Add Rpcs needed to download files via HTTP. (#80)

* Add an Rpc to perform an HTTP download using DownloadManager.
* Add file operation Rpcs.

4 files changed, 185 insertions, 1 deletions

diff --git a/src/main/AndroidManifest.xml b/src/main/AndroidManifest.xml
index ef882c8..dc5d0af 100644
--- a/src/main/AndroidManifest.xml
+++ b/src/main/AndroidManifest.xml
@@ -13,6 +13,7 @@
     <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
     <uses-permission android:name="android.permission.GET_ACCOUNTS" />
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
@@ -38,6 +39,7 @@
                            com.google.android.mobly.snippet.bundled.NotificationSnippet,
                            com.google.android.mobly.snippet.bundled.TelephonySnippet,
                            com.google.android.mobly.snippet.bundled.NetworkingSnippet,
+                           com.google.android.mobly.snippet.bundled.FileSnippet,
                            com.google.android.mobly.snippet.bundled.SmsSnippet,
                            com.google.android.mobly.snippet.bundled.WifiManagerSnippet" />
     </application>
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/FileSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/FileSnippet.java
new file mode 100644
index 0000000..571d57f
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/FileSnippet.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.google.android.mobly.snippet.bundled;
+
+import java.io.IOException;
+import java.security.MessageDigest;
+import java.security.DigestInputStream;
+import java.security.NoSuchAlgorithmException;
+import android.content.Context;
+import android.net.Uri;
+import android.os.ParcelFileDescriptor;
+import android.support.test.InstrumentationRegistry;
+import com.google.android.mobly.snippet.Snippet;
+import com.google.android.mobly.snippet.bundled.utils.Utils;
+import com.google.android.mobly.snippet.rpc.Rpc;
+
+/** Snippet class for File and abstract storage URI operation RPCs. */
+public class FileSnippet implements Snippet {
+
+    private final Context mContext;
+
+    public FileSnippet() {
+        mContext = InstrumentationRegistry.getContext();
+    }
+
+    private static class FileSnippetException extends Exception {
+
+        private static final long serialVersionUID = 8081L;
+
+        public FileSnippetException(String msg) {
+            super(msg);
+        }
+    }
+
+    @Rpc(description = "Compute MD5 hash on a content URI. Return the MD5 has has a hex string.")
+    public String fileMd5Hash(String uri) throws IOException, NoSuchAlgorithmException  {
+        Uri uri_ = Uri.parse(uri);
+        ParcelFileDescriptor pfd = mContext.getContentResolver().openFileDescriptor(uri_, "r");
+        MessageDigest md = MessageDigest.getInstance("MD5");
+        int length = (int) pfd.getStatSize();
+        byte[] buf = new byte[length];
+        ParcelFileDescriptor.AutoCloseInputStream stream = new ParcelFileDescriptor.AutoCloseInputStream(pfd);
+        DigestInputStream dis = new DigestInputStream(stream, md);
+        try {
+            dis.read(buf, 0, length);
+            return Utils.bytesToHexString(md.digest());
+        } finally {
+            dis.close();
+            stream.close();
+        }
+    }
+
+    @Rpc(description = "Remove a file pointed to by the content URI.")
+    public void fileDeleteContent(String uri) {
+        Uri uri_ = Uri.parse(uri);
+        mContext.getContentResolver().delete(uri_, null, null);
+    }
+
+    @Override
+    public void shutdown() {}
+}
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/NetworkingSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/NetworkingSnippet.java
index d72205a..f175fdd 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/NetworkingSnippet.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/NetworkingSnippet.java
@@ -16,17 +16,47 @@
 
 package com.google.android.mobly.snippet.bundled;
 
+import java.util.List;
 import java.net.InetAddress;
 import java.net.Socket;
 import java.io.IOException;
 import java.net.UnknownHostException;
+import android.content.Intent;
+import android.content.Context;
+import android.content.IntentFilter;
+import android.content.BroadcastReceiver;
+import android.net.Uri;
+import android.os.Environment;
+import android.os.ParcelFileDescriptor;
+import android.app.DownloadManager;
+import android.support.test.InstrumentationRegistry;
 import com.google.android.mobly.snippet.Snippet;
+import com.google.android.mobly.snippet.bundled.utils.Utils;
 import com.google.android.mobly.snippet.rpc.Rpc;
 import com.google.android.mobly.snippet.util.Log;
 
 /** Snippet class for networking RPCs. */
 public class NetworkingSnippet implements Snippet {
 
+    private final Context mContext;
+    private final DownloadManager mDownloadManager;
+    private volatile boolean mIsDownloadComplete = false;
+    private volatile long mReqid = 0;
+
+    public NetworkingSnippet() {
+        mContext = InstrumentationRegistry.getContext();
+        mDownloadManager = (DownloadManager) mContext.getSystemService(Context.DOWNLOAD_SERVICE);
+    }
+
+    private static class NetworkingSnippetException extends Exception {
+
+        private static final long serialVersionUID = 8080L;
+
+        public NetworkingSnippetException(String msg) {
+            super(msg);
+        }
+    }
+
     @Rpc(description = "Check if a host and port are connectable using a TCP connection attempt.")
     public boolean networkIsTcpConnectable(String host, int port) {
         InetAddress addr;
@@ -47,6 +77,61 @@ public class NetworkingSnippet implements Snippet {
         return true;
     }
 
+    @Rpc(description = "Download a file using HTTP. Return content Uri (file remains on device). "
+                       + "The Uri should be treated as an opaque handle for further operations.")
+    public String networkHttpDownload(String url) throws IllegalArgumentException, NetworkingSnippetException {
+
+        Uri uri = Uri.parse(url);
+        List<String> pathsegments = uri.getPathSegments();
+        if (pathsegments.size() < 1) {
+            throw new IllegalArgumentException(String.format("The Uri %s does not have a path.", uri.toString()));
+        }
+        DownloadManager.Request request = new DownloadManager.Request(uri);
+        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,
+                                                  pathsegments.get(pathsegments.size() - 1));
+        mIsDownloadComplete = false;
+        mReqid = 0;
+        IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
+        BroadcastReceiver receiver = new DownloadReceiver();
+        mContext.registerReceiver(receiver, filter);
+        try {
+            mReqid = mDownloadManager.enqueue(request);
+            Log.d(String.format("networkHttpDownload download of %s with id %d", url, mReqid));
+            if (!Utils.waitUntil(() -> mIsDownloadComplete, 30)) {
+                Log.d(String.format("networkHttpDownload timed out waiting for completion"));
+                throw new NetworkingSnippetException("networkHttpDownload timed out.");
+            }
+        } finally {
+            mContext.unregisterReceiver(receiver);
+        }
+        Uri resp = mDownloadManager.getUriForDownloadedFile(mReqid);
+        if (resp != null) {
+            Log.d(String.format("networkHttpDownload completed to %s", resp.toString()));
+            mReqid = 0;
+            return resp.toString();
+        } else {
+            Log.d(String.format("networkHttpDownload Failed to download %s", uri.toString()));
+            throw new NetworkingSnippetException("networkHttpDownload didn't get downloaded file.");
+        }
+    }
+
+    private class DownloadReceiver extends BroadcastReceiver {
+
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            String action = intent.getAction();
+            long gotid = (long) intent.getExtras().get("extra_download_id");
+            if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)
+                            && gotid == mReqid) {
+                mIsDownloadComplete = true;
+            }
+        }
+    }
+
     @Override
-    public void shutdown() {}
+    public void shutdown() {
+        if (mReqid != 0) {
+            mDownloadManager.remove(mReqid);
+        }
+    }
 }
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
index c68ae5a..e4c0dbd 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
@@ -30,6 +30,8 @@ import java.util.concurrent.TimeoutException;
 
 public final class Utils {
 
+    private final static char[] hexArray = "0123456789abcdef".toCharArray();
+
     private Utils() {}
 
     /**
@@ -190,4 +192,24 @@ public final class Utils {
             throw e.getCause();
         }
     }
+
+    /**
+     * Convert a byte array (binary data) to a hexadecimal string (ASCII)
+     * representation.
+
+     * [\x01\x02] -&gt; "0102"
+     *
+     * @param bytes The array of byte to convert.
+     * @return a String with the ASCII hex representation.
+     */
+    public static String bytesToHexString(byte[] bytes) {
+        char[] hexChars = new char[bytes.length * 2];
+        for ( int j = 0; j < bytes.length; j++ ) {
+            int v = bytes[j] & 0xFF;
+            hexChars[j * 2] = hexArray[v >>> 4];
+            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
+        }
+        return new String(hexChars);
+    }
+
 }