Add multipart response download task (2nd edition)

Reviewed By: mmmulani

Differential Revision: D3976605

fbshipit-source-id: c15cc859aa1288e831f70256566f743f4a8d9cd2

React/Base/RCTMultipartDataTask.m

@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "RCTMultipartDataTask.h"
+
+@interface RCTMultipartDataTask () <NSURLSessionDataDelegate, NSURLSessionDataDelegate>
+
+@end
+
+// We need this ugly runtime check because [streamTask captureStreams] below fails on iOS version
+// earlier than 9.0. Unfortunately none of the proper ways of checking worked:
+//
+// - NSURLSessionStreamTask class is available and is not Null on iOS 8
+// - [[NSURLSessionStreamTask new] respondsToSelector:@selector(captureStreams)] is always NO
+// - The instance we get in URLSession:dataTask:didBecomeStreamTask: is of __NSCFURLLocalStreamTaskFromDataTask
+//   and it responds to captureStreams on iOS 9+ but doesn't on iOS 8. Which means we can't get direct access
+//   to the streams on iOS 8 and at that point it's too late to change the behavior back to dataTask
+// - The compile-time #ifdef's can't be used because an app compiled for iOS8 can still run on iOS9
+
+static BOOL isStreamTaskSupported() {
+  return [[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion:(NSOperatingSystemVersion){9,0,0}];
+}
+
+@implementation RCTMultipartDataTask {
+  NSURL *_url;
+  RCTMultipartDataTaskCallback _partHandler;
+  NSInteger _statusCode;
+  NSDictionary *_headers;
+  NSString *_boundary;
+  NSMutableData *_data;
+}
+
+- (instancetype)initWithURL:(NSURL *)url partHandler:(RCTMultipartDataTaskCallback)partHandler
+{
+  if (self = [super init]) {
+    _url = url;
+    _partHandler = [partHandler copy];
+  }
+  return self;
+}
+
+- (void)startTask
+{
+  NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]
+                                                        delegate:self delegateQueue:nil];
+  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:_url];
+  if (isStreamTaskSupported()) {
+    [request addValue:@"multipart/mixed" forHTTPHeaderField:@"Accept"];
+  }
+  NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request];
+  [dataTask resume];
+}
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler
+{
+  if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
+    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
+    _headers = [httpResponse allHeaderFields];
+    _statusCode = [httpResponse statusCode];
+
+    NSString *contentType = @"";
+    for (NSString *key in [_headers keyEnumerator]) {
+      if ([[key lowercaseString] isEqualToString:@"content-type"]) {
+        contentType = [_headers valueForKey:key];
+        break;
+      }
+    }
+
+    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"multipart/mixed;.*boundary=\"([^\"]+)\"" options:0 error:nil];
+    NSTextCheckingResult *match = [regex firstMatchInString:contentType options:0 range:NSMakeRange(0, contentType.length)];
+    if (match) {
+      _boundary = [contentType substringWithRange:[match rangeAtIndex:1]];
+      completionHandler(NSURLSessionResponseBecomeStream);
+      return;
+    }
+  }
+
+  // In case the server doesn't support multipart/mixed responses, fallback to normal download
+  _data = [[NSMutableData alloc] initWithCapacity:1024 * 1024];
+  completionHandler(NSURLSessionResponseAllow);
+}
+
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
+{
+  _partHandler(_statusCode, _headers, _data, error, YES);
+}
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
+{
+  [_data appendData:data];
+}
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didBecomeStreamTask:(NSURLSessionStreamTask *)streamTask
+{
+  [streamTask captureStreams];
+}
+
+- (void)URLSession:(NSURLSession *)session streamTask:(NSURLSessionStreamTask *)streamTask didBecomeInputStream:(NSInputStream *)inputStream outputStream:(NSOutputStream *)outputStream
+{
+  RCTMultipartStreamReader *reader = [[RCTMultipartStreamReader alloc] initWithInputStream:inputStream boundary:_boundary];
+  RCTMultipartDataTaskCallback partHandler = _partHandler;
+  NSInteger statusCode = _statusCode;
+
+  BOOL completed = [reader readAllParts:^(NSDictionary *headers, NSData *content, BOOL done) {
+    partHandler(statusCode, headers, content, nil, done);
+  }];
+  if (!completed) {
+    partHandler(statusCode, nil, nil, [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCancelled userInfo:nil], YES);
+  }
+}
+
+
+@end