E2-1815: download files directly from URL instead of API call (#355)

* filename to URL parsing

* fcu

* fixes

* add parse test

* rename method and var

* add null check

Author: e7mac

AndroidSDKCore/src/main/java/com/leanplum/Leanplum.java

@@ -811,6 +811,8 @@ protected Void doInBackground(Void... params) {
             if (variants == null) {
               Log.d("No variants received from the server.");
             }
+            Map<String, String> filenameToURLs = parseFilenameToURLs(response);
+            FileManager.setFilenameToURLs(filenameToURLs);
 
             if (BuildUtil.isNotificationChannelSupported(context)) {
               // Get notification channels and groups.
@@ -2109,6 +2111,8 @@ public void response(JSONObject response) {
               }
 
               parseVariantDebugInfo(response);
+              Map<String, String> filenameToURLs = parseFilenameToURLs(response);
+              FileManager.setFilenameToURLs(filenameToURLs);
             }
             if (callback != null) {
               OsHandler.getInstance().post(callback);
@@ -2303,6 +2307,16 @@ public static Set<String> parseFeatureFlags(JSONObject response) {
     return featureFlagSet;
   }
 
+  @VisibleForTesting
+  public static Map<String, String> parseFilenameToURLs(JSONObject response) {
+    JSONObject filesObject = response.optJSONObject(
+            Constants.Keys.FILES);
+    if (filesObject != null) {
+      return JsonConverter.mapFromJson(filesObject);
+    }
+    return null;
+  }
+
   private static Set<String> toSet(JSONArray array) {
     Set<String> set = new HashSet<>();
     if (array != null) {

AndroidSDKCore/src/main/java/com/leanplum/internal/Constants.java

@@ -212,6 +212,7 @@ public static class Keys {
     public static final String LOGGING_ENABLED = "loggingEnabled";
     public static final String ENABLED_COUNTERS = "enabledSdkCounters";
     public static final String ENABLED_FEATURE_FLAGS = "enabledFeatureFlags";
+    public static final String FILES = "files";
     public static final String TIMEZONE = "timezone";
     public static final String TIMEZONE_OFFSET_SECONDS = "timezoneOffsetSeconds";
     public static final String TITLE = "Title";

AndroidSDKCore/src/main/java/com/leanplum/internal/FileManager.java

@@ -66,6 +66,7 @@ interface ResourceUpdateCallback {
   private static boolean initializing = false;
   static final Object initializingLock = new Object();
   public static Var<HashMap<String, Object>> resources = null;
+  public static Map<String, String> filenameToURLs = null;
 
   public enum DownloadFileResult {
     NONE,
@@ -108,6 +109,9 @@ public static DownloadFileResult maybeDownloadFile(boolean isResource, String st
       if (!FileManager.fileExistsAtPath(realPath)) {
         realPath = FileManager.fileRelativeToDocuments(stringValue);
         if (!FileManager.fileExistsAtPath(realPath)) {
+          if (FileManager.filenameToURLs != null && FileManager.filenameToURLs.containsKey(stringValue) && urlValue == null) {
+            urlValue = FileManager.filenameToURLs.get(stringValue);
+          }
           RequestOld downloadRequest = RequestOld.get(Constants.Methods.DOWNLOAD_FILE, null);
           downloadRequest.onResponse(new RequestOld.ResponseCallback() {
             @Override
@@ -185,6 +189,10 @@ public static boolean fileExistsAtPath(String path) {
     return path != null && new File(path).exists();
   }
 
+  public static void setFilenameToURLs(Map<String, String> filenameToURLs) {
+    FileManager.filenameToURLs = filenameToURLs;
+  }
+
   @SuppressWarnings("SameReturnValue")
   private static String appBundlePath() {
     return "";

AndroidSDKTests/src/test/java/com/leanplum/LeanplumTest.java

@@ -1358,6 +1358,31 @@ public void testParseSdkCounters() throws JSONException {
     assertEquals(new HashSet<>(Arrays.asList("test")), parsedCounters);
   }
 
+  @Test
+  public void testParseFilenameToURLs() throws JSONException {
+    JSONObject response = new JSONObject();
+    JSONObject files = new JSONObject();
+    files.put("file.jpg", "https://www.domain.com/file.jpg");
+    response.put(Constants.Keys.FILES, files);
+
+    Map<String, String> parsedFiles= Leanplum.parseFilenameToURLs(response);
+    assertEquals(JsonConverter.mapFromJson(files), parsedFiles);
+  }
+
+  /**
+   * Tests for parsing filenameToURLs
+   */
+  @Test
+  public void testStartResponseShouldParseFilenameToURLs() {
+    // Setup sdk.
+    setupSDK(mContext, "/responses/simple_start_response.json");
+
+    Map<String, String> files = new HashMap<>();
+    files.put("file1.jpg", "http://www.domain.com/file1.jpg");
+    files.put("file2.jpg", "http://www.domain.com/file2.jpg");
+
+    assertEquals(files, FileManager.filenameToURLs);
+  }
 
   /**
    * Tests for parsing feature flags

AndroidSDKTests/src/test/resources/responses/simple_start_response.json

@@ -332,6 +332,10 @@
         "testFeatureFlag1",
         "testFeatureFlag2"
       ],
+      "files": {
+        "file1.jpg" : "http://www.domain.com/file1.jpg",
+        "file2.jpg" : "http://www.domain.com/file2.jpg"
+      },
       "syncNewsfeed": false,
       "success": true,
       "interfaceEvents": [