[Connect SDK] Enable downloads in the Connect SDK (#9583)

* Initial implementation

* minor refactors

* Fix strict mode violations

* implement basic download finished toast

* Remove file opening code (not working), make internal

* Add test

* Fix test

* Fix lint (unused import)

* Close resource

* Refactor into interfaces

* Make interfaces internal

* Move scope into toast manager

* Better abstractions

* Fix test

connect/build.gradle

@@ -54,7 +54,6 @@ dependencies {
     testImplementation testLibs.mockito.kotlin
     testImplementation testLibs.robolectric
     testImplementation testLibs.truth
-    testImplementation project(':stripe-core')
 
     androidTestImplementation testLibs.androidx.composeUi
     androidTestImplementation testLibs.androidx.coreKtx

connect/res/values/strings.xml

@@ -1,4 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <string name="stripe_not_yet_built">Not yet built…</string>
+    <string name="stripe_downloading_file">Downloading file</string>
+    <string name="stripe_download_complete">Download complete</string>
+    <string name="stripe_unable_to_download_file">Unable to download file</string>
 </resources>

connect/src/main/java/com/stripe/android/connect/webview/StripeConnectWebViewClient.kt

@@ -54,6 +54,9 @@ internal class StripeConnectWebViewClient(
                 useWideViewPort = true
                 userAgentString = "$userAgentString - stripe-android/${StripeSdkVersion.VERSION_NAME}"
             }
+
+            setDownloadListener(StripeDownloadListener(webView.context))
+
             addJavascriptInterface(StripeJsInterface(), ANDROID_JS_INTERFACE)
             addJavascriptInterface(StripeJsInterfaceInternal(this), ANDROID_JS_INTERNAL_INTERFACE)
 

connect/src/main/java/com/stripe/android/connect/webview/StripeDownloadListener.kt

@@ -0,0 +1,68 @@
+package com.stripe.android.connect.webview
+
+import android.app.DownloadManager.STATUS_PAUSED
+import android.app.DownloadManager.STATUS_PENDING
+import android.app.DownloadManager.STATUS_RUNNING
+import android.content.Context
+import android.webkit.DownloadListener
+import com.stripe.android.connect.R
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+
+internal class StripeDownloadListener(
+    private val context: Context,
+    private val stripeDownloadManager: StripeDownloadManager = StripeDownloadManagerImpl(context),
+    private val stripeToastManager: StripeToastManager = StripeToastManagerImpl(context),
+    private val ioScope: CoroutineScope = CoroutineScope(Dispatchers.IO),
+) : DownloadListener {
+
+    override fun onDownloadStart(
+        url: String?,
+        userAgent: String?,
+        contentDisposition: String?,
+        mimetype: String?,
+        contentLength: Long
+    ) {
+        if (url == null) {
+            showErrorToast()
+            return
+        }
+
+        ioScope.launch {
+            val downloadId = stripeDownloadManager.enqueueDownload(url, contentDisposition, mimetype)
+            if (downloadId == null) {
+                showErrorToast()
+                return@launch
+            }
+
+            // Monitor the download progress and show a toast when done
+            val query = stripeDownloadManager.getQueryById(downloadId)
+            var isDownloading = true
+            while (isDownloading) {
+                val status = stripeDownloadManager.getDownloadStatus(query)
+                if (status == null) {
+                    showErrorToast()
+                    return@launch
+                } else if (status !in listOf(STATUS_PENDING, STATUS_RUNNING, STATUS_PAUSED)) {
+                    showOpenFileToast()
+                    isDownloading = false // download complete - exit the loop
+                }
+                delay(DOWNLOAD_DELAY_MS)
+            }
+        }
+    }
+
+    private fun showErrorToast() {
+        stripeToastManager.showToast(context.getString(R.string.stripe_unable_to_download_file))
+    }
+
+    private fun showOpenFileToast() {
+        stripeToastManager.showToast(context.getString(R.string.stripe_download_complete))
+    }
+
+    internal companion object {
+        private const val DOWNLOAD_DELAY_MS = 1_000L
+    }
+}

connect/src/main/java/com/stripe/android/connect/webview/StripeDownloadManager.kt

@@ -0,0 +1,69 @@
+package com.stripe.android.connect.webview
+
+import android.app.DownloadManager
+import android.app.DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED
+import android.content.Context
+import android.net.Uri
+import android.os.Environment.DIRECTORY_DOWNLOADS
+import android.webkit.URLUtil
+import com.stripe.android.connect.R
+
+/**
+ * Provides an interface for various download and file operations. Useful for mocking in tests.
+ */
+internal interface StripeDownloadManager {
+
+    /**
+     * Enqueues a download for the given URL, content disposition, and MIME type.
+     * Returns null if a download could not be started.
+     */
+    fun enqueueDownload(url: String, contentDisposition: String? = null, mimeType: String? = null): Long?
+
+    /**
+     * Returns a [DownloadManager.Query] for the given download ID, used for monitoring the status of a download.
+     */
+    fun getQueryById(id: Long): DownloadManager.Query
+
+    /**
+     * Returns the status of the download represented by [query]. Maps to [DownloadManager.COLUMN_STATUS], ie.
+     * [DownloadManager.STATUS_PENDING], [DownloadManager.STATUS_RUNNING], [DownloadManager.STATUS_PAUSED], etc.
+     *
+     * Returns null if the status could not be determined. This operation should not be retried if null is returned.
+     */
+    fun getDownloadStatus(query: DownloadManager.Query): Int?
+}
+
+internal class StripeDownloadManagerImpl(private val context: Context) : StripeDownloadManager {
+    private val downloadManager: DownloadManager? =
+        context.getSystemService(Context.DOWNLOAD_SERVICE) as? DownloadManager
+
+    override fun enqueueDownload(url: String, contentDisposition: String?, mimeType: String?): Long? {
+        downloadManager ?: return null
+
+        val request = DownloadManager.Request(Uri.parse(url))
+        val fileName = URLUtil.guessFileName(url, contentDisposition, mimeType)
+        request.setDestinationInExternalPublicDir(DIRECTORY_DOWNLOADS, fileName)
+        request.setNotificationVisibility(VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
+        request.setTitle(fileName)
+        request.setDescription(context.getString(R.string.stripe_downloading_file))
+        request.setMimeType(mimeType)
+
+        return downloadManager.enqueue(request)
+    }
+
+    override fun getQueryById(id: Long): DownloadManager.Query {
+        return DownloadManager.Query().setFilterById(id)
+    }
+
+    override fun getDownloadStatus(query: DownloadManager.Query): Int? {
+        downloadManager ?: return null
+
+        val cursor = downloadManager.query(query) ?: return null
+        return cursor.use { resource ->
+            resource.moveToFirst()
+            val index = resource.getColumnIndex(DownloadManager.COLUMN_STATUS)
+            if (index < 0) return null // status does not exist - abort
+            resource.getInt(index)
+        }
+    }
+}

connect/src/main/java/com/stripe/android/connect/webview/StripeToastManager.kt

@@ -0,0 +1,25 @@
+package com.stripe.android.connect.webview
+
+import android.content.Context
+import android.widget.Toast
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.MainScope
+import kotlinx.coroutines.launch
+
+/**
+ * Provides an interface for various download and file operations. Useful for mocking in tests.
+ */
+internal interface StripeToastManager {
+    fun showToast(toastString: String)
+}
+
+internal class StripeToastManagerImpl(
+    private val context: Context,
+    private val scope: CoroutineScope = MainScope()
+) : StripeToastManager {
+    override fun showToast(toastString: String) {
+        scope.launch {
+            Toast.makeText(context, toastString, Toast.LENGTH_LONG).show()
+        }
+    }
+}

connect/src/test/java/com/stripe/android/connect/webview/StripeConnectWebViewClientTest.kt

@@ -25,6 +25,7 @@ class StripeConnectWebViewClientTest {
     }
     private val mockWebView: WebView = mock {
         on { settings } doReturn mockSettings
+        on { context } doReturn mock()
     }
 
     private lateinit var webViewClient: StripeConnectWebViewClient

connect/src/test/java/com/stripe/android/connect/webview/StripeDownloadListenerTest.kt

@@ -0,0 +1,95 @@
+package com.stripe.android.connect.webview
+
+import android.app.DownloadManager
+import android.content.Context
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.Before
+import org.junit.Test
+import org.mockito.kotlin.any
+import org.mockito.kotlin.anyOrNull
+import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.verifyNoInteractions
+import org.mockito.kotlin.whenever
+
+class StripeDownloadListenerTest {
+
+    private val context: Context = mock {
+        on { getString(any()) } doReturn "Placeholder string"
+    }
+    private val stripeDownloadManager: StripeDownloadManager = mock {
+        on { enqueueDownload(any(), anyOrNull(), anyOrNull()) } doReturn 123L
+        on { getQueryById(any()) } doReturn mock()
+        on { getDownloadStatus(any()) } doReturn DownloadManager.STATUS_SUCCESSFUL
+    }
+    private val stripeToastManager: StripeToastManager = mock()
+    private val testScope = TestScope()
+
+    private lateinit var stripeDownloadListener: StripeDownloadListener
+
+    @Before
+    fun setup() {
+        Dispatchers.setMain(UnconfinedTestDispatcher())
+        initDownloadListener()
+    }
+
+    private fun initDownloadListener(
+        context: Context = this.context,
+        stripeDownloadManager: StripeDownloadManager = this.stripeDownloadManager,
+        stripeToastManager: StripeToastManager = this.stripeToastManager,
+        ioScope: CoroutineScope = testScope,
+    ) {
+        stripeDownloadListener = StripeDownloadListener(
+            context = context,
+            stripeDownloadManager = stripeDownloadManager,
+            stripeToastManager = stripeToastManager,
+            ioScope = ioScope,
+        )
+    }
+
+    @Test
+    fun `onDownloadStart creates download request`() = runTest {
+        val url = "https://example.com/file.pdf"
+        val userAgent = "Mozilla/5.0"
+        val contentDisposition = "attachment; filename=file.pdf"
+        val mimeType = "application/pdf"
+        val contentLength = 1024L
+
+        stripeDownloadListener.onDownloadStart(url, userAgent, contentDisposition, mimeType, contentLength)
+        testScope.testScheduler.advanceUntilIdle()
+
+        verify(stripeDownloadManager).enqueueDownload(url, contentDisposition, mimeType)
+        verify(stripeToastManager).showToast(any())
+    }
+
+    @Test
+    fun `onDownloadStart does nothing when URL is null`() = runTest {
+        stripeDownloadListener.onDownloadStart(null, "", "", "", 0)
+        testScope.testScheduler.advanceUntilIdle()
+
+        verifyNoInteractions(stripeDownloadManager)
+        verify(stripeToastManager).showToast(any())
+    }
+
+    @Test
+    fun `onDownloadStart shows error toast when enqueue returns null`() = runTest {
+        whenever(stripeDownloadManager.enqueueDownload(any(), anyOrNull(), anyOrNull())).thenReturn(null)
+
+        val url = "https://example.com/file.pdf"
+        val userAgent = "Mozilla/5.0"
+        val contentDisposition = "attachment; filename=file.pdf"
+        val mimeType = "application/pdf"
+        val contentLength = 1024L
+
+        stripeDownloadListener.onDownloadStart(url, userAgent, contentDisposition, mimeType, contentLength)
+        testScope.testScheduler.advanceUntilIdle()
+
+        verify(stripeToastManager).showToast(any())
+    }
+}