserTabFragment :
         webView?.let {
             it.isSafeWebViewEnabled = safeWebViewFeature.self().isEnabled()
             it.webViewClient = webViewClient
+            webViewClient.triggerJSInit(it)
             it.webChromeClient = webChromeClient
             it.clearSslPreferences()
 

app/src/main/java/com/duckduckgo/app/browser/BrowserWebViewClient.kt

@@ -463,14 +463,29 @@ class BrowserWebViewClient @Inject constructor(
         webView.settings.mediaPlaybackRequiresUserGesture = mediaPlayback.doesMediaPlaybackRequireUserGestureForUrl(url)
     }
 
+    fun triggerJSInit(webView: WebView) {
+        appCoroutineScope.launch(dispatcherProvider.main()) {
+            val activeExperiments = contentScopeExperiments.getActiveExperiments()
+            jsPlugins.getPlugins().forEach {
+                it.onInit(webView, activeExperiments)
+            }
+        }
+    }
+
+    // TODO check new API
     @UiThread
     override fun onPageFinished(webView: WebView, url: String?) {
         logcat(VERBOSE) { "onPageFinished webViewUrl: ${webView.url} URL: $url progress: ${webView.progress}" }
 
         // See https://app.asana.com/0/0/1206159443951489/f (WebView limitations)
         if (webView.progress == 100) {
             jsPlugins.getPlugins().forEach {
-                it.onPageFinished(webView, url, webViewClientListener?.getSite())
+                val activeExperiments = webViewClientListener?.getSite()?.activeContentScopeExperiments ?: listOf()
+                it.onPageFinished(
+                    webView,
+                    url,
+                    activeExperiments,
+                )
             }
 
             url?.let {

browser-api/src/main/java/com/duckduckgo/browser/api/JsInjectorPlugin.kt

@@ -17,11 +17,18 @@
 package com.duckduckgo.browser.api
 
 import android.webkit.WebView
-import com.duckduckgo.app.global.model.Site
 import com.duckduckgo.feature.toggles.api.Toggle
 
 /** Public interface to inject JS code to a website */
 interface JsInjectorPlugin {
+    /**
+     * On init of webview this is called and receives a [webView] instance.
+     */
+    fun onInit(
+        webView: WebView,
+        activeExperiments: List<Toggle>,
+    )
+
     /**
      * This method is called during onPageStarted and receives a [webView] instance, the [url] of the website and the [site]
      */
@@ -35,5 +42,9 @@ interface JsInjectorPlugin {
     /**
      * This method is called during onPageFinished and receives a [webView] instance, the [url] of the website and the [site]
      */
-    fun onPageFinished(webView: WebView, url: String?, site: Site?)
+    fun onPageFinished(
+        webView: WebView,
+        url: String?,
+        activeExperiments: List<Toggle>,
+    )
 }

content-scope-scripts/content-scope-scripts-impl/build.gradle

@@ -36,6 +36,7 @@ dependencies {
     implementation project(':js-messaging-api')
     implementation project(':duckplayer-api')
     implementation project(':data-store-api')
+    implementation AndroidX.webkit
 
     anvil project(':anvil-compiler')
     implementation project(':anvil-annotations')

content-scope-scripts/content-scope-scripts-impl/src/main/java/com/duckduckgo/contentscopescripts/impl/ContentScopeJSReader.kt

@@ -21,26 +21,49 @@ import com.squareup.anvil.annotations.ContributesBinding
 import dagger.SingleInstanceIn
 import java.io.BufferedReader
 import javax.inject.Inject
+import javax.inject.Named
 
 interface ContentScopeJSReader {
     fun getContentScopeJS(): String
 }
 
-@SingleInstanceIn(AppScope::class)
-@ContributesBinding(AppScope::class)
-class RealContentScopeJSReader @Inject constructor() : ContentScopeJSReader {
+abstract class GenericContentScopeJSReader {
+    abstract val fileName: String
+
     private lateinit var contentScopeJS: String
 
-    override fun getContentScopeJS(): String {
+    protected fun getContentScopeJSFile(): String {
         if (!this::contentScopeJS.isInitialized) {
-            contentScopeJS = loadJs("contentScope.js")
+            contentScopeJS = readResource(fileName).use { it?.readText() }.orEmpty()
         }
         return contentScopeJS
     }
 
-    fun loadJs(resourceName: String): String = readResource(resourceName).use { it?.readText() }.orEmpty()
-
     private fun readResource(resourceName: String): BufferedReader? {
         return javaClass.classLoader?.getResource(resourceName)?.openStream()?.bufferedReader()
     }
 }
+
+@SingleInstanceIn(AppScope::class)
+@ContributesBinding(AppScope::class, boundType = ContentScopeJSReader::class)
+@Named("contentScope")
+class RealContentScopeJSReader @Inject constructor() : GenericContentScopeJSReader(), ContentScopeJSReader {
+    override val fileName: String
+        get() = "contentScope.js"
+
+    override fun getContentScopeJS(): String {
+        return getContentScopeJSFile()
+    }
+}
+
+@SingleInstanceIn(AppScope::class)
+@ContributesBinding(AppScope::class, boundType = ContentScopeJSReader::class)
+@Named("adsJS")
+class AdsContentScopeJSReader @Inject constructor() : GenericContentScopeJSReader(), ContentScopeJSReader {
+    override val fileName: String
+        get() = "adsjsContentScope.js"
+
+    override fun getContentScopeJS(): String {
+        return getContentScopeJSFile()
+    }
+}

content-scope-scripts/content-scope-scripts-impl/src/main/java/com/duckduckgo/contentscopescripts/impl/ContentScopeScriptsJsInjectorPlugin.kt

@@ -17,7 +17,9 @@
 package com.duckduckgo.contentscopescripts.impl
 
 import android.webkit.WebView
-import com.duckduckgo.app.global.model.Site
+import androidx.webkit.ScriptHandler
+import androidx.webkit.WebViewCompat
+import androidx.webkit.WebViewFeature
 import com.duckduckgo.browser.api.JsInjectorPlugin
 import com.duckduckgo.di.scopes.AppScope
 import com.duckduckgo.feature.toggles.api.Toggle
@@ -27,7 +29,39 @@ import javax.inject.Inject
 @ContributesMultibinding(AppScope::class)
 class ContentScopeScriptsJsInjectorPlugin @Inject constructor(
     private val coreContentScopeScripts: CoreContentScopeScripts,
+    private val adsJsContentScopeScripts: AdsJsContentScopeScripts,
 ) : JsInjectorPlugin {
+    private var script: ScriptHandler? = null
+    private var currentScriptString: String? = null
+
+    private fun reloadJSIfNeeded(
+        webView: WebView,
+        activeExperiments: List<Toggle>,
+    ) {
+        if (!WebViewFeature.isFeatureSupported(WebViewFeature.DOCUMENT_START_SCRIPT)) {
+            return
+        }
+        val scriptString = adsJsContentScopeScripts.getScript(activeExperiments)
+        if (scriptString == currentScriptString) {
+            return
+        }
+        script?.let {
+            it.remove()
+            script = null
+        }
+        if (coreContentScopeScripts.isEnabled()) {
+            currentScriptString = scriptString
+            script = WebViewCompat.addDocumentStartJavaScript(webView, scriptString, setOf("*"))
+        }
+    }
+
+    override fun onInit(
+        webView: WebView,
+        activeExperiments: List<Toggle>,
+    ) {
+        reloadJSIfNeeded(webView, activeExperiments)
+    }
+
     override fun onPageStarted(
         webView: WebView,
         url: String?,
@@ -39,7 +73,11 @@ class ContentScopeScriptsJsInjectorPlugin @Inject constructor(
         }
     }
 
-    override fun onPageFinished(webView: WebView, url: String?, site: Site?) {
-        // NOOP
+    override fun onPageFinished(
+        webView: WebView,
+        url: String?,
+        activeExperiments: List<Toggle>,
+    ) {
+        reloadJSIfNeeded(webView, activeExperiments)
     }
 }