From 87149c2b57be0f78f045c85e62a42c7eb27ec0cc Mon Sep 17 00:00:00 2001
From: Aaron Franks <aaron.franks@gmail.com>
Date: Fri, 20 May 2016 16:07:05 -0700
Subject: [PATCH] First pass at native code to support background downloads

---
 Downloader.h |  2 +-
 Downloader.m | 50 ++++++++++++++++++++++++--------------------------
 2 files changed, 25 insertions(+), 27 deletions(-)

diff --git a/Downloader.h b/Downloader.h
index 1faaf34..a9af75b 100644
--- a/Downloader.h
+++ b/Downloader.h
@@ -16,7 +16,7 @@ typedef void (^ProgressCallback)(NSNumber*, NSNumber*);
 
 @end
 
-@interface Downloader : NSObject <NSURLConnectionDelegate>
+@interface Downloader : NSObject <NSURLSessionDelegate, NSURLSessionDownloadDelegate>
 
 - (void)downloadFile:(DownloadParams*)params;
 - (void)stopDownload;
diff --git a/Downloader.m b/Downloader.m
index 888361a..96bbb0a 100644
--- a/Downloader.m
+++ b/Downloader.m
@@ -8,7 +8,8 @@
 
 @property (copy) DownloadParams* params;
 
-@property (retain) NSURLConnection* connection;
+@property (retain) NSURLSession* session;
+@property (retain) NSURLSessionTask* task;
 @property (retain) NSNumber* statusCode;
 @property (retain) NSNumber* contentLength;
 @property (retain) NSNumber* bytesWritten;
@@ -27,12 +28,7 @@
 
   NSURL* url = [NSURL URLWithString:_params.fromUrl];
 
-  NSMutableURLRequest* downloadRequest = [NSMutableURLRequest requestWithURL:url
-                                                                 cachePolicy:NSURLRequestUseProtocolCachePolicy
-                                                             timeoutInterval:30];
-
   [[NSFileManager defaultManager] createFileAtPath:_params.toFile contents:nil attributes:nil];
-
   _fileHandle = [NSFileHandle fileHandleForWritingAtPath:_params.toFile];
 
   if (!_fileHandle) {
@@ -41,31 +37,26 @@
     return _params.errorCallback(error);
   }
 
-  _connection = [[NSURLConnection alloc] initWithRequest:downloadRequest delegate:self startImmediately:NO];
+  NSURLSessionConfiguration *config;
+  config = [NSURLSessionConfiguration defaultSessionConfiguration];
+  // TODO: use the following config for session objects:
+  //config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:fromUrl];
 
-  [_connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
-
-  [_connection start];
+  _session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
+  _task = [_session downloadTaskWithURL:url];
+  [_task resume];
 }
 
-- (void)connection:(NSURLConnection*)connection didFailWithError:(NSError*)error
+- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didReceiveResponse:(NSURLResponse *)response
 {
-  [_fileHandle closeFile];
+  NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)downloadTask.response;
+  _statusCode = [NSNumber numberWithLong:httpResponse.statusCode];
+  _contentLength = [NSNumber numberWithLong:httpResponse.expectedContentLength];
 
-  return _params.errorCallback(error);
+  return _params.beginCallback(_statusCode, _contentLength, httpResponse.allHeaderFields);
 }
 
-- (void)connection:(NSURLConnection*)connection didReceiveResponse:(NSURLResponse*)response
-{
-  NSHTTPURLResponse* httpUrlResponse = (NSHTTPURLResponse*)response;
-
-  _statusCode = [NSNumber numberWithLong:httpUrlResponse.statusCode];
-  _contentLength = [NSNumber numberWithLongLong: httpUrlResponse.expectedContentLength];
-
-  return _params.beginCallback(_statusCode, _contentLength, httpUrlResponse.allHeaderFields);
-}
-
-- (void)connection:(NSURLConnection*)connection didReceiveData:(NSData*)data
+- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(NSData *)data
 {
   if ([_statusCode isEqualToNumber:[NSNumber numberWithInt:200]]) {
     [_fileHandle writeData:data];
@@ -76,16 +67,23 @@
   }
 }
 
-- (void)connectionDidFinishLoading:(NSURLConnection*)connection
+- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
 {
   [_fileHandle closeFile];
 
   return _params.completeCallback(_statusCode, _bytesWritten);
 }
 
+- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionTask *)downloadTask didCompleteWithError:(NSError *)error
+{
+  [_fileHandle closeFile];
+  return _params.errorCallback(error);
+}
+
+
 - (void)stopDownload
 {
-  [_connection cancel];
+  [_task cancel];
 }
 
 @end