Adding error handling for file transformer in case the file transformer errors out.

Author: mmathewsTableau

android/src/main/java/com/ReactNativeBlobUtil/ReactNativeBlobUtilReq.java

@@ -578,6 +578,9 @@ private void done(Response resp) {
                             }
                             try (FileOutputStream fos = new FileOutputStream(file)) {
                                 fos.write(ReactNativeBlobUtilFileTransformer.sharedFileTransformer.onWriteFile(b));
+                            } catch(Exception e) {
+                                callback.invoke("Error from file transformer:" + e.getLocalizedMessage(), null);
+                                return;
                             }
                             callback.invoke(null, ReactNativeBlobUtilConst.RNFB_RESPONSE_PATH, this.destPath);
                             return;

ios/ReactNativeBlobUtilFS.m

@@ -538,7 +538,13 @@ + (void) readFile:(NSString *)path
         if (transformFile) {
             NSObject<FileTransformer>* fileTransformer = [ReactNativeBlobUtilFileTransformer getFileTransformer];
             if (fileTransformer) {
-                fileContent = [fileTransformer onReadFile:fileContent];
+                @try{
+                    fileContent = [fileTransformer onReadFile:fileContent];
+                } @catch (NSException * ex)
+                {
+                    onComplete(nil, @"EUNSPECIFIED", [NSString stringWithFormat:@"Exception on File Transformer: '%@' ", [ex description]]);
+                    return;
+                }
             } else {
                 onComplete(nil, @"EUNSPECIFIED", @"Transform specified but transformer not set");
                 return;

ios/ReactNativeBlobUtilRequest.m

@@ -406,8 +406,13 @@ - (void) URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCom
             if (!fileTransformer) {
                 errMsg = @"Transform file specified but file transfomer not set";
             } else {
-                NSData* transformedData = [fileTransformer onWriteFile:respData];
-                [writeStream write:[transformedData bytes] maxLength:[transformedData length]];
+                @try{
+                    NSData* transformedData = [fileTransformer onWriteFile:respData];
+                    [writeStream write:[transformedData bytes] maxLength:[transformedData length]];
+                } @catch(NSException * ex)
+                {
+                    errMsg = [NSString stringWithFormat:@"Exception on File Transformer: '%@' ", [ex description]];
+                }
             }
         }
         [writeStream close];